Some health problems can make it hard for a person's body to absorb these vitamins. If you have a chronic health condition, ask your doctor about whether your vitamin absorption will be affected.
How Much Vitamin D Is Enough?
The National Institutes of Health recommend that men and women ages 19 to 50 consume a minimum of 200 IU (or 5 mcg) of vitamin D each day. People ages 51 and over should consume at least 400 IU (or 10 mcg) of vitamin D daily. The need for vitamin D increases with age because your bodyâ€™s ability to convert sunlight to vitamin D decreases.
You should always eat foods or supplements rich in vitamin D with foods rich in calcium for better absorption. When you are exposed to the sunâ€™s rays, your body converts a cholesterol compound in the skin to vitamin D, so aim for three 15-minute sessions of sun exposure a week.
Sources of Vitamin D
- Fortified milk
- Fortified cereals
- Fish-liver oils
- Sun exposure
Can You Have Too Much or Too Little?
Too little vitamin D in the diet can lead to weakened bones and an increased risk of fractures.
Overconsuming vitamin D can cause nausea, vomiting, poor appetite, constipation, weakness and weight loss. Calcinosis, the deposition of calcium and phosphate in soft tissues like the kidney, can be caused by vitamin D toxicity.
Antacids, some cholesterol lowering drugs, mineral oil, some anti-seizure medications, and steroids interfere with the absorption of vitamin D.
If you want to get the most vitamins possible from your food, refrigerate fresh produce, and keep milk and grains away from strong light. Vitamins are easily destroyed and washed out during food preparation and storage. If you take vitamin supplements, store them at room temperature in a dry place that's free of moisture.