Small amounts of something bad may be good for you

Small amounts of something bad may be good for you

by Donald L. Smith

The Hormesis Conundrum

The term hormesis refers to the beneficial effects derived from low doses of potentially harmful substances. Therefore, the hormesis conundrum states that while too much of a good thing may be bad for you, a small amount of something bad may be good for you. A New Look

The worldwide healthcare community is beginning to take another look at hormesis due to its importance, particularly in the case of substances such as vitamins and minerals that are essential for life at low doses but toxic at higher ones. Moreover, while pharmaceutical drugs provide benefits at lower dosage levels, they generally have harmful properties at higher levels.

One example is aspirin. One aspirin tablet daily can reduce the risk of heart attack and two tablets can help relieve pain and fever; however, 20 or more tablets in a single dose would cause gastric irritation and the potential for serious ulceration, bleeding disorders and possibly death.

There are many other examples that can be included. Exercise and caloric restriction are examples of processes that are harmful in the extreme and beneficial in moderation. Finally, excessive stress can cause both emotional and physical disabilities while less intensive stressful life situations provide feelings of accomplishment and usefulness.

Likewise, the benefits of sensible, moderate and responsible exposure to UVR, defined as a dose of UVR below the level that will cause UVR-induced sunburn, far outweigh the minimal and risks involved. On the other hand, overexposure, which is defined as a dose sufficient to cause UVR-induced sunburn, clearly is detrimental and harmful and always should be avoided.

Toxic vs. Therapeutic Levels

To paraphrase the Swiss physician Paracelsus, "It is the size of the dose that makes the poison either harmful or beneficial."

This simple statement is the basis for the hormesis conundrum. Toxicity is defined as the quality of being poisonous. A poison is any substance which, when ingested, inhaled, absorbed, injected or applied, may cause damage to structure or disturbance of function. Therefore, the toxic level of a substance or process is a dose that will be harmful to an individual.

On the other hand, therapy is defined as the science and art of healing. The therapeutic level of a substance or process is a dose that is below the toxic level and yet strong enough to be beneficial. It is common for the toxic dose and the therapeutic dose to be quite close together which is why it is so important to always follow directions when taking prescription drugs.

At the top end of the therapeutic range is the optimal dose for a given substance or process. This is the level that is most beneficial to the individual. Anyone who is receiving a sub-optimal level of a given substance or process is considered to be receiving insufficient levels. If the level is decreased further, the person may become outright deficient.

For example, a person who is deficient of vitamin D develops rickets (a serious disease that causes deformity of the bone). Meanwhile, someone who is receiving insufficient amounts of vitamin D may develop less serious bone diseases. However, it is important to note that sub-optimal levels of vitamin D now are known to contribute to the development of breast cancer, colon cancer, prostate cancer, osteoporosis, osteomalacia, coronary heart disease and type II adult onset diabetes.

Vitamin D supplements try to mimic the vitamin D that is produced naturally by the action of UVR on our skin. The problem is that while it takes 1,000 IU (International Units) to 1,200 IU to maintain optimal levels of vitamin D, ingestion of more than 600 mg/dl per day can be toxic to some individuals. Fortunately, any excess vitamin D that is produced by the skin is eliminated by the liver and there has been no known toxicity reported from the normal, natural vitamin D produced by UVR.

The medical community has known the profile of those individuals who are most sensitive to UVR for more than 20 years. All Caucasian Skin Type 1 individuals and Skin Type 2, 3 and 4 individuals who do not develop and maintain a year-round tan are susceptible to sunburn and skin damage. Those individuals should avoid the sun for protracted periods of time between 10 a.m. and 3 p.m. and they should properly apply (2 mg of lotion/cm² of skin) an SPF 8 or 15 sunscreen when they must be outside or they should wear protective clothing.

Is A Tan Protective?

Barbara A. Gilchrest, M.D. and Mark S. Eller, M.D., of the Department of Dermatology at the Boston University School of Medicine published an article in the September 1999 issue of Journal of Investigative Dermatology that answers this question. The authors found that:

• Both natural skin color and an adaptive tan provide protection against UV-induced damage to the skin.
• UV photons directly are absorbed by melanin polymers which helps the body get rid of the otherwise injurious energy as heat and the melanin polymers also can absorb potentially damaging free radicals.
• The thickening of the stratum corneum during the tanning process also provides photoprotection especially in individuals with lower skin types.
• Tanned skin becomes far more resistant (by a factor of three to five times) to subsequent UVR injury. (That means that a tan acts like an SPF 3-5 sunscreen.)
• The darkening of the skin during the tanning process and the enhanced DNA repair capacity that results (and possibly other unknown factors) can be presumed important in protecting the skin from both sunburn and chronic (including the development of skin cancer) UV damage.

The bottom line is that it does not matter whether an individual is born with darker natural skin colors or acquires and maintains a tan year-round, the photoprotective benefits are the same. According to Gilchrest and Eller, these benefits are not limited to the prevention of sunburn, but specifically include preventing the development of skin cancer.

That is why it is important to take the time to explain to your clients the concept of hormesis and that it substantiates the premise that the benefits of sensible, moderate and responsible exposure to UVR outweigh the minimal and manageable risks involved. Explain that indoor tanning salons provide a source of controlled UVR as compared to the sunlight.

Take the time to explain that the tanning process is contravolitional which means that it occurs without conscious thought. Tanning should be embraced by the American public if for no other reason than because it is the natural, normal way for an individual to protect themselves from UVR damage.