Vitamin D — Why It's So Important

A lot of people know that vitamin D allows the body to use calcium for maintaining strong bones. But it’s more than just a supplemental supplement: vitamin D is necessary for proper muscle, nerve, and immune function—and inadequate levels have been linked to osteoporosis, heart disease, hypertension, and multiple cancers. “Everyone can benefit from vitamin D supplementation, especially vegetarians,” says Dr. Moses Goldberg, ND (docmoses.com), of the Naturopathic Wellness Center in Santa Rosa, Calif.

Power Source 
Vitamin D is obtainable through diet and direct exposure to sunlight, but there are inherent difficulties. The short list of sources includes cod liver oil, fatty fish, eggs, and vitamin D–fortified milks, juices, and cereals. Meanwhile, the amount of vitamin D obtained from sunlight may be reduced by age, the accumulation of toxins in the liver and kidneys (where vitamin D is activated), dark skin (or those with fair skin who use sunscreen), shorter winter days, or living north of the southernmost U.S. states.

Use It Right 
“There are two forms of vitamin D to choose from: ergocalciferol (D2) and cholecalciferol (D3),” explains Goldberg. “D2 is synthesized by plants, while D3—the more active, bioavailable form—is synthesized by the skin after UVB-ray exposure. Supplements and fortified foods may contain either D2 or D3.” The recommended dietary allowance for vitamin D is 600 international units for adults and 800 IU for seniors; take it with a fatty food to improve absorption. Higher intakes are frequently recommended for health maintenance and specific conditions; consult your practitioner on dosage and if you should be taking calcium as well.

Watch Out For
The National Institutes of Health has set a tolerable upper limit for vitamin D at 4,000 IU daily; excess intake may be marked by thirst, poor appetite, stomach upset, or fatigue. Interactions have occurred with Lipitor, Prednisone, Lanoxin, calcium channel blockers, anti-seizure medications, and long-term use of antacids.

TWO TO TRY:
Bluebonnet Vitamin D3
$20/180 1,000-IU vegetarian capsules;
bluebonnetnutrition.com

Pure Encapsulations Vitamin D3
$20/120 1,000-IU vegetarian capsules;
pureencapsulations.com

Los Angeles—based David Kalmansohn has a long history of covering issues of mind, body, and spirit. He is the former executive editor of Natural Health and the former deputy editor of Men’s Fitness.