Commonly tagged “the sunshine vitamin,” vitamin D plays a key role in promoting healthy bones, since it helps your body absorb calcium. A vitamin D deficiency, particularly in your older years, can lead to osteoporosis (bone weakening) or osteomalacia (bone softening). New research also indicates that low levels of vitamin D can lead to an increased risk of type 1 diabetes, muscle and bone pain, heart disease, and, perhaps, cancers of the breast, colon, prostate, ovaries, esophagus, and lymphatic system.
Your body makes vitamin D by itself–but only if your skin is exposed to sufficient sunlight. During the winter when the temperatures drop, people tend to stay inside more often and bundle up when going out. Thus your body is most likely not getting enough sunlight to generate the vitamin D it needs.
How Much Vitamin D is Enough?
Unless you live in Southern California or the deep South and spend a fair amount of time outside in the winter, you’ll most likely need to get your quota of vitamin D from foods or supplements. But first, you need to understand how much vitamin D you’ll need.
If you get virtually no vitamin D from sunshine during the winter— and you get adequate amounts of calcium–the Institute of Medicine (IOM) recommends getting the following amounts of vitamin D from diet or supplements:
- Infants age 0 to 6 months: adequate intake, 400 IU/day; maximum safe upper level of intake, 1,000 IU/day
- Infants age 6 to 12 months: adequate intake, 400 IU/day; maximum safe upper level of intake, 1,500 IU/day
- Age 1-3 years: adequate intake, 600 IU/day; maximum safe upper level of intake, 2,500 IU/day
- Age 4-8 years: adequate intake, 600 IU/day; maximum safe upper level of intake, 3,000 IU/day
- Age 9-70: adequate intake, 600 IU/day; maximum safe upper level of intake, 4,000 IU/day
- Age 71+ years: adequate intake, 800 IU/day; maximum safe upper level of intake, 4,000 IU/day
The IOM’s recommendations are conservative and some experts in the medical community believe the minimum amounts should be raised. But there’s one thing most everyone agrees on, if you’re considering taking more vitamin D than the IOM committee recommends, check first with your physician.
Getting Vitamin D from Food and Supplements
Many foods do not contain natural vitamin D but there are three foods that are especially good sources:
- Salmon
- Mackerel
- Mushrooms exposed to ultraviolet light to increase vitamin D
Other food sources of vitamin D include:
- Cod liver oil (warning: too much may be bad for you)
- Tuna canned in water
- Sardines canned in oil
- Milk or yogurt fortified with vitamin D
- Beef or calf liver
- Egg yolks
- Cheese
When it comes to supplements, the recommended form of vitamin D is vitamin D3 or cholecalciferol, which is the form of vitamin D that your body makes from sunlight. Supplements are made from the fat of lambs’ wool.
Some studies also suggest the vitamin D2 or calciferol works just as well. Many supplements contain vitamin D2, which is derived from irradiated fungus. Just remember, Vitamin D2, however, is not the type made by your body.
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