Vitamin D recommendations increased, but report says most Americans already reach adequate levels
The report from the Institute of Medicine, noted that over the past 10 years, the public has heard conflicting messages about other benefits of nutrients, especially vitamin D, and how much calcium and vitamin D is needed to be healthy.
The report says there is good evidence to indicate that calcium and vita­min D play important roles in bone health. But, it notes that current evidence does not support other benefits for vitamin D or calcium intake.
“The committee emphasizes that, with a few exceptions, all North Americans are receiving enough calcium and vita­min D. Higher levels have not been shown to confer greater benefits, and in fact, they have been linked to other health problems, challenging the concept that ‘more is better’,” concluded the authors, led by committee chair Catharine Ross, Professor of Nutrition at Pennsylvania State University.
Prof Ross and co workers said the updated dietary reference intakes (DRIs) “are intended to serve as a guide for good nutrition and provide the basis for the development of nutrient guidelines.”
The report found that most Americans and Canadians “need no more than 600 international units (IUs) of vitamin D per day to maintain health”, but added that people aged over 71 may need an increased level of up to 800 IUs, because of potential physical and behavioral changes related to aging.
According to the research, evidence for the role of calcium in bone health shows that for virtually all adults aged between 19 and 50 1,000 milligrams will cover daily calcium needs, however women aged over 51 and everyone aged over 71 require no higher than 1,200 milligrams per day.
In addition, the tolerable upper intake level was doubled from 2,000 to 4,000 IU/day for adults.
Douglas MacKay, vice president of scientific and regulatory affairs at the Council for Responsible Nutrition (CRN), told NutraIngredients-USA.com that the increasing RDI levels were “a step in the right direction” for vitamin D. However he added that vitamin D status is very often an individual story, in which some people will need take far higher doses than others due to their lifestyles and situations.
Vitamin D role
The researchers said that the reports findings and the new intake levels were formed on the basis of a large amount of evidence, which confirmed the roles of calcium and vitamin D in promoting skeletal growth and maintenance, and the amounts needed to avoid poor bone health.
However they pointed that the report also reviewed hundreds of studies on the possible health effects of vitamin D, such as protection against cancer, heart disease, autoimmune diseases, and diabetes. Indicating that although the studies suggest possibilities that warrant further investigation, they have yielded conflicting and mixed results, and so do not currently offer the evidence needed to confirm that vitamin D has such health benefits.
Prof. Ross and colleagues said higher amounts of food fortification, coupled with the rising rates of supplement use have increased the chances that people consume high amounts of nutrients.
Too much calcium from dietary supplements has been associated with kidney stones, whilst excessive vitamin D has been linked with kidney and heart damage, according to the report.
“While it is too early to make definitive statements about the risks associated with routine high doses of vitamin D and calcium, people don't need more than the amounts established in this report,” said Ross.
“Past cases such as hormone replacement therapy and high doses of beta carotene remind us that some therapies that seemed to show promise for treating or preventing health problems ultimately did not work out and even caused harm. This is why it is appropriate to approach emerging evidence about an intervention cautiously, but with an open mind,” she concluded.
Andrew Shao, senior vice president, scientific and regulatory affairs, CRN, said an increase in vitamin D recommendation will benefit the public overall, but added that “such a conservative increase for the nutrient lags behind the mountain of research demonstrating a need for vitamin D intake at levels possibly as high as 2,000 IU/day for adults”
The Institute of Medicine report “Dietary Reference Intakes for Calcium and Vitamin D” can be found HERE