American Journal of Clinical Nutrition, Vol. 86, No. 5, 1486-1494,

November 2007
© 2007 American Society for Nutrition

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ORIGINAL RESEARCH COMMUNICATION

Prospective study of dietary pattern and risk of Parkinson disease1,2,3
Xiang Gao, Honglei Chen, Teresa T Fung, Giancarlo Logroscino, Michael A Schwarzschild, Frank B Hu and Alberto Ascherio
1 From the Departments of Nutrition (XG, TTF, FBH, and AA) and Epidemiology (GL, FBH, and AA), Harvard School of Public Health, Cambridge, MA; the Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School (FBH and AA), Boston, MA; the Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC (HC); the Department of Nutrition, Simmons College, Boston, MA (TTF); and the Department of Neurology, Massachusetts General Hospital, Boston, MA (MAS)


Background: Several studies have shown associations between Parkinson Disease (PD) risk and individual foods and nutrients with inconsistent results.

Objective: We examined associations between dietary patterns and risk of PD in the Health Professionals Follow-Up Study (1986–2002) and the Nurses' Health Study (1984–2000).

Design: We included 49 692 men and 81 676 women free of PD at baseline and used principal components analysis to identify major dietary patterns and the Alternate Healthy Eating Index (AHEI) and the alternate Mediterranean Diet Score (aMed) to assess diet quality. Relative risks (RRs) were computed by using Cox proportional hazards models within each cohort and were pooled by using a random-effects model.

Results: We documented 508 new PD cases after 16 y of follow-up. The principal components analysis identified 2 dietary patterns: prudent and Western.
The prudent dietary pattern, characterized by high intakes of fruit, vegetables, and fish, was inversely associated with PD risk, but the Western pattern was not.
The pooled multivariate-adjusted RR for the top compared with the bottom quintiles of the prudent score was 0.78 (95% CI: 0.56, 1.07; P for trend = 0.04). For the AHEI, the pooled multivariate-adjusted RR for the top compared with the bottom quintile was 0.70 (95% CI: 0.51, 0.94; P for trend = 0.01) and for aMED was 0.75 (95% CI: 0.57, 1.00; P for trend = 0.07).

Conclusions: Dietary patterns with a high intake of fruit, vegetables, legumes, whole grains, nuts, fish, and poultry and a low intake of saturated fat and a moderate intake of alcohol may protect against PD. Benefits of a plant-based dietary pattern including fish to PD merit further investigation. Key Words: Parkinson disease • dietary pattern • prospective study • dietary index • principal components analysis

Staying on Top of Oxidative Stress

By Stephen Byrnes, ND, RNCP

Editor's Note: Oxidative stress (OS) is fast becoming the nutritional and medical buzzword for the 21st century. Implicated in a growing list of diseases, from cataracts to cancer, health-conscious people should take steps to protect themselves against the ravages of free radicals, the active criminals in OS. Despite the growing dangers of OS, there are some simple, but powerful, weapons against it. An avoidance of factors that contribute to OS; a diet of whole, organic, unprocessed foods; and supplemental anti-oxidants, afford the best protection against this serious and insidious condition.

Oxidative Stress (OS) is not, in and of itself, a disease but a condition that can lead to or accelerate it. OS occurs when the available supply of the body's antioxidants is insufficient to handle and neutralize free radicals of different types. The result is massive cell damage that can result in cellular mutations, tissue breakdown and immune compromise.

What are free radicals? They are highly unstable molecules that interact quickly and aggressively with other molecules in our bodies to create abnormal cells. They are capable of penetrating into the DNA of a cell and damaging its "blueprint" so that the cell will produce mutated cells that can then replicate without normal controls. Free radicals are unstable because they have unpaired electrons in their molecular structure. This causes them to react almost instantly with any substance in their vicinity. Oxygen, or oxyl, free radicals are especially dangerous.

Surprisingly, however, free radicals are involved in many cellular functions and are a normal part of living. When, for example, a mitochondria within a cell burns glucose for fuel, the mitochondria oxidizes the glucose and in so doing generates free radicals. White blood cells also use free radicals to attack and destroy bacteria, viruses and virus-infected cells. The detoxifying actions of the liver also require free radicals.

Although free radicals have useful functions in the body under controlled conditions, they are extremely unstable molecules that can damage cells if left uncontrolled. Free radicals destroy cellular membranes; enzymes and DNA. They accelerate aging and contribute to the development of many diseases, including cancer and heart disease.

Its important to note here that free radicals are also released in the body from the breaking down or detoxification of various chemical compounds. Additionally, certain foods contain free radicals which, when eaten, enter the body and damage it. The major sources of dietary free radicals are chemically-altered fats from commercial vegetable oils, vegetable shortening and all oils heated to very high temperatures.

Antioxidants to the Rescue
Fortunately, the body maintains a sophisticated system of chemical and biochemical defenses to control and neutralize free radicals. Chemical antioxidants scavenge free radicals, that is, they stabilize the unstable free radicals by giving them the electron they need to "calm down." The antioxidants are usually consumed or used up in this process--they sacrifice themselves.

The main antioxidants are vitamins A, E and C, betacarotene, glutathione, bioflavonoids, selenium, zinc, CoQ10 (ubiquinone), and various phyto-chemicals from herbs and foods. Green tea, for example, is rich in polyphenols--powerful antioxidants that help fight cancer.

Biochemical antioxidants not only scavenge free radicals, but also inhibit their formation inside the body. These include lipoic acid, and repair enzymes such as catalase, superoxide dismutase (SOD), glutathione peroxidase. Melatonin, a hormone produced by the pineal gland, is also a potent antioxidant. Cholesterol, produced by the liver, is another major antioxidant, which the body uses to repair damaged blood vessels. It is probably for this reason that serum cholesterol levels rise as people age. With age comes more free radical activity and in response the body produces more cholesterol to help contain and control the damage.

Of all the antioxidants, glutathione appears to be pivotal. Made up of three amino acids (cysteine, glycine, and glutamic acid), glutathione is part of the antioxidant enzyme glutathione peroxidase and is THE major liver antioxidant. It is a basic tenet of natural medicine that health cannot exist if the liver is toxic. Not surprisingly, extremely low levels of glutathione are found in people suffering from severe OS. People with AIDS, cancer and Parkinson's disease, for example, typically have very low glutathione levels.

As noted earlier, oxidative stress occurs when the amount of free radicals in the body exceeds its pool of available antioxidants. Obviously, knowing the varied sources of free radicals and avoiding them is an important part of minimizing their harmful effects.

Where Do They Come From?
As noted above, diet can be a major source of free radical stressors with processed or highly heated oils being the main offenders. If you are still using "foods" like refined vegetable oils, margarine or shortening (or "foods" made with them such as all commercial baked goods and "snack" chips), you need to remove them from your diet. Replace these harmful fats with natural, cold pressed oils such as olive oil (which can be used for cooking) and small amounts of flax oil or walnut oil (which should never be heated). Food grade, unrefined coconut oil and organic butter are also excellent choices, especially for cooking. Both of these naturally saturated fats are rich in certain fatty acids that have proven activity against bacteria, harmful yeasts, fungi and tumor cells.

Additionally, since saturated fats (from animal foods and the tropical oils) and monounsaturated oils (from olive oil and cold-pressed nut oils) are more chemically stable, they are much less susceptible to oxidation and rancidity than their polyunsaturated cousins, which are mostly found in vegetable oils. As a general rule, then, although the body does require a small amount of naturally occurring polyunsaturated oils in the diet each day, it's best not to consume too much of them as they are more prone to free radical attack in the body. As Linus Pauling, PhD noted: "A diet high in unsaturated fatty acids, especially the polyunsaturated ones, can destroy the body's supply of vitamin E and cause muscular lesions, brain lesions, and degeneration of blood vessels. Care must be taken not to include a large amount of polyunsaurated oil in the diet

The best food sources for polyunsaturates are fish, flax oil, sesame oil, walnut oil and dark green, leafy vegetables. One caveat: canola oil is not recommended due to its chemical instability and its content of trans-fatty acids (TFAs), formed during processing. TFAs are increasingly being linked wtih cancer, immune system dysfunction and heart disease.

Excessive sugar intake can also contribute to free radical damage. White and brown sugars, and even sugar from so-called natural sources, such as fruit and fruit juices, maple syrup and honey, get converted into triglycerides by the liver and are subject to free radical damage. These damaged fats then promptly attack your arteries and directly contribute to cardiovascular disease. Additionally, cancer and tumor cells feed off of sugar. It is for this reason that excessive sugar intake correlates very strongly with heart disease, cancer and a host of other ailments.

Poor nutrition in general contributes to OS. When the body is fed poorly, it slowly starves and all of its systems suffer. Weak organ systems are prime targets for free radical attack.

Free radicals are also released in the body from the detoxification of drugs (whether legal or illegal), artificial food colorings and flavorings, smog, preservatives in processed foods, alcohol, cigarette smoke, chlorinated drinking water, pesticides, radiation, cleaning fluids, heavy metals such as cadmium and lead, and assorted chemicals such as solvent traces found in processed foods and aromatic hydrocarbons such as benzene and naphthalene (found in moth balls).

Even psychological and emotional stress can contribute to OS. When the body is under stress, it produces certain hormones that generate free radicals. Moreover, the liver must eventually detoxify them and that process also generates free radicals.

Heightened OS has also been observed in athletes after intensive workouts due to the physical stress placed on the body. Both physical and emotional stress also prompt the release of endogenous cortisol, an adrenal hormone that reduces inflammation, but also suppresses the immune system.

It should be obvious that all of us are exposed to free radicals from a variety of sources. Those of us living in cities are exposed to very high levels due to increased smog and pollution. Certainly, all of us need to take preventive action. If not, we could face the following conditions in our futures.

Determining OS
When OS occurs, certain by-products are left behind that are excreted by the body, mostly in the urine. These by-products are oxidized DNA bases, lipid peroxides, and malonidialdehyde from damaged lipids and proteins. The higher the levels of these various markers, the greater the chance there is of an OS-induced disease, or the aggravation and acceleration of an existing one. People with Down's Syndrome, for example, a genetic disorder, are subject to enormous OS due to increased cellular production of hydrogen peroxide, a potent oxidising agent, and frequently develop Alzheimer's-like conditions in their 30s.

These tests can be ordered by a doctor, naturopath or nutritionist. If you are concerned, ask your health care provider.

Even if you do not have access to formal testing, anyone can do the following simple test to see how much the body has been affected by free radicals: hold out your hand, palm down, in a relaxed position. Pinch the skin on the back of the hand, lift up the fold and then release it. If you have minimal free radical damage, the skin will snap back into place quickly. If the skin takes a few seconds to go back into place, this is not a good sign and action must be taken.

Solutions to OS
Obviously, the first step is to avoid as much as possible the various stressors listed earlier. The next step is to adjust one's diet to include those foods and herbs rich in antioxidants. The last step is to consider supplementation. Supplementation is recommended if one lives in a polluted environment, is subject to extreme stress, smokes, or has a condition associated with OS. Food sources of antioxidants are best. (See above.)

Supplements
Studies have shown that antioxidants work best in combination. Although there is value in supplementing with extra amounts of one or two antioxidants, better results are always obtained when a "cocktail" is administered. The reason for this is simple logic: different antioxidants neutralise different free radicals. If you take a combination, then more free radicals will be neutralised. You can, however, "slant" the antioxidant effect towards a particular ailment or organ if the nutrient has a particular affinity to them. For example, glutathione would be recommended for hepatitis, Parkinson's, AIDS and liver disease; vitamins E and C would be recommended for arteriosclerosis; CoQ10 would be recommended for heart disease; and alpha lipoic acid would be recommended for diabetes. See your health care professional to help you select the best antioxidant combination for you.

Staying on top of oxidative stress is a necessity in our increasingly toxic world. Taking care to avoid those toxins as much as possible and to enrich our diets with life-giving antioxidants is a wise step to take in our endless quest for wellness.

Resources

For more technical papers on oxidative stress, see www.virusmyth.com
For more info on coconut oil, see www.lauric.org
For more info on testing for OS: ICMT, 1305 Richmond Rd., Ottawa, Ontario K2B 7Y4, Canada; (613) 820-6755.
References

Linus Pauling, PhD. How to Live Longer and Feel Better, page 204
H. Seis, ed. Oxidative Stress: Oxidants and Antioxidants (Academic Press; London), 1991.
Roberto Giraldo, MD. AIDS and Stressors (Fundacion Arte y Ciencia; Columbia), 1997.
Montagnier, Olivier, and Pasquier, eds. Oxidative Stress in Cancer, AIDS, and Neuro-Degenerative Diseases (Marcel Dekker, Inc; New York), 1998.
Siro Passi, "Progressive Increase in Oxidative Stress in Advancing Human Immunodeficiency," Continuum, Summer 1998.
About the Author

The late Stephen Byrnes was a nutritionist and naturopath.

Visit his website at

www.PowerHealth.net to read more of his articles.