A recent study examined the vitamin D status of 3,262 Chinese people between 50 and 70 and found that 69% were deficient and 24% insufficient with their levels of 25-hydroxyvitamin D (25OHD). Researchers found that 42% of Chinese subjects with low 25OHD had the Metabolic Syndrome (MetS), which is associated with insulin resistance and increased risk of developing type 2 diabetes mellitus and cardiovascular disease.1 People in the lowest quintile of 25OHD in their blood were 52% more likely to have the MetS than the 20% with the most 25OHD. Only 6% of these older Chinese people had an adequate level of vitamin D in their tissues. These low levels of 25OHD are similar to what is seen in England and the U.S.A., where most older adults are known to have low or deficient stores of 25OHD. According to Dr. Franco, the lead researcher of this study: "Vitamin D deficiency is now recognized as a worldwide concern and metabolic syndrome has become a global epidemic."
Another study of more than 3,000 European men ages 40 to 79, found those with lower 25OHD levels in their blood did worse on a task designed to test mental ability. The results were published in the May 2009 Journal Neurology Neurosurgery and Psychiatry. This adds to growing research linking inadequate vitamin D status with an increased risk of senility.
Vitamin D and its active metabolite 1,25di-OH D is a steroid hormone. A review of the literature found that low levels of vitamin D appear to reduce athletic performance. Dr. Cannell's review noted that randomized controlled trials in mostly older adults show that vitamin D supplements increase muscles. Fewer fast twitch muscle fibers appear to result from inadequate vitamin D status.2
Americans should be encouraged to spend a little time in the sun several days a week. Those who live in northern states should be encouraged to take a supplement of vitamin D3 during the fall and winter months.
By James J. Kenney, PhD, RD, FACN
1. Diabetes Care doi:10.2337/dc09-0209
2. Med Sci Sports Exerc 2009;41:1102-1110
Judy’s passion for cooking began with helping her grandmother make raisin oatmeal for breakfast. From there she earned her first food service job at 15, was accepted to the world famous Culinary Institute of America at 18 (where she graduated second in her class), and went on to the Fachschule Richemont in Switzerland where she focused on pastry arts and baking. But after learning that the quality of a croissant directly varies with how much butter it has, Judy sought to challenge herself by coming up with recipes that were as healthy as they were tasty.
Judy received The Culinary Institute of America’s Pro Chef II certification, the American Culinary Federation Bronze Medal, Gold Medal, and ACF Chef of the Year. Her enthusiasm for eating nutritiously and deliciously leads her to constantly innovate and use the latest in nutritional science to guide her creativity, from putting new twists on fajitas to adapting Italian brownies to include ingredients like toasted nuts and cooked honey. Judy’s publishing company, Food and Health Communications, is dedicated to her vision that everyone can make food that tastes as good as it is for you.