Rising evidence is linking vitamin D deficiency to increased risk of chronic diseases such as hypertension, heart disease, autoimmune diseases, and cancer. Also known as the sunshine vitamin, vitamin D is converted to a hormone within the body and acts as a chemical messenger between cells. Over 200 genes respond to vitamin D where it has a pivotal influence on bone health as well as controlling inflammation, making it a determinant factor in the development of many diseases.
42% of US adults are deficient in vitamin D, the highest rates were among African Americans and Hispanics according to a 2010 study in Nutrition Journal. People living in the Northern United States above Richmond, VA were more at risk for developing vitamin D deficiency in the winter due to the angle of the sun preventing UVB rays from being absorbed by the skin.
Vitamin D is called the sunshine vitamin because the body can produce its own supply from sunlight. Sun exposure allows the body to synthesize vitamin D in the skin, where it is then metabolized in the liver and kidneys to become activated for use. To prevent deficiency it is recommended to expose arms and legs to sunlight for 5-30 minutes between 10am-3pm twice per week; although season, latitude, and skin pigmentation could alter exposure time requirements.
Vitamin D is also found in some foods such as fortified dairy products, salmon, sardines, mackerel, fortified oatmeal, fortified orange juice, fortified cereal, and some mushrooms.
You are at higher risk for vitamin D deficiency if you are African American or have darker skin tones, are elderly since vitamin D is not synthesizes as effectively, have a bowl disease such as IBS or Crohn’s, have limited sun exposure, are overweight since it is harder for the body to retrieve stored vitamin D imbedded in deeper adipose stores, and if you have kidney or liver disease.
Symptoms of deficiency are subtle, often people report bone pain or muscle weakness. Many times people do not have any symptoms at all. A blood test measuring the amount of vitamin D in your blood can assess whether you are deficient.
One study following 50,000 men for 10 years found those deficient in vitamin D were twice as likely to have a heart attack compared to men with sufficient vitamin D levels. Low vitamin D levels were also associated with higher risk of heart failure, sudden cardiac death, stroke, and cardiovascular disease.
Vitamin D has a role in lowering blood pressure and deficiency could result in higher blood pressure levels. Research shows vitamin D also plays a role in insulin secretion and vitamin D deficiency resulted in impaired insulin secretions and glucose intolerance in type 2 diabetics. In addition to increasing the risk of chronic diseases, deficiency can also cause rickets in children and osteoporosis in adults.
The recommendation for most people is to obtain sufficient sunlight or to consume 600 IU of vitamin D daily, 800 IU for people over 70 years of age. Since vitamin D is fat soluble taking too much could lead to toxicity. Do not exceed 4,000 IU daily unless under doctor