We are told to be cautious of the sun and its effects on our skin. Rightly so - UVA and UVB rays are dangerous, esepcially down here in South Florida! But because most Americans spend a good amount of the year indoors and the rest covered with sunscreen, there is a big deficiency in Vitamin D which is leading to many health problems in our country.
Here it why it’s so important:
• Needed for calcium absorption
• Helps maintain bones and teeth (reduces the incidence of fractured bones)
• Prevents rickets and osteoporosis by assisting in the absorption of calcium; promotes bone mineralization
• Assists in immune function, cell growth, and fetal development
• Regulates insulin secretion and metabolism, both which affect energy levels
• Protects from hypertension, psoriasis, and several autoimmune diseases
(including multiple sclerosis and rheumatoid arthritis)
• Shown to reduce risks of cancer (studies link a deficiency of vitamin D to as many as 18 different cancers!)
Vitamin D is actually a fat-soluble hormone that the body can synthesize naturally. There are several forms, including two that are important to humans: D2 and D3. Vitamin D2 (ergocalciferol) is synthesized by plants, and vitamin D3 (cholecalciferol) is synthesized by humans when skin is exposed to ultraviolet-B (UVB) rays from sunlight. The active form of the vitamin is calcitriol, synthesized from either D2 or D3 in the kidneys. Vitamin D helps to maintain normal blood levels of calcium and phosphorus.
How much should I get and how? According to Dr. Weil, adults need 2,000 IU of vitamin D per day. Look for supplements that provide D3 (cholecalciferol) rather than D2 (ergocalciferol). It's the most potent form. Anyone with vitamin D deficiencies should discuss intake levels with his or her physician. Also, get out in the sun for at least 15 minutes per day when possible without sunscreen! After that, please put some on to prevent skin cancer - all we need is 15 minutes to start the synthesis of this vitamin in our systems. It’s also found in fatty fish, cod liver oil, and egg yolks.
Sources and Additional Reading:
Institute for Integrative Nutrition, August 2011.
Weil, Andrew. "8 Weeks to Optimal Health", 1995.