Recommended Dietary Allowances (RDAs)

For many years the National Research Council of the United States National Academy of Sciences has taken responsibility for establishing guidelines on what quantities of the various nutrients should be eaten by human males and females at various ages. However, on August 13, 1997, the Institute of Medicine of the National Academy published a report that:

set new standards for calcium intake (as well as for Vitamin D, fluoride, magnesium, and phosphorus)
dropped the name RDA in favor of Dietary Reference Intakes (DRIs)
added three new categories:
- adequate intake ("AI"), where no RDA has been established
- estimated safe and adequate daily dietary intake ("ESADDI"), expected to satisfy the needs of 50% of the people in that age group)
- tolerable upper intake levels ("UL"), to caution against excess intake of nutrients - like vitamin D - that can be harmful in large amounts.

While we wait for their complete findings, here is a table of RDAs for men and women between the ages of 19 and 22 with the new calcium recommendation shown in red (the old value was 800). (After the menopause, women who do not take estrogen supplements should increase their intake of calcium to 1200 mg/day.)

	Females	Males		Females	Males
Protein	44 g	56 g	Pantothenic acid	4-7 mg	same
Vitamin A	800µg*	1000 µg*	Biotin	100-200 µg	same
Vitamin D	7.5 µg*	same	Calcium	1000 mg	same
Vitamin E	8 mg	10 mg	Phosphorus	700 mg	same
Vitamin C	60 mg	same	Magnesium	255 mg	same
Thiamine	1.1 mg	1.5 mg	Iron	15 mg	10 mg
Riboflavin	1.3 mg	1.7 mg	Zinc	12 mg	same
Niacin	14 mg	19 mg	Iodine	150 µg	same
Vitamin B₆	2 mg	2.2 mg	Fluoride	3.1 mg	same
Folacin	400 µg	same	Selenium	55 µg	same
Vitamin B₁₂	3 µg	same	Potassium	2 g	same

*to the extent that the vitamin A requirement is met by ingested beta-carotene, the amount should be multiplied by 6.
*7.5 µg = 300 IU ("International Units").

Some nutritionists think that the allowances for vitamins C, D, and E are too low.

A study published in April 1996 suggests that 200 mg of Vitamin C per day is probably optimal. This is more than three times higher than the current RDA, but far lower than the 1,000 or more mg/day that some people take in the hope of warding off colds, cancer, etc.
The National Institute of Medicine has now established the following AIs for vitamin D:
- 200 IU for adults from age 20 to 50
- 400 IU for those between 50 and 70
- 600 IU for those over 70 years of age
However, a study reported in the 19 March 1998 issue of The New England Journal of Medicine indicates that perhaps all adults should receive 800 - 1000 IU (20 to 25 µg) of vitamin D per day.

There is also evidence that beta-carotene has important functions besides being the precursor of vitamin A and therefore should be ingested in amounts greater than needed to meet the vitamin A requirement.

Welcome&Next Search

8 October 1999