The cross-linking theory suggests that molecular changes occur in the protein molecules of body tissues that cause microfibers to be laid down against the normal direction of other tissue fibers. This creates aging through loss of elasticity, stiffness, and degeneration. This may always be going on as the underlying mechanism for tissue change, inflammation, and degeneration, but it is more likely a result of the biochemical process of free-radical formation.

The free-radical theory, currently the most accepted aging hypothesis, offers an explanation of the basis of degenerative disease. It suggests that free radicals—unstable, reactive molecules with a free electron—seek to latch onto whatever they can find. When they are not countered by antioxidant nutrients, they may attack cell membranes, fat molecules, or tissue linings. Free radicals are generated by the metabolism of oxygen and other chemicals. Singlet oxygens, hydroxyl ions, peroxides, and superoxide molecules are some of the products of oxidation. Unsaturated fats, certain reactive chemicals, both inhaled and consumed in food or water, microbes, and smoking cigarettes all generate free radicals.

The antioxidants, also termed "free-radical scavengers," protect us by binding the free radicals. When we get sufficient levels of these antioxidants, such as vitamins E and C, selenium, and beta-carotene (vitamin A precursor) in our diet or as supplements, we can neutralize the free radicals and prevent cellular and tissue damage. Our body produces superoxide dismutase (SOD) and glutathione peroxidase (GP), enzymes that also counteract free radicals. These enzymes, however, are themselves unstable and are not specifically helpful as supplements because they are metabolized very rapidly and are not readily absorbed. By keeping our liver and its cells functioning well, we can support the production and function of these important antioxidant enzymes.

Other aging theories include errors in DNA (which could be generated by free radicals), chemical exposure, general toxicity, and basic genetic tendencies. Changes in brain function and the regulation of balance in the hormonal and nervous systems may also be at the core of the aging process. Autoimmunity and a general breakdown of immune function is another theory of degeneration; stress, which likely increases free-radical formation, may itself be at the heart of the aging process, as well as diminishing other vital physiological processes. The general process of aging probably involves combinations of all of the above theories working together in varying ways within each individual.

• Regularly undereat. Avoid obesity; eat more low-calorie foods, such as vegetables, especially those high in beta-carotene.
• Minimize fat intake. The diet should be low in saturated and animal fats, with only moderate intake of vegetable-oil foods and cold-pressed vegetable oils and very low intake of fried fats or oils. Overall, not more than 25 percent of the calories in the diet should come from fat.
• Focus the diet on complex-carbohydrate-containing foods to acquire more fiber and sustained energy without overconsumption and congestion. Complex carbohydrates such as whole grains (specifically, brown rice, millet, oats, barley, buckwheat, and whole wheat), legumes, potatoes, and other starch vegetables and squashes are the key to any diet for longevity.
• Protein intake should be moderate—no more than 50–70 grams daily—with an increase in vegetable proteins such as nuts, seeds, and whole grain/legume combinations to about 75 percent of the dietary protein intake.
• Eat a chemical-free diet as much as possible. Most chemicals have some toxic properties, and many generate free-radical production. Some, such as certain pesticides and the nitrates and nitrites in cured meats, can even be carcinogenic in the body.
• Moderate salt, sugar, alcohol, nicotine, and caffeine. Each of these has specific irritating properties; however, regular nicotine use is the worst in regard to aging.
• Drink plenty of good drinking water, free of toxic pesticides and other chemicals. Proper hydration is important to skin health, digestive function, proper elimination, and all bodily functions.
• Follow the Anti-Aging program for micronutrients and antioxidants presented in the table below.
• Use periods of detoxification, or cleansing, to balance and rest the body’s systems. Fasting or cleansing, I feel, is the missing link in Western nutrition. It is very important to regenerate optimum function and to enhance elimination. It helps improve many body functions, including the important digestion-assimilation-elimination cycle (see the programs on Fasting and General Detoxification in the last chapter for more information).

Supplements are important to the Anti-Aging program. First, a general and complete multivitamin-mineral formula is recommended. There are now more high-quality multivitamins that contain additional antioxidants; because these extra nutrients counteract so many disease processes as well as stress, likely the underlying cause of many problems. In addition to a general formula, the following nutrients are specific to the Anti-Aging program (the first seven are antioxidants):

• Vitamin E is an important antioxidant nutrient when taken in doses well above the RDA, usually at least 400–1,000 IUs daily. Vitamin E protects cell membranes and in particular prevents lipid irritation and breakdown. It also counteracts some of the negative effects of air pollution chemicals and metals.

• Selenium is an antioxidant mineral that works synergistically with vitamin E; that is, together they have a better effect than each separately. The selenium-containing enzyme, glutathione peroxidase, protects cellular membranes and irritation from metals. Selenium deficiency is associated with an increased risk of cancer, and adequate selenium intake is correlated with a reduced incidence of malignancy, particularly of the breasts, colon, and lungs, common sites of cancer.

• Beta-carotene is another cancer-preventing antioxidant nutrient. As an antiaging nutrient, this form of vitamin A is better than retinol (from animal sources). Beta-carotene is a dual vitamin A molecule that can be split easily in the small intestine or liver. Vitamin A deficiencies are associated with an increased risk of cancer, particularly cervical and lung cancer. Beta-carotene specifically protects smokers from lung cancer (it reduces but does not eliminate the risk) in amounts of 25,000–40,000 IUs daily taken in one or two doses.

• Vitamin C is a crucial antioxidant nutrient. It is also an anticancer nutrient, as it has been shown to reduce cervical dysplasia, an early stage of cancer, and to prevent the conversion of nitrites to the carcinogenic nitrosamines. Ascorbic acid specifically protects cell membranes from viruses and may prevent chemical irritations. It also helps to lower blood fats, thus decreasing cardiovascular disease risk, and reduces irritation from cigarette smoke and air pollution. Bioflavonoids, found in many vitamin C foods, may also have antioxidant properties. Adequate amounts of bioflavonoids in the diet can help strengthen and protect blood vessels, improve enzyme activity, and may even help reduce the incidence of cataracts. Vitamin C supplements should contain some bioflavonoids.

• L-Cysteine is a sulfur-containing amino acid that acts as a free-radical scavenger, binding and neutralizing those irritating molecules. It aids detoxification, in part by supporting the liver in producing and storing glutathione, a tripeptide (protein) that is part of an important antioxidant enzyme system. L-cysteine gives cellular and tissue protection from chemicals as well. This amino acid is usually taken with vitamin C to protect the kidney from forming stones made of cystine (a by-product of cysteine metabolism). The recommended dose is 250 mg. of L-cysteine with 1 gram of vitamin C twice daily. If this amino acid is taken regularly, it is wise to also take a general formula containing the other required amino acids.

• Zinc also has mild antioxidant effects through its function in the enzyme superoxide dismutase, a free-radical scavenger. Zinc also contributes to immune support. A daily dose of 30–60 mg., including diet, is part of the Anti-Aging plan.

• Manganese and copper act as mild antioxidants, mainly as support, along with zinc, of the superoxide dismutase (SOD) enzymes, which metabolize the superoxide free radicals.

• Fiber is necessary as part of the diet and as a supplement. It helps colon elimination and may reduce the likelihood of cancer, especially in the breast and colon. Low-fiber, high-fat diets have been associated with an increased incidence of colon cancer.

• Water is a vital part of the "fountain of youth" program. It helps all the body functions, nourishes the skin, and is necessary for good elimination.

• Calcium protects against carcinogenic changes of the cells in the colon lining. It is also important to energy (ATP) production, heart and nerve function, good teeth, and bone health, protecting against osteoporosis.

• Magnesium protects the cardiovascular system by supporting heart function and preventing vascular spasms. It also aids in relaxation by reducing nervous tensions, an important part of staying healthy. Magnesium is also necessary for amino acid metabolism and energy (ATP) production.

• Chromium supports glucose tolerance, often reducing sugar cravings and possibly the incidence of diabetes, and also helps to lower blood cholesterol, thereby helping to prevent the main degenerative disease, atherosclerosis.

• Molybdenum is another trace mineral that may play a role in inhibiting cancer.

• Niacin is the active circulatory stimulant form of vitamin B3. This nutrient helps improve circulation and also lowers cholesterol, two factors that reduce the risk of cardiovascular disease.

• Vitamin B12 helps keep energy up and protects nerve coverings. B12 is needed in the production of red blood cells and in the synthesis of DNA and RNA, important rebuilding processes in the body.

• Folic acid also helps in RNA and DNA (and red blood cells) production, but only in dosages higher than the 400 mcg. RDA. A dose of 1–2 mg. twice daily is commonly prescribed in Canada for this supportive function.

• RNA, as is found in foods such as the blue-green algae, chlorella, spirulina, and wheatgrass, all high in chlorophyll as well, help slow the aging process. RNA supplements have not been shown, however, to be very effective in actually increasing RNA in the tissues.

• Choline, as is found in lecithin, supports production of cell membranes and the important neurotransmitter acetylcholine.

• Omega-3 fatty acids, such as EPA and DHA, help reduce cholesterol and cardiovascular disease risk. Flaxseed oil contains both these omega-3 and omega-6 essential fatty acids.

• L-carnitine is a nonessential amino acid that helps to balance fat metabolism (utilization) and support energy production within the cell and in the muscles. L-carnitine may also reduce body fat and weight, which is important to longevity.

• Coenzyme Q10, also called ubiquinone, improves the function of the cardiac muscle, our body’s most important pump for longevity. It also may enhance specific immune functions.

• Lactobacillus acidophilus and other intestinal bacteria are also important at times to support the normal colon ecology and for the breakdown of food and production of colon vitamins. Reimplanting healthy bacteria may also help reduce other organisms, yeasts, or parasites.