Dietary Allowances

Recommended Dietary Allowances

The Recommended Dietary Allowances (RDA) are designed to prevent deficiency diseases in most healthy people. But deficiency diseases such as scurvy and beriberi are not the problems of the civilized world. These are the RDAs, as set forth by the Food and Nutrition Board of the National Research Council.


Vitamin A (& beta-carotene)* 5000/4000 IU
Vitamin C 60 mg
Vitamin D 200 IU
Vitamin E* 15/12 IU
Vitamin K* 80/60 mcg
Thiamin (B1)* 1.5/1.1 mg
Riboflavin (B2)* 1.7/1.3 mg
Niacin (& niacinamide; B3)* 19/15 mg
Pyridoxine (B6)* 2.0/1.6 mg
Folate (folic acid)* 0.2/0.18 mg
Cobalamin (B12) 2 mcg
Biotin* 0.3 mg
Pantothenic acid (B5)* 4/7 mg
Calcium 800 mg
Iron* 10/15 mg
Phosphorus 800 mg
Iodine 150 mcg
Magnesium* 350/280 mg
Zinc 15 mg
Copper 1.5-3 mg
Sodium 500 mg
Potassium 2000 mg
Selenium* 70/55 mcg


*Second value is for women.

Daily Values

On food and supplement labels, you will see nutrients listed as “Percent Daily Value,” or the relative amount of that nutrient in a portion of food, compared to another standard of dietary needs. This “DV” amount is different from the RDA.


Vitamin A (& beta-carotene) 5000 IU
Vitamin C 60 mg
Vitamin D 400 IU
Vitamin E 30 IU
Thiamin (B1) 1.5 mg
Riboflavin (B2) 1.7 mg
Niacin (& niacinamide; B3) 20 mg
Pyridoxine (B6) 2.0 mg
Folate (folic acid) 0.4 mg
Cobalamin (B12) 6.0 mcg
Biotin 0.3 mg
Pantothenic acid (B5) 10 mg
Calcium 1000 mg
Iron 18 mg
Phosphorus 1000 mg
Iodine 150 mcg
Magnesium 400 mcg
Zinc 15 mg
Copper 2 mg
Sodium 2500 mg
Potassium 4000 mg


There are no Daily Values for other nutrients, such as vitamin K, manganese, selenium and chromium, but this does not mean they are unimportant.

Healthy Dietary Allowances

My own recommendations of minimums for basic health are clearly different from the RDA levels and the Daily Values. They reflect both food sources and extra nutrients derived from dietary supplements.

For basic preventive medicine, free-radical protection, and health enhancement I recommend:


Vitamin A (& beta-carotene) 25,000 IU
Vitamin C 4,000 mg
Vitamin D 400 IU
Vitamin E 400 IU
Thiamin (B1) 100 mg
Riboflavin (B2) 50 mg
Niacin (& niacinamide; B3) 150 mg
Pyridoxine (B6) 100 mg
Folate (folic acid) 5,000 mcg
Cobalamin (B12) 100 mcg
Biotin 0.3 mg
Pantothenic acid (B5) 100 mg
Calcium 500 mg
Iron 18 mg
Phosphorus 1,000 mg
Iodine 150 mcg
Magnesium 500 mg
Zinc 30 mg
Copper 3 mg
Sodium 1,000 mg
Potassium 4,000 mg


Notice that my recommended level for sodium is lower than the DV. It is more a reflection of need than the DV, since excess sodium is unhealthy. The DV is based, in part, on what people are actually getting from food, rather than what is ideal for health. Since consumption of salt is usually so high (5000-13,000 mg daily!), the DV is actually above what you really need.

My recommendation for calcium is also lower than the RDA. This is predicated on your eating a healthier diet than the one common in the United States and many other industrialized countries. If you eat too much protein (especially animal protein), caffeine, sugar, salt, and sodas, then you will very likely need more calcium. You may also need more calcium if you lead a sedentary lifestyle, although more dietary calcium is no substitute for weight-bearing exercise, such as walking or jogging, if maintaining bone density is one of your goals. If you have adequate mag-nesium nutrition, it is probably quite safe to take extra calcium.

Older standards suggested getting twice as much calcium as magnesium. This was based on the ratio of the two minerals in the blood, and does not necessarily reflect dietary needs. Variations in absorption, utilization, and the physiology of the two minerals make the blood levels unreliable figures for determining dietary needs.

Magnesium deficiencies are quite common, marginal deficiencies are difficult to detect, and long-term consequences of low magnesium intake are quite serious. They include neurologic, heart and kidney diseases. For these reasons I recommend at least as much magnesium as calcium. High calcium intake also increases the need for magnesium.

A healthy diet naturally contains a lot of potassium. However, people taking certain diuretics or those eating a large amount of salt may need potassium supplements.

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Avatar Written by Michael Janson MD

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