Are You Getting the Right Type of Vitamin D?

Vitamin D has been linked with a number of health benefits. Although it’s called a vitamin, vitamin D is actually more like a hormone affecting proteins that regulate your immune system and control inflammation. Plus, vitamin D affects cell growth. Low vitamin D levels have been linked with a number of health problems including autoimmune diseases, muscle pain, depression, heart disease, obesity and some types of cancer, although most of the research is still preliminary. Vitamin D is also important for absorption of calcium from your digestive tract and low levels increase your risk for osteoporosis.

Unfortunately, a significant number of people have low or borderline-low levels of vitamin D, particularly older people, people who live in Northern latitudes and those who aren’t exposed to daily sunlight. Sunlight is the best natural source of vitamin D. When sunlight hits your skin, it converts vitamin D precursors on your skin to a form that can be further activated by your liver and kidneys. That’s why experts recommend exposing your skin to the sun for 10 to 15 minutes several days a week. Unfortunately, this amount of sunlight exposure may not be enough for people who live in Northern latitudes where the sun’s rays are weak in the winter months. That’s why sunlight is not always a reliable way to get enough vitamin D.

Natural Vitamin D versus Vitamin D Supplements

It’s usually better to get vitamins and nutrients naturally through diet but that isn’t always possible with vitamin D. Most foods are not naturally good sources of this vitamin. Fatty fish like salmon is one of the best natural sources, but you can also get vitamin D from foods that contain added vitamin D including milk. Some breakfast cereals and other foods are also fortified with vitamin D.

The problem with vitamin D in fortified foods like milk and breakfast cereals is it isn’t always in its“optimal” form. There are two types of vitamin D. Vitamin D3, also called cholecalciferol, is the form your body makes when you expose your skin to sunlight. This is also the type of vitamin D found naturally in fatty fish like salmon. The other form of vitamin D is ergocalciferol, or vitamin D2. This type comes from non-animal sources and is usually made by exposing fungi to ultraviolet light.

Why is this important? Research shows that vitamin D3 has more vitamin D activity than vitamin D2 that comes from non-animal sources. That’s why vitamin D3 (cholecalciferol) is the form you should be getting. When you buy foods with added vitamin D, they may be fortified with vitamin D2, the less active form, cheating you out of some benefits. Many milk manufacturers have converted over to the vitamin D3 form – but not all. Plus, other foods that contain vitamin D like cereal are often in the vitamin D2 form. Unless you’re getting the D3 or cholecalciferol form, you’re not getting the full benefits. All vitamin D isn’t created equal.

What about Vitamin D Supplements?

If you don’t get expose yourself to the sun daily, you may have problems getting enough vitamin D through diet along unless you drink several glasses of vitamin D fortified milk a day that contains the D3 form of vitamin D and eat fatty fish several times a week as well. That’s why some people turn to vitamin D supplements. Supplements are a good option for people who are deficient and don’t get enough vitamin D naturally, but make sure you know what your blood level of vitamin D is before supplementing. Your doctor can do a blood test to check your level.

If you’re deficient, read the label and choose a supplement with the vitamin D3 or cholecalciferol form, not vitamin D2 or ergocalciferol, to ensure you’re getting maximal benefits. Make sure your doctor knows you’re taking a vitamin D supplement since very high levels can be toxic, and get your blood levels checked every six months while you’re on a supplement.

References:

National Institutes of Health. “Vitamin D”

Am. J. Clin. Nutr. October 2006. Volume 84, No.4.