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How Much Sunlight Do Humans Need to Prevent Vitamin D Deficiency?

author image Sara Ipatenco
Sara Ipatenco has taught writing, health and nutrition. She started writing in 2007 and has been published in Teaching Tolerance magazine. Ipatenco holds a bachelor's degree and a master's degree in education, both from the University of Denver.
How Much Sunlight Do Humans Need to Prevent Vitamin D Deficiency?
Unprotected sun exposure is one way to raise your vitamin D levels.

Vitamin D is fat-soluble nutrient that is not present in many foods but can be synthesized in your body with sun exposure. Many people are deficient in vitamin D, which can cause numerous health problems. Because vitamin D is not available in a wide variety of foods, sun exposure may help you achieve and maintain a healthy level of this essential nutrient.

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Importance of Vitamin D

One of the primary responsibilities of vitamin D is to help you absorb the calcium from your food and beverages. Vitamin D also aids your body in retaining phosphorus, another mineral necessary for the health of your bones. This important vitamin also contributes to new bone growth and assists in remodeling your bones. You also need vitamin D for proper immune function, cell growth and for reducing inflammation. An insufficient intake of vitamin D contributes to weak and brittle bones and may increase your risk of cancer, multiple sclerosis and heart disease.

Sun Exposure for Vitamin D

When sunlight hits your unprotected skin, it encourages synthesis of vitamin D, a process that takes place when your liver converts vitamin D into a substance called calcidiol. The UVB rays given off by the sun are responsible for triggering this process, but many factors have reduced the amount of sunlight the average person is exposed to. Sunscreen, cloud cover, location, time of year and climate all play a role in how much sunlight is available for vitamin D. The Harvard School of Public Health recommends 15 minutes of sunlight each day for the most vitamin D benefits.

Dangers of Too Much Sun Exposure

One reason that vitamin D levels may be decreasing among most populations is because of the widespread effort to educate people about the risks of unprotected sun exposure. Being out in the sun without sunscreen increases your risk of sunburn, which may increase your risk of developing skin cancer. If you are deficient in vitamin D, speak with your doctor about whether unprotected sun exposure is right for you.

Alternate Ways to Raise Vitamin D Levels

The National Institutes of Health reports that adults between the ages of 19 and 70 need 600 international units of vitamin D per day and adults over the age of 70 require 800 IU each day. If you and your doctor have determined that unprotected sun exposure is not right for you, adding certain foods can help increase you intake of vitamin D. Fortified milk is the most common source, but salmon, mackerel, tuna, fortified juice, fortified yogurt, egg yolk, sardines and cod liver oil are all food sources as well. If you cannot get enough vitamin D from your diet, your doctor may recommend a supplement to help you reach the recommended amount.

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