Vitamin D deficiency is a global public health issue. About 1 billion people worldwide have a deficiency and 50% of the population demonstrate a vitamin insufficiency. The Institute of Medicine considers blood serum levels of <50 ng/mL to mark a deficiency or insufficiency in most of the general population. This is based on what is generally considered adequate for bone and overall health.
Because of this, vitamin D has been of vast interest in the health and wellness sector. It is well known for its role in bone health but studies have also shown that vitamin D enhances antimicrobial effects in immune cells, which in turn allows your body to fight against pathogens. The pathway to doing so is intricate and works through many aspects of the immune system.
Vitamin D comes from three potential sources: food, skin contact with UV rays, or supplements. Very few foods contain (natural, non-fortified) relevant amounts of vitamin D: fatty fish (salmon, mackerel, sardines, cod liver oil) or some types of mushrooms (Shiitake), especially if sundried. Getting adequate amounts from the sun depends on the following factors: season, time of day, length of day, cloud cover, smog, skin melanin content, and sunscreen. The suggestion is to get approximately 5-30 minutes of sun exposure between 10 AM and 3 PM at least twice a week to the face, arms, legs, or back without sunscreen.
Dietary supplements include both D2 (ergocalciferol) and D3 (cholecalciferol) forms. Both appear to be effective for bone health, but D3 tends to be more potent at high doses. Adults without deficiencies should aim to get at least 600 IU per day, not exceeding 4,000 IU. The amount of vitamin D required to treat a deficiency depends largely on the degree of the deficiency and underlying risk factors. If you find yourself having a deficiency, speak to your doctor or a dietitian to determine the best route for you.
Addressing vitamin D deficiencies and insufficiencies is crucial to not only supporting bone health but also supporting immune health. If you would like to see whether you have a deficiency, the Results Center now offers functional testing that can test for 33 vitamins and minerals, including vitamin D. We also offer supplements that contain both vitamin D and K because of their synergistic relationship. A particular study called the Framingham Offspring Study, found that higher serum levels of both vitamins D and K were associated with stronger immune function and a balanced inflammatory response.