I have not been feeling very energetic lately, so I visited my primary care doctor to get a set of labs. We discovered that I have a significant vitamin D deficiency. I was surprised by this. Most of us who live in the northern United States have a vitamin D deficiency in the winter months, but it was not expected of the summer months. I spend a lot of time outdoors in the summer, but more in the evenings. I also take a daily multi-vitamin that has 1,000 units of vitamin D. I eat vitamin D fortified cereal and drink milk almost daily. So how can I possibly be deficient???
Vitamin D is produced by the body when skin is exposed to sunlight. It also occurs naturally in some common foods—fish, egg yolk and fortified dairy and grains. Vitamin D helps the body use calcium that we take in our diet and supports strong bones. Low levels can lead to increased risk of death from cardiovascular disease, cognitive impairment in older adults and severe asthma in children. Vitamin D can protect from developing diabetes, hypertension, glucose intolerance and multiple sclerosis.
Vitamin D deficiency occurs when you do not get enough natural sunlight exposure. Those who work full time in day shift indoors, wear sunblock, or wear clothing that covers the majority of your body when you are outdoors. Dark skin can also prevent absorption of sunlight for appropriate vitamin D synthesis.
Other causes of vitamin D deficiency are related to diet or medical problems. Most vitamin D occurs in animal products, thus vegans are at high risk for vitamin D Deficiency. Food items that are fortified with vitamin D are not usually sufficient to support your body’s need for vitamin D. Sometimes kidneys are unable to convert vitamin D to an active form, especially as you get older. Some people have medical problems related to their gastrointestinal tract that prevent adequate absorption of vitamin D. Fat cells in those with obesity can extract vitamin D from the blood causing vitamin D deficiency.
A simple blood test for 25-hydroxy vitamin D will determine if you have vitamin D deficiency. A normal level is 20-50 nanograms/milliliter. A level less than 20 is called Vitamin D insufficiency. Those with a level less than 12 are diagnosed with vitamin D deficiency. The CDC estimates that 32% of adults and children in the U.S. have vitamin D deficiency. That’s 1 in 3 people who have vitamin D deficiency, so get your level checked!
If you find you have a low level of vitamin D, you should discuss with your medical provider a plan to supplement and retest your level. Some ways to help optimize your level is to expose your skin to sunlight during peak hours of the day, consider sitting outside to eat your lunch or take a walk outdoors during your lunch break. When you supplement vitamin D, keep in mind that it is fat-soluble. Thus it should be taken with a meal to optimize absorption.
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