Nutrition expert comments on new vitamin D recommendations
WEST LAFAYETTE, Ind. - Even though the new recommendations for vitamin D increased three-fold, not everyone is going to feel that is enough, says a Purdue University foods and nutrition expert.
James C. Fleet
"The interest in vitamin D has been historically linked to bone health, but new research suggests this nutrient may do other things like prevent cancer and diabetes as well as reduce blood pressure," said James C. Fleet, a professor of foods and nutrition who studies how vitamin D controls calcium metabolism as well as its role in colon and prostate cancer prevention. "There is a consensus among most experts that many people have low serum of vitamin D levels, an indicator of vitamin D status, but there is disagreement on how high those levels need to be and how much is needed to raise vitamin D to a healthy level.
"Some believe that vitamin D has incredible benefits and the recommended amount should be even higher than the new recommendation. However, research does not yet mirror those beliefs, so there is more work to be done."
The dietary reference intake guidelines, which were released Tuesday (Nov. 30), are evidence-based recommendations for healthy people that are provided separately for men and women and are broken up into different age groups. For example, the recommendation for men and women ages 14-70 increased from 200 international units to 600 international units, which are the common measurement for vitamins. The recommended vitamin D intake is lower for some groups - 400 international units for infants to 13 years old - and higher for others - 800 international units for adults over the age of 71.
The previous recommendations were set in 1997 by the Food and Nutrition Board of the National Academy of Science's Institute of Medicine. The new recommendations will serve as the federal guidelines for many nutrition programs, including the food stamp program; school lunch program; and the Woman, Infants and Children program, also known as WIC.
Vitamin D, also known as cholecalciferol, is key to bone health because it helps transport calcium and phosphorous through the gut. Calcium is essential to preserving bone strength, and phosphorous also is important to bone health as well as cell strength and energy production.
Sunlight can stimulate your skin to make a lot of vitamin D, but sun exposure also has been linked to skin cancer. It also is difficult to recommend a specific level of sunlight because people's ability to make vitamin D in skin varies depending on individual skin tones and factors such as how much sunscreen a person uses. The amount of vitamin D produced in the skin also is lower in the winter, especially if someone lives in the northern part of the United States.
"For most people, and assuming they live somewhere there is ample sunlight, it really doesn't take much sun to make adequate levels of vitamin D," Fleet said. "However, that said, the dermatology community believes that there is no such thing as safe sun, so people need to get vitamin D from supplements or their diet."
Vitamin D is found in a few foods naturally, such as salmon, sardines, eggs and shrimp. And it also is fortified, which means added, to milk, breakfast cereals and orange juice.
"While these foods provide vitamin D, people do not typically consume enough of them daily to meet the requirement," Fleet said. "Most multivitamin supplements are made to provide 50 to 100 percent of the requirement, so you can easily fill any dietary vitamin D gaps with one."
Four thousand international units of vitamin D is considered the upper safe limit that anyone 9 years or older should take daily. The previous maximum recommended level was 2,000 international units. Fleet said people who want to take more vitamin D than the requirement should consult with their doctor.
"Several groups need to especially pay attention to their vitamin D levels," Fleet said. "For example, people with dark skin or those who cover up can't make vitamin D in their skin. Also, we lose the ability to make vitamin D in the skin as we age. At the same time, older adults' bones are becoming weaker, especially for postmenopausal women, so it is critical that vitamin D is consumed adequately to preserve bone health."
Writer: Amy Patterson Neubert, 765-494-9723, apatterson@purdue.edu
Source: James C. Fleet, 765-494-0302, fleet@purdue.edu
Related videos:
What is Vitamin D? https://www.youtube.com/watch?v=zQcsoWTAxHo
Are You Getting Enough Vitamin D? https://www.youtube.com/watch?v=YXgqC-mYQMc
Where Can I Get Vitamin D? https://www.youtube.com/watch?v=YXgqC-mYQMc