Vitamin D and Multiple Sclerosis-How They’re Connected
Dr. James Dowd is an expert in vitamin D. Here he discusses how it is connected to multiple sclerosis. He also discusses the importance of vitamin d in the early years including pregnancy.
Vitamin D supplementation may slow the progression of type 2 diabetes in newly diagnosed patients and those with prediabetes, according to a study published in the European Journal of Endocrinology. The study findings suggest that high-dose supplementation of vitamin D can improve glucose metabolism to help prevent the development and progression of diabetes.
Type 2 diabetes is an increasingly prevalent disease that places a huge burden on patients and society and can lead to serious health problems including nerve damage, blindness and kidney failure. People at high risk of developing type 2 diabetes (prediabetes) can be identified by several risk factors including obesity or a family history of the disease. Although low vitamin D levels have previously been associated with an increased risk of developing type 2 diabetes, some studies have reported no improvement in metabolic function. However, these often had a low number of participants or included individuals with normal vitamin D levels at the start who were metabolically healthy, or who had long-standing type 2 diabetes. Whether vitamin D supplementation has any beneficial effect in patients with prediabetes or with newly diagnosed diabetes, especially in those who have low vitamin D levels, remains uncertain.
In this study, Dr Claudia Gagnon, and colleagues from Université Laval in Quebec, examined the effect of vitamin D supplementation on glucose metabolism in patients newly diagnosed with type 2 diabetes or identified as at high risk of developing the condition. Markers of insulin function and glucose metabolism were measured before and after six months of high-dose vitamin D supplementation (approximately 5-10 times the recommended dose). Although only 46% of study participants were determined to have low vitamin D levels at the start of the study, supplementation with vitamin D significantly improved the action of insulin in muscle tissue of participants after six months.
Dr Claudia Gagnon comments, “The reason we saw improvements in glucose metabolism following vitamin D supplementation in those at high risk of diabetes, or with newly diagnosed diabetes, while other studies failed to demonstrate an effect in people with long-standing type 2 diabetes is unclear. This could be due to the fact that improvements in metabolic function are harder to detect in those with longer-term disease or that a longer treatment time is needed to see the benefits.”
Dr Gagnon suggests future studies should evaluate whether there are individual clinical or genetic factors that affect how different people respond to vitamin D supplementation and if the positive effect on metabolism is maintained in the longer term.
Dr Claudia Gagnon adds, “Type 2 diabetes and prediabetes are a growing public health concern and although our results are promising, further studies are required to confirm our findings, to identify whether some people may benefit more from this intervention, and to evaluate the safety of high-dose vitamin D supplementation in the long term. Until then I would suggest that current vitamin D supplementation recommendations be followed.”
Research shows vitamin D signaling is needed for normal muscle size and strength
Professor Jenny Gunton from the Westmead Institute for Medical Research. The Westmead Institute for Medical Research.
A recent study conducted at The Westmead Institute for Medical Research has shed light on the role of vitamin D in muscle cells. The study looked at the role of vitamin D in muscles in mice, and showed that vitamin D signaling (how cells communicate with one another) is needed for normal muscle size and strength.
Researchers found that mice missing the vitamin D receptor only in myocytes (muscle cells) had smaller muscles, and they were less strong. They also had significantly decreased running speed and didn’t run as far as mice with normal vitamin D action.
Lead researcher, Professor Jenny Gunton says, “For a long time, we have known that vitamin D deficiency is associated with muscle weakness and greater risk of falls and fractures. However, whether vitamin D played a direct role in muscle wasn’t known.
“We show that vitamin D receptor is present in low levels in normal muscle, and our study found that deleting muscle cell vitamin D receptors had important effects on muscle function.”
Professor Gunton says that, compared to a previous study she conducted that looked at mice missing vitamin D receptors across their whole body, this new study has highlighted some important differences.
“We found that mice missing muscle cell vitamin D receptors had normal body size but less muscle mass and more fat mass.
“In terms of choosing to run on a wheel in their cage, the mice had shorter running distance and slower speed. These might contribute to the lower muscle mass and increase in fat.
In terms of muscle strength, these mice also had a significantly decreased grip strength from a very early age.”
While more research is needed, Professor Gunton says that these results suggest that maintaining normal vitamin D signaling in muscle is important for preserving muscle bulk and function.
“These findings also have the potential to open up avenues to pursue new therapies that target muscle cell vitamin D receptors. These therapies could help to address or prevent age-related sarcopenia (degenerative loss of skeletal muscle mass) and other disorders related to muscle function.”
The research paper was published in the Journal of Cachexia, Sarcopenia and Muscle.
A case study in CMAJ highlights the dangers of taking too much vitamin D.
A 54-year-old man, after returning from a trip to Southeast Asia where he spent much of his holiday sunbathing, showed increased levels of creatinine, suggesting kidney damage or malfunction. After referral to a kidney specialist and further testing, it was discovered that he had been prescribed high doses of vitamin D by a naturopath, who recommended a dose of 8 drops every day. Over 2 ½ years, the patient, who did not have a history of bone loss or vitamin D deficiency, took 8-12 drops of vitamin D daily, totalling 8000-12 000 IU. As a result, he had very high levels of calcium in the blood, which left him with significant kidney damage.
“Although vitamin D toxicity is rare owing to a large therapeutic range, its widespread availability in various over-the-counter formulations may pose a substantial risk to uninformed patients,” writes Dr. Bourne Auguste, a Clinical Fellow in Home Dialysis at Toronto General Hospital and the University of Toronto.
The recommended daily allowance is 400-1000 IU, with 800-2000 IU recommended for adults at high-risk of osteoporosis and for older adults.
“Our experience informs us that patients and clinicians should be better informed about the risks regarding the unfettered use of vitamin D. Given new findings from the US Preventive Services Task Force, current Canadian guidelines regarding its use in low-risk individuals should be revisited,” the authors suggest.
“Use of vitamin D drops leading to kidney failure in a 54-year-old man” is published April 8, 2019.
How much vitamin D can boost memory, learning and decision-making in older adults, and how much is too much? A unique Rutgers-led study found that overweight and obese older women who took more than three times the recommended daily dose of vitamin D showed improvements in memory and learning — but also had slower reaction times. The researchers hypothesize that slower reaction times may increase the risk of falling among older people. Sue Shapses/Rutgers University-New Brunswick
How much vitamin D can boost memory, learning and decision-making in older adults, and how much is too much?
A unique Rutgers-led study found that overweight and obese older women who took more than three times the recommended daily dose of vitamin D showed improvements in memory and learning – but also had slower reaction times. The researchers hypothesize that slower reaction times may increase the risk of falling among older people.
The researchers, whose work is in the Journals of Gerontology: Series A, used computers to assess the impact of vitamin D on cognitive function. The researchers evaluated three groups of women between 50 and 70 years old in a randomized controlled trial.
One group took the recommended daily dose of 600 international units (IU), equivalent to 15 micrograms, of vitamin D each day for a year. Another group took 2,000 IU per day and the third took 4,000. All women participated in lifestyle counseling and were encouraged to lose a modest amount of weight.
The researchers found that memory and learning improved in the group that took 2,000 IU per day, but not in the group that took the higher dosage. Meanwhile, the women’s reaction time showed a trend to be slower at 2,000 IU daily and was significantly slower at the higher dosage.
“The slower reaction time may have other negative outcomes such as potentially increasing the risk of falling and fractures,” said senior author Sue Shapses, a professor in the Department of Nutritional Sciences at Rutgers University-New Brunswick and director of the New Jersey Obesity Group. “This is possible since other researchers have found that vitamin D supplementation at about 2,000 IU daily or more increased risk of falls, but they did not understand the cause. Our team’s findings indicating a slower reaction time may be one answer. Many people think that more vitamin D supplementation is better, but this study shows that is not always the case.”
Shapses said 4,000 IU a day might not be a problem for younger people but for the elderly it could compromise walking or catching one’s balance to avoid a fall because their reaction time is slower. This is a presumption until future research can cover vitamin D levels, cognition and falls in one study, she added.
Vitamin D – known for its importance for bone health – is obtained through sun exposure and some foods. Researchers have also found that vitamin D has a major impact on how the body, including the brain, functions.
Cognitive impairment and dementia are significant public health problems, especially with aging, the study notes. Evidence shows that vitamin D plays a role in cognition and the normal functioning of the central nervous system.
More than one in four adults 65 and older fall each year, according to the U.S. Centers for Disease Control and Prevention. The annual U.S. toll includes 29 million falls, 3 million emergency department visits, 800,000 hospitalizations and 28,000 deaths. Falling also leads to more than $31 billion in annual Medicare costs, and the costs will surge unless the problem is recognized and prevention is stressed.
More research is needed to determine whether reaction time is related to rates of falls and injuries in at-risk populations. Examining different doses of vitamin D supplementation and from dietary sources in both men and women of different ages, and people of different races over a longer period, also needs to be studied, Shapses said. Larger studies are needed as well.