Antioxidants & Aging
In 1956, D. Harman proposed a
free radical theory of aging, hypothesizing that oxygen-derived free radicals
(reactive oxygen species – ROS) are generated throughout all cells and tissues,
resulting in progressive, random damage to enzymes, proteins, unsaturated lipids,
cell membranes, and to our genes. The end result is cell senescence. Since then,
abundant experimental and observational evidence supports the idea that aging
is the sum of all free radical reactions throughout all cells and tissues, or
at least they are major contributors to it.
Free
Radicals
Oxygen-derived radicals (ROS) are produced in abundance
in all animal cells and tissues as part of our normal metabolic processes. Fortunately,
our body has numerous natural defenses to either prevent their formation or to
neutralize them after they are formed. In spite of our natural defenses, it has
been estimated that each human cell undergoes 10,000 “hits” by free
radicals each day. Although most free radicals are potentially harmful, others
are essential to many intracellular metabolic reactions. For example, they are
deployed by phagocytic cells to kill ingested microorganisms.
The
aging and nutrition connection?
Aging is a complex process which
results from cellular, physiological, and psychological changes. While all people
show a decline in metabolic activities and organ functions as they age, they exhibit
declines differently and at different rates. Why? The theory goes that those who
have a closer association with poor health habits, such as smoking, high consumption
of alcohol, increased stress, and poor diets do not age well.
Ideally,
we should all practice preventive nutritional tactics, eating foods which have
minimal processing such as fruits, vegetables, whole grains, legumes, non-fat
dairy products, lean meats, and lots of fish. Taking multi-vitamins and mineral
supplements in moderate doses can also be beneficial, and there is a lot of talk
around the power of antioxidants.
Antioxidant
Supplementation
There is evidence showing that antioxidants can potentially
delay the aging process, and also protect against the development of age-related
diseases.
In a study of centenarians, the plasma levels of vitamins
C and E were higher compared to subjects 70-99 years old. Another study evaluated
the maximal life-span potential of humans as well as other mammalian species.
The authors suggested that carotenoid content of serum and brain tissue may be
the most significant factor in determining life span, and there is a link between
longevity, antioxidant concentration, and protection against free radical damage.