Dear Dr. Roach: I am a 68-year-old woman who takes calcium supplements daily. Almost all calcium supplements today contain vitamin D. Since I spend two to four hours every day in the sun, Iím concerned I might be getting too much of the vitamin. Do I need to find a calcium supplement withoout vitamin D?
Dear B.W.: According to your letter, you live in Florida, so you get sun exposure year-round. Sunlight makes a vitamin D precursor in the skin into the vitamin. The liver and kidney tweak the skin-produced vitamin into other forms that are the active material.
People your age make 75 percent less vitamin D from the sunís transformation of the skin precursor than younger people. It isnít a matter of lack of sun exposure, which is a factor in vitamin D deficiency for people in Northern climates. Itís a matter of age-related production. One of the worldís most respected investigators of vitamin D said, ďThere has never been a case of vitamin D intoxication from sun exposure.Ē
Add all the vitamin D contained in your calcium supplements. If it comes to less than 1,000 IU a day, you have no worries. The upper limit for vitamin D intake is 2,000 IU.
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