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Vitamin D is naturally produced within the body when the precursor cholesterol, found within the skin, is exposed to sunlight. It may be more difficult to obtain adequate exposure to sunlight during the fall and winter months, however, leaving many to search for vitamin D supplements to promote their health. It is important when buying vitamin D to determine whether a vitamin D supplement contains vitamin D2 or vitamin D3, as each form reacts differently in the body and only one form is close to the natural source of vitamin D required by the body. Vitamin D serves an important function in regulating blood sugar metabolism and calcium absorption, and is a vitamin required by the body every day.
Supplements marketed with the label vitamin D may contain either the form D2 or D3. Vitamin D2 is synthesized by plants and plays a very small role in promoting human health. The form in which humans synthesize from sunlight is called vitamin D3. This is the closest natural form of vitamin D required by the body. When buying vitamin D, it is important to read the label to determine which form of vitamin D is used.
Buying vitamin D capsules is fairly easy, as these forms of supplements are readily available in drug stores and Internet supplement warehouses. Vitamin D capsules are usually small, gel-like capsules which make swallowing them easier for people who have trouble taking pills. Most vitamin D supplements contain 1,000 international units of vitamin D. The recommended units for an average adult is 5,000 units a day from some sources, to adequately supply the body with its full range of health benefits.
Liquid vitamin D may be much easier to swallow for some individuals. When buying vitamin D in liquid form, it is important to also see the amount of vitamin D per serving, as it is very easy to overdose on liquid vitamin. The upper limit for vitamin D is recommended at 10,000 international units per day, and anything beyond this point may lead to vitamin D toxicity. Symptoms of vitamin D toxicity include dehydration, decreased appetite and constipation.
Following 30 minutes of sun exposure, the human body usually makes the upper limit for vitamin D, or 10,000 international units. Sun exposure throughout the day is a natural vitamin D source which is free to use and doesn't require having to remember to take supplements every day. Another natural source of vitamin D is herring, a type of fish which contains 1,383 international units per 3 ounce serving. It is usually preferable to use natural sources of vitamin D throughout the spring and summer months over buying vitamin D supplements as it is thought to be better absorbed by the body.
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