Light nutrition is just as important to the health of the human mind and body as is food nutrition.
As we know, the source of life on this planet is the sun --- life has evolved for millions of years under the influence and through the vital power of sunlight. As a result, all living beings have developed a variety of biochemical and physiological responses and dependencies with respect to the special characteristics of solar radiation and it's daily and seasonal variations. There is growing evidence that fundamental biochemical and hormonal cycles of the mind/body are directly and indirectly synchronized by the 24-hour light-dark cycle. As light has an important influence on human health, our growing exposure to artificial lighting has harmful effects of which we are rarely aware.
The solar light spectrum is made up of various wavelengths of energy -- the shorter wavelengths have higher frequencies and the longer wavelengths lower frequencies. From short to long these rays are called gamma rays, radioactive isotopes, x-rays, ultraviolet rays, visible light or color, infrared, microwaves, television waves, radio waves, sound waves, and finally waves detectable by touch. All wavelengths of the spectrum influence us in their own subtle and unique ways.
The shorter wavelengths have the ability to penetrate human tissues with no problem (gamma waves, x-rays, etc.), often passing all the way through the body. As the wavelength lengthens the ability to penetrate decreases. Visible light is apparently able to penetrate to a considerable depth while ultra-violet radiation barely reaches the capillaries of the skin. While our tissues respond to this penetration in various localized ways there is another avenue to the body by which light rays have systemic effects. This is through the eyes. Light rays penetrate the eye and activate photoreceptors in the retina, giving rise to a nerve impulse that travels to a part of the brain known as the hypothalamus. The hypothalamus has a small bulb which juts off of it called the pituitary gland. The pituitary gland is half brain tissue and half glandular tissue. It is considered the "master gland", directing and coordinating the function of all the other glands in the body (glands such as the thyroid, adrenals, pancreas, gonads and hypothyroid). The pituitary gland is similar to a switching or transfer station between the hypothalamus and the glandular system of the body. The hypothalamus converts the electromagnetic energy from the suns rays into neuro-chemical impulses which stimulate the pituitary in its organization and direction of our total glandular functioning. Sunlight stimulates the release of serotonin from the brain/ pituitary, a hormone that improves mood and stabilizes well-being. Low serotonin levels can cause seasonal SAD (seasonal affective disorder)
In some people in the winter months when sunlight is in short supply. Decreased seasonal sunlight has also been associated with PMS and anxiety. Studies have shown that there are numerous health conditions that have been linked to a frequency with low sunlight in the environment. It is believed that lack of vitamin D is associated with these higher disease risks. Vitamin D is produced in the skin through a photosynthetic process stimulated by exposure to sunlight (specifically the UVB radiation). To read more about current knowledge with respect to sunlight and the numerous aspects of our health that are related to sunlight exposure and vitamin D.
It is also believed that light influences the body through the pineal gland. This mysterious gland, once thought to be vestigial and non-functioning in modern man, is now known to be an active, secreting gland throughout life. The electromagnetic light energy enters via the eyes, travels down the optic nerve and into the brain, communicating through the central nervous system, eventually stimulating the photoreceptive pineal gland. The pineal gland then stimulates the hypothalamus which influences the entire body and all of its functions via the pituitary gland and the autonomic nervous system.
It is also interesting to note that the action of the pineal gland is related to the alpha wave activity of the brain, sleep induction, vivid dreaming, increased frequency of REM (rapid eye movement) cycles during sleep, moderate feelings of elation and experiences of visual imagery. The pineal functions primarily during sleep when the body and mind are cleansing, restoring, regenerating and stabilizing themselves with respect to daytime activities and stresses. In fact, at Massachusetts Institute of Technology, they have discovered that pineal activity is more than 15 times greater at night then in the daytime.
+ it is the primary source of synchronization of biological rhythms, an aspect of life which we are only just beginning to explore and understand
+ the ultra-violet light interacts with the skin to produce vitamin D, a vitamin which is absolutely necessary for the correct absorption and utilization of calcium and the building of bone
+ ultra-violet light causes both darkening (due to the increase in melanin pigment) and thickening of the outer skin
+ light is often effective in healing psoriasis, eczema, and other skin disorders
+ neonatal jaundice (a condition arising immediately after birth in which the infant's immature liver is unable to excrete the blood bilirubin) is cured by
exposure to light, which decreases the flood bilirubin by a photochemical reaction with it
These are just a few of the important effects of light that we know of --- most likely there is much more yet to be discovered.