Vitamin D Not All It’s Cracked Up to Be

vitamin DA study released Friday by The Lancet Diabetes & Endocrinology shows vitamin D is not all it’s cracked up to be. This comes on the heels of various studies on vitamins released in December, proving vitamins are not worth the money spent on them if consumers are generally healthy.

Healthy levels of vitamin D contribute to effective absorption of calcium and phosphorus in the bones. This is why getting sufficient calcium in the diet is imperative for good health, which vitamin D helps to promote. Vitamin D is fairly easy to obtain if one gets enough sun during the day and eats fatty fish (salmon, mackerel, tuna) and fortified foods such as milk, cereals and orange juice. Granted, it’s easier to fulfill calcium intake requirements but enough foods are fortified with vitamin D that sufficient intake is not too difficult to fulfill on a daily basis.

The vitamin D study, led by Dr. Mark Bolland of the University of Auckland in New Zealand, is based on results gleaned from 40 randomized controlled studies on health effects of vitamins, but hones in on specific benefits of vitamin D and its effect on heart disease or heart attack, stroke, cancer and bone health. The population studied were healthy and hospitalized patients, and the study results point to vitamin D not being all it’s cracked up to be.

What Dr. Bolland and his team learned is that vitamin D supplementation in healthy people reap nearly no benefit from the vitamin, which does not prevent chronic disease. And neither does it affect mortality in health people. Low levels of vitamin D can lead to cardiovascular disease, cognitive impairment, asthma in children and cancer, but the study cannot determine cause and effect, Dr. Bolland says. Those with low levels of vitamin D tend to be older, obese and do not get enough sunlight. If these people took vitamin D to improve their health, the results would be negligible. Prior studies show that  low vitamin D levels lead to poor health and early mortality but taking the vitamin to prevent this is not proven to be of benefit, at least not more than 15 percent, which is the baseline Dr. Bolland and his team used. Simply put, it is of little benefit to take vitamin D to prevent chronic illness or disease.

Other studies on vitamin D have yielded results similar to Bolland’s, especially a study out of Lyon, France, in which vitamin D insufficiency was deemed the result of poor health, not the cause.

The upside to Bolland’s study is that institutionalized patients (those who live in nursing and care homes) do benefit from ingesting vitamin D, as it reduces bone fractures. A recent study (boosted by the support of the U.S. National Institutes of Health) of over 36,000 post-menopausal women who took vitamin D with calcium supplements saw a reduction in the risk of hip fractures. Elderly people reportedly decrease their risk of falling by taking vitamin D, and people at risk for osteoporosis will benefit from the vitamin.

Michael Holick, a professor of medicine at Boston University and advocate of vitamin D, disagrees with Bolland’s findings, saying that the studies on which Bolland based his study gave participants too low doses of vitamin D, about 200 to 400 international units (IU) per day. Holick says he believes a higher dose, such as 2,000 IU currently being administered in a major U.S. trial, would yield benefit. The vitamin D promoter also points out that Bolland neglects to explain the connection between low vitamin D levels in persons with chronic diseases (such as MS and colon cancer) and living in areas with little sun exposure.

Every year, people spend $20 billion on vitamins and $600 million on vitamin D supplements. For healthy people, this is likely a waste of money. The Bolland study, and various others, demonstrate that vitamin D is not all it’s cracked up to be.

By Juana Poareo 


Medical News Today

USA Today

Bloomberg Businessweek

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