How Much Sun is too Much?

The Vitamin D Dilemma

Our bodies are ready to soak up some sun and our system needs to be recharged after a long, cold winter. For generations, we have been told that we need sun to grow healthy bones and to prevent colds. Now we are told that the same sun rays will give us skin cancer. There should some balance between what is enough sun, without being at risk of developing skin cancer. If only scientists could agree on what it is.

Why do we need vitamin D?

Vitamin D is one of the micronutrients we cannot live without. It helps the absorption of calcium and concentration of phosphate necessary for the bone growth and remodeling. Without enough vitamin D, our bones become brittle or misshapen, kids develop rickets and older people osteoporosis. Vitamin D also controls cell growth, regulates immunity and prevents inflammation.

It is not easy to get enough vitamin D. Its sources are fatty fish such as cod, salmon, tuna, and sardines. Older generation remembers cod liver oil being stuffed down their throats religiously by mothers. Milk also contains some vitamin D, and so do mushrooms. Most vitamin D3 is produced after our skin is exposed to ultra-violet B light from the sun.

There is huge amount of research on the benefits of vitamin D. Low levels of vitamin D are associated with cognitive decline in older people. World Health Organization reports that children with vitamin D deficiency are more at risk for developing respiratory infections. Another study reports that insufficient amount of vitamin D is linked to cardio-vascular deaths.

Vitamin D vs. Skin Cancer

One of the latest studies published in the Archives of Internal Medicine, conducted on almost 19,000 Americans between 1984 and 2004, shows that the vitamin D insufficiency is on the rise. The researchers also found that current recommendations for the amount of vitamin D supplements are inadequate. The scientists believe that the reason for the decline is too much dependency on supplements and not enough on the sunlight exposure, which is the ” “primary determinant of vitamin D statusin humans” . Other reason for the decline is too successful campaign to limit sun exposure due to the danger of skin cancer, and overall lack of outdoor activities in the general population.

Skin Cancer Foundation reports that skin cancer, despite its decline in the last few years, is still the most common type of cancer in the United States. Every year, 3.5 million Americans are diagnosed with skin cancers – more than the prostate, breast, colon and lung combined. The decline in new cases is attributed to the successful public campaign for the protection from the damaging ultraviolet sun rays.

Just enough sun

Scientists from the National Institute of Health produced guidelines   which suggest that approximately 5-30 minutes of exposure to the direct sun between ten o”clock in the morning and three o”clock in the afternoon at least twice a week should be enough to activate vitamin D in our skin, without too much risk of skin cancer. The exposure should be to the face, back, arms and legs, and without any sunscreen. People who cannot get that much sun should make sure that they get enough vitamin D from a good supplement.

This guidelines are, of course, dependent on where you live, on the season, time of day, length of day, pollution, cloud cover and the darkness of your skin (skin melanin content).   For example, total cloud cover reduces UV power by 50 percent, shade by 60 percents. Ultraviolet B rays do not pass through glass, and any lotion with SPF factor of eight and higher will block UV rays enough to prevent vitamin B synthesis.

An interesting fact about SPF lotions is that they do not do a good job of protecting us from the UV rays because most of us do not apply them as often as we should, or as it is recommended. That means that we will still get some vitamin D even when we have sunscreen on, if we apply it sporadically, as most of us do. If only we could get off our sofas and get out a bit, enjoy the sun and smell the roses.


HealthStatus has been operating since 1998 providing the best interactive health tools on the Internet, millions of visitors have used our blood alcohol, body fat and calories burned calculators. The HealthStatus editorial team has continued that commitment to excellence by providing our visitors with easy to understand high quality health content for many years. Our team of health professionals, and researchers use peer reviewed studies as source elements in our articles. Our high quality content has been featured in a number of leading websites, USA Today, the Chicago Tribune, Live Strong, GQ, and many more.

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