Vitamin D, also known as calciferol, is a fat-soluble vitamin that is naturally present in some foods and added to others. It is also produced by cholesterol when sunlight strikes your skin. It is estimated that 40% of all adults in the USA are Vitamin D deficient. People living in the northern hemisphere (that’s us) are especially prone to vitamin D deficiency. Vitamin D is needed by the body to help absorb calcium and phosphorus; two minerals needed for bone health. Inadequate levels of Vitamin D can lead to osteoporosis, cancer, depression, muscle weakness, and death. Getting enough sunlight is essential to health, but too much sun comes with its own health risks, so how much is enough? Studies show that about 15-30 minutes of sun, three times per week, with face, arms and legs exposed, was enough for the body to produce adequate Vitamin D. This is for fair skinned, Caucasian individuals. People with darker skin or those who tan easily have increased melatonin which adds a natural layer of sun protection. These individuals need increased sun exposure to produce adequate vitamin D levels. Studies also indicated that midmorning to noon was the most ideal time to get this sun exposure to minimize health risks whereas later afternoon sun exposure was shown to have negative effects on health. So, what about sunscreen? Sunscreen starts to block the UV rays as soon as it is applied but takes 15-20 minutes to take full effect. Applying sunscreen immediately if you plan to be outside for longer than 15-20 minutes will still allow your body time to absorb some sunshine without risking too much sun exposure.
April Sorensen, RDN