Aging is a global process we all understand but only now begin to understand on a scientific level. Medically, we can document the gradual decline in the functioning of the cardiovascular system, the pulmonary system, the musculoskeletal system, the endocrine system, the immune system, the skin, the liver and selected groups of neurons in the brain. Often the most limiting and functionally damaging age-related changes are seen when a particular organ or system is called upon to respond to a challenge at a high level. Muscles show a reduced metabolic capacity for strenuous exercise. The heart loses its capacity to sustain high levels of exertion. The immune system shows diminished capacity to kill and remove cells infected by viruses, such as pneumonia. The stress systems of the brain and endocrine system show a diminished capability for a rapid return to baseline functioning after vigorous activation. Each system and organ, and even specific cell types and specific biochemical activities show age-related alterations.
One of the current challenges in geriatric research is understanding why so many age-related changes do occur, and also why some structures, such as many regions of the brain, do not appear to demonstrate age-related deterioration.
Each cell type, organ, and system of the body may have its own pattern of characteristic changes with aging, but a basic set of underlying principles govern the actual phenomena of cell damage, cell death, and reduced physiological capacity.
Several theories have been proposed to account for age-related changes in cell functioning and physiological capability. The free radical theory is perhaps the strongest and best-established theory scientifically to account for many age-related changes. Free radicals are molecules with one or more unpaired electrons; they seek stability by taking electrons from other molecules (a process called oxidation). As a consequence, free radicals damage the molecules from which they take electrons, leading to cell damage, impaired functioning, and even cell death. The prime molecules in the body that are damaged by free radicals are DNA, lipids, and proteins.
Free radical damage to DNA can overwhelm the repair mechanisms in cells, leading to impaired cellular functioning or even cell death. Free radicals also can alter some parts of DNA, provoking uncontrolled cell growth, resulting in cancer, a process that occurs with increased frequency with age. Damage to the DNA in mitochondria, the "energy plants" in cells that generate the energy-producing molecule, ATP, can cause diminished ability of some parts of the body to produce adequate energy for high demands.
Free radical damage to lipids can encourage the damaging oxidation of low-density lipoproteins (LDLs), leading to artery-clogging plaques (atherosclerosis). At the same time, free radical damage to the cells lining the blood vessels (endothelial cells) reduces their ability to react quickly and efficiently to maintain proper blood flow to vital organs. The consequence of these problems is increased heart attacks, strokes, kidney failure, and high blood pressure (hypertension), to name a few of the more dangerous outcomes.
Free radicals also promote a harmful complexing of proteins and carbohydrates, called glycosylation. This process is greatly accelerated in diabetes, and also appears to contribute to cataract formation, damage to arteries, reduced movement of the joints, and other chronic problems.
Smoking and exposure to secondary smoke generate large amounts of free radicals in the body and increase the risk for many chronic diseases. Similarly, toxic pollutants in the environment (both air and water), especially components of smog, do similar damage by generating free radicals. Ultraviolet (UV) light is particularly able to stimulate the generation of free radicals in the skin, leading to premature wrinkling and loss of texture, as well as an increased risk of skin cancer. A great deal of evidence now is accumulating to show that inflammatory molecules generate free radicals and damage target tissues. This process is quite evident at sites such as inflamed joints in patients with rheumatoid arthritis, or in the brain following head trauma. Sometimes this process of inflammatory damage can be rather insidious, as in the case of inflammatory molecules accumulating in the brains of susceptible individuals and accelerating neuron damage in Alzheimer's Disease or other degenerative diseases of the brain.
If optimal benefits of lifestyle approaches are to be appreciated, one cannot wait until after the first heart attack or stroke and then decide that some lifestyle changes are appropriate. This principle was evident in a recent study of patients who had suffered a heart attack and had additional risk factors, such as diabetes. When provided vitamin E supplements for a few years, these individuals did not show improved health outcomes. Far better would have been a lifetime of proper lifestyle interventions, including robust anti-oxidant supplementation. Some approaches to reducing free radical production and damage in the body are obvious. Stop smoking or never begin and stay away from secondary smoke. Minimize exposure to smog and air pollution. Keep skin covered or well shielded with UV skin blocking lotion. And vigorously treat inflammatory problems with anti-inflammatory agents.
An obvious starting point is a diet high in consumption of fruits and vegetables. An excellent source of advice on natural food anti-oxidants, supplements, and phytonutrients is "Dr. Gaynor's Cancer Prevention Program" by Drs. Mitchell Gaynor and Jerry Hickey (Kensington Books, New York, 1999). In addition to dietary anti-oxidants, some supplements are very helpful. Supplements of vitamin E, vitamin C, and selenium should be a major component of everyone's nutritional program. Coenzyme Q10, Pycnogenol, and grape seed extract are additional outstanding supplements. The anti-oxidant actions of the bioflavonoids in the latter two products are particularly good at synergizing the actions of the anti-oxidant vitamins, C and E. As always, a dietary program of foods rich in antioxidants, and anti-oxidant supplements, is best when started early and continued throughout the lifespan.
Ideally, we would like to see a double-blind placebo-controlled study on lifetime (or at least very long term) use of antioxidant supplements, especially as a preventive measure. Unfortunately, such a study is unlikely to be done because of massive costs and the long time demands required. But current scientific evidence overwhelmingly supports the benefits of anti-oxidant supplementation.
David Felten, MD, PhD, is founding Director of the Center for Neuroimmunology and Professor of Pathology and Human Anatomy and Professor of Neurology at Loma Linda University School of Medicine in Loma Linda California. He is an internationally known researcher whose contributions helped to establish the field of psychoneuroimmunology.
© 2000 David L. Felten, M.D., Ph.D.
May 11, 2006 -- Researchers are now getting a better understanding of how much of a class of healthy antioxidants Americans are eating every day.
A new study shows the average American consumes 12.5 milligrams of anthocyanins from fruits, vegetables, and other sources per day.
Anthocynanins are pigments responsible for the blue, purple, and red colors of blueberries, grapes, and other fruits. Recent research has suggested that anthocyanins are potent antioxidants and may provide a variety of health benefits, from promoting a healthy heart to fighting cancer.
Researchers say the total anthocyanin content of various foods varies greatly; many commonly eaten foods have not been analyzed for anthocyanin content. In their study, researchers measured the anthocyanin content of more than 100 foods.
The results showed the highest concentrations of anthocyanins were found in fresh berries -- such as blueberries, raspberries, and blackberries -- as well as other fruits and vegetables. Wine and grape juice also contain significant levels of anthocyanins.
Researchers then estimated the average daily intake of these nutrients based on national dietary surveys. They found the overall daily intake of anthocyanins was 12.5 milligrams per day, much less than estimates published in the 1970s that put average daily anthocyanin intake at 215 milligrams in summer and 180 milligrams in winter.
The main reason for this huge difference in the amount of anthocyanin in American diets is that the 1970 figures were not based on such detailed food surveys as the present study.
Major sources of anthocyanins in the average American diet were fruits, berries, grape juice, and wine. Researchers say with the increasing availability of fresh fruits and vegetables year-round, the average intake of these antioxidants may increase in the future.
Incorporating frozen berries into the diet during the winter months or using nutritional supplements rich in anthocyanins may also help boost Americans' intake of these nutrients.
