Contrary to some earlier findings, most Americans and Canadians are getting enough vitamin D and calcium, according to a new report from the Institute of Medicine.
The report updates the institute's recommendations for daily intake of these two nutrients, and was written by an expert committee using information from more than 1,000 published studies.
The committee concluded that people between the ages of 1 and 70 need no more than 600 international units (IU) of vitamin D per day, while those over 70 could need up to 800 IUs.
When it comes to calcium, people need between 700 milligrams and 1,300 milligrams per day depending on their age. [Related Infographic: See a complete table of the recommendations for people of all ages.]
Based on the committee's analysis, the number of people in North America declared to have vitamin D deficiency has been overestimated. The error stems in part from the fact that there is no standard for determining whether someone is deficient. In fact, a person might be told they have deficient or sufficient levels depending on the laboratory that conducts their blood test, the researchers said.
And while studies based on dietary intake show the majority of North Americans don't get enough vitamin D from the food they eat, other findings reveal that most people do have sufficient vitamin D in their blood. The missing piece of the puzzle is the sun — sunlight triggers the production of vitamin D from other compounds in the body. The report indicates that for many individuals, the sun is an important contributor to a person's overall vitamin D levels.
However, the report found that girls between the ages of 9 and 18 were at risk of not getting enough calcium, and the elderly miss the mark for both vitamin D and calcium recommendations. People in these groups may need to increase their vitamin D and calcium intake through foods, or possibly a supplement, the researchers said.
The recommendations are made mainly with bone health in mind, the committee said. Although mounting studies have shown vitamin D has a host of health benefits, including protection against diabetes, heart disease and cancer, the committee said the evidence was inconsistent and inconclusive. More studies are needed to determine whether these nutrients have any other health advantages.
How much is too much?
The committee also weighed in on the upper limits for vitamin D and calcium intake. Getting too much calcium could put people at risk for kidney stones, and too much vitamin D could damage the heart and kidneys and may increase the risk of death, the researchers said.
As food producers increase the amount of these nutrients in their products, and people more frequently turn to supplements, there is a greater likelihood that people will take in high doses of vitamin D and calcium.
The researchers emphasized the upper limits are not something people should strive to achieve. The vitamin D limit for people over age 8 is 4,000 IUs. For calcium, those from 19 through 50 should limit their intake to 2,500 milligrams daily, and those 51 and older should limit their intake to 2,000 milligrams daily, the committee said.
The new recommendations come in three forms — the Estimated Average Requirement (EAR), which is the level at which 50 percent of the population's nutrition requirements are met; the Recommended Dietary Allowance (RDA), which is the level that will cover 97.5 percent of the population's nutrition needs, and the upper level intake.
The EAR is useful for evaluating the intake of large groups of people, such as setting the standard for nutrition in school lunches. The RDA is more appropriate for individuals to consider, and might be what a doctor recommends to his or her patient.
There is not enough evidence available to make EAR or RDA recommendations for children younger than a year, said Dr. Steven Abrams, a professor of pediatrics at the Baylor College of Medicine, who was a member of the committee. As a result, the committee provided only a rough estimate of recommendations for this age group, known as Adequate Intakes. It is recommended infants younger than a year get 400 IU per day of vitamin D and 200 to 260 milligrams per day of calcium, depending on their age, Abrams said.
The IOM advises breastfed babies should be given vitamin D supplements, as breast milk does not contain adequate levels of vitamin D, Abrams told MyHealthNewsDaily. On the other hand, it does contain sufficient levels of calcium.
The study was sponsored by the U.S. Department of Health and Human Services, U.S. Department of Agriculture, U.S. Department of Defense, and Health Canada.
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