If you don't think you need to take a vitamin D supplement every day, a new study just might change your mind.
Researchers from the University of Saskatchewan, Statistics Canada, and the Public Health Agency of Canada report that foods fortified with vitamin D aren't enough to ensure an adequate intake of the “sunshine vitamin,” and that one quarter of Canadians aren't meeting the Recommended Dietary Allowance (RDA).
The study, published May 25, 2011 online in the American Journal of Clinical Nutrition, indicates that 25% of the 5,306 participants (aged six through 79) of the Canadian Health Measures Survey (2007–2009) had blood levels below the RDA of 50 nmol/L. It also found that supplement users had higher blood levels of vitamin D than non-users; more than one third of Canadians not using supplements didn't meet the RDA in winter.
The full text of this study, entitled The vitamin D status of Canadians relative to the 2011 Dietary Reference Intakes: an examination in children and adults with and without supplement use, can be downloaded by clicking here.
The new report adds to findings from a review published last year in Molecular Nutrition & Food Research, which indicated that inadequate levels of vitamin D may be causing about 37,000 premature deaths in Canada and costing the country billions of dollars a year. Scientists from the Sunlight, Nutrition, and Health Research Center (SUNARC) in San Francisco reported that the economic burden would also decrease if vitamin D levels were improved, and would save about $14.4 billion.
Scientific research links vitamin D inadequacy to an increased risk for certain cancers, cardiovascular disease, osteoporosis, and diabetes, and suggests that higher intakes of vitamin D may help reduce the risk of these diseases.
Vitamin D pill a day may improve exercise performance and lower risk of heart disease
2 November 2015
Taking vitamin D supplements can improve exercise performance and lower the risk of heart disease, according to the findings of a preliminary study presented today at the Society for Endocrinology annual conference in Edinburgh.
Vitamin D, which is both a vitamin and a hormone, helps control levels of calcium and phosphate in the blood and is essential for the formation of bones and teeth. Sources of Vitamin D include oily fish and eggs, but it can be difficult to get enough through diet alone. Most people generate vitamin D by exposing their skin to ultraviolet B rays in sunlight.
Previous studies suggest that vitamin D can block the action of enzyme 11-βHSD1, which is needed to make the "stress hormone" cortisol. High levels of cortisol may raise blood pressure by restricting arteries, narrowing blood vessels and stimulating the kidneys to retain water. As Vitamin D may reduce circulating levels of cortisol, it could theoretically improve exercise performance and lower cardiovascular risk factors.
In this study, researchers from Queen Margaret University in Edinburgh gave 13 healthy adults matched by age and weight 50μg of vitamin D per day or a placebo over a period of two weeks.
Adults supplementing with vitamin D had lower blood pressure compared to those given a placebo, as well as having lower levels of the stress hormone cortisol in their urine. A fitness test found that the group taking vitamin D could cycle 6.5km in 20 minutes, compared to just 5km at the start of the experiment. Despite cycling 30% further in the same time, the group taking vitamin D supplements also showed lower signs of physical exertion.
Around ten million people in England may have low vitamin D levels. On average, one in ten adults has low levels of vitamin D in summer, compared to two in five in winter. Because people with darker skin are less efficient at using sunlight to make vitamin D, up to three out of four adults with dark skin are deficient in winter.
"Our pilot study suggests that taking vitamin D supplements can improve fitness levels and lower cardiovascular risk factors such as blood pressure," said Dr Raquel Revuelta Iniesta, co-author of the study. "Our next step is to perform a larger clinical trial for a longer period of time in both healthy individuals and large groups of athletes such as cyclists or long-distance runners."
"Vitamin D deficiency is a silent syndrome linked to insulin resistance, diabetes, rheumatoid arthritis, and a higher risk for certain cancers," said lead author of the study Dr Emad Al-Dujaili. "Our study adds to the body of evidence showing the importance of tackling this widespread problem."
Source: Society for Endocrinology
Elderly women should take more vitamin D supplementation during the wintertime, suggests researchers
Published on November 4, 2015
Osteoporosis is one of the chief reasons why the elderly often suffer
broken bones from relatively minor injuries. Postmenopausal women in
particular experience a relatively rapid loss in bone mass due to a
reduced concentration of oestrogen, which is responsible for strong bone
growth during youth. Maintaining bone mass requires physical exercise
and vitamin D, which is mainly produced in the skin with the help of UVB
radiation. This is why, especially in the wintertime, many elderly
women are prescribed a vitamin D supplement by their doctor to maintain
bone mass.
How much is enough?
Surprisingly, the results of their study have come out clearly in
favour of higher supplement doses. Particularly in the wintertime, much
higher dosages of vitamin D are necessary than previously assumed in
order to maintain bone health. In the study, the researchers come to the
conclusion that a vitamin D concentration of 40 micrograms per litre of
serum in the bloodstream is ideal for slowing or preventing bone
degeneration in postmenopausal women.
Increased calcium absorption
At the same time, the researchers noted that the ratio of calcium-41
to calcium-40 decreased abruptly following the start of the
supplementation regimen - a sure sign that bone degeneration had been
reduced.
Increasing vitamin D supplementation
"Experts are divided as to the ideal daily dose of vitamin D for
maintaining bone mass," says Zimmermann. This study has provided
important new insights with respect to this topic.
In principle the body creates vitamin D in the form of
cholecalciferol within the skin itself. But for this to occur, the body
needs to be exposed to a sufficient amount of sunlight. In the winter
months the sun is too low in the sky beyond the 40th latitude, which
causes the body's natural vitamin D production to be too low. Only a few
food types, such as cod liver oil or saltwater fish, contain larger
quantities of natural vitamin D; smaller quantities can be found in
eggs, meats, milk and butter. Vegetables, nuts and fruits contain only
very little if any vitamin D. Not only is this vital nutrient necessary
for optimum uptake of calcium in the bones, it also controls countless
important cellular and immune processes. One example of severe vitamin D
deficiency is rickets, which causes skeletal deformation.
Read the rest of the article: News-Medical.Net
Vitamin D3 improves heart function
Published on April 4, 2016
A daily dose of vitamin D3 improves heart function in people with chronic heart failure, a five-year University of Leeds research project has found.
This is a significant breakthrough for patients. It is the first evidence that vitamin D3 can improve heart function of people with heart muscle weakness – known as heart failure. These findings could make a significant difference to the care of heart failure patients.
Vitamin D3 can be boosted by exposure to sunlight, but heart failure patients are often deficient in it even during the summer because older people make less vitamin D3 in response to sunlight than younger people. Vitamin D3 production in the skin is also reduced by sunscreen.
In the 80 patients who took Vitamin D3, the heart’s pumping function improved from 26% to 34%. In the others, who took placebo, there was no change in cardiac function.
This means that for some heart disease patients, taking vitamin D3 regularly may lessen the need for them to be fitted with an implantable cardioverter defibrillator (ICD), a device which detects dangerous irregular heart rhythms and can shock the heart to restore a normal rhythm.
Heart failure affects about 900,000 people in the UK and more than 23 million worldwide.
Read the rest of the article: University of Leeds
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