Vitamin D3 is the biologically active form of vitamin D, a fat-soluble vitamin that is essential to human health. Vitamin D may be obtained through a healthy diet, as well as sun exposure.
This is one extremely underrated supplement, and given that it's so cheap, nearly everyone should take 2000IU-5000IU extra and benefit. Look at your multivitamin to make sure you're not already getting a lot of it before supplementing higher dosages.
According to the National Institutes of Health, even though direct sunlight is an important source of vitamin D, "it is prudent to limit exposure of skin to sunlight in order to lower the risk for skin cancer. When out in the sun for more than a few minutes, wear protective clothing and apply sunscreen with an SPF (sun protection factor) of 8 or more. Tanning beds also cause the skin to make vitamin D, but pose similar risks for skin cancer."[9, 10]
What if you're not getting enough vitamin D? Should you be concerned? Today, vitamin D deficiency is identified as a pandemic.
Vitamin D deficiency increases your risk for:
- Several bone diseases
- Muscle weakness
- More than a dozen types of cancers
- Multiple sclerosis
- Type 1 diabetes mellitus
Suboptimal levels of vitamin D could result in lower testosterone levels. A 2010 study published in the journal Clinical Endocrinology, found that men with sufficient vitamin D levels — 25(OH)D — had significantly higher levels of testosterone and significantly lower levels of sex hormone binding-globulin (SHBG), compared to men who had insufficient levels of the vitamin.
Testosterone is important for:
In recent years, experts have advocated for raising the RDA for vitamin D.
- Optimal libido/sexual function
- Enhanced muscle mass
- Greater body composition
- Increased quality of life
- Decrease cardiovascular disease risk
Sufficient vitamin D levels may also reduce your chances of developing different types of cancers. A 2008 study performed at the University of Maine at Orono indicates that an increasing body of research supports the idea that the active form of vitamin D has "significant, protective effects against the development of cancer." Further, studies show an inverse association between sun exposure, vitamin D intake and serum levels, and risk of developing and/or surviving cancer."
With all of this positive news about vitamin D and what it can do to optimize your health, researchers are still conducting research to identify optimal daily vitamin D supplementation amounts. Currently, the recommended daily allowance (RDA) for vitamin D is 600 IU, or international units.
Vitamin D plays a fundamental role in bone health. According to noted vitamin D expert, Dr. Michael Holick,"Vitamin D deficiency is an unrecognized epidemic among both children and adults in the United States. Vitamin D deficiency not only causes rickets among children but also precipitates and exacerbates osteoporosis among adults and causes the painful bone disease osteomalacia."
In an earlier study, published in the Journal of Nutrition, Holick explains that "Vitamin D insufficiency and vitamin D deficiency is now being recognized as a major cause of metabolic bone disease in the elderly." Even at that time, experts understood that deficiency was responsible for causing osteomalacia and worsens osteoporosis.
To maintain bone health, Holick suggests increasing calcium intake to 1000mg to 1500mg per day, coupled with an adequate source of 400 IU/ vitamin D.
Are you getting enough
Your doctor can perform a simple blood test that evaluates your vitamin D blood serum levels: 25-hydroxyvitamin D, or 25(OH)D.
If you reside in a sunny climate, you're more likely to have higher vitamin D levels compared to those who live in areas that get less sunlight. That's why it's important to have your levels checked annually, especially if you live in northern states, or Canada.
In recent years, experts have advocated for raising the RDA for vitamin D. Starting in 2010, some in the medical community began talking about the country's collective vitamin D deficiency, and calling for officially raising RDA for all age groups. But not all organizations agreed. While the Institute of Medicine called for upping intake from 400 IU per day to 600 IU per day, the Vitamin D Council suggested an even higher RDA: 1,000 IU for infants and kids and 5,000 IU for adults.
|Age||Vitamin D Council||Food and Nutrition Board|
|Infants||1,000 IU/day||400 IU/day|
|Kids and Teens||1,000 IU/day per 25 lbs of body weight||600 IU/day|
|Adults||5,000 IU/day||600 IU/day, 800 IU/day for seniors|
In addition to upping the RDA for vitamin D, many organization suggested raising the upper tolerable limit as well, from 2,000 IU per day to 4,000 IU. These changes were made in the belief that previous dietary reference intake amounts were insufficient.
Current vitamin D requirements are being evaluated:
"The current vitamin D requirements in the United States are based on protection against bone diseases. These guidelines are being revised upward in light of new findings, especially for soft tissue health. The consensus of scientific understanding appears to be that vitamin D deficiency is reached for serum 25-hydroxyvitamin D levels less than 20ng/mL, insufficiency in the range from 20ng/mL to 32ng/mL, and sufficiency in the range from 33ng/mL to 80ng/mL, with normal in sunny regions range from 54ng/mL to 90ng/mL."
A main function of vitamin D is to increase the absorption of calcium from the intestine. Calcium is a mineral that promotes bone health, regulates blood clotting, and signals muscles to contract.
Vitamin D is generally regarded as very safe. Most people will not get to toxic levels, specifically those who get their vitamin D from food sources and sunlight. Taking mega-doses of the nutrient, however, can lead to toxicity.
The first sign is nausea and vomiting, and then excess urination and thirst. Daytime fatigue is another symptom of vitamin D overload.
Taking too much vitamin D over time can result in dangerously low blood pressure and blood sugar levels, which could cause complications for people with diabetes or hypoglycemia.
The biggest risks are for those who are already diagnosed with diseases, such as hyperparathyroidism, sarcoidosis, tuberculosis, and/or kidney disease. As always, speak to your doctor before beginning any diet or supplementation program.
Foods rich in vitamin D include fatty fish, eggs, cheese, and milk. One of the easiest ways of getting your RDA is through direct sunlight. It takes roughly 15 minutes in the sun for your skin to synthesize the nutrient. According to the Vitamin D Council, "How much vitamin D is produced from sunlight depends on the time of day, where you live in the world and the color of your skin. The more skin you expose the more vitamin D is produced." Note that your body will create the vitamin very rapidly, "around half the time it takes for your skin to turn pink and begin to burn," according to the Council
It's very important to understand that exposure to sunlight carries a significant risk for developing a dangerous melanoma. If you have a family history of skin cancer, the safest way to get vitamin D is through supplementation or food sources.
Best vitamin D supplement
We're big fans of NOW Foods. They have a massive selection, and provide high quality vitamin D supplements at low prices — exactly what we look for here on PricePlow!
Where to buy
At PricePlow, we do the hard work for you and are constantly on the lookout for the best deals.
When you buy online, you save between 30% and 50% off retail prices. That might not be too much with Vitamin D since it's so cheap -- but it definitely adds up when looking at other products on this site, such as more costly staples, like protein products and multivitamins.
- Christakos S; Molecular and Cellular Endocrinology; "Vitamin D and intestinal calcium absorption;" December 2011
- Grant WB, Holick MF; Alternative Medicine Review; "Benefits and requirements of vitamin D for optimal health: a review;" June 2005
- University of California, Riverside; "History of Vitamin D;" Updated November 2011
- Holick MF, Chen TC; American Journal of Clinical Nutrition; "Vitamin D deficiency: a worldwide problem with health consequences;" April 2008
- Ingraham BA, et. al.; Current Medical Research and Opinion; "Molecular basis of the potential of vitamin D to prevent cancer;" January 2008
- Holick MF; American Journal of Clinical Nutrition; "Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease;" December 2004
- Holick MF; Journal of Nutrition; "Vitamin D and Bone Health;" April 1996
- Bassil N, et. al.; Therapeutics and Clinical Risk Management; "The benefits and risks of testosterone replacement therapy: a review;" June 2009
- Vitamin D. June 2011
- The Office of Dietary Supplements; Vitamin D;" Reviewed June 2011
- Wehr E, et. al.; Clinical Endocrinology; "Association of vitamin D status with serum androgen levels in men;" August 2010
- Mayo Clinic, "Vitamin D;" Updated November 2013
- Vitamin D Council; "How do I get the vitamin D my body needs?"
- National Osteoporosis Foundation; "Calcium and Vitamin D: What You Need to Know"
- Joel Fuhrman, M.D.; Huffington Post; "How Much Vitamin D? Why Many Experts Take Issue With The IOM's New Recommendations;" December 2010
- Dr. Fuhrman: How to Live for Life; "Vitamin D recommendations have been raised, but not enough"