Vitamin Sunshine: Don’t Avoid All Sun Exposure

Created: 24 May 2011 | Written by Dr. Wilson for Citrus County Chronicle

The Florida sun can quickly cause painful sunburn, but did you know that your body needs a certain amount of exposure to the sun to stay healthy? Vitamin D (often called the “sunshine vitamin”), synthesized by your skin when it is exposed to sunlight, is essential for building strong bones, regulating hormones and maintaining a healthy immune system. Although vitamin D occurs naturally in a few foods including fish (salmon, tuna, and mackerel), fish liver oils and egg yolks, and is an additive in milk, bread, and cereals, you cannot get enough of it from your diet alone.

Our ancestors naturally got enough sun exposure to produce the vitamin D their bodies needed. Today many of us work indoors all day and travel in cars. When we do go outside, we apply sunblock. Children increasingly spend time indoors watching television or playing video games. Glazed windows or sunblock with an SPF rating of 15 or higher block 99 percent of the ultraviolet B (UVB) rays necessary for the production of vitamin D.

According to a March 2010 report by the U.S. National Center for Health Statistics, about a fourth of the U.S. population is at risk for vitamin D inadequacy and 8 percent are at risk for vitamin D deficiency. In infants and children, a lack of vitamin D causes rickets (soft bones), bone deformities, and delayed dental formation. Vitamin D deficiency contributes to osteoporosis and is associated with sclerosis, hypertension, fatigue, mood swings, and depression. It is also linked to certain cancers, type 2 diabetes, and obesity.

During the summer months, your skin will produce enough vitamin D if you are exposed to the sun for 15 minutes (without sunblock) in the early morning and late afternoon. Skin with darker pigment (melanin) may require up to 40 minutes. If you work indoors, eat lunch outside two or three times a week, or take short walks during your breaks. Children and infants should be exposed to sunlight for 10 minutes before you apply sunscreen. Breast-fed infants are particularly susceptible to vitamin D deficiency if they do not regularly spend time outdoors without sunblock.

As your skin ages it becomes less efficient at producing vitamin D and certain health conditions including kidney problems or intestinal disorders, such as Crohn’s disease, may impair the body’s ability to absorb vitamin D from foods. Talk to your doctor about taking vitamin D supplements, especially if you spend a lot of time in a cold climate or regularly cover yourself up to avoid exposure to sunlight.

Once you have received your daily dose of sunlight, get out the sunscreen. After 15 minutes of exposure to the sun’s rays, your skin begins to redden and burn. Even, one severe sunburn can cause damage that could lead to skin cancer later on. If you are outdoors between 10 a.m. and 4 p.m. daylight savings time (9 a.m. to 3 p.m. standard time):

• Apply sunscreen with a minimum SPF rating of 15, and reapply every two hours and after swimming or any activity that causes you to sweat.
• Wear a hat with a wide brim. If you wear a baseball cap, put sunscreen on your ears and neck.
• Stay in the shade as much as possible, especially during midday hours.
• Wear sunglasses that block close to 100 percent of both UVA and UVB rays. Wrap-around sunglasses prevent UV rays from hitting your eyes from the side.
• Wear protective clothing. Remember that a typical T-shirt has an SPF rating lower than 15, and a wet T-shirt has a lower rating than a dry one. Some sports clothing blocks UV rays; this is indicated on the label.
• All sunscreens are not alike. There are two types of harmful rays: UVB and UVA. Sunscreens that block only UVB rays prevent sunburn but do not prevent the formation of harmful free radicals caused by UVA rays.
• A poor-quality sunscreen can deceive you into thinking you are protected when you are not. Read the label carefully when choosing a product. Select one that blocks both UVA and UVB rays.
• Sunscreens are combinations of organic and inorganic chemicals that absorb some of the UV rays and reflect them as heat. Sunblock contains tiny particles of zinc oxide or titanium oxide that reflect or scatter the light away so it     does not reach the skin.
• Many sunscreens contain some sunblock ingredients.
• Sunblock particles are apparently not absorbed into the body, but there is concern some of the chemicals in sunscreens penetrate the skin and could present health hazards. Oxybenzone, the most common active ingredient in sunscreen, is not recommended for use on children because of its potential for hormone disruption and allergic reactions. If possible, use only sunblock products on children.

Sunscreen products have a shelf life of about three years, but deteriorate more quickly in the heat. Sunscreen cannot do its job if it is not applied liberally. Follow the directions on the label and slather it on generously.