The Latest News about Vitamin D

What is Vitamin D? Vitamin D is a fat soluble vitamin.  There are two forms – ergocalciferol or D2, which is produced by plants, and cholecalciferol or D3, which is produced by mammals.  D3 is the type of vitamin D which can be synthesized by our skin in the presence of sunlight.  Most supplements contain the D3 form of the vitamin, and this is the most easily absorbed. Why is Vitamin D so important? The main function of Vitamin D is to maintain levels of calcium and phosporus in the blood, by helping the body absorb these minerals from the diet.  It is very important that blood calcium levels stay within a narrow range in order for the nervous system to function properly.  If the level of calcium in the blood drops, your body will take this mineral from the bones.   In addition to maintaining calcium levels, vitamin D also inhibits cell proliferation, in cases where it should not be happening such as cancer growth.  It has a considerable influence on the immune system and may help prevent autoimmune diseases.  Vitamin D plays a role in the secretion of insulin, and some studies suggest it may affect glucose tolerance for some diabetics.  Vitamin D may be important for decreasing the risk of high blood pressure.  Vitamin D deficiency can cause muscle weakness and pain for children and adults. Severe vitamin D deficiency in children shows up in the form of rickets, a disease where the bones are softened and can become bowed (legs) or have other deformities.  Even though several basic foods are now fortified with vitamin D, cases of rickets are still being in seen in the United States and other Western countries.  In adults vitamin D deficiency can cause osteomalacia, and may contribute to a host of health problems like diabetes, heart disease and cancer. How much Vitamin D can you get from sunlight? UVB rays (sunlight) stimulate production of Vitamin D in your skin, and people who live in the right place on earth can make all they need, with the help of the sun, year round.  However, if you go 40 degrees north or south of the equator this begins to diminish, and you won't get enough UVB radiation from November to March to produce vitamin D.  Some cities at this latitude are Bursa, Turkey; Madrid, Spain; Pittsburgh, Pa; Salt Lake City, Utah; Thessalonika, Greece and Naples, Italy.  If you go another 10 degrees north or south you can add another 4 weeks to the time when you can't synthesize Vitamin D.  Some cities at this latitude are Krakow, Poland; Frankfurt, Germany; Brussels, Belgium; and Calgary, Alberta, Canada.  South of the equator, the 40 degree latitude runs through Argentina and New Zealand, and the 50 degree mark goes through the Falkland Islands. During the summer months, a light skinned individual would need only 10-15 minutes of full body exposure to produce a whopping 10,000-20,000 IU's of vitamin D.  However the realities of life add so many confounding factors to that picture.  The actual amount of vitamin D produced depends on the amount of clothing you wear, sunscreen, amount of pollution in the air, cloud cover, your skin pigmentation and body mass.  It is so difficult to estimate how much vitamin D each individual can make that scientists who set the daily requirement assume you are not synthesizing any of your vitamin D through sunlight, but getting it all through your diet. Who is at risk for Vitamin D deficiency? If you live in a northern climate or a rainy climate without much sun, or if you use a lot of sun screen and wear clothing that covers most of your skin, you may not be getting enough sun to produce vitamin D.  Dark-skinned people who live in northern climates are especially at risk because they absorb less UV rays to begin with.  Babies who are completely breastfed are at risk, especially if the mother has low stores of Vitamin D.  This doesn't mean you shouldn't breastfeed!  You should ask your doctor about giving your baby a supplement.  People who cannot absorb fats, or are taking antiseizure medication, may be deficient in vitamin D.  Vitamin D doesn't occur naturally in very many foods.  Milk is fortified with vitamin D (it has been added to the  milk) to help you absorb the calcium.  If you don't drink much milk, you may need to really take a look at how you can get more vitamin D in your diet. How can you get the Vitamin D that you need? If you are NOT that lucky person living near the equator and getting full body exposure to the sun, here are some ways you can make sure you get enough vitamin D.  A 3 oz can of pink salmon will provide over 500 IUs (12.5 µg) of vitamin D, which is all you need for the day.  Canned sardines and mackerel have a lesser amount but are still good sources, around 200 IUs (5 µg) for 3 oz.  You can drink a cup (8 oz) of cows milk, orange juice or soy milk to get 100 IUs (2.5 µg) of vitamin D, which is about a quarter of your daily requirement.  Some cereals are fortified with vitamin D – usually about 50 IUs per cup – and an egg yolk has about 20 IUs (.5 µg). Baby formula contains as  much vitamin D as a baby needs.  However breastmilk does not have this level, so breastfed babies should be given a supplement.  Talk to your pediatrician about this.  You can find your daily requirement for vitamin D at thirdplanetfood.com.  1 µg is equal to 40 IUs.  If you aren't getting enough of these foods in your diet every day, you should make sure you are taking a supplement of 400 IUs, or 10 µg, of vitamin D.  This can be included in your multivitamin. Babies and young children are at a huge risk of health problems if they don't get enough vitamin D, since their bones are growing at a rapid rate.  Women should also pay attention to this vitamin so they can avoid problems with bone loss.  We can't ignore the men, as vitamin D may be able to help prevent things like cancer, heart disease and diabetes.  So whether you get it from the sun, from a careful diet or take it in a pill, make sure and your family get your vitamin D. Resources:  USDA DRI (Dietary Reference Intake) Report on Vitamin D                    American Academy of Pediatrics news release on Vitamin D recommendation                    The Linus Pauling Institute Micronutrient Information Center