You need vitamin D to absorb calcium, fortify your immune system and for proper cell growth and function. Vitamin D, however, is naturally found in very few foods -- mostly fatty fish -- but it is typically made when sunlight hits your skin. If you cannot get enough vitamin D outside, supplementing with D3 is your best bet. Talk to your doctor before taking vitamin D, as too much can be harmful.
Types of Vitamin D
The two types of vitamin D that can be used by humans are D2 and D3. D2, or ergocalciferol, is synthesized by plants and fungus while D3, also called cholecalciferol, is made by animals and humans when sunlight hits the skin. These types of vitamin D are both used in supplements as well as in fortifying foods and beverages. However, vitamin D3 is believed more potent than D2, providing better support for your dietary needs.
D2 Vs. D3
A study published in the "Journal of Clinical Endocrinology & Metabolism" in November 2004 investigated the effects of D2 versus D3 over a period 28 days. Results found that vitamin D2 had less than 1/3 the effectiveness of D3 -- participants who took D3 saw peak effectiveness at 14 days while at day 14 D2 participants vitamin D levels dropped back to baseline. The study concluded that D3 is more potent and physicians recommending D2 should be aware of its lower level of efficacy.
Sunlight
The surest way to obtain enough vitamin D to prevent deficiency is to get outside in the sun a few times per week. According to MayoClinic.com, exposing your skin to sunlight for approximately 10 minutes gives you an adequate daily supply of vitamin D. Those with dark skin and the elderly have less ability to synthesize the vitamin in sunlight. Also, if you are prone to sunburn, you likely use sunblock to protect yourself from harmful rays -- sunblock effectively stops UVB rays from hitting your skin, interrupting vitamin D production. Living at a certain latitude or in a specific area can also decrease your chances of seeing the sun. In any of these cases, supplementation may be beneficial.
Supplementation Recommendations
Talk to your doctor before taking additional vitamin D -- too much can result in bone loss and kidney stones. The Linus Pauling Institute recommends up to 600 IU of vitamin D per day for children and adults, even if you are pregnant or breastfeeding. Infants under the age of one only need 400 IU per day while adults over 71 should take 800 IU.
Member Comments