a website for people on special diets due to allergies, intolerances
or lifestyle choice.
line decor
line decor


Fall, 2007

Why Light Matters
courtesy, Colleen Huber, N.D.

Evening Sun RaysBone health is greatly dependent on quality light. We make Vitamin D through our skin when exposed to optimal levels of sunlight. Vitamin D is 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 one's exposure to full spectrum light it is possible to optimize hormone levels in the body. Such balance is key to avoiding osteoporosis and fractures, as well as minimizing tooth decay.

Recent research has confirmed the essential role of Vitamin D in such necessary functions as 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 [1]. Only a century ago, we had no light bulbs at all, and we had no fluorescent lights until 50 years ago.

A nine-month long study of first grade children in windowless classrooms found that those under full-spectrum fluorescent lights had many fewer cavities in their newly formed permanent teeth than those under standard "cool white" fluorescent bulbs. It turned out that ten times as many children under cool white bulbs had new cavities [2]. 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 fifteen weeks had five times more cavities and ten times greater tooth loss per cavity (a total of 50 times greater tooth loss) than those 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 those hamsters under cool white light as compared to those 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. [3]

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.

Much research on this subject has been summarized by the German ophthalmologist Fritz Hollwich, MD [4], as well as by John Ott, Hon. D. Sci., a researcher on the properties of light [5]. The array of bodily organs and systems that depend on full-spectrum light through the eyes is astounding. When the eyes are exposed to natural sunlight or full-spectrum light, the pituitary gland, thyroid gland, adrenal glands, ovaries, testes, pancreas, liver and kidneys all function better, according to the numerous studies presented in these two books. Full-spectrum light includes a balance of wavelengths from all colors of the visible spectrum plus ultraviolet and infrared. On the other hand, cool white fluorescent bulbs, which are now used for the great majority of interior commercial lighting, have strong yellow, but are very deficient in most of the other wavelengths, with no ultraviolet or infrared.

Unfortunately, however, UV light has received a bad name, primarily because of individuals who have a history of blistering sunburns followed by skin cancer. There has never been any research showing health benefits of blocking UV light to the eyes. However, it is now impossible to buy eyeglasses that allow full-spectrum light. All of the lenses made in the last ten years for eyeglasses are made to block UV light, even plastic lenses, which if untreated, would allow full-spectrum light. However, full-spectrum light to the eyes is necessary for proper functioning of ovaries, testes and thyroid, according to Hollwich and the research he summarizes.

Earl Staelin, writing in the current issue of the Well Being Journal, summarizes the recommendations of those who have studied light and its health effects, and recommends that individuals who must wear glasses try to get outdoors everyday for 20 to 60 minutes or more without wearing any glasses. If the weather makes this impractical, then it would be beneficial to try to function without glasses indoors under full-spectrum lighting, because the amount of UV light that strikes the retina from around the edges of glasses is insignificant compared to the large amount of light coming through the eye and through the lenses. The full spectrum of daylight need not come from direct sunlight, but is available also on a cloudy day or under the shade of a tree or porch. Glass windows however, do block out UV light, so try to get out in the fresh air if at all possible. On days when even this is difficult, there is yet another recourse, which is distilled cod liver oil. The distillation takes out mercury and other heavy metals, which are all too prevalent in both salt and freshwater fish. Cod liver oil is high in vitamins D and A. I take an average of 2 tablespoons a day, but for your optimal intake, depending on your sun exposure, other health conditions and weight, you should really check with your naturopathic physician.

  1. Earl Staelin, "The Central Roles of Hormones and Natural Light." Well Being Journal. May/June 2006. p27+.
  2. Mayron, Ott, Amontree and Nations, "Caries reduction in school children." Applied Radiology. July/August 1975. pp 56-58.
  3. Sharon, Feller and Burney, "The effects of lights of different spectra on caries incidence in the golden hamster." Archives of Oral Biology. Vol 1, No. 12 1971. pp 1427-1432.
  4. Fritz Hollwich MD. "The Influence of Ocular Light Perception on Metabolism in Man and Animal." Springer Verlag. New York. 1979.
  5. John Ott D. Sci Hon. "Health and Light." Devin Adair Co. 1976.

This article was originally published on Colleen Huber's website, Naturopathy Works. It appeared in the May 2006 Newsletter. Reprinted with permission.

Above photo from stock.xchange.

Previous Page

The content on this site should not take the place of advice from your doctor. Visitors to this site agree to the terms and conditions in the disclaimer.

Copyright © 1999-2012 Robin L. Russell