Vitamin D is constantly in the news today. While we know it's good for our bone health, now we are hearing that vitamin D is related to a wide variety of health issues and that people are often deficient in vitamin D. To understand the benefits, it is important to understand the basics about vitamin D and why it's so important to good health.

What is Vitamin D?
Vitamin D is a vitamin that is actually produced in our body. In order for the body to produce vitamin D, it must be exposed to adequate sunlight (about an hour per week). The vitamin D that we get from the sun and from fortified foods must then be converted to an active form in our body. This involves both the liver and the kidneys. The active form of vitamin D is vitamin D3 or calcitriol. As we get older, we may produce less vitamin D. In addition, most of us in the Northwest do not get adequate sunlight to produce vitamin D.

What does it do?
Vitamin D is most well known for its involvement with bone health. It is necessary to absorb calcium. Therefore, people with low vitamin D levels may be more likely to suffer from osteoporosis or joint pain. However, new research is showing that vitamin D has many more functions in the body than just helping our bones.

Vitamin D also effects the neuromuscular and immune systems and can reduce inflammation. Because of these functions, vitamin D deficiency has been related to a variety of disease states including: autoimmune disorders, cancer, diabetes, heart disease, hypertension, multiple sclerosis, osteoarthritis and osteoporosis.

Where do I get vitamin D?
The best sources of vitamin D are the flesh of fish including tuna, mackerel and salmon along with fish liver oils. Fortified foods such as milk, orange juice, yogurt and some cereals also contain vitamin D.

How much vitamin D do I need?
The recommended amount of vitamin D for adults per the Institutes of Medicine Recommended dietary levels are: 200 IU for people 50 years or younger, 400 IU for 51-70 years and 600 IU for those over aged 70. This is the amount needed to prevent the bone disease rickets so is most likely not adequate to support the other functions of vitamin D in the body. These recommendations will be reviewed this year and are most likely to increase to at least 400 IU for younger adults and 800 IU to 1000 IU for older adults.

Who is at risk for vitamin D deficiency?
Those at risk of vitamin D deficiency include breastfed infants, older adults, people with limited sun exposure, people with dark skin, those who can not absorb fat and people with a body mass index greater or equal than 30.

How do I know if I am deficient?
The best way is to have your vitamin D level measured. This will give your doctor the tool to help determine the appropriate vitamin D supplement level for you.

Can I take too much vitamin D?
Excessive vitamin D may cause nausea, vomiting, poor appetite, weight loss, weakness and constipation along with raising calcium levels. If both calcium and vitamin D are taken as supplements in excess, there is more of a risk for kidney stones or soft tissue calcification. Again the best way is to have your levels checked to see what is the right treatment for you.