Most adults need no more than 600 IU of vitamin D per day to maintain health, and those aged 71 years and older may need as much as 800 IU, according to a report from the Institute of Medicine.
The daily recommendations of calcium are based on age and range from 700 mg to 1,300 mg, according to the report.
“There is abundant science to confidently state how much vitamin D and calcium people need,” Institute of Medicine (IOM) committee chair Catharine Ross, PhD, stated in a press release. “We scrutinized the evidence, looking for indications of beneficial effects at all levels of intake. Amounts higher than those specified in this report are not necessary to maintain bone health.”
The recommended 600 IU of vitamin D per day meets the needs for nearly all American and Canadian adults. However, those older than 70 years may require up to 800 IU per day because of potential physical and behavioral changes related to aging, according to the statement.
The committee concluded that daily calcium of 700 mg is sufficient for children aged 1 to 3 years; 1,000 mg is sufficient for children aged 4 to 8 years; and no more than 1,300 mg is sufficient for adolescents aged 9 to 18 years. For adults aged 19 to 71 years, 1,000 mg is sufficient to meet daily calcium needs. Women aged 51 years and older and men older than 71 years need no more than 1,200 mg per day.
Although the committee said most Americans and Canadians receive sufficient vitamin D and calcium, some adolescent girls may not get enough calcium, and there is a greater chance that the elderly may fall short of the necessary amounts of calcium and vitamin D. It is recommended that they increase their intake of foods containing calcium and vitamin D or take a supplement.
Upper levels of intake
Upper intake levels represent the upper safe boundary and should not be misunderstood as amounts people need or should strive to consume, the committee said.
“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,” Ross, a professor and Dorothy Foehr Huck Chair of the department of nutritional sciences at Pennsylvania State University, stated in the release. “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.”
The measurements of sufficiency and deficiency that clinical laboratories use to report test results have not been based on rigorous scientific studies and are not standardized, the committee stated. This lack of standardization may result in an overestimation of the number of people with vitamin D deficiency because many labs appear to use cut points that are higher than the evidence indicates as appropriate.
Basis for recommendations
Because of conflicting messages about the benefits of calcium and vitamin D, the U.S. and Canadian governments asked the IOM to assess the current data on health outcomes associated with the two nutrients.
The new dietary reference intakes are based on more information and higher-quality study results than were available when the intakes for these nutrients were first set in 1997. At that time, limitations in the evidence resulted in take levels called “adequate intakes,” which are rougher estimates of people’s requirements than the new values.
The recommendations in the report take into account nearly 1,000 published articles, as well as testimony from scientists and stakeholders. A large amount of evidence, which formed the basis of the new intake values, confirms the roles of calcium and vitamin D in promoting skeletal health and maintenance and the amounts needed to avoid poor bone health. The committee also reviewed hundreds of studies and reports on other possible health effects of vitamin D, such as protection against diabetes, cancer, heart disease and autoimmune diseases.
These new guidelines are conservative. My advice for adults, which is congruent with that of many vitamin D scientists, is a vitamin D dose of 2,000 IU to 4,000 IU per day. A lifetime intake of this safe and ideal dose would prevent borderline vitamin D deficiency, reduce many diseases, increase the longevity and quality of life, and diminish medical care costs worldwide.
— Anthony W. Norman, MD
Distinguished Professor of Biochemistry and Biomedical Sciences,
University of California, Riverside