Fact Sheet on Vitamin D
This page is a fact sheet on vitamin D helping you to answer what foods contain vitamin D, the health benefits of vitamin D, along with the importance of vitamin D in improving depression, anxiety, schizophrenia and other mental health problems.
What is Vitamin D?
Vitamin D is a fat-soluble vitamin that has properties of both a vitamin and a hormone. There are several forms of vitamin D, the primary ones being vitamin D2 and D3. Vitamin D2 (ergocalciferol) comes from food sources and vitamin D3 (cholecalciferol) is created in the skin in response to exposure to the sun’s ultraviolet rays. Vitamin D3 is considered the natural form of vitamin D and is the most active.
A unique aspect of vitamin D is that it functions like a hormone and is often referred as one. It targets organs such as the kidneys, intestines, brain, pancreas, skin, bones, reproductive organs, and some cancer cells.
What Foods Contain Vitamin D?
Foods containing vitamin D includes fish liver oils, fatty saltwater fish, dairy products, and eggs. Vitamin D is also obtained from cod liver oil. Small amounts of vitamin D are also contained in fortified foods such as fortified milk, orange juice and cereals. Unfortunately, it is almost impossible to get adequate amounts of vitamin D from food.
Other Sources of Vitamin D
- Sunlight and UVB Exposure. Sun exposure and not dietary intake is the principal source of circulating vitamin D stores in the body. Some people can also obtain vitamin D from commercial tanning beds.
- Supplements. Most multivitamin and mineral supplements, along with a range of other nutritional supplements contain vitamin D.
Health Benefits of Vitamin D
No fact sheet on vitamin D is complete without a discussion on the many functions of vitamin D in the body. Studies show that it plays numerous crucial roles in the body. Some of these are outlined below:
- Bone Health/ Osteoporosis. Both calcium and phosphorous are important for bones, however, when vitamin D levels are low, absorption of both these minerals is significantly reduced. For example, studies have shown that low vitamin D levels result in absorption of only 10 to 15 percent of dietary calcium. However, when levels are high approximately 30 percent of calcium is absorbed
- Cardiovascular Disease. The risk of heart attack is twice as high for those with vitamin D levels less than 85 (nmol/L) than for those with vitamin D status above this level.
- Hypertension. Increasing vitamin D levels has been shown to reduce blood pressure.
- Type 2 Diabetes. Studies have shown that people with high levels of vitamin D have significantly lowered glucose levels and significantly better insulin sensitivity compared to those with lower levels. One study showed the popular anti-diabetic drug metformin improved insulin sensitivity by 13 percent. Higher vitamin D status was, however, associated with a 60 percent improvement in insulin sensitivity.
- Osteoarthritis. Both the prevention and progression of osteoarthritis is improved by optimising vitamin D levels.
- Depression, anxiety, schizophrenia and other mental disorders. Vitamin D is widely involved in brain function and some studies have shown that supplementation with vitamin D can improve mood. Research has shown that people suffering from anxiety and depression have lowered levels of vitamin D. Click here for more information about vitamin D and depression and other mental health disorders.
- Autoimmune/ Inflammatory conditions. Deficiency of vitamin D is common among patients with inflammatory and autoimmune disorders such as Grave’s disease, systemic lupus erythematosus, and rheumatoid arthritis.
- Other Benefits. Optimising vitamin D status has also been shown to be important for the following conditions: epilepsy, polycystic ovarian syndrome, multiple sclerosis, musculoskeletal pain, psoriasis, periodontal disease, colds and flus, migraine, macular degeneration, chronic pain and even cancer prevention.
As outlined in this fact sheet on vitamin D, there are many health benefits of vitamin D. Vitamin D deficiency and the consequences of this can be substantial. Click the links below for more information about vitamin D
Testing of vitamin D and vitamin D deficiency treatment