The following is a sample of recommended dietary
allowances (RDA) for certain vitamins and minerals, and upper limits as
recommended by RDA is as follows:
- Vitamin A: RDA - 900 micrograms for men, 700 for women.
Found in carrots and other dark-colored vegetables and fruits. Upper limit -
- Vitamin B12: RDA - 2.4 micrograms, the amount in 3
ounces of beef. Many people over 50 lose the ability to absorb B12 from
natural food sources and so should consider fortified foods, like cereals, or
- Vitamin C: RDA - 75 milligrams for women, 90 for men.
Eight ounces of orange juice yields a day's supply. Smokers need 35 more
milligrams. Upper limit - 2,000 milligrams; more can cause diarrhea.
- Vitamin D: RDA - 200 international units for most
people; 400 IUs for people ages 51 to 70. Found in fortified milk.
- Vitamin E: RDA - 15 milligrams. Upper limit - 1,000
milligrams; higher levels risk uncontrolled bleeding.
- Folic Acid: RDA - 400 micrograms. Found in spinach,
orange juice, and fortified foods. Because folic acid in the first days of
pregnancy prevents certain birth defects, women of childbearing age are
routinely advised to take a supplement. Upper limit - 1 milligram a day; more
can cause nerve damage.
- Calcium: RDA for most adults - 1,000 milligrams daily;
for teen-agers - 1,300 milligrams; for those over age 50 - 1,200 milligrams.
Highest food sources are dairy and calcium-fortified orange juice.
- Vitamin K: RDA - 120 micrograms for men, 90 for women.
Found in green leafy vegetables.
- Iron: RDA - 8 milligrams for men and
postmenopausal women. Premenopausal women need 18 milligrams; pregnant women
27 milligrams. Upper limit - 45 milligrams or stomach upset can occur.
- Zinc: RDA - 11 milligrams for men, 8 for women. Upper
limit - 40 milligrams; more can block absorption of another vital nutrient,
The intake for anti-aging purposes is much higher. RDA
level is good to prevent disease such as scurvy or rickets. To reverse a current
diseased condition or to optimize your health requires much more according to
anti-aging researchers. The RDA for vitamin C is only 75 mg for women, but most
in anti-aging experts are taking 500 mg or more. Many are taking from 3 grams to
10 grams a day. The noted two-time Nobel Laureate Dr. Linus Pauling took 18
grams a day. He died at the age of 94 and contributed the last 12 years of his
life to vitamin C supplementation.