Have you had your vitamin D today?
Federal guidelines call for 200 international units (IU) for people under age 50 and 400 IU per day for people age 51 to 70.
A 3.5-ounce piece of salmon and a glass of fortified milk satisfy the requirement. You can also stand in the sun, without sunscreen, for 20 minutes three times each week.
But some scientists say indoor living, sunscreen and poor diet habits have left many - up to 75 percent of us - lacking in this essential nutrient.
When Dr. Mehmet Oz began promoting on television 1,000 IU of vitamin D per day to ward off high blood pressure, osteoporosis, diabetes, heart disease and cancer, supplement sales rose.
"Most everybody needs vitamin D," said Phyllis McKaig, a saleswoman at Nutrition World in East Brainerd. The store's staff advise customers to take a vitamin D blood test before taking the supplements, she added.
Dr. Suzan House, a rheumatologist with Arthritis Associates in Hixson, said she recommends up to 2,000 IU per day. She treats fibromyalgia and osteoporosis patients with verified vitamin D deficiency with up to 50,000 IU twice a month until vitamin D returns to normal levels.
"It's extremely hard to overdose on vitamin D," Dr. House said.
Sue Gouge, a family medicine physician at Collegedale Medical Center, has boosted her recommendation to 400 to 800 IU.
"There's a lot of good ideas and some excitement, but the studies aren't there yet to show us what indeed it does do," Dr. Gouge said.
Erlanger East family practice physician James Newby called for caution. Years ago, estrogen was hailed as a cure-all for menopause symptoms, bone loss and heart disease. When tested, women began dying more often of heart disease.
Vitamin D may not follow this path, but studies still have not directly shown its ability to prevent cancer or heart disease without side effects, experts say. Benefits of vitamin D may come from another cause. Scientists do not yet know for sure.
* Vitamin D helps build strong bones and reduce inflammation. Vertebrates, plants and fungus produce it in their bodies when exposed to sunlight.
* Vitamin D supplements are made of cod liver oil or extracted from either the lanolin found in sheep's wool or from a fungus.
* Vitamin D sources include: 15-20 minutes of sunshine (10,000-20,000 IU), 1 tablespoon cod liver oil (1,360), multivitamin (400), 3.5 ounces canned salmon 360), 3 ounces canned tuna (200), 1 cup fortified milk (98), 1 cup fortified cereal (40), 1 egg yolk (20).
- U.S. National Institutes