Bright Light On Human Health
How the sun and seasons affect our well-being
Fall is a special time of year for a lot of us. Not only are many headed back to school, but others are headed outdoors for amazing colors and wildlife. Summer this year was shadowed by smoke and high temperatures. Fall, I hope, will be a refreshing and settling season.
It seems we are guided by the position of the sun in many of our activities. How much light there is, how warm we feel, the growth and nurturing of foliage and plants. The sun also is a big factor in our health. Certainly, we tend to be more active during the longer days of the year.
A widely understood health benefit of the sun is vitamin D. One form of this compound is a hormone that regulates over 1,000 different genes in the body, including those responsible for bone mineralization and immune response.
The body makes the D3 form of vitamin D through photosynthesis and then converts this into other forms primarily in the liver. It is estimated that if you were in a bathing suit in the summer sun for 30 minutes your body would generate between 8,000 and 50,000 IUs of vitamin D. If your skin is darker, you may need five to six times more solar exposure than someone with pale skin.
Of course, most of us typically don't get exposed to that much sun, nor walk around in bathing suits. Thus, vitamin D has become one of the most common deficiencies I encounter.
Avoiding sun exposure has risen with warnings about sun induced health problems. With so many cautions about the harmful effects of the sun, we often keep our bodies covered even during the summer. Excessive sun exposure can be problematic. There are some that think the emphasis on preventing skin cancer, though, has obscured the benefits of an appropriate amount of sun.
Too little sun exposure can be problematic in terms of vitamin D levels. That is why so many of us end up supplementing. Low levels of sun exposure at higher latitudes are showing potential links to multiple sclerosis, type 1 diabetes, metabolic syndrome, hypertension, cardiovascular disease, rheumatoid arthritis, asthma, and infectious diseases.
Interestingly enough, in one study tanning beds that use full-spectrum lighting were shown to increase vitamin D levels 180% which resulted in a corresponding decrease in blood pressures in participants.
Studies are not always enough to be definitive and can be misinterpreted. Nevertheless, the benefits of vitamin D have become consistently clear. Especially for mood, sleep regulation, and immune response to viral infections.
I think having enough vitamin D is essential. How much is enough then becomes an important question. The best way to know is to take a blood test and see what your levels are, then adjust from there.
Here in North Idaho, I see the average adult range between 4,000 and 10,000 IUs a day. More in the winter, less in the summer. Taking vitamin K with vitamin D is essential from my perspective. It acts synergistically and helps make sure calcium gets to the right places and not stuck in our arteries.
Andy Pottenger, PharmD, supports optimal health and well being through functional medicine and integrative nutrition.