Vitamin D is known as the sunshine vitamin because we get much of our vitamin D from the sun. Over the last two decades, studies have found that the level of vitamin D has dropped dramatically in Americans, which is probably because we have been told to stay out of the sun or use sunscreen and our diets have become worse. Vitamin D might be the most important vitamin for good health.
The Two Types of Vitamin D
There are two types of vitamin D, one is D2 (ergocalciferol) and the other is D3 (cholecalciferol). Vitamin D3 is the best for us to take. When you look at multivitamins or supplements, look for vitamin D3. The label should say D3 and or cholecalciferol.
A good multivitamin should have 700-800 IU of D3. Vitamin D is a fat-soluble vitamin, when you take it you need to also have something with fat in it, a spoonful of peanut butter for example.
Vitamin D Studies
There is new enthusiasm with vitamin D studies showing that it does boost the immune system and fight off viral infections such as the flu and at the same time tempers the immune system from overworking, which can create more mucus and fluid in the lungs causing further problems such as pneumonia.
Michael Holick, a professor of medicine, physiology, and biophysics at Boston University School of Medicine said, “What vitamin D really does is play a sentinel role”.
What that means is vitamin D is used by the immune system to fight infection and it also tempers the immune response and limits inflammation.
Researches from the Harvard Medical School did a study between 1988 and 1994 with 19,000 people between 12 years of age and older, with an average age of 39, and found a link between low levels of vitamin D and upper respiratory infections.
Vitamin D signals the intestines to absorb calcium. With low levels of vitamin D, the body will break down bones to get the calcium it needs.
Without enough vitamin D, the body cannot absorb enough calcium to satisfy the body’s need for calcium, no matter how much calcium you consume in food or supplements.
A link has also been found between low levels of vitamin D and certain cancers. New studies have shown that vitamin D could be protective against colon, prostate, breast and other cancers.
There is also evidence that vitamin D could play a role in the prevention and treatment of diabetes type I and type II, hypertension, glucose intolerance, multiple sclerosis, some autoimmune diseases, schizophrenia, and other medical conditions.
Two small studies have suggested that vitamin D3 supplements provided benefits in people with active tuberculosis. In 2007, an analysis of 18 different randomized studies found that vitamin D supplementation might even help people live longer.
Researchers at the University of Pennsylvania have found that vitamin D may slow the decline in the ability to breath in people with Asthma and COPD.
The researchers believe that by slowing this progressive decline, they can prevent or delay the irreversible decline in breathing that leaves many asthmatics even more vulnerable when they suffer an asthma attack.
Since there aren’t that many foods with much vitamin D, the sun is then our only source for getting vitamin D. We have been told to stay out of the sun or use sunscreen, and sunscreen does an effective job of blocking the vitamin D.
During the fall and winter months, we don’t get much if any vitamin D from the sun, and most of us don’t even get 400 IU from our diet since there just aren’t enough foods with vitamin D in them.
To get just the minimal RDA required 400 IU per day, you would have to drink 1 quart of milk or eat 5 ounces of salmon or a 6-ounce can of tuna. Milk doesn’t have any vitamin D in it naturally; it is fortified with it in the US.
Many are recommending that the amount of Vitamin D3 should be increased to 2,000 IU (50 mcg) in the fall and winter for healthy adults and 1,000 IU for adolescents. The foods with the most vitamin D are cod liver oil, oily fish and fortified milk.
If you eat a plant-based or vegan diet, you can also get vegan vitamin D supplements.
Vitamin D Protects Against Bone Fractures
A recent study concerning how calcium, dairy products or vitamin D was associated with bone fractures in adolescent girls aged 9-15 was published.
The study had the mothers of 6,712 girls fill out a food frequency questionnaire every 12-24 months between 1996 and 2001 with a 7-year follow up period.
The conclusion of the study found that taking vitamin D was associated with lower stress fractures in adolescent girls who participated in high impact sports and activities. Calcium and dairy products were not found to protect against stress factors [1].
Vitamin D Keeps the Flu Away
A new study reported in the American Journal of Clinical Nutrition found that vitamin D3 can keep children from getting the flu.
A randomized double-blind placebo-controlled study with 167 children found that those who took vitamin D3 got the flu less than those who didn’t take the vitamin D3. [2]
A Supplement Worth Taking
To sum this up, here is an impressive quote from the NIH report “A recent meta-analysis found that use of vitamin D supplements was associated with a reduction in overall mortality from any cause by a statistically significant 7%”.
The studies linking low levels of vitamin D and illnesses make this supplement worth taking. Getting at least 700 IU in the summer in a multivitamin should be fine.
Drugs That Reduce Calcium and Vitamin D
Certain medications can affect the body’s ability to absorb calcium and vitamin D properly. If you take any medications and want to take a vitamin D supplement, you should ask your doctor if there are any problems.
Steroids: Corticosteroid medications such as prednisone can reduce calcium absorption and impair vitamin D metabolism.
The weight loss drug Orlistat (brand names Xenical® and alli™) and the cholesterol-lowering drug cholestyramine (brand names Questran®, LoCholest®, and Prevalite®) can reduce the absorption of vitamins D and other fat-soluble vitamins.
Both phenobarbital and phenytoin (brand name Dilantin®), used to prevent and control epileptic seizures, increase the hepatic metabolism of vitamin D to inactive compounds and reduce calcium absorption
2018 Vitamin D Study Update
In 2010, a new study called the VITAL study followed healthy, racially diverse group of 25,871 American men age 50 and older and women age 55 and older for up to six years.
The purpose of this study was to find out whether more vitamin D was needed. Patients were randomly assigned supplements with a daily dose of 2,000 IUs (international units), while others received a placebo.
The results of this study was released in November 2018. The results found that vitamin D did not significantly affect the odds of having a heart attack or a stroke or developing cancer (for example, breast, prostate, or colorectal cancers).
On a positive note, the study found that after two years of taking D, participants who developed cancer had a 25 percent reduced risk of dying from the disease.
The study confirmed that taking 2,000 IUs per day was safe and well tolerated.
Drug Interactions
Vitamin D supplements can interact with several medicines such as heart medications and drugs for high blood pressure.
Make sure you talk to your doctor if you take any medication before taking a vitamin D supplement.
About the Author
Sam Montana is a certified Food Over Medicine instructor from the Wellness Forum Health Center and certified in optimal nutrition from the Harvard T.H. Chan School of Public Health.
© 2009-2019 Sam Montana
