VITAMIN D, SUN & SUNSCREEN

Posted by Dr. Ann Marie Rogers on Jun 5, 2018 9:08:36 AM

Vitamin D is a fat-soluble vitamin. Very few foods naturally contain vitamin D, with the exception of fatty fish. Most types of milk and some breakfast cereals are fortified with this vitamin. Synthesis in sunscreen -412408-editedthe skin is the major source of the vitamin.

The vitamin D synthesized in the dermis (the thick layer of living tissue below the epidermis) or obtained from the diet is biologically inactive and requires conversion to an active metabolite, which the body does nicely.

Vitamin D, in its active form, has a significant role, as it has an interrelationship with calcium and bone metabolism. Severe deficiency can cause Ricketts in children and osteomalacia (softening of the bones) in children and adults.

Subclinical vitamin D deficiency (levels below 20-25 ng/ml) can lead to the development of osteoporosis and an increase risk of fractures and falls in adults.

Sources: As very few foods naturally contain Vitamin D, dermal synthesis is the major natural source. Pre-vitamin D is synthesized in the skin during exposure to ultraviolet rays in sunlight. It forms vitamin D3. The length of daily exposure required to obtain the sunlight equivalent of oral vitamin D supplementation varies with the skin type (the darker the skin, the less production of vitamin D), latitude, season and time of day.

Recommended Intake: Infants under one year of age should have 400 IU per day. Formulas are fortified, but supplementation is recommended for breast fed babies. For children 1 year to 18 years and most adults, the recommendation is 600 IU per day. For children who do not drink 32 oz of milk per day, should receive at least 400 IU of vitamin D supplementation per day.

Sun: Sunlight is essential for synthesis of vitamin D; however, the ultraviolet (UV) radiation is also responsible for acute and long-term detrimental effects on human skin, including sunburns, photo-aging and skin cancer. Ultraviolet B or UVB represents only 5% of the UV radiation reaching earth's surface, but is the biologically most active wavelengths. It is responsible for sunburn, inflammation, hyper pigmentation and photocarcinogensis.

UVA contributes to photo-aging and has a major role in pigment darkening and may be involved in cancer induction. The best photoprotection includes avoidance of sun during peak hours, sun-protective clothing and sunscreens.

Sunscreens: These topical preparations contain filters that reflect or absorb radiation in the UV wavelength range. In the US, 17 different UV filters are approved by the FDA. The sunscreens can be classified as organic or inorganic. Broad-spectrum sunscreens are combinations that are able to absorb both UVB and UVA radiation. The sun protection factor (SPF) only measures UVB in the US. Europe has a rating system for both UVA and UVB protection.

The American Academy of Dermatology recommends the choice of sunscreen products that have a SPF of 30 or higher, broad-spectrum coverage (both UVA and UVB) and water or sweat resistance.

Products with a SPF or >50 provide only a negligible increase in the protection from UV radiation. The only three ingredients that satisfy UVB, UVA2, UVA1 protection are: Avobenzone (organic), Zinc Oxide (inorganic) and Titanium Dioxide (inorganic). Oil based emulsions of inorganic filters (titanium dioxide or zinc oxide) are preferred, as they offer broad-spectrum protection and have minimal irritation, sensitization and skin penetration potential. One of my favorites is "Blue Lizard", an Australian sunscreen with Zinc Oxide and Titanium Dioxide.

Proper Use of Sunscreens: sunscreens must be applied liberally, repeatedly and to all sun exposed parts of the skin. There is a "teaspoon rule" which advises a teaspoon to the face and neck, 1 to each extremity, 2 to the front & back torso and to each lower extremity. The sunscreen should be applied 15" before exposure and reapplied every 2 hours and after swimming or sweating.

Photo-protective Clothing: (UPF) is the degree of protection provided by clothes. A UPF of 15-24 is good, UPF of 25-39 us very good and a UPF of 40-50 is excellent.

Dr. Ann Marie Rogers, founder of Rainbow Pediatrics, was named one of the "Outstanding Pediatricians in Central Ohio" by Columbus Monthly, and also Ohio's "Outstanding Pediatrician of the Year," according to the American Academy of Pediatrics (AAP), Ohio Chapter. Dr. Rogers was also awarded the Lifetime Achievement award from Nationwide Children's Hospital.

Learn More  about Rainbow Pediatrics 

Topics: vitamin D, sunscreen