Dr. Magryta: The importance of sun and Vitamin D
Sun exposure and vitamin D is so important that I offer a yearly refresher on this critical issue.
Vitamin D is arguably the most important micronutrient. It is one of the four fat soluble vitamins and has the added benefit of being synthesized in our skin via the sun’s UVB rays.
We all love sunny days and the effect the sun has on our psyche. For centuries humans have lived by the sun, whether by regulating our sleep cycle or producing our natural foods. Yet recently we have shunned the sun by avoiding it and overusing sun-blocking agents and lotions. Skin cancer during the 60s and 70s ushered in a period of phobia. True to our nature, we chose the extremist way: total avoidance.
This has helped produce a generation of Vitamin D deficient Americans. In the recent past the medical community believed that Vitamin D simply controlled calcium and phosphorus metabolism and bone health. Recent evidence has shown this to be the tip of the iceberg. Vitamin D stimulates the immune system from birth and plays a role in natural immune system function. Inadequate levels are being linked to autoimmune disease like multiple sclerosis and cancers.
Vitamin D-associated diseases are noted to be more common at northern latitudes on the globe where sun exposure is limited by temperature and the sun’s height in the sky.
Our lifestyles have increased sedentary indoor work and recreation thereby reducing sun exposure. Sunscreens also effectively reduce the suns beneficial effects. According to the National Institutes of Health there is an inverse relationship between Vitamin D levels in the body and cancer. It is time for everyone to pay attention to this ever-important hormone made in our skin.
The goal of prevention of skin cancer should be to avoid sunburns which are noted to be a risk factor for cancer. Exposure to 15 to 30 minutes of direct sun a day has never been shown in any way to be dangerous. However, the beneficial effects on Vitamin D levels are well known at roughly 10 to 15,000 IU of Vitamin D during this brief exposure. You would need 100 cups of milk to equal this amount!!
Dr. Holick, a dermatologist and Vitamin D specialist from Boston University, has espoused prudent sun exposure and the evaluation of your Vitamin D status especially if one suffers from bone pain, muscle weakness, chronic fibromyalgias, osteoporosis, irritable bowel syndrome and other non-specific inflammatory diseases. The recommendations for supplemental Vitamin D also increase as one ages. The skin of the elderly is less able to synthesize Vitamin D through sun exposure.
Part of this diet includes eating fish where 3 ounces of salmon will provide 400IU of Vitamin D. Weight bearing exercise is also a part of a healthy aging plan. .
Children who are exclusively breastfed may require Vitamin D supplementation. The American Academy of Pediatrics recommends 400IU of vitamin D per day in these infants.
Food sources of Vitamin D are dairy, fish, eggs, mushrooms and fortified foods like orange juice and cereals.
As we age we have a harder time synthesizing vitamin D via our skin surface, making supplementation necessary. Remember that your skin color dictates how fast you can make D. Darker skin = more time to generate adequate D and lighter skin is the converse. Between the months of November and April, it is quite difficult for most individuals to generate adequate D from the sun in the mid to northern United States.
Most adults need 2000-5000 IU/day; incrementally less for kids. This is easily obtained from the sun for most individuals. Your place of residence and skin color will effect the ability to obtain D from sun exposure. The farther north you live in the United States, the more time in the sun you will need to produce vitamin D. If you you have dark skin tones that reflect the sun back, you will need more exposure for adequate D development. Dark skin color is an advantage for preventing skin cancer, but a disadvantage for developing D.
Over-consumption of vitamin D can be toxic as it is fat soluble and can accumulate in our fat cells. Symptoms of toxicity include hypercalcemia, bone pain, kidney stones, calcium deposits in the body.
Diseases that could increase the risk of toxicity include: sarcoidosis, hyperparathyroidism, tuberculosis, lymphoma and other cancers. There is only one way to be sure that you are not in the toxic range and that is to test blood levels. I highly recommend this test, if you are taking 5000IU or more daily for adults and incremental less for kids.
People at risk for insufficiency or deficiency have: sun avoidance behavior, issues with intestinal fat malabsorption, intestinal dysbiosis, inflammatory bowel disease, eating disorders, celiac disease and disorders of bile production or pancreatic enzyme production, chronic kidney disease, magnesium deficiency and older age.
There are many drugs that interfere with vitamin D.
Dr. Magryta is a physician at Salisbury Pediatric Associates. Contact him at firstname.lastname@example.org