Do tissues and organs wear out, or are they gradually destroyed by processes which could possibly be avoided? Scientific opinion agrees that the human life span potential is about 120 years, and some estimates go higher. These estimates are probably conservative, because quite a number of people are known to have exceeded 110 years without making any special efforts at all to preserve themselves. Be that as it may, the consensus of opinion is that by taking reasonable care, the degeneration which constitutes the aging process can be slowed down so that old age is postponed.

Old Age Defined

Old age is a degenerative disease of the entire body, the progress of which is determined more by the degenerating factors in a person's lifestyle than by their chronological age.

Old Age Described

Everyone knows what old age looks like from the outside, but what changes occur inside the body? In his book The Span of Life., Dr William Malisoff described the atrophy and degeneration of every organ and tissue in the body that accompanies old age and the malfunctions which occur as a result. He said:

"The system of organs is so thoroughly connected that all these changes have mutual repercussions. Thus too the liver, pancreas, spleen, kidneys, urinary organs, become atrophied, hardened and degenerated. The capsule of the kidney is thickened, the parenchyma hardened; the connective tissue scleroses and compresses tubules and glomeruli, impairing their action. The changes in the brain, in the spinal cord, in the nerves, are of a similar character.

The description of the changes would fill many volumes. We can summarize that they fall into several classes: the atrophies, which have been commented on; the fibroses as replacements by fiber; pigmentations; metaplasias; hyperkeratoses, or skin changes and the like; renunciation of functions, as those of the germ cells and the instance of fat cells which no longer store fat."

Dr Arnold Lorand of Austria, in his book Old Age Deferred, described old age as a condition in which there is a diminution of metabolism, ie the assimilation and conversion of food into energy, and is characterized by the abundant growth of connective tissue in vital organs, diminution of oxidation and increased auto-intoxication.

Dr Charles de Lacy Evans of England in his book How to Prolong Life: An Inquiry into the Cause of Old Age and Natural Death Showing the Diet and Agents Best Adapted for a Lengthened Prolongation of Human Life on Earth, written one hundred years ago, was more specific; he said:

"The most marked feature in old age is that fibrinous, gelatinous and earthy deposit has taken place in the system; the latter being chiefly of phosphate and carbonate of lime, with small quantities of sulphate of lime, magnesia and traces of other earths."

He added that the deposits occur in all tissues, including the bones and blood vessels, which harden and reduce in caliber, and quoted a Doctor C. J. B. Williams, who said:

" 'The process is, therefore, to be viewed as almost entirely of a chemical nature, and as consisting of the concretion and accumulation of calcareous salts, phosphate and carbonate of lime in the debris of animal matter.' "

Dr de Lacy Evans went on to explain how the fibrinous, gelatinous substances were formed by the oxidation within the bloodstream and tissues of excessive albumin (protein), and how the earthy deposits were derived mainly from grain products and root and leafy vegetables and to a lesser extent from animal products. Dr Evans tended to blame the formation of the fibrinous, gelatinous substances on the presence of oxygen, just as some biochemists do today with their 'free radical' theory of aging. More pertinent to the argument, in the author's opinion, is that if the diet is correct then neither the excess albumin nor the free radicals will present themselves in the first place to improperly use the body's valuable oxygen. Dr Arthur C. Giese, Professor of Biology Emeritus, Stanford University, in his book Living With Our Sun's Ultraviolet Rays said:

"In our multi-cellular bodies some cells, such as those of the epidermal basal layer, continue to divide throughout life; others--for example nerve and muscle cells--differentiate and cease dividing at birth. Nevertheless, they continue to function for a lifetime, with gradually lessening activity and progressively filling with insoluble wastes and pigments."

As the tissues slowly acquire these characteristics of old age their decline is further characterized by, and is measurable by, a corresponding decrease in enzyme levels and activity. On the other hand, animal tissue cells grown in cultures in the laboratory, properly cleansed and drained, do not degenerate in this fashion and may outlast the animal from which they originated many times over. It is held by some researchers (at least in theory) that in ideal circumstances immortality is possible. Other experiments with live animals fed on minimum rations showed improved health and a life extension of fifty to one hundred per cent over that of unrestricted control animals on the same diet.

The longest lived populations in the world are accepted generally to be the people of Hunza in northern Pakistan, Vilcabarnba in Ecuador, and Georgia in Rassia. An analysis of these peoples' living habits carried out under the auspices of the National Geographic in 1971 by Dr Alexander Leaf of New York provided a good reason why they outlived people of the Western world. The traditional diets of these long-lived (by our standards) people contained only half to two thirds the kilojoules of the average American intake, about a quarter the amount of fat and half the protein. Their carbohydrate intake was about the same but was unprocessed instead of processed. As well, these people got more outdoor exercise and were less subject to stress than Americans.

In his book, Dr de Lacy Evans when reviewing a study of centenarians in England in the 19th Century said:

"On reviewing nearly 2,000 reported cases of persons who lived more than a century, we generally find some peculiarity of diet or habits to account for their alleged longevity; we find some were living amongst all the luxuries life could afford, others in the most abject poverty--begging their bread; some were samples of symmetry and physique, others cripples; some drank large quantities of water, others little; some were total abstainers from alcoholic drinks, other drunkards; some smoked tobacco, others did not; some lived entirely on vegetables, others to a great extent on animal foods; some led active lives, others sedentary; some worked with their brain, others with their hands; some ate only one meal a day, others four or five; some few ate large quantities of food, others a small amount; in fact, we notice great divergence both in habits and diet, but in those cases where we have been able to obtain a reliable account of the diet, we find one great cause which accounts for the majority of cases of longevity, moderation in the quantity of food."

Thus perhaps the first rule in dieting for longevity is to eat sparingly, whatever the make up of the diet. Even on a bad diet this rule will still permit better health and extended life because less wear and tear will have to be endured by the body.

So it becomes clear that "old age" occurs because we take into our bodies, mainly via food, harmful substances which overtax the digestive system, cause toxemia of the milieu interieur, overtax the eliminatory organs, and to a greater or lesser extent gradually accumulate in the tissues and cells to increasingly impede their functions.

It follows then that old age can be deferred by selecting foods which provide the best nutrition with the least digestive effort and the least amount of harmful residues, and consuming such foods in great moderation.