Help your patients live longer! Antioxidants combat the effects of aging

Help your patients live longer! Antioxidants combat the effects of aging
June 2007
By Kelly Kwiatkowski, MA
Chiropractic Economics

Aging is inextricably linked to increased incidence of chronic disease. Onset of cardiovascular disease, cancer, diabetes, and neurological diseases such as Alzheimer's is more common later in life.

One characteristic these diseases share is oxidative stress.1 Antioxidants play a key role in protecting the body from oxidative stress.

When discussing antioxidants, the focus is usually on vitamins C and E, as well as beta carotene, since they are identified as powerful antioxidant agents in the human diet and are heavily researched. Scientists debate whether oxidative stress causes or contributes to chronic diseases; however, research shows that antioxidants have the potential to have positive effects on health.

Cell culture and epidemiological studies demonstrate antioxidants' ability to combat free radical damage and defend against oxidative stress. But, large randomized control trials studying the effects of these antioxidants individually demonstrate little or no health benefit.2

So, if the research is so mixed, why worry about dietary antioxidants?

Research is just beginning to recognize the shortcomings of studying antioxidant nutrients in isolation. Scientists are studying a dizzying array of natural compounds with antioxidant properties, with hundreds more yet to be identified.

Similarly, the antioxidant system is intricate and complex, involving many functions of the body, and the specific mechanisms responsible for the protective effects of antioxidants remain unclear.3 Scientists know that a higher intake of antioxidant-rich fruits and vegetables is associated with a reduced risk for many chronic diseases including cardiovascular disease, cancer, diabetes, and neurological diseases.4, 5, 6, 7

One hypothesis is that the high antioxidant content of these foods contributes to the protection of cells from free radical damage. Presumably, the numerous antioxidant phytochemicals in whole foods work synergistically to reduce the risk of disease.8

Let's review what's known about free radicals and the antioxidant system, and what kinds of dietary interventions may be done to promote longevity and reduce the risks of age-related diseases.

FREE RADICALS

Free radicals are unstable molecules that may react harmfully with DNA, proteins, and lipids in cells, eventually causing decreased metabolic function and disease. They originate both from the body's normal metabolic processes and from external sources such as cigarette smoke and other environmental chemicals.

The body requires oxygen to produce energy and perform many biological processes to keep it functioning properly. Oxidation, a reaction in which atoms or molecules gain oxygen or lose hydrogen or electrons, is part of the process by which the body derives energy, but is also sometimes harmful to the body's cells.

Under normal conditions, the body effectively neutralizes free radicals before they are produced in excess. However, when detoxification mechanisms are overwhelmed, the excess free radicals generated can lead to oxidative stress. The body's antioxidant system is designed to prevent and defend against oxidative stress.

THE ANTIOXIDANT SYSTEM

Antioxidants are chemicals either produced by the body or acquired through diet. They counteract the effects of oxidation on cells by neutralizing free radicals.

Antioxidant enzymes occur naturally in the body and provide an important defense against oxidation. Dietary antioxidants found in many foods Û particularly fruits and vegetables Û are antioxidants that also neutralize free radicals. These provide an additional defense against oxidation. Benefits from these antioxidants can only be obtained through diet, as the body cannot manufacture them.

OXIDATIVE STRESS AND DISEASE

Oxidative stress is the imbalance between the production of free radicals and the body's ability to keep them in check.9 Throughout our lives, our bodies are repeatedly exposed to and regularly challenged with ridding themselves of toxins. As we age, it is hypothesized that the accumulation of toxins, leading to oxidative damage, creates such an imbalance that it causes physio-logical impairment and disease.10

Research on the links between oxidative stress and cardiovascular disease, neurological disease, and cancer suggests that free radical damage may be a causative factor in their pathology. It is hypothesized that free radical damage to low density lipoprotein (LDL) may be a causative factor in cardiovascular disease,1 and free radical damage to DNA may be a factor in the development of cancer.11 DNA damage,12 protein oxidation,13 and lipid peroxidation14 have all been implicated in age-related neurological diseases such as Alzheimer's and Parkinson's disease.

Reducing risk of disease

Help your patients take advantage of the power of antioxidants to combat the effects of aging. Advise them to:

Ô Eat lots of whole foods Û especially fruits and vegetables;

Ô Maintain a healthy weight; and

Ô Exercise regularly.

These three action items can significantly reduce risks for many chronic diseases. Increased intake of fruits and vegetables is associated with a lower risk of all-cause mortality, cancer, and cardiovascular disease.5

In particular, epidemiological studies show that dietary intake of carotenoid-rich fruits and vegetables is associated with a reduced risk of many cancers15 and cardiovascular disease.16

Studies also demonstrate that consumption of cruciferous vegetables improves cholesterol metabolism, decreases markers of oxidative stress,17, 18, 19 and may reduce the risk of many types of cancer.20

Editor's note: Studies referenced in this article can be found at www.ChiroEco.com/history. Look under BONUS articles.

THE ANTIOXIDANT POWER OF PHYTOCHEMICALS

The mechanisms behind the health-protective effects of fruits and vegetables are unclear, but it is believed the antioxidant capacity of the phytochemicals contained in fruits and vegetables play a significant role.

Many phytochemicals, including the common pigments found in plants, have been shown to have strong antioxidant and antipro-liferative activities which may contribute to a reduction of risk of many chronic diseases. Major classes of phytochemicals which demonstrate antioxidant activity include the turpenoids, polyphenols, and organosulfides. Table 1 shows some of the major classes of antioxidant phytochemicals and their food sources.

Carotenoids refer to a class of fat-soluble pigments in many fruits and vegetables. Cell culture studies support the epidemiological evidence that carotenoids have strong antioxidant action which may provide protection to the heart and in the body's cells.21, 22

Flavonoids, flavanols, and anthocyanidins are subclasses of the large class of polyphenolic phytochemical compounds. There is good evidence of rutin's anti-inflammatory effects23, 24, 25 and its ability to effectively decrease free radicals.26 Intake of resveratrol is often associated with reduced risk of heart disease and cancer.27 Research demonstrates that dietary intake of resveratrol inhibits lipid peroxidation28, 29 and has shown to inhibit free radical production.30 Catechins, flavanol chemicals found in different varieties of tea, have powerful antioxidant activity and are noted for their chemoprotective, cardioprotective, and anti-inflammatory effects.31, 32, 33

Research strongly suggests that foods rich in antioxidants have a protective effect against diseases influenced by oxidative damage. Although studies examining the effects of individual antioxidants have been disappointing, it is important to recognize the diversity of phytochemicals found in whole foods may be responsible for those protective effects.

Researchers are working to fully understand the complex metabolic processes involved in the anti-oxidant mechanisms of food. Until then, eating an antioxidant-rich diet is the body's best dietary defense against harmful free radicals and the best way to maintain longevity.

NOTE: The article also includes a table, which can be viewed at the website.