Light for Life:
update on the therapeutic applications of light
Light from the sun is the primary source of energy driving all life in the surface of our planet, so it is not surprising that it plays such a powerful role in human health. The use of light for healing is as old as humanity itself, and is documented in ancient Egyptian, Indian and Greek texts. Sunlight was a key medical tool for the ancients, either in its pure form as heliotherapy, or filtered through colored materials such as gems. In the West however, its role was obscured for many centuries because Christianity deemed heliotherapy to be a form of sun worship and proscribed it as paganism.
Only towards the end of the 19th century did it begin to arouse renewed interest, with numerous heliotherapy sanatoriums throughout the world becoming the preferred medical providers for intractable diseases such as tuberculosis. Such was the respect accorded to light medicine during this period that one of the very first Nobel Prizes for Medicine was awarded to Niels Ryberg Finsen in 1903 for his pioneering work in phototherapy. Unfortunately, this was not to last: following the rise of antibiotics in the 1930s light therapy was once again relegated to “medical paganism”, this time through the conflict between orthodox (pharmaceutical) and alternative (naturopathic) medicines. There it remained for the rest of the 20th century, mostly considered as quackery – until two key discoveries initiated the current renaissance in light medicine.
The first discovery, dating from the 1990s, is that light can directly enhance cell metabolism through a complex chain of biochemical processes termed photobiomodulation occurring within the mitochondria (tiny energy engines within each of our cells). This understanding opened the whole new field of Low Level Light Therapy (LLLT), where non-thermal low levels of light are used for various regenerative purposes. Kick-started by NASA in the early 2000s for the treatment of its astronauts, LLLT is now gaining widespread medical acceptance.
Today the underlying cellular processes involved in photobiomodulation are the focus of intensive worldwide research, and the specific effects of different colors are being explored. For example, blue is used for acne treatment, yellow-orange for skin toning, red for wound healing, infrared for joint relief. One of the most promising recent developments is transcranial light therapy, where infrared light shining through the cranium (which, surprisingly, transmits 2-3% of its flux) heals brain cells and can alleviate strokes, dementia and depression.
Light, in addition to fulfilling the practical functions we are familiar with, also has a profound impact on our health and well-being. While light has traditionally been used for therapeutic purposes by most ancient cultures, since the beginning of the 21st century we are witnessing a remarkable acceleration in the amount of scientific research devoted to light medicine, with thousands of articles now published yearly.