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Posted on Dec 30, 2005, 8 p.m.
By Bill Freeman
GENERAL DESCRIPTION: Vitamin D is derived from sunshine (manufactured through the skin), fish liver oils such as cod liver oil, liver, and egg yolks. Margarine and cereals are often fortified with vitamin D. It is unlikely that food alone will provide sufficient vitamin D, thus, several sources recommend trying to obtain 5-15 minutes of exposure to sunshine each day.
GENERAL DESCRIPTION:
Vitamin D is derived from sunshine (manufactured through the skin), fish liver oils such as cod liver oil, liver, and egg yolks. Margarine and cereals are often fortified with vitamin D. It is unlikely that food alone will provide sufficient vitamin D, thus, several sources recommend trying to obtain 5-15 minutes of exposure to sunshine each day!
ROLE IN ANTI-AGING:
Vitamin D enhances the absorption of calcium from the intestine and the utilization of calcium and phosphorus in the body, thus, ensuring that calcium and phosphorus levels are high enough to support the constant breakdown and rebuilding of bone tissue. It is therefore essential for strong and healthy bones. Vitamin D is also necessary for the proper functioning of the thyroid and pituitary glands. It is used to improve psoriasis and maintenance of cell membrane fluidity. Both animal and human studies suggest that vitamin D may protect people from multiple sclerosis, autoimmune arthritis, and type I diabetes. Recent studies suggest that vitamin D may also protect against breast, colon, and prostate cancers. Results of a study published in 2002 suggest that vitamin D may also protect against heart disease. Results of the study by researchers at the University of California San Francisco revealed that women over the age of 65 who regularly took vitamin D were nearly one-third less likely to die from heart disease, compared with women who did not take the vitamin.
DEFICIENCY SYMPTOMS:
Osteomalacia (softening of the bones) in adults, rickets in children, irritability, restlessness, fitful sleeping, frequent crying, heavy perspiration behind the neck in babies, delayed ruption of teeth, soft and yielding skull, bowed legs, knock knees, depressions in the chest, pigeon-chest deformity of the rib cage, swayback, overly prominent forehead causing the appearance of sunken eyes, delayed walking.
THERAPEUTIC DAILY AMOUNT:
400-800 I.U. from fish liver oil. The RDA for vitamin D is 200 I.U. a day for men and women aged 19 to 50, 400 I.U. for those aged 51 to 70, and 600 I.U. for people aged 71 and over. The European RDA is 5mcg.
MAXIMUM SAFE LEVEL:
10mcg (long-term); 50mcg (short-term). A daily intake (both from fortified food and supplements) of more than 1,000 I.U. of vitamin D is not advisable. Regular consumption of vitamin D at doses greater than 1,000 IU day may cause high blood pressure, premature hardening of the arteries, deterioration of bone, calcium build-up in muscles and soft tissues, and kidney damage.
SIDE EFFECTS/CONTRAINDICATIONS:
Pregnant or breast-feeding women should limit their vitamin D intake to no more than 800 IU a day as higher doses have been linked to birth abnormalities. Vitamin D supplements should not be used by people taking antacids containing magnesium and thiazide diuretics, such as hydrochlorothiazide.
SOLUBILITY:
Fat soluble
