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Study Shows Brains With More Vitamin D Function Better

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According to a new study from Tufts University, adults who suffered from varying rates of cognitive decline had better cognitive function with higher levels of vitamin D in their brains. People get vitamin D from sun exposure, foods (such as fatty fish), and supplements.

A new study, the first to examine vitamin D levels in brain tissue, may help scientists further understand dementia and its causes.

Worldwide, an estimated 55 million people live with dementia, a number that’s expected to rise as the global population ages. In the United States alone, there are an estimated 6.5 million people living with

Scientists at Tufts University have completed the first study examining levels of vitamin D in brain tissue, specifically in adults who suffered from varying rates of cognitive decline. They discovered that members of this group with higher levels of vitamin D in their brains had better cognitive function. The study was published on December 7 in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

“This research reinforces the importance of studying how food and nutrients create resilience to protect the aging brain against diseases such as Alzheimer’s disease and other related dementias,” said senior and corresponding author Sarah Booth, director of the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts and lead scientist of the HNRCA’s Vitamin K Team.

Vitamin D supports many functions in the body, including immune responses and maintaining healthy bones. Dietary sources include fatty fish and fortified beverages (such as milk or orange juice); brief exposure to sunlight also provides a dose of vitamin D.

“Many studies have implicated dietary or nutritional factors in cognitive performance or function in older adults, including many studies of vitamin D, but all of them are based on either dietary intakes or blood measures of vitamin D,” said lead author Kyla Shea, a scientist on the Vitamin K Team and an associate professor at the Friedman School of Nutrition Science and Policy at Tufts. “We wanted to know if vitamin D is even present in the brain, and if it is, how those concentrations are linked to cognitive decline.”

Booth, Shea, and their team examined samples of brain tissue from 209 participants in the Rush Memory and Aging Project, a long-term study of Alzheimer’s disease that began in 1997. Researchers at Rush University assessed the cognitive function of the participants, older people with no signs of cognitive impairment, as they aged, and analyzed irregularities in their brain tissue after death.

In the Tufts study, researchers looked for vitamin D in four regions of the brain—two associated with changes linked to Alzheimer’s disease, one associated with forms of dementia linked to blood flow, and one region without any known associations with cognitive decline related to Alzheimer’s disease or vascular disease. They found that vitamin D was indeed present in brain tissue, and high vitamin D levels in all four regions of the brain correlated with better cognitive function.

However, the levels of vitamin D in the brain didn’t associate with any of the physiological markers associated with Alzheimer’s disease in the brain studied, including amyloid plaque buildup, Lewy body disease, or evidence of chronic or microscopic strokes. This means it’s still unclear exactly how vitamin D might affect brain function. 

“Dementia is multifactorial, and lots of the pathological mechanisms underlying it have not been well characterized,” Shea says. “Vitamin D could be related to outcomes that we didn’t look at yet, but plan to study in the future.”

Vitamin D is also known to vary between racial and ethnic populations, and most of the participants in the original Rush cohort were white. The researchers are planning followup studies using a more diverse group of subjects to look at other brain changes associated with cognitive decline. They hope their work leads to a better understanding of the role vitamin D may play in staving off dementia.

However, experts caution people not to use large doses of vitamin D supplements as a preventive measure. The recommended dose of vitamin D is 600 IU for people 1-70 years old, and 800 IU for those older—excessive amounts can cause harm, and have been linked to the risk of falling.

“We now know that vitamin D is present in reasonable amounts in human brains, and it seems to be correlated with less decline in cognitive function,” Shea says. “But we need to do more research to identify the neuropathology that vitamin D is linked to in the brain before we start designing future interventions.”

Reference: “Brain vitamin D forms, cognitive decline, and neuropathology in community-dwelling older adults” by M. Kyla Shea, Kathryn Barger, Bess Dawson-Hughes, Sue E. Leurgans, Xueyan Fu, Bryan D. James, Thomas M. Holland, Puja Agarwal, Jifan Wang, Gregory Matuszek, Nicholas E. Heger, Julie A. Schneider and Sarah L. Booth, 7 December 2022, Alzheimer s & Dementia.
DOI: 10.1002/alz.12836

Research reported in this article was supported by the National Institutes of Health’s National Institute on Aging under award numbers R01AG051641 and R01AG17917, as well as the U.S. Department of Agriculture’s Agricultural Research Service. Complete information on authors, funders, and conflicts of interest is available in the published paper. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the U.S. Department of Agriculture.



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Brains With More Vitamin D Function Better

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Summary: Older adults with cognitive decline who have higher levels of vitamin D in their brains had better cognitive function than their peers with lower levels of vitamin D.

Source: Tufts University

An estimated 55 million people worldwide live with dementia, a number that’s expected to rise as the global population ages. To find treatments that can slow or stop the disease, scientists need to better understand the factors that can cause dementia.

Researchers at Tufts University have completed the first study examining levels of vitamin D in brain tissue, specifically in adults who suffered from varying rates of cognitive decline. They found that members of this group with higher levels of vitamin D in their brains had better cognitive function.

The study was published December 7 in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

“This research reinforces the importance of studying how food and nutrients create resilience to protect the aging brain against diseases such as Alzheimer’s disease and other related dementias,” said senior and corresponding author Sarah Booth, director of the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts and lead scientist of the HNRCA’s Vitamin K Team.

Vitamin D supports many functions in the body, including immune responses and maintaining healthy bones. Dietary sources include fatty fish and fortified beverages (such as milk or orange juice); brief exposure to sunlight also provides a dose of vitamin D.

 “Many studies have implicated dietary or nutritional factors in cognitive performance or function in older adults, including many studies of vitamin D, but all of them are based on either dietary intakes or blood measures of vitamin D,” said lead author Kyla Shea, a scientist on the Vitamin K Team and an associate professor at the Friedman School of Nutrition Science and Policy at Tufts.

“We wanted to know if vitamin D is even present in the brain, and if it is, how those concentrations are linked to cognitive decline.”

Booth, Shea, and their team examined samples of brain tissue from 209 participants in the Rush Memory and Aging Project, a long-term study of Alzheimer’s disease that began in 1997. Researchers at Rush University assessed the cognitive function of the participants, older people with no signs of cognitive impairment, as they aged, and analyzed irregularities in their brain tissue after death.

In the Tufts study, researchers looked for vitamin D in four regions of the brain—two associated with changes linked to Alzheimer’s disease, one associated with forms of dementia linked to blood flow, and one region without any known associations with cognitive decline related to Alzheimer’s disease or vascular disease.

They found that vitamin D was indeed present in brain tissue, and high vitamin D levels in all four regions of the brain correlated with better cognitive function.

However, the levels of vitamin D in the brain didn’t associate with any of the physiological markers associated with Alzheimer’s disease in the brain studied, including amyloid plaque buildup, Lewy body disease, or evidence of chronic or microscopic strokes. This means it’s still unclear exactly how vitamin D might affect brain function. 

“Dementia is multifactorial, and lots of the pathological mechanisms underlying it have not been well characterized,” Shea says. “Vitamin D could be related to outcomes that we didn’t look at yet, but plan to study in the future.”

Vitamin D is also known to vary between racial and ethnic populations, and most of the participants in the original Rush cohort were white. The researchers are planning followup studies using a more diverse group of subjects to look at other brain changes associated with cognitive decline. They hope their work leads to a better understanding of the role vitamin D may play in staving off dementia.

Vitamin D supports many functions in the body, including immune responses and maintaining healthy bones. Image is in the public domain

However, experts caution people not to use large doses of vitamin D supplements as a preventive measure. The recommended dose of vitamin D is 600 IU for people 1-70 years old, and 800 IU for those older—excessive amounts can cause harm, and have been linked to the risk of falling.

“We now know that vitamin D is present in reasonable amounts in human brains, and it seems to be correlated with less decline in cognitive function,” Shea says. “But we need to do more research to identify the neuropathology that vitamin D is linked to in the brain before we start designing future interventions.”

Funding: Research reported in this article was supported by the National Institutes of Health’s National Institute on Aging under award numbers R01AG051641 and R01AG17917, as well as the U.S. Department of Agriculture’s Agricultural Research Service. Complete information on authors, funders, and conflicts of interest is available in the published paper. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the U.S. Department of Agriculture.

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About this vitamin D and cognitive function research news

Author: Tara Pettinato
Source: Tufts University
Contact: Tara Pettinato – Tufts University
Image: The image is in the public domain

Original Research: Open access.
“Brain vitamin D forms, cognitive decline, and neuropathology in community-dwelling older adults” by Sarah Booth et al. Alzheimer’s and Dementia

Abstract

Brain vitamin D forms, cognitive decline, and neuropathology in community-dwelling older adults

Introduction

Vitamin D purportedly protects against cognitive decline and dementia based on observational data using circulating 25-hydroxyvitamin D (25(OH)D). Little is known about vitamin D in the human brain and the association with dementia or neuropathology.

Methods

Decedents of the Rush Memory and Aging Project (n = 290) had vitamin D concentrations measured in four brain regions. Associations with cognitive and neuropathological outcomes were estimated using linear and logistic regression.

Results

The main form of vitamin D in all brain regions measured was 25(OH)D3. Higher brain 25(OH)D3 concentrations were associated with a 25% to 33% lower odds of dementia or mild cognitive impairment (MCI) at the last visit before death (all P ≤ .031). However, brain 25(OH)D concentrations were not associated with any post-mortem neuropathology outcome studied.

Discussion

Higher brain 25(OH)D3 concentrations were associated with better cognitive function prior to death. Additional research is needed to clarify the specific mechanisms underlying this potentially protective relationship.

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New Study Finds That Vitamin D Could Help Extend Your Life

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Vitamin D is a vitamin that your body requires to keep your bones and muscles healthy.

The research linked vitamin D deficiency to premature death.

One in three Australian individuals still have mild, moderate, or severe vitamin D deficiency despite the fact that sunlight is a major source of the vitamin.

Now, a new study from the University of South Australia provides compelling evidence that vitamin D deficiency is linked to early mortality, prompting calls for individuals to follow healthy vitamin D level guidelines.

The research, which was published in the journal Annals of Internal Medicine, indicated that the risk of death increased with the severity of the vitamin D deficiency.

Vitamin D is an essential nutrient that helps us maintain good health by keeping our bones and muscles strong and healthy.

Josh Sutherland, the first author and a Ph.D. student at UniSA, notes that while vitamin D has been linked to mortality, its causal effects have been difficult to prove.

“While severe vitamin D deficiency is rarer in Australia than elsewhere in the world, it can still affect those who have health vulnerabilities, the elderly, and those who do not acquire enough vitamin D from healthy sun exposure and dietary sources,” Sutherland says.

“Our study provides strong evidence for the connection between low levels of vitamin D and mortality, and this is the first study of its kind to also include respiratory disease-related mortality as an outcome. We used a new genetic method to explore and affirm the non-linear relationships that we’ve seen in observational settings, and through this, we’ve been able to give strong evidence for the connection between low vitamin D status and premature death.”

He continues, “Vitamin D deficiency has been connected with mortality, but as clinical trials have often failed to recruit people with low vitamin D levels – or have been prohibited from including vitamin deficient participants – it’s been challenging to establish causal relationships.”

The Mendelian randomization study evaluated 307,601 records from the UK Biobank. Low levels of vitamin D were noted as less than <25 nmol/L with the average concentration found to be 45.2 nmol/L. Over a 14-year follow-up period, researchers found that the risk for death significantly decreased with increased vitamin D concentrations, with the strongest effects seen among those with severe deficiencies.

Senior investigator and Director of UniSA’s Australian Centre for Precision Health, Professor Elina Hyppönen, says more research is now needed to establish effective public health strategies that can help achieve national guidelines and reduce the risk of premature death associated with low vitamin D levels.

“The take-home message here is simple – the key is in the prevention. It is not good enough to think about vitamin D deficiency when already facing life-challenging situations when early action could make all the difference,” Prof Hyppönen says.

“It is very important to continue public health efforts to ensure the vulnerable and elderly maintain sufficient vitamin D levels throughout the year.”

Reference: “Vitamin D Deficiency Increases Mortality Risk in the UK Biobank” by Joshua P. Sutherland, BHSc Nut Med (Hons), Ang Zhou, Ph.D. and Elina Hyppönen, Ph.D., November 2022, Annals of Internal Medicine.
DOI: 10.7326/M21-3324

The study was funded by the National Health and Medical Research Council. 



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Here’s Exactly How Much Vitamin D is Safe, as Man Hospitalized With Intoxication — Eat This Not That

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A man in the UK was hospitalized after taking almost 400 times the daily recommended amount of vitamin D, highlighting once again the serious danger of taking unsafe doses of over-the-counter vitamins and supplements. “Vitamin D toxicity, also called hypervitaminosis D, is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body,” says Katherine Zeratsky, RD, LD. “Vitamin D toxicity is usually caused by large doses of vitamin D supplements — not by diet or sun exposure. That’s because your body regulates the amount of vitamin D produced by sun exposure, and even fortified foods don’t contain large amounts of vitamin D.” 

So what happens when too many vitamin D supplements are taken? “The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination,” Zeratsky says. “Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones. Treatment includes stopping vitamin D intake and restricting dietary calcium. Your doctor might also prescribe intravenous fluids and medications, such as corticosteroids or bisphosphonates.”

Vitamin D—in the correct amount—is crucial for good health. “We have known for a long time that vitamin D is important for bone health,” says Marci A. Goolsby, MD. “One of the jobs of vitamin D is to help your gut absorb the calcium and phosphorus from your diet. These minerals in turn help build and maintain the strength of your bones. Low levels of vitamin D have been linked to stress fractures and other problems with the bones. But vitamin D has many other functions as well. I describe it to my patients as a delicate symphony of everything that goes on in your body. If one of the instruments — in this case, your vitamin D — is off, it can throw off the whole symphony.”

Here is the official recommended daily amount of vitamin D, according to the National Institutes of Health.

Life Stage                  Recommended Amount

Birth to 12 months      10 mcg (400 IU)

Children 1–13 years   15 mcg (600 IU)

Teens 14–18 years     15 mcg (600 IU)

Adults 19–70 years     15 mcg (600 IU)

Adults 71 years and older     20 mcg (800 IU)

Pregnant and breastfeeding teens and women     15 mcg (600 IU)

Vitamin D is not the only vitamin that can cause serious health issues if incorrectly dosed: Here are five other supplements that can make you sick if you don’t follow the recommended daily amounts. Read on—and to ensure your health and the health of others, don’t miss these Sure Signs You’ve Already Had COVID.

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Adults should not take more than 2000 mg of vitamin C a day. 

The good: “Vitamin C, or ascorbic acid (AA), is first and foremost an electron donor,” says Bogdan Popa, MD. “This means it can directly donate electrons to function as an antioxidant. Functioning as an antioxidant allows it to neutralize harmful free radicals and act as a cofactor, also donating electrons to enzymes containing iron or copper. This donation is a critical step in keeping these enzymes ‘active.’ Enzymes that use vitamin C as a cofactor have widespread influence on our energy levels, structural integrity, and DNA. They are involved in maintaining methylation/demethylation balance (or turning on gene expression), making collagen, and furnishing L-carnitine and norepinephrine.” There is also fascinating research about the impact of vitamin C and fasting in treating some cancers. 

The bad: “Taking too much vitamin C can cause diarrhea, nausea, and stomach cramps,” says the NIH. “In people with a condition called hemochromatosis, which causes the body to store too much iron, high doses of vitamin C could worsen iron overload and damage body tissues. Vitamin C dietary supplements might interact with cancer treatments, such as chemotherapy and radiation therapy. It is not clear whether vitamin C might have the unwanted effect of protecting tumor cells from cancer treatments or whether it might help protect normal tissues from getting damaged.

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Adults should not take more than 40 mg of zinc a day, which is the Tolerable Upper Intake Level. The recommended daily amount is 11 mg a day for men and 8 mg for women. 

The good: “Zinc is a trace mineral, meaning that the body only needs small amounts, and yet it is necessary for almost 100 enzymes to carry out vital chemical reactions,” says Harvard Health. “It is a major player in the creation of DNA, growth of cells, building proteins, healing damaged tissue, and supporting a healthy immune system. Because it helps cells to grow and multiply, adequate zinc is required during times of rapid growth, such as childhood, adolescence, and pregnancy. Zinc is also involved with the senses of taste and smell.”

The bad: “Yes, too much zinc can be harmful,” says the National Institutes of Health (NIH). “Signs of too much zinc include nausea, dizziness, headaches, upset stomach, vomiting, and loss of appetite. If you take too much zinc for a long time, you could have problems such as lower immunity, low levels of HDL (“good”) cholesterol, and low copper levels. Taking very high doses of supplemental zinc can reduce your body’s absorption of magnesium. Using large amounts of denture creams that contain zinc, well beyond what the label recommends, could lead to excessive zinc intake and copper deficiency. This can cause neurological problems, including loss of coordination, numbness, and weakness in the arms, legs, and feet.”

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The recommended daily amount of iron for adults is 8mg for men and 18 mg for women, which goes up to 27 mg for pregnant women.

The good: “Iron is an essential element for blood production,” says UCSF Health. “About 70 percent of your body’s iron is found in the red blood cells of your blood called hemoglobin and in muscle cells called myoglobin. Hemoglobin is essential for transferring oxygen in your blood from the lungs to the tissues. Myoglobin, in muscle cells, accepts, stores, transports and releases oxygen. About 6 percent of body iron is a component of certain proteins, essential for respiration and energy metabolism, and as a component of enzymes involved in the synthesis of collagen and some neurotransmitters. Iron also is needed for proper immune function.”

The bad: “Although iron ingestion is no longer the leading cause of poisoning deaths, it is not uncommon and can be a potentially fatal toxicologic emergency,” says University of Utah Health. In 2020, 4688 single cases of iron ingestion (as iron or iron salt formulations) were reported to US poison centers, with 2004 of those cases being in children under the age of 5 years. Also in 2020, there were about 8800 single cases of ingestion of a multivitamin formulation containing iron. Iron can cause direct injury to gastrointestinal mucosa, vasodilation, and impairment of cellular metabolism in the heart, liver, and central nervous system by disrupting oxidative phosphorylation and formation of free radicals. The toxicity of iron depends on the amount of elemental iron ingested, and elemental iron amounts vary between products… Patients who ingest 20-60 mg/kg of elemental iron may develop nausea and vomiting but are at a low-risk for severe toxicity, while > 60 mg/kg is associated with a high-risk for severe toxicity and death.”

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The recommended daily amount of omega-3 according to the NIH is 1.6 g for men and 1.1 g for women, going up to 1.4 g during pregnancy.

The good: “​​For heart health, you may have heard a lot of talk about the benefits of fish oil supplements,” says Penn Health. “While studies have shown that fish oil supplements may provide some benefits to some people with some heart health issues, the real source of these cardiovascular health benefits is from a family of polyunsaturated fats called omega-3 fatty acids. Here’s what you should know about fish oil, omega-3 fatty acids, and heart disease… The most consistent evidence for omega-3s and heart health is their ability to lower triglyceride levels. Triglycerides are a type of fat found in your blood and are stored as body fat. High levels of triglycerides have been linked with fatty build-up in the artery walls, which increases your risk of heart attack and stroke.”

The bad: “Very high doses of fish oil may suppress the immune system as well as have blood-thinning effects,” says Tod Cooperman, MD. “In people taking highly concentrated prescription fish oil, elevations in “bad” LDL cholesterol and certain liver enzymes, and an increase in episodes of atrial fibrillation or atrial flutter in people who already have this heart rhythm disorder, have been reported. Be aware that cod and other fish liver oils can be high in vitamins A and D, which can be toxic in high doses. Too much vitamin A, for example, can cause liver damage. Too much vitamin D can cause hypercalcemia (too much calcium in the blood), resulting in symptoms such as constipation, confusion, weakness and loss of appetite. While fish oil is not believed to adversely affect blood sugar levels in people with diabetes, one study found that taking a large amount of krill oil which contained relatively modest amounts of EPA + DHA (230 mg and 154 mg, respectively) was shown to significantly reduce insulin sensitivity in overweight, middle-aged men, which could potentially increase the risk of the risk of diabetes and cardiovascular disease.”

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The recommended daily amount for adults is 400 mcg of dietary folate equivalents (DFE), going up to 600 mcg for pregnant women.

The good: “Folate is the natural form of vitamin B9, water-soluble and naturally found in many foods,” says Harvard Health. “It is also added to foods and sold as a supplement in the form of folic acid; this form is actually better absorbed than that from food sources—85% vs. 50%, respectively. Folate helps to form DNA and RNA and is involved in protein metabolism. It plays a key role in breaking down homocysteine, an amino acid that can exert harmful effects in the body if it is present in high amounts. Folate is also needed to produce healthy red blood cells and is critical during periods of rapid growth, such as during pregnancy and fetal development.”

The bad: “Unfortunately, many prenatal supplements provide 800 mcg or more of folic acid — double the recommended amount from a supplement,” says Dr. Cooperman. “That’s not all. Folic acid is absorbed much better (about 70% better) than folate from foods. This means that a prenatal supplement with 800 mcg of folic acid gives you the equivalent of 1,360 mcg DFE of folate. On top of this, many manufacturers put in extra folic acid (30% or more is not uncommon), so it’s quite possible that your supplement which lists 800 mcg of folate from folic acid is giving you the equivalent of about 1,800 mcg of folate… Prolonged intake of excessive folic acid can cause kidney damage and can complicate the diagnosis of vitamin B-12 deficiency (folic acid supplementation can mask a symptom of vitamin B-12 deficiency). Of particular concern to pregnant women is that excessively high blood levels of folate (>59 nmol/L) in their blood was found to be associated with an approximate twofold increased risk of autism in their children according to an observational study in Baltimore in which 10% of women exceeded this level.”

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Popular Vitamin Supplement Causes Cancer Risk and Brain Metastasis

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New research finds that the popular dietary supplement nicotinamide riboside could increase the risk of serious disease, including developing cancer.

University of Missouri researchers made the discovery while using bioluminescent imaging technology to study how nicotinamide riboside supplements work inside the body.

Commercial dietary supplements like nicotinamide riboside (NR), a form of vitamin B3, were linked to benefits related to cardiovascular, metabolic, and neurological health in previous studies. However, new research from the University of Missouri (MU) has found NR could actually increase the risk of serious disease, including developing cancer.

Supplements containing nicotinamide riboside are often marketed as NAD+ boosters claimed benefits including increased energy, anti-aging/longevity/healthy aging, improved cellular energy metabolism and repair, increased vitality, and improved heart health.

Scientists discovered that high levels of NR could not only increase someone’s risk of developing triple-negative breast cancer, but also could cause the cancer to metastasize or spread to the brain. The international team of researchers was led by Elena Goun, an associate professor of chemistry at MU and the corresponding author on the study. She said that once the cancer reaches the brain, the results are deadly because no viable treatment options exist at this time.

“Some people take them [vitamins and supplements] because they automatically assume that vitamins and supplements only have positive health benefits, but very little is known about how they actually work,” Goun said. “Because of this lack of knowledge, we were inspired to study the basic questions surrounding how vitamins and supplements work in the body.”

Following the death of her 59-year-old father only three months after being diagnosed with colon cancer, Goun was moved by her father’s passing to pursue a better scientific understanding of cancer metabolism, or the energy through which cancer spreads in the body. Since NR is a known supplement for helping increase levels of cellular energy, and cancer cells feed off of that energy with their increased metabolism, Goun wanted to investigate NR’s role in the development and spread of cancer.

Elena Goun. Credit: University of Missouri

“Our work is especially important given the wide commercial availability and a large number of ongoing human clinical trials where NR is used to mitigate the side effects of cancer therapy in patients,” Goun said.

The researchers used this technology to compare and examine how much NR levels were present in cancer cells, T cells, and healthy tissues.

“While NR is already being widely used in people and is being investigated in so many ongoing clinical trials for additional applications, much of how NR works is a black box — it’s not understood,” Goun said. “So that inspired us to come up with this novel imaging technique based on ultrasensitive bioluminescent imaging that allows quantification of NR levels in real time in a non-invasive manner. The presence of NR is shown with light, and the brighter the light is, the more NR is present.”

Goun said the findings of the study emphasize the importance of having careful investigations of potential side effects for supplements like NR prior to their use in people who may have different types of health conditions. In the future, Goun would like to provide information that could potentially lead to the development of certain inhibitors to help make cancer therapies like chemotherapy more effective in treating cancer. The key to this approach, Goun said, is to look at it from a personalized medicine standpoint.

“Not all cancers are the same in every person, especially from the standpoint of metabolic signatures,” Goun said. “Often times cancers can even change their metabolism before or after chemotherapy.”

Reference: “A bioluminescent-based probe for in vivo non-invasive monitoring of nicotinamide riboside uptake reveals a link between metastasis and NAD+ metabolism” by Tamara Maric, Arkadiy Bazhin, Pavlo Khodakivskyi, Georgy Mikhaylov, Ekaterina Solodnikova, Aleksey Yevtodiyenko, Greta Maria Paola Giordano Attianese, George Coukos, Melita Irving, Magali Joffraud, Carles Cantó and Elena Goun,  29 October 2022, Biosensors and Bioelectronics.
DOI: 10.1016/j.bios.2022.114826

Other authors on the study are Arkadiy Bazhin, Pavlo Khodakivskyi, Ekaterina Solodnikova and Aleksey Yevtodiyenko at MU; Tamara Maric at the Swiss Federal Institute of Technology; Greta Maria Paola Giordano Attianese, George Coukos and Melita Irving at The Ludwig Institute for Cancer Research in Switzerland; and Magali Joffraud and Carles Cantó at the Nestlé Institute of Health Sciences in Switzerland. Bazhin, Khodakivskyi, Mikhaylov, Solodnikova, Yevtodiyenko, and Goun are also affiliated with the Swiss Federal Institute of Technology. Mikhaylov, Yevtodiyenko, and Goun are also affiliated with SwissLumix SARL in Switzerland.

Funding was provided by grants from the European Research Council (ERC-2019-COG, 866338) and Swiss National Foundation (51NF40_185898), as well as support from NCCR Chemical Biology.



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Seven benefits of vitamin D

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The benefits of vitamin D have long been reported, but are you getting enough of this nutrient in your everyday diet for optimal health and wellbeing? Whether you opt for a daily dose of sunshine, a supplement, or fortified foods, getting enough vitamin D is vital when it comes to keeping your bones strong and your immune system firing on all cylinders. 

Vitamin D is a nutrient with abundant benefits for our physical and mental health. However, very few foods naturally contain vitamin D besides fortified foods and drinks such as milk, breakfast cereals, yogurts and orange juices. The best food sources of vitamin D are fatty fish such as salmon, mackerel, and fish liver oils, while eggs, cheese and mushrooms contain small amounts. 

Our bodies also make vitamin D when our skin is exposed to the sun. But as we all know, it’s important to wear sunscreen and stay in the shade to reduce our risk of skin cancer. Older people and people with dark skin struggle to make enough vitamin D in sunlight. So how can we make sure we’re getting enough of this vital nutrient?

One of the easiest ways to get enough vitamin D into our everyday diet is through the best vitamin D supplements, available in capsules, sprays and chewables. Make sure you check out what levels of vitamin D the National Institutes of Health (opens in new tab) recommends, depending on your age.

What are the benefits of vitamin D?

According to Rahaf Al Bochi, registered nutritionist and spokesperson for the Academy of Nutrition and Dietetics (opens in new tab), there are several benefits to vitamin D. “Vitamin D helps absorb calcium and phosphorus, which is important for bone and teeth health,” she says. “Vitamin D also plays a role in disease prevention such as heart disease and type 2 diabetes, reducing the risk for depression.”

Rahaf Al Bochi, RDN, LDN

Al Bochi is a registered nutritionist and spokesperson for the Academy of Nutrition and Dietetics. She practices through an intuitive eating approach and specializes in the Mediterranean eating pattern. Al Bochi is a member of the Academy’s Nutrition Entrepreneurs dietetic practice group and a graduate of Ryerson University.

We’ve taken a deeper dive into some of these key benefits, along with others, to discover what this important nutrient can do for our physical and mental wellbeing.

1. It supports the immune system

Vitamin D is already known to help our immune system resist invading bacteria and viruses, according to the Centers for Disease Control and Prevention (opens in new tab) (CDC). But the recent Covid-19 pandemic has shown how powerful vitamin D can be in supporting our immune systems against more severe diseases.

A review released in 2022 (opens in new tab) into the role vitamin D plays in fighting Covid-19 found that low vitamin D levels may increase the risk of infection and may also increase its severity. Researchers concluded that vitamin D supplementation could protect people from respiratory diseases and prevent it from progressing in severity, reducing the risk of death. 

(Image credit: JUAN GAERTNER/SCIENCE PHOTO LIBRARY via Getty Images)

2. It builds strong bones and teeth

Vitamin D is vital to building and maintaining strong, healthy bones and teeth. It does this by promoting calcium and phosphorus absorption in the gut, which helps bones to mineralize, increasing strength and hardness.

Not getting enough vitamin D can lead to tooth loss and leave bones brittle and weak. It can even cause rickets in children and osteoporosis in older adults. With more than 53 million adults (opens in new tab) in the U.S. at risk of developing osteoporosis, vitamin D could be a powerful tool in increasing bone health. 

3. It supports a healthy heart

Vitamin D helps to regulate heart function and reduce blood pressure, while vitamin D deficiency is associated with heart problems, stiffening arteries and high blood pressure.

Although there is not enough evidence to support the idea that vitamin D supplementation can lower the risk of cardiovascular disease (CVD), many health experts argue that it reduces blood cholesterol levels (opens in new tab) and high blood pressure (opens in new tab), both of which can contribute to CVD.

(Image credit: Getty/ Sarinya Pinngam / EyeEm)

4. May prevent type 2 diabetes

Vitamin D may help the body improve its sensitivity to insulin, which is the hormone that regulates blood sugar levels. This can reduce the risk of insulin resistance, which can lead to type 2 diabetes. Numerous studies, such as one published in the Biochemical Journal (opens in new tab), have also linked vitamin D deficiency to developing type 2 diabetes. 

5. May inhibit cancer spread

According to the NIH (opens in new tab), vitamin D can inhibit or slow the progressions of certain cancer tumors. This may be because of its anti-inflammatory effect or because it may be able to stop the tumor from growing blood vessels. 

A 2019 meta-analysis of trials into vitamin D supplementation and cancer incidence and mortality published in Annals of Oncology (opens in new tab) found that while vitamin D did not reduce cancer incidents, it significantly reduced cancer deaths by as much as 13% (opens in new tab).

However, one study reported an association between a higher intake of vitamin A and invasive breast cancer, with subjects experiencing a 28% rise (opens in new tab) in risk. 

People with cancer should always speak to their oncologist before opting for vitamin A supplementation.

(Image credit: Getty Images)

6. May reduce the risk of multiple sclerosis (MS)

Lots of studies over the years, including one published in the journal of Multiple Sclerosis and Related Disorders (opens in new tab), have shown that people who get more sunlight exposure and vitamin D from their diet have a reduced risk of developing MS, an autoimmune disease affecting the central nervous system. As the NIH (opens in new tab) notes, people who live in hotter, more sunny countries rarely develop this condition compared to those who live in cooler, cloudier countries. 

Some experts suggest vitamin D supplements could reduce the risk of developing the disease or improve symptoms associated with MS, as a 2021 article published in Annals of Agricultural and Environmental Medicine (opens in new tab) argues. However, we need more evidence to be sure of the benefits. 

7. May reduce the risk of depression

More evidence is emerging that vitamin D can be an essential tool to support mental wellbeing. In 2020, a systematic review and meta-analysis published in Depression and Anxiety (opens in new tab) compared the effect of a vitamin D supplement and a placebo on thousands of participants with ‘negative emotions.’ Researchers found that vitamin D supplementation improved the mood of patients with major depressive disorder.

However, a 2021 review in the Journal of Clinical Medicine (opens in new tab) that looked into the use of vitamin D in healthy adults did not find consistent evidence to support the use of vitamin D in combating other mental health problems. Researchers also noted that some studies recommended physical activity in addition to supplementation or recommended food sources of vitamin D instead.

So while we can cautiously say vitamin D may have a mood-boosting effect, especially on those with depression, we need more research on how it does this and how it should be combined with other methods of supporting mental health.

This article is for informational purposes only and is not meant to offer medical advice.

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Exhaustion, low mood and being short of breath are all symptoms of vitamin B12 deficiency

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Motivated by the health benefits of a plant-based diet, Carly Minsky, then in her mid-20s, saw cutting out meat and fish as a natural and desirable step.

At first, she ‘felt great’, she says, as she committed enthusiastically to her new regimen. After a year, though, it was a different story entirely.

‘I began feeling very fatigued,’ recalls Carly. ‘It wasn’t just tiredness, it was extreme fatigue.’ She also put on weight.

‘I went on like this for six years, not sure what was wrong, and by 2020 I could barely walk because I was so exhausted,’ says the journalist, 33, from London.

Finally, concerned it might be a problem with her thyroid gland (which produces hormones to regulate metabolism), in 2021 she saw her GP, who sent her for blood tests.

Motivated by the health benefits of a plant-based diet, Carly Minsky, then in her mid-20s, saw cutting out meat and fish as a natural and desirable step. At first, she ‘felt great’, she says, as she committed enthusiastically to her new regimen. After a year, though, it was a different story entirely

Within days, Carly was summoned back to the surgery and told her vitamin B12 levels had dropped so dramatically that she would need emergency vitamin injections every other day for the next six weeks, and then high-potency vitamin B12 tablets every day for life. The cause? Her diet.

Vitamin B12 is mainly found in animal and dairy products — meat, fish, eggs, milk and cheese, for instance — and is vital for numerous key body functions, including brain health and the production of red blood cells.

A deficiency can lead to health problems including anaemia (low levels of iron in the blood), tiredness, heart palpitations, shortness of breath, nerve problems and mental health issues.

Those aged over 60, who are more likely to have dietary deficiencies, and people with pernicious anaemia, an autoimmune condition that means the body is unable to absorb B12 properly, are at risk. So, too, are vegans.

Earlier this year, the National Institute for Health and Care Excellence (NICE) reported that 6 per cent of the population under the age of 60 is deficient in B12, rising to 11 per cent among vegans.

Although Carly still ate cheese and eggs, and drank milk, her intake over those years of vegetarianism wasn’t enough and her vitamin B12 levels had dropped.

‘My GP said I was at the dangerously low end of the scale and needed immediate B12 injections,’ she says. ‘It was a huge shock. I had no idea I’d become so unwell.

‘It took two months of injections before I began to feel better, and obviously I am still taking vitamin B12 tablets daily.’

Most people get enough B12 from their diets — the recommended intake is 1.5 micrograms a day (an average diet containing chicken, fish, beef and eggs will give you enough).

‘But some people — including those on restrictive diets who do not consume animal products, or who eat a bad diet high in processed foods — do not get enough vitamin B12,’ says Sue Pavord, a consultant haematologist at Oxford University Hospitals and vice president of the British Society for Haematology.

Vitamin B12 is mainly found in animal and dairy products — meat, fish, eggs, milk and cheese, for instance — and is vital for numerous key body functions, including brain health and the production of red blood cells

She says that B12 deficiency is a seriously neglected area of public health, which affects 10 per cent of those over 60.

‘The human body is not able to make B12 and therefore needs it from food,’ she explains. ‘Early symptoms of a deficiency can be vague, such as fatigue or symptoms of anaemia — palpitations, breathlessness and exhaustion.

‘But as the deficiency progresses, neurological symptoms can develop — such as tingling in the fingers and toes, or loss of balance.’

This is because B12 is vital for the maintenance and formation of protective sheaths that cover the nerves, ensuring fast and effective transmission of messages, explains Dr Moez Dungarwalla, a consultant haematologist at Milton Keynes University Hospital.

‘A fatty substance called myelin is essential for the formation of these sheaths, and vitamin B12 plays a significant role in the synthesis and maintenance of myelin,’ he explains. ‘The neurological problems caused by B12 deficiency are in part due to damage caused to the myelin sheath.’

In extreme cases, a vitamin B12 deficiency has been linked to macular degeneration (which can lead to a decline in vision), heart disease, cognitive impairment, dementia, stroke and psychosis.

However, the vague — or lack of — early symptoms can mean some people are unaware that they are suffering from a potentially serious deficiency, as former counsellor Stephen Wright discovered.

The 70-year-old, from Dorset, only learned he had a B12 deficiency at a GP check-up two years ago. Routine blood tests revealed he was severely deficient in the vitamin and would need injections every six weeks for life to prevent neurological disorders developing.

Doctors believe his deficiency was down to his age and his unhealthy diet.

Some existing conditions can also lead to a deficiency — the most common being pernicious anaemia, says David Smith, a professor emeritus of pharmacology at Oxford University.

‘Pernicious anaemia affects one in 1,000, and up to one in 500 in the over-60s,’ he says. ‘It is an autoimmune disease with family links. It is not known what triggers it, but it prevents absorption of vitamin B12 in the intestine.’

Other diseases that impair B12 absorption include reduced acid secretion in the stomach (again, common with age) and Crohn’s and coeliac disease.

Some drugs interfere with vitamin B12 absorption, including metformin (used to treat diabetes) and proton pump inhibitors such as omeprazole (for acid reflux).

The good news is that symptoms can be reversed for most patients.

As Professor Smith explains: ‘Most people will be able to correct their low vitamin B12 status by taking tablets, and a good starting dose is 1 microgram a day. Injections are needed for many patients with pernicious anaemia.’

But people often don’t find out they’re deficient until damage has been done.

‘If someone does not get treatment, there can be irreversible changes to the neurological system,’ says Dr Pavord. ‘That includes difficulty walking, due to weakness; loss of balance and sensation; and disturbed vision.’

As well as having B12 jabs, Stephen adopted a low-carb regimen, lost three stone and feels much more energetic. ‘I’d no idea how important vitamin B12 was until I went through it,’ he says.

Carly’s symptoms were resolved within two months of starting the vitamin B12 treatment. ‘It was like my energy had been switched back on,’ she says.

Doctor Ink 

The tattoos being used for medical purposes. This week: To monitor bowel polyps

Tattooing is a technique that doctors use inside people’s colons to help monitor and remove lesions — relying on commercially available dark inks.

However, these diffuse quickly, which makes it harder to identify a lesion, and leakage may lead to abscesses. Using ‘biomedical’ ink offers a safer alternative, according to research presented at the American Chemical Society conference.

The ink uses tiny metal-derived particles which provide the dark colour needed to be seen under the light of a colonoscopy. It also diffuses a lot less than commercial inks.

 

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I Was Diagnosed With a Vitamin B12 Deficiency When My Limbs Went Numb

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  • When I experienced unexplained pins and needles and weakness in all my limbs, I started to panic.
  • About a week later, I went to the doctor and found out I had a severe vitamin B12 deficiency. 
  • Here’s what a B12 deficiency can look like, plus treatment, as well as how I’m feeling today.

On a Wednesday morning in May, I went for my regular run around lower Manhattan. I enjoyed the breezy weather, ate my usual meals, and went to work. Then, as I was settling in for the night, something unusual happened.

I was lying on my right side in bed when pins and needles radiated through my left arm. I wasn’t putting pressure on my left arm, so why was it asleep? I shook it out and contorted my body, trying to stretch my limb to rid myself of the feeling but felt no relief.

Then my left hand went numb. After 30 minutes of panic, I convinced myself it was all in my head and eventually fell asleep. By the time I woke up in the morning, the same tingling sensation had spread to both arms, hands, legs, and feet. I was really freaking out.

I was panicked and looking for answers

I hobbled over to a nearby urgent-care center, where the doctor told me the tingling could be explained by a viral infection, even though she didn’t run any tests or give me any prescriptions. I left feeling even more hopeless than when I had stumbled in — and more tingly.

With no change in my symptoms, I saw my internist, who promptly conducted an extensive blood-work panel. As I waited five days for results, I became so weak that it was debilitating; I couldn’t even take a lap around my block. 

Finally, the panel came back: I had a severe vitamin B12 deficiency.

What it’s like to have a severe vitamin B12 deficiency

According to Dr. Edwin Serrano, a neurology resident physician at MedStar Georgetown University Hospital, a B12 levels of about 300 picograms per milliliter is considered normal, and below 200 pg/ml is considered low. Mine was hovering around 175 pg/ml. My numbers probably didn’t plummet this low overnight. 

“Typically, symptoms occur after vitamin B12 deficiency has been untreated for years,” said Dr. Brad Kamitaki, an assistant professor of neurology at Rutgers Robert Wood Johnson Medical School.

Many people are initially asymptomatic. He added that B12 deficiency “can be undiagnosed or underdiagnosed since symptoms can be nonspecific,” like cognitive slowing, fatigue, tongue swelling, arm or leg tingling, and difficulty walking.

B12 deficiency typically has two causes: malabsorption or inadequate intake. Some conditions, like atrophic gastritis or celiac disease, can block the absorption of B12, while vegan and vegetarian diets can lead to insufficient intake, as animal products are a main source of B12.

Symptoms did not go away immediately once I started treatment

At least the treatment sounded easy: vitamin B12 injections for a month, then daily supplements. I figured my symptoms would vanish after a week of shots — I was wrong. Your body takes awhile to replenish its B12, Serrano said: “If there are neurological symptoms, these can linger between three months to one year.” 

That was the case for me. Even though I was getting treatment, my symptoms worsened before they improved — and the way my symptoms affected my life cannot be overstated. Leg numbness persisted. I also found myself without an appetite and regularly skipped meals. My brain fog was overwhelming. Headaches became so excruciating I could no longer sleep. My vision became blurry. Alarmed, my doctor thought the two latter symptoms warranted an MRI brain scan to rule out a tumor or multiple sclerosis; a neurologist later told me B12 deficiency explained both.

It’s important to note there are some folks who may be more at risk of a vitamin B12 deficiency than others, including those on plant-based diets, Kamitaki said.

“I’d also want people to be aware that adequate vitamin B12 intake is essential during pregnancy and if exclusively breastfeeding, as effects of vitamin B12 deficiency in the developing fetus and infant can be significant,” Kamitaki said.

Serrano added that older populations were also at higher risk, as cases of B12 deficiency increase with age.

I was extremely lucky that I acted as quickly as I did. Serrano said that if symptoms went untreated, it could cause “irreversible damage” to the nervous system and lead to the inability to walk as normal, permanent muscle tightness, and loss of motor function in your legs. He added that untreated symptoms could alter the ability to produce red blood cells, which increases risk of heart failure, and may even increase a person’s risk of dementia. 

Nearly five months after my initial panic in May, my symptoms have virtually disappeared. My strength and energy have returned, my brain fog has lifted, my numbness has subsided, and I’m able to take my morning run again.

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Supplements are NOT elixirs of youth: Vitamin D3 and omega-3 fatty acids NOT helpful against frailty

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Popping vitamin D3 and Omega-3 fatty acid pills every day will not stop older adults from suffering inflammation and becoming frail, a study has found.

Scientists at the Brigham and Women’s Hospital, Massachusetts, behind the five-year research urged Americans over 50 years old to drop the ‘unnecessary’ pills Tuesday, and instead focus on exercise and the Mediterranean diet to protect their health.

Herbal medicine sellers argue that the supplements — sold by a $6.8-billion industry — can help cut inflammation and slow age-related muscle loss, key risks for frailty. But scientific evidence for this is patchy, with the latest paper just the latest to suggest they have little benefit.

Dr Ariela Orkaby, an aging expert who led the study, said today: ‘We should consider deprescribing unnecessary pills, and instead promoting healthy lifestyle habits.

‘Regular exercise and the Mediterranean diet are proven strategies for prevention of frailty and should be encouraged for all older adults.’

Shown above are the frailty scores for American adults over 50 years old who took Omega-3 fatty acid supplements once a day (yellow dot) and no supplements (blue dot) for the five-year study. It shows there is no difference in frailty levels (Shown by the Y axis) between the groups, meaning the pills did not reduce the risk of developing frailty

This graph shows the frailty scores (Y axis) for American adults over 50 years old who took vitamin D3 tablets (yellow) once a day for the study against those who took no pill (blue dot). It shows no difference in frailty levels between the groups, meaning the pills had no impact reducing frailty levels

Shown above are Omega-3 fatty acid supplements rolling off a production line

WHAT SHOULD A BALANCED DIET LOOK LIKE?

Meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain, according to the NHS

• Eat at least 5 portions of a variety of fruit and vegetables every day. All fresh, frozen, dried and canned fruit and vegetables count

• Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain

• 30 grams of fibre a day: This is the same as eating all of the following: 5 portions of fruit and vegetables, 2 whole-wheat cereal biscuits, 2 thick slices of wholemeal bread and large baked potato with the skin on

• Have some dairy or dairy alternatives (such as soya drinks) choosing lower fat and lower sugar options

• Eat some beans, pulses, fish, eggs, meat and other proteins (including 2 portions of fish every week, one of which should be oily)

• Choose unsaturated oils and spreads and consuming in small amounts

• Drink 6-8 cups/glasses of water a day

• Adults should have less than 6g of salt and 20g of saturated fat for women or 30g for men a day

Source: NHS Eatwell Guide 

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In the study — published today in the journal JAMA Network Open —  scientists re-analyzed data from the VITAL study, which looked at whether the supplements could combat heart disease or cancer.

They recruited 25,000 adults over 50 years old, with an even sex-split and a BMI of about 28 — putting them in the overweight group. They were from all 50 U.S. states.

First, participants were split into four groups with a quarter given both vitamin D3 and Omega-3 fatty acids, one each given just one of the supplements, and one receiving neither.

Participants were then asked to take the pills every day, with the Vitamin D ones containing 2,000 international units (IU) while the others had 840 micrograms of Omega-3 fatty acids.

This was above the recommended levels from the Food and Drug Administration (FDA), which says every American adult should aim for 800IUs of vitamin D per day and up to 500mg of Omega 3 fatty acids.

To measure frailty, they filled in a questionnaire at the start of the study on their physical activity, mood and underlying health conditions.

Participants re-completed the survey six months later, and then once a year for the following four years.

Results showed at the beginning of the study that 3,174 individuals (12.7 percent) were classified as frail.

But after five years another 2,487 individuals (further 11.3 percent) moved to being classified as frail.

The frailty score — a measure of the condition — was calculated as 0.109 at the start of the study. But by the end it had risen to 0.121.

There was no significant difference in the numbers who were frail between the groups who received the supplements, and the one that did not.

The scientists concluded: ‘These results do not support the routine supplementation of healthy community-dwelling adults with vitamin D3 or omega-3 fatty acids for the prevention of frailty.

‘[But] regular exercise and the Mediterranean diet are proven strategies for the prevention of frailty and should be encouraged for older adults.’

Frailty can be triggered by inflammation and poor nutrition, with some suggesting supplements could help combat it.

The scientists added it was possible the pills could still have a positive effect for the population with major health issues. They were not studied in this paper. 

Dr JoAnn Manson, who directed the vital program and is also at the Brigham and Women’s hospital, said: ‘These new findings from VITAL are an important reminder that dietary supplements are not miracle pills or elixirs of youth.’ 

Participants were recruited between November 2011 and March 2014, with the study continuing until December 2017. The data was re-analyzed by scientists in Massachusetts last year.

Industry figures estimate the Omega-3 fatty acid market is worth $0.62billion annually in North America while the vitamin D3 market is $0.43 billion.

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Vitamin D won’t protect you from Covid or respiratory infections, studies say

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Vitamin D supplementation at either dose “did not result in reduced risk of all-cause acute respiratory infections (ARI), or in risk or severity of COVID-19 specifically,” said study author Dr. Adrian Martineau, a professor of respiratory infection and immunity at the Institute of Population Health Sciences at Queen Mary University of London via email.

A second double-blinded, randomized clinical trial, also done during the pandemic, gave over 34,000 Norwegians cod liver oil or a placebo to test the impact of vitamin D on Covid and respiratory disease prevention. Cod liver oil naturally contains low doses of vitamin D, along with vitamin A and omega-3 fatty acids.

The British Medical Journal released both studies Wednesday.

“The major takeaway is that for people in general, a vitamin D supplement did not prevent COVID-19, serious COVID-19 or symptomatic acute respiratory tract infections,” said study author Dr. Arne Søraas, a researcher in the department of microbiology at Oslo University Hospital in Norway, in an email.

Søraas added that the UK study design “complements ours in several ways, with a higher dose of vitamin D given to participants only after measuring their vitamin D status. Nevertheless, their result is supporting our findings and that is the key takeaway too: Neither study found any preventive effect after supplementation with vitamin D.”

The findings of both studies counter a study done in 2020 in Mexico City, where health professionals were given either 4,000 IU of vitamin D a day or a placebo. Researchers found protective effects from the vitamin in just one month. Two more clinical trials that are underway in the United States and Canada will add more data, Martineau said.

The studies were done before vaccinations were widely available, both authors noted. “We can be completely sure that vaccination is way more effective than vitamin D which probably does not prevent COVID-19 at all,” Søraas said.

Vitamin D’s popularity

The primary function of vitamin D is to help the body absorb calcium and phosphate, thus keeping muscles and teeth healthy and bones strong and less likely to break. However, vitamin D is also known to help the immune system fight off invading bacteria and viruses.

Research has shown that vitamin D deficiency impairs the immune system, and some studies have found vitamin D supplements may reduce the risk of respiratory virus infections and calm immune system overreaction.

During the early days of the pandemic, physicians on the front lines began noticing people with lower levels of vitamin D appeared to have a higher risk of dying from Covid-19. Suddenly, the internet was flooded with speculation that taking supplemental doses of vitamin D — even if not needed — would prevent the coronavirus from taking hold.

However, “unlike vitamin C, vitamin D is a fat-soluble vitamin that can ‘build up’ in the system and cause toxicity if taken at very high doses over long periods,” Martineau explained.

Research has suggested that long-term use of higher levels of vitamin D is associated with increases in all-cause mortality, greater risk of cancer, cardiovascular events and more falls and fractures among the elderly.

The recommended daily dose of vitamin D for people in the US between the ages of 1 and 70 is 600 international units (UI) a day, rising to 800 IU a day for those over 70. In the UK, the recommended daily amount is 400 IU a day. Levels in other parts of the world are country-specific to reflect environmental and dietary differences, but typically also range between 400 and 800 IU a day.

Studying people with low vitamin D levels

The UK study was part of COVIDENCE UK, a national study designed to investigate risk factors for developing Covid-19. Researchers enrolled 6,200 adults, age 16 or older, who were not taking vitamin D supplements, and conducted the study between December 2020 and June 2021.

A randomized sample of the participants were given a vitamin D blood test and 3,100 people were found to have low vitamin D levels. The other 3,100 people were assigned to be controls.

The study participants with low levels of vitamin D were then randomized into two groups of 1,550 people who were assigned to take either 3,200 IU or 800 IU of a vitamin D supplement each day for six months. However, the study was not blinded or placebo controlled: Each person knew they were taking a supplement provided by two pharmaceutical companies that supported the study.

During the six months of the trial, neither the high nor low dose of vitamin D had any effect on preventing respiratory tract infections or confirmed Covid-19 cases when compared with the control group, according to the study.

The results contradict two previous meta-analyses of randomized clinical trials conducted by Martineau and his colleagues that did find a significant, albeit small, protective impact against catching respiratory illnesses.

Using a low dose

The Norwegian study, conducted between November 2020 and June 2021, divided 34,601 people between the ages of 18 and 75 into two groups. Each group took either 1 teaspoon (5 milliliters) of cod liver oil or 1 teaspoon of corn oil, which served as a placebo, each day for six months over the winter.

Each teaspoon of cod liver oil contained approximately 400 IU (10 micrograms) of vitamin D, Søraas said. Cod liver oil is a staple in Norway, used for centuries to add vitamin D and omega-3 fatty acids to the Norwegian diet. However, 75.5% of the people in the study were not using vitamin D supplements before enrollment.

Unlike the study from the UK, where many people were vitamin D deficient, testing in Norway showed 90% of people in the cod liver oil group and 72% of those in the placebo group had adequate levels at the start of the study: “But we did not find that this measure influenced the chance of getting COVID-19 or other acute respiratory infections,” Søraas said.

However, just like the UK study, the Norwegian study found vitamin D in cod liver oil had no preventive impact on respiratory infections or confirmed cases of Covid-19.

“The overall message is consistent — two differently-designed studies investigating related interventions in slightly different populations — but the same bottom line — no effect seen,” UK study author Martineau said.

“As a medical doctor I see much speculation that very high doses of vitamin D could have beneficial effects for a range of different diseases, but I would encourage everybody to follow science-based government recommendations for all nutrients,” Søraas said.

“Our results support existing recommendations which do not include massive doses.”

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