Vitamin D is known for supporting Immune Health, bone density and moods.
Why is vitamin D so important? Vitamin D, known as the “sunshine vitamin,” is one of the most critical and influential nutrients for supporting the immune system. Numerous studies have shown how it helps reduce the risk of colds and flu. Unfortunately, a high percentage of the population is deficient, so daily supplementation (ideally in the form of vitamin D3) offers the best protection. Studies reveal that low vitamin D levels in the body are associated with: • Increased loss of muscle strength and mass as we age • Increased risk of cancers • Lower levels of immunity • Higher blood pressure • The development of neurological disorders • The development of diabetes What Does It Do in Your Body? Vitamin D needs to undergo two conversion steps to become. First, it is converted to calcidiol, or 25(OH)D, in your liver. This is the storage form of the vitamin. Second, it is converted to calcitriol, or 1,25(OH)2D, mostly in your kidneys. This is the active, steroid-hormone form of vitamin D. Calcitriol interacts with the vitamin D receptor (VDR), which is found in almost every single cell in your body. When the active form of vitamin D binds to this receptor, it turns genes on or off, leading to changes in your cells. This is similar to how most other steroid hormones work. Vitamin D affects various cells related to bone health. For example, it promotes the absorption of calcium and phosphorus from your gut. But scientists have recently discovered that it also plays roles in other areas of health, such as immune function and protection against cancer. Sunshine Is an Effective Way to Get Vitamin D Vitamin D can be produced from cholesterol in your skin when it’s exposed to ultraviolet B (UVB) rays from the sun. If you live in an area with abundant sunshine, you can probably get all the vitamin D you need by sunbathing a few times per week. Keep in mind that you need to expose a large part of your body. If you're only exposing your face and hands, you will produce much less vitamin D. Also, if you stay behind glass or use sunscreen, you will produce less vitamin D — or none at all. However, you should make sure to use sunscreen when staying in the sun for extended periods. Sunshine is healthy, but sunburns can cause premature skin aging and raise your risk of skin cancer. If you're staying in the sun for a long time, consider going without sunscreen for the first 10–30 minutes — depending on your sensitivity to sunlight — then applying it before you start to burn. As vitamin D gets stored in your body for weeks or months at a time, you may only need occasional sunshine to keep your blood levels adequate. That said, if you live in an area without adequate sunlight, getting vitamin D from foods or supplements is absolutely essential — especially during winter. How Much Should You Take? The only way to know if you are deficient — and thus need to supplement — is by having your blood levels measured. Your healthcare provider will measure the storage form of vitamin D, which is known as calcifediol. Anything under 12 ng/ml is considered deficient, and anything above 20 ng/ml is considered adequate.
The RDI for vitamin D is as follows:
• 400 IU (10 mcg): infants, 0–12 months • 600 IU (15 mcg): children and adults, 1–70 years old • 800 IU (20 mcg): older adults and pregnant or breastfeeding women
Although adequacy is measured at 20 ng/ml, many health experts believe that people should aim for blood levels higher than 30 ng/ml for optimal health and disease prevention. Additionally, many believe that the recommended intake is far too low and that people need much more to reach optimal blood levels. According to the U.S. National Academy of Medicine, the safe upper limit is 4,000 IU (100 mcg) per day. Vitamin D3 supplements appear to be more effective at raising vitamin D levels than D2 supplements. The Bottom Line Vitamin D is a fat-soluble vitamin important for bone health. For those low in this nutrient, increasing intake may also reduce depression and improve strength. Your skin produces vitamin D when exposed to sunlight. Foods like fatty fish, fish oil, and liver also contain vitamin D — as well as certain fortified foods and supplements. Deficiency is fairly common due to limited sunlight exposure and a small selection of rich dietary sources. If you don’t spend much time in the sun and rarely eat fatty fish, consider supplementing. Getting enough vitamin D can go a long way to boosting your health.