Vitamin D: Things to Know Before You Use a Supplement
Vitamin D is easy to get through your diet and sun exposure, which should be utilized before choosing a vitamin D supplement and know if you are experiencing symptoms of vitamin D deficiency. There are many possible symptoms of vitamin D deficiency such as visual problems, bone disease, gum disease, cataracts, rickets in children (softening of bones due to inablility to calcify the bone matrix), joint pain, bone density loss and bone strength. Interestingly, WedMD claims that vitamin D blood tests are "often inaccurate". If supplementation is required to bring vitamin D levels up for bone loss, then supplementation is a good choice (short term) or for individuals who don't get sunlight exposure.
The optimum source to get D3 (cholecalciferol)is exposure to the sun as your body manufactures it with the combination of cholesterol from your body. Other sources are from egg yolks, butter, halibut, cod liver oil, beef liver, cheese, salmon and tuna. Basically, D3 is found in animal sources. D2 (ergocalciferol) is found in vegetable sources like mushrooms grown in UV light and oatmeal (from the plant oils). Shiitake mushrooms grows on oak, chaga is grows on birch trees and there are field mushrooms like morel, meadow and oyster to name a few. Also, a scientific study indicates that vitamin D has anticancer properties against colon and breast cancer.
When you expose your body to sunlight, it changes it to vitamin D and then 7-dehydrocholesterol into D3 which is known as cholecalciferol. It is then absorbed into the blood stream to be transported to the liver and converted into an enzyme called 25-hydroxycholecalciferol that is 5 times stronger than D3 (cholecaliciferol). The kidneys converts it to 1,25-dihydroxycholecalciferol with the help of an enzyme. This is 10 times stronger than D3 (cholecalciferol). Then it continues to promote calcium absorption in bones and resorption. Vitamin D rich foods consumed through the diet goes through the same process, except the change happens in the intestines.
Here's the twist...if you have an impaired liver and/or kidneys, then the conversions won't be even. For example, individuals suffering with osteoporosis usually have high 25-hydroxycholecaliciferol levels and low 1,25-dihydroxycholecalciferol levels. This may be caused by an imbalanced relationship between magnesium and estrogen levels, slugglish liver, kidney disease or many other root causes like low boron or K2 levels. With the diet, the intestines and/or whole digestive system may not be functioning properly which can be a factor in this process. This means that your vitamin D supplement might not be utilized either with a compromised digestive system.
When it is recommended that you should supplement vitamin D until your levels are up to par, I would carefully considered your options. A store shelf D3 can be cost efficient, but the source can be questionable. I personally am not a fan of consuming oil from sheep wool. I don't see it as being natural to my body and I grew up on a farm. Vitamin D3 is usually recommended to raise levels because research shows it is more effective than D2 . Both these vitamins do the same thing with the only difference being how the liver changes them into 25-hydroxycholecaliciferol. Cod liver oil or a mushroom formula would be a better source if you decide to supplement short term, but uping your vitamin D food source is always best.
Murray, Michael T., N.D. Encyclopedia of Nutritional Supplements. Three Rivers Press. New York: New York. 39-43, 1996.
DeLuca HF, "The Vitamin D Story: A collaborative effort of basic science and clinical medicine". FASEB/2, 224-236, 1988.
Lore F, Nuti R, Vattimo A, and Caniggia, "Vitamin D Metabolites in Postmenopausal Osteoporosis". Horm Metabol Res 16, 58, 1984.
Garland CF and Garland FC, "Do Sunlight and Vitamin D Reduce the Likelihood of Colon Cancer?" Int J Epidemiol 9, 227-231, 1978.
Reichel H, Koeffler HP, and Norman AW, "The Role of Vitamin-D Endocrine System in Health and Disease". New Engl J Med 320, 980-981, 1989.
Balch, Phyllis A., CNC. Prescription for Dietary Wellness. Avery. New York: New York, 2003.