On June 21, those of us in the Northern Hemisphere will experience the summer solstice, the longest day of the year – also known as midsummer. In the mid-Atlantic region of the Eastern U.S. time zone, the sun will rise at 5:48 a.m. and set at 8:34 p.m., giving us a delightful 14 hours and 45 minutes of daylight! It’s enlightening to compare this to the winter solstice six months later on December 21, when the sun will rise at 7:20 a.m. and set at 4:55 p.m., providing us with just nine hours and 34 minutes of daylight. Let’s revel in the sunshine while we have so much of it!
We’ve all learned the importance of wearing sunscreen with a high SPF (sun protection factor) and a hat when we’ll be out in the sun to help prevent skin cancer. However, with so much emphasis on sunscreen, you may have forgotten that there are benefits to allowing your body to absorb a limited amount of sunshine without sunscreen for a short amount of time each day.
The reason a short amount of unprotected sun time is beneficial is that it stimulates your body to produce vitamin D. Vitamin D is a fat-soluble vitamin that helps the body absorb calcium and phosphorous, which keeps bones and teeth strong and supports immune system function. Those lacking in vitamin D risk bone abnormalities including osteoporosis. You can get enough vitamin D from either exposing bare skin to sunlight or by taking supplements. Unfortunately, you can’t get the right amount of vitamin D for optimal health from food alone.
Vitamin D has the following health benefits:
- Supports healthy development and maintenance of teeth and bones
- Helps prevent the risk of fractures in older adults
- Reduces risk of developing osteoporosis, multiple sclerosis, diabetes and heart disease
- Reduces risk of contracting the influenza virus
- Regulates mood and can reduce the risk of developing depression
- May help prevent cancer by regulating cell growth and cellular communication
- Can help you lose weight
Some recent studies estimate that up to 50% of adults worldwide are deficient in vitamin D levels – especially in the winter because vitamin D has a half-life of only two weeks. Let’s answer a few common questions about vitamin D and the sun.
How long should I stay in the sun without sunscreen to stimulate vitamin D production?
It varies, according to the time of year, time of day, proximity to the equator, and your skin type. Typically, your body can make all the vitamin D it needs for the day in about half the time it would take for your skin to start getting pink, an indicator that it’s starting to burn. For fair-skinned people, that’s between five and 15 minutes, and again ― is about half the time it would take for your skin to start getting pink and burning. Monitor the time carefully and seek shade or apply sunscreen as soon as your skin starts getting pink! People with very dark skin may need to spend an hour or two in the sun to get enough vitamin D and/or they may need to take supplements. As we get older, it becomes more difficult for our bodies to produce vitamin D, so we need to take supplements.
How much vitamin D do you need each day?
Various organizations have different official recommendations. Your best bet is to ask your doctor. The Vitamin D Council recommends that adults take 5,000 IUs (international units) per day, the Endocrine Society recommends adults take 1,500-2,000 IU/day and the Food and Nutrition Board, where the U.S. Government gets its official recommendations, advises 600 IU/day for adults and 800 IU/day for seniors. When choosing a vitamin D supplement, opt for vitamin D3 (rather than D2) because it’s easier for your body to utilize.
How much vitamin D does the body make when skin is exposed to sunlight?
When bare skin is exposed to the sun, your body is capable of making large quantities of vitamin D from the sun’s ultraviolet B (UVB) rays. And remember: you don’t need to tan or burn to achieve this. Your body can make 10,000 to 25,000 IU in a rapid amount of time – before your skin begins to get pink! The more skin you expose – such as your back vs. only your arms – the more vitamin D you will make.
Many factors influence how much vitamin D you can make, including the time of year, time of day, distance from the equator, and your skin type. When the sun’s rays hit the Earth at an extreme angle, such as during midwinter and in the morning or evening during summer, there aren’t enough UVB rays reaching the Earth’s surface to stimulate vitamin D production. There’s an easy way to tell: if your shadow is longer than you are tall, there aren’t sufficient UVB rays reaching you to stimulate vitamin D production.
If you work inside most weekdays, the Vitamin D Council recommends taking a vitamin D3 supplement on days when you’re not outside in the sun to stimulate your body’s internal vitamin D factory. Your doctor can advise the right vitamin D supplementation strategy for you. You’ll most likely need to depend solely on supplements in the wintertime, and a mix of supplements and natural sunshine in the summer. You can read more on the Vitamin D Council’s website.
And please remember: after you’ve spent the short amount of time it takes for your body to start producing vitamin D naturally, go into the shade and/or apply sunscreen with a high SPF to prevent skin from burning and increasing your risk of developing skin cancer. With the sun’s intense summer rays, a little goes a long way!