Scientific Update

The Institute of Medicine recently issued new guidelines for intakes of calcium, vitamin D, and other nutrients involved in bone health. This report recommends intake levels for those in the U.S. and Canada. These recommendations take the place of the Recommended Dietary Allowances (RDAs) which were last updated in 1989.

The most dramatic changes in recommendations were in calcium, as shown in the sidebar. As this table shows, the new calcium recommendations are lower for infants and toddlers, higher for children and teens from 9-18 years, lower for young adults, and higher for those 25 years and older. Recommendations are also higher in teen pregnancy and breastfeeding, lower for older pregnant and breastfeeding women. The recommendations for calcium are higher beginning at age 9 because early adolescence is an important time for bone development. Higher calcium intakes for older adults are recommended in order to reduce the risk of osteoporosis.

The report does address other factors, including exercise and intakes of other nutrients which affect bone health. The authors of this report did not believe there was a need to adjust calcium intake recommendations based on the amount of protein in the diet, nor did they think there was a need for different calcium recommendations for vegetarians. Vegan sources of calcium identified in this report include calcium-fortified juice (what about soymilk?), Chinese cabbage, kale, and broccoli.

In addition to calcium needs, the report also recommends slightly higher intakes of magnesium for most age groups, little change in fluoride intakes, lower levels of phosphorus, and a marked increase in vitamin D intake for older adults (51 to 70 years) and for those age 70 and older. Magnesium is found in green leafy vegetables, unrefined grains, and nuts; so it is not difficult for most vegetarians to meet the newest recommendations. The levels of vitamin D which are recommended were chosen to provide enough vitamin D even for those who spend no time in the sun. Vegetarian sources of vitamin D include fortified foods (some soy and rice beverages, some cereals, and cow's milk). The new recommendations for vitamin D call for 5 micrograms (200 IU) daily for those 50 years and younger and for pregnant and breastfeeding women, 10 micrograms (400 IU) daily for those 51 through 70 years, and 15 micrograms (600 IU) daily for those over 70.

These recommendations are also different because they are designed to reflect intakes which will lead to optimal health. The old RDAs were developed to identify the lowest level of a nutrient which would protect most of the population from developing a deficiency. The new recommendations also establish an upper limit for nutrients. This upper limit is the maximum amount of a nutrient which is unlikely to pose a health risk for most people. It is not a level to strive to achieve.

The RDAs are being revised in seven stages. Reports will focus on folate and other B vitamins, antioxidants, macronutrients (protein, fat, carbohydrates), trace elements (iron, zinc, etc.), electrolytes and water, and other food components (like fiber and phytoestrogens). The entire project is scheduled to be completed in 2000.

According to the Food and Drug Administration's Office of Food Labeling, the changes that have been made to these nutrient recommendations will not affect food labels in the foreseeable future. The Daily Value (a labeling term that reflects current nutritional recommendations) assigned to calcium on food labels, for instance, is 1,000 milligrams per day for a 2,000 calorie reference diet. Food labels give the percent of the Daily Value met by one serving of the food.

Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Food and Nutrition Board, Institute of Medicine. 1997. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, DC: National Academy Press.

Comparison of old and new recommendations for calcium

The new guidelines have different age groupings. Values listed are in milligrams per day.