Scientific evidence shows vitamin D may go beyond its traditionally known role in maintaining bone integrity, according to new research presented at the Institute of Food Technologists Annual Meeting and Food Expo® earlier this month. It may play a role in preventing autoimmune diseases such as multiple sclerosis and rheumatoid arthritis, some types of cancer (breast, ovarian, colorectal and prostate).
Advancing technologies to add vitamin D to natural cheese, fruit juice, and other beverages and foods create offerings that provide excellent sources of both vitamin D and calcium which can help consumers achieve dietary adequacy of these largely under-consumed nutrients.
Recent headlines tout vitamin D as the new wonder supplement, with claims ranging from its ability to reduce cancer risk to its link to cognitive function in older men. While studies show connections exist, experts debate the amount of vitamin D necessary for optimal health, however.
“Low vitamin D status is linked to a number of different conditions,” said James C. Fleet, Ph.D. professor in the department of foods and nutrition at Purdue University. “These include certain cancers, muscle weakness and types I and II diabetes—possibly even schizophrenia and multiple sclerosis.”
Muscle weakness in cases of low levels of vitamin D may be explained by muscle's low levels of vitamin D receptors. "Studies with mice show that without vitamin D receptors, cells can't absorb the vitamin," said Dr. Fleet. "Research also shows a correlation between high vitamin D status and improved lower body muscle function in men and women over 60 years old."
Studies also show a decrease in colon cancer with an increase in vitamin D status, and it seems protective against other cancer risks as well. "One theory is that vitamin D may indirectly inhibit pro-cancer pathways," said Fleet. "The question is finding the protective level, which remains under some debate."
Although it remains controversial, 30 nanograms/milliliter (ng/mL) of vitamin D is associated with fewer fractures and falls, according to Karen Hansen, assistant professor of medicine within the rheumatology section at the University of Wisconsin. "Vitamin D deficiency causes osteoporosis by triggering decreased calcium absorption, secondary hyperparathyroidism, increased bone resorption and decreased bone mineral density." Study variables and inconsistencies make further studies necessary. Currently, 700 to 800 International Units (IU) of vitamin D a day seems most effective. Recommendations for an "adequate intake" of vitamin D will likely be increased