by Kirsten Falcone, RN
The Sunshine Vitamin:
Benefits of Vitamin D
As the medical world makes discoveries, often what we think we’ve learned flies out the window. An example that quickly comes to mind is the discussion regarding the amount of coffee to drink, or how much red wine is a good thing. Should you get a suntan or stay in the shade? Is avoiding fat in your diet always a good thing? What about sodium? It seems the experts are always changing their minds. However, some recent findings have added to the knowledge about vitamin D, and you may find them thought-provoking.
What is vitamin D, and why do we need it? Your body needs vitamin D, a “fat-soluble” vitamin, to function properly. Fat-soluble vitamins need dietary fat in order to be absorbed into the body, and they are also stored in fatty tissues for future use. There are two kinds of vitamin D—vitamin D2 (found in food) and vitamin D3 (photosynthesized in the skin), but, for the sake of this article, we will refer to both simply as vitamin D. Vitamin D is most well-known for helping your body absorb calcium and thereby keeping bones strong and healthy, but vitamin D also:
- Recently was shown to lower the risk of respiratory infections.
- Increases muscle strength.
- Helps prevent certain types of cancer.
- Plays a role in type 1 and 2 diabetes prevention.
- May be helpful with some forms of arthritis.
- Defends against aggressive breast cancer.
- Lessens the symptoms of depression.
- Helps protect against multiple sclerosis and its symptoms.
- Protects against age-related bone loss.
- May protect against cardiovascular disease.
- Possibly contributes to successful weight loss in obese patients.
How is vitamin D acquired? Vitamin D can be acquired in three ways. One way is by exposing our skin to the ultraviolet rays of the sun. This sets off a chain reaction involving skin cholesterol, the liver and the kidneys, until converting into a compound the body can use. This compound assists the electrolyte calcium in strengthening bones. The second way the body acquires vitamin D is in food. Supplements are the third way, and they should be used as a last resort (see below).
Here are some tips for acquiring vitamin D:
- When outdoors, apply sunscreen after about 20 minutes (longer for darker skin), so enough of the ultraviolet rays can be absorbed. (Vitamin D deficiency is higher in black Americans, according to a 2012 CDC report, estimated at 31 percent.)
- Expose yourself to the sun when it is highest in the sky, between the hours of 9:00 a.m. and 3:00 p.m. (Be careful to avoid sunburn, by putting on sunscreen after 20 minutes or more, depending on your skin pigmentation.)
- Live closer to the equator. People in the northern half of the United States, and anywhere north of 40 degrees latitude are less likely to be exposed to enough ultraviolet light. (The 40 degree latitude line can be drawn horizontally across approximately the center of the United States.)
- Eat foods, such as salmon, swordfish, mackerel, tuna, sardines, egg yolk, beef liver, mushrooms, and fortified foods, such as cereal, orange juice and milk.
- The recommended daily allowance (RDA) for vitamin D is 600 International Units (IU) for people up to 70 years of age, and 800 IU for those older than 71.
- Vitamin D is considered a fat-soluble vitamin, which simply means it can be stored in your body for when you need it. You cannot overdose on vitamin D synthesized from sunlight or from food, but it is possible to overdose on supplements. Symptoms of a vitamin D overdose are weakness, mental confusion, diarrhea, vomiting, loss of appetite, and calcium deposit formations in tissues such as the liver, kidneys and heart.
- Be aware that tattoos that cover a large amount of skin are capable of blocking the production of vitamin D. Tattoos also make it uncomfortable to sit in the full sun because they heat up faster than the surrounding skin, causing itchiness. Therefore, having a tattoo is contraindicated for people who wish to sunbathe or acquire vitamin D in this manner.
- Blood tests for vitamin D are available through your doctor.
Widely known diseases caused by vitamin D deficiency are rickets, osteomalacia, and osteoporosis. Rickets can be found in children whose bones form improperly, due to lack of vitamin D. With osteomalacia, bones are weak, cause pain, and are more susceptible to fractures. In cases of osteoporosis, the bones become more porous and break easily.
We have been told that we should always wear sunscreen, and that fat in our diets is bad. But, there are times when using sunscreen is not to your advantage, and eating some fat is good for you!
For more information, visit these Web sites:
WebMD, slideshow on vitamin D:
WebMD, Breast cancer link:
MedlinePlus, Vitamin D lowers risk of respiratory infections:
CDC (Center for Disease Control and Prevention) 2012 Levels of nutrients in U.S. population:
CDC (Center for Disease Control and Prevention) vitamin D nutrition report:
Mayo Clinic, vitamin D dosage information: