Very few foods naturally contain vitamin D, which promotes your body's absorption of calcium. Vitamin D also plays a part in protecting against osteoporosis, controlling cell growth and supporting immune system function. If you are taking vitamin D supplements, foods high in vitamin A may block or reduce your body's absorption of vitamin D. Consult your doctor before making significant dietary changes.
Orange and Yellow Vegetables
Orange and yellow vegetables containing large quantities of vitamin A can block vitamin D absorption. Sweet potatoes and butternut squash are rich sources of vitamin A, with several times the recommended daily allowance, RDA, contained in a 100 g serving. Powdered plant-based spices including paprika and cayenne pepper powders contain significant quantities of vitamin A. Carrots, however, provide the vitamin A precursor beta carotene, which does not block vitamin D absorption.
Fruits
Apricots, mangoes, papaya and cantaloupe contain significant quantities of vitamin A; thus, when taking vitamin D supplements, avoid excessive consumption of these fruits. Dried apricots contain almost a full day's intake of vitamin A in a single cup, at 4,685 International Units, IU. Cantaloupe provides more than 100 percent of the RDA for vitamin A in a cup of melon balls. It is easy to consume more than the RDA of vitamin A with a relatively small portion of these fruits.
Strategies
If you are taking a vitamin D supplement, you can reduce the vitamin-blocking effects of vitamin A with careful scheduling. If you commonly eat cantaloupe at breakfast, for example, consider taking your vitamin D supplement at night so the cantaloupe is not in your digestive system at the same time as your supplement. Also consider that laxatives or foods with a laxative effect could reduce your ability to absorb vitamin D from supplements.
Vitamin D Dosage and Sources
Your need for vitamin D increases throughout life. The RDA for an infant is 400 IU and increases to 600 IU for ages 14 to 70. Over 70, the RDA for vitamin D is 800 IU. Food sources of vitamin D include oily fish such as mackerel, tuna and salmon. Fish liver oils are commonly used as a dietary supplement for vitamin D. Cheese and egg yolks also contain vitamin D. For vegetarians and vegans, non-fish vitamin D supplements and fortified orange juice may be important sources of vitamin D.
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