If you live in certain regions of the country, it’s almost certain that you spend most of your winter days indoors and, when outside, you are covered from head to toe.
But is just a few minutes of sun exposure on your face and hands every day enough to get the adequate amount of vitamin D that our body needs?
Vitamin D is synthesized in the skin after exposure to the sun’s ultraviolet B rays and is crucial for calcium absorption and maintaining strong and healthy bones, according to the Academy of Nutrition and Dietetics. A deficiency of this vitamin can cause soft, weak, and brittle bones, which can lead to fractures. Vitamin D can also affect other areas of health, including inflammation, autoimmune disease risk, heart health, and cognitive function.
Most healthy people with fair skin can produce enough vitamin D during the summer by exposing their faces, arms, and legs to sunlight for about five to 10 minutes several times a week at noon, when the sun is highest and its UVB rays are most powerful. Those with more melanin or darker skin pigmentation need longer periods of sun exposure because melanin reduces vitamin D synthesis.
Winter sun, however, does not have the same effect if you live in the northern regions of the country. In these areas, during the cold weather months (around October or November to April or March), the sun’s UVB rays are weak.
How much vitamin D do you need?
There is much controversy about how much vitamin D you should have in your blood for optimal health. In general, most major medical organizations recommend at least 20 nanograms per milliliter measured by a simple blood test.
How much vitamin D you should obtain from food or supplements is also debated, as it is difficult to suggest a recommendation that works for everyone. Skin color, age, health conditions, and sun exposure during the warmer months, among others, influence the amount of vitamin D you need per day.
However, federal authorities recommend that, in general, to maintain good bone health and normal calcium metabolism, people aged 1 to 70 should consume 600 international units (or 15 micrograms) per day – from food, supplements, or both. Those over 70 should receive 800 IU (or 20 micrograms), and infants up to 12 months need 400 IU (or 10 micrograms).
But if you are concerned about a possible vitamin D deficiency, are at risk for osteoporosis, or have a condition that affects how you absorb nutrients, the best course of action is to talk to a doctor about how to test your vitamin D level and, if deficient, let your specialist determine the ideal amount for you to supplement.
How to get vitamin D without sunlight
The foods that provide the highest amounts of natural vitamin D include fatty fish (such as salmon, tuna, and sardines), cod liver oil, beef liver, egg yolk, and some mushrooms. But since the typical American diet tends to not include many or enough of these foods, manufacturers have been fortifying foods with vitamin D since the 1930s. Good sources of vitamin D-fortified foods are cow’s milk, soy milk, cereals, and orange juice.
Keep in mind, however, that for many people it can be difficult to get enough vitamin D from food sources alone. In this case, supplements can help. When looking for supplements, experts recommend choosing vitamin D3 instead of vitamin D2, as research suggests that the human body can absorb it more effectively. Additionally, look for a supplement that has the U.S.P. mark on the bottle, indicating that the product contains the ingredients listed on the label and does not contain harmful contaminants.
Source: The New York Times