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Why Light Matters

Written by Colleen Huber, NMD   
Monday, 01 December 2008 00:00
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Bone health is greatly dependent on quality light. We make vitamin D when our skin is exposed to optimal levels of sunlight. Vitamin D is the key to a proper quantity and balance of calcium and magnesium in the body, as well as a healthy balance of hormones. A growing body of research demonstrates that, by increasing exposure to full spectrum light, it is possible to optimize hormone levels in the body. Such balance is vital to prevent osteoporosis and fractures, as well as minimizing tooth decay.

Recent research has confirmed the essential role of vitamin D in necessary functions, including insulin secretion, cancer prevention, bone health, and hormone formation.

Historically, osteoporosis and age-related fractures have hit hardest at those populations who stay in the dark. Contemporary Americans and Europeans who stay indoors much of the time have much higher rates of osteoporosis than people whose lifestyle kept them outdoors or dependent on natural light. Between the 1950s and 1980s the incidence of hip and other fractures among the elderly in Sweden and England roughly doubled. Only a century ago, we had no light bulbs at all, and we had no fluorescent lights until 50 years ago.

A 9-month study of first grade children in windowless classrooms found that children under full-spectrum fluorescent lights had many fewer cavities in their newly formed permanent teeth than those under standard “coolwhite” fluorescent bulbs. It turned out that 10 times as many children under cool-white bulbs had new cavities. Many fewer cavities were also found when incandescent bulbs, which are higher in red and infrared, were used instead of full-spectrum fluorescent bulbs. The authors also found that a broad spectrum of ultraviolet, red, and infrared light was important for the formation of teeth as well as resistance to decay.

Animal studies have confirmed this. Hamsters placed under cool-white bulbs 12 hours per day for 15 weeks had 5 times more cavities and 10 times greater tooth loss per cavity (a total of 50 times greater tooth loss) than hamsters placed under fluorescent bulbs with ultraviolet added to approximate natural sunlight.

Furthermore, the development of the male sexual organs was only one-fifth as great in hamsters under cool-white light as compared to hamsters under full spectrum light. Of course, this result correlates with our knowledge that testosterone, a steroid hormone, is dependent on vitamin D for its synthesis, a vitamin that we make from sunlight.

It has also been found that the role of full-spectrum light benefits the eyes as well as when it strikes the skin. The natural light received by the eyes plays a vital role in body chemistry. The light received by the eyes influences the hypothalamus, which in turn influences the pituitary and pineal glands. The pineal gland especially is involved in our diurnal rhythms, and our lack of quality light through the retina may be the source of many sleep disorders that are increasingly common among people who are always indoors.