Often referred to as the sunshine vitamin, vitamin D is an umbrella term that refers to a family of similar compounds. Vitamins D-2 and D-3 come from different sources but they're converted into the same active hormone in your body. Since they both end up as the same substance, it doesn't matter which form of vitamin D you get. All that matters is that you consume your recommended daily intake.
When you expose your skin to sunlight, specialized cells produce vitamin D-3. The time you spend in the sun, the amount of skin exposed to sunlight and your natural skin color affect how much vitamin D your body makes. Wearing sunscreen also interferes with the amount of ultraviolet light your skin can absorb and turn into vitamin D-3. However, protecting your skin from the damaging effect of the sun is so important that the American Academy of Dermatology recommends always wearing sunscreen and getting vitamin D through your diet.
Finding Vitamin D in Food
Very few foods are natural sources of vitamin D. Some types of fatty fish, such as salmon, sardines and mackerel, contain vitamin D-3. This means you can also get vitamin D from some fish oil supplements, but the amount varies, so check the labels on the brands you buy. When hens are fed vitamin D, they produce eggs that contain vitamin D-3. Vitamin D-2 is the form of the vitamin naturally produced in mushrooms. Much like human skin, the amount of vitamin D-2 in mushrooms depends on how much ultraviolet light they were exposed to. Most vitamin D is obtain through fortified foods, such as milk and other dairy products, orange juice and breakfast cereals.
Getting What Your Body Needs
After you consume vitamins D-2 and D-3, or your skin produces vitamin D-3, they travel through your liver and then your kidney, going through several transformations before the vitamin is finally converted into the hormone calcitriol. In this form, your body uses vitamin D to support your immune system, control cell growth and help regulate blood pressure. Vitamin D is also essential for your body to metabolize calcium. Women need to consume 600 international units, or 15 micrograms, of vitamin D daily.
Dangers of Deficiency
Without a sufficient amount of vitamin D, you won't absorb calcium and your bones will become weak. This is a vital concern for women because they're more likely to develop osteoporosis. Your bones reach their peak mass and strength between the ages of 20 and 30. After that, you lose bone mass at the rate of about 0.5 to 1 percent every year, up until menopause when the loss accelerates, according to Purdue University. In addition to natural bone loss, your body maintains strong bones by regularly removing and replacing old and worn out bone. If you do not give your body a daily supply of vitamin D along with calcium, it won't be able to keep up with bone rebuilding.
- Linus Pauling Institute: Vitamin D
- National Institute of Health: Dietary Supplement Fact Sheet – Vitamin D
- Journal of Pharmacology and Pharmacotherapeutics: Vitamin D - The Sunshine Vitamin
- Purdue University Extension: Osteoporosis: What You Should Know
- American Academy of Dermatology and AAD Association: Position Statement on Vitamin D
- Pixland/Pixland/Getty Images
This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.