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How much vitamin D is enough?

Published:Wednesday | June 13, 2012 | 12:00 AM

Charlyn Fargo, Contributor

Most of us know we need vitamin D, but new research finds that too much vitamin D can be as unhealthy as not enough. Researchers at the University of Copenhagen looked at blood samples from 247,574 Copenhageners. The results have just been published in the reputed scientific Journal of Clinical Endocrinology and Metabolism.

Vitamin D is a steroid vitamin, a group of fat-soluble prohormones that encourages the absorption and metabolism of calcium and phosphorous. People who are exposed to normal quantities of sunlight do not need vitamin D supplements because sunlight promotes sufficient vitamin D synthesis in the skin. Vitamin D is instrumental in helping calcium reach our bones, thus lessening the risk from falls and the risk of broken hips.

Combats cardiac disease

Research suggests that vitamin D is also beneficial in combating cardiac disease, depression and certain types of cancers. The results from a study conducted by the Faculty of Health and Medical Sciences now support the benefits of vitamin D in terms of mortality risk. However, the research results also show higher mortality in people with too high levels of vitamin D in their bloodstream.

"We have had access to blood tests from a quarter of a million Copenhageners. We found higher mortality in people with a low level of vitamin D in their blood, but to our surprise, we also found it in people with a high level of vitamin D. We can draw a graph showing that perhaps it is harmful with too little and too much vitamin D," said Darshana Durup, researcher.

The bottom line is that you can get too much of a good thing. As with all foods and nutrition, moderation is the key.

- Information courtesy of Medical News Today and the Journal of Clinical Endocrinology and Metabolism.

Charlyn Fargo is a registered dietitian at Creators Syndicate; website at

Vinegar and blood sugar level

Q: Does vinegar reduce the rise in blood sugar following a meal? If so, would that be a good way to help control insulin levels, too?

A: In a few studies, when vinegar was consumed with a test meal of potatoes or rice porridge, blood sugars did not go up as high immediately following the test meal as without it.

However, these were very small studies and did not test the effect of a carbohydrate-containing food eaten as part of a regular meal. In normal circumstances, the dietary fibre found in whole grains, vegetables, fruits and beans that are part of the meal slows the digestion and absorption of carbohydrate, and thus leads to a slower blood sugar rise.

The best ways to avoid large blood sugar rises after a meal are to choose these healthy sources of carbohydrate and choose appropriate portions. Taking a walk after a meal is another good way to reduce blood sugar elevations; activity stimulates muscles' ability to take up sugar from the bloodstream in the short term. Of course, it is also essential to continue medication to control your blood sugar if your doctor has prescribed it.

- Information courtesy of the American Institute for Cancer Research.