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THE BENEFITS OF RAW FOOD AS DETERMINED BY DR. FRANCIS POTTENGER, JR.

Archaeological evidence indicates humans used fire at least four hundred thousand years ago; splintered and charred bones of large mammals that Peking man hunted littered his caves. These early humans probably used fire to help get at the marrow, and they may have roasted some meat.

Cooked food is more quickly chewed than raw and thus the change from an entirely raw to a partially cooked diet freed some time formerly spent eating. The time was now spent cooking. Cooking has always been both social and practical, combined with elements of ceremony, habit, convenience, and pleasure.

A home heated by wood gathers people near a fire for hours in cold months. In caves and later primitive shelters, cooking and sharing meals around the warmth of fire was an everyday routine; it has been so in all native cultures since. And yet in every native culture examined, anthropologists find that customs dictate certain foods be eaten raw. Reasons given by the people invariably relate to preventing disease, ensuring fertility, and promoting optimal growth in children.

THE WORK OF DR. FRANCIS POTTENGER, JR.

Francis M. Pottenger, Jr. was a physician and researcher whose work demonstrated that raw foods contain unique nutrients vital to human beings. Part of his research included a now-classic series of controlled experiments that involved more than nine hundred cats for more than ten years. He also kept detailed records of his thousands of human patients for more than thirty years. He discovered correlations between the cat experiments, the discoveries of his contemporary Weston Price, and his clinical work treating people with chronic and acute diseases.

The son of the physician who founded the once-famous Pottenger Sanatorium for the treatment of tuberculosis in Monrovia, California, Pottenger completed his residency at Los Angeles County Hospital in 1930 and became a full-time assistant at the sanatorium. From 1932 to 1942, he also conducted what became known as the “Pottenger’s Cats” study.

In 1940, he founded the Francis M. Pottenger, Jr. Hospital at Monrovia. Until closing in 1960, the hospital specialized in treating nontubercular diseases of the respiratory system, especially asthma. Pottenger maintained his private practice until his death in 1967.

A regular and prolific contributor to the medical and scientific literature, Pottenger served as president of several professional organizations, including the Los Angeles County Medical Association, the American Academy of Applied Nutrition, and the American Therapeutic Society. He was a member of a long list of other professional organizations.

Pottenger’s Cats and Raw Foods: The Ten-Year Study

Extracts from adrenal glands of cows and steers were part of treatment that patients received at the tuberculosis sanatorium, which manufactured the extracts from fresh glands shipped from Denver and Los Angeles. No laboratory assays capable of determining hormone content of biological extracts existed in the 1930s. To determine potency, cats that had had their adrenal glands removed were kept alive with extract; the amount required to maintain animals adequately determined the level of that batch’s potency.

Despite careful surgical techniques and a diet of raw milk, cod-liver oil, and meat scraps from the sanatorium kitchen, many cats died after the surgery to remove their adrenal glands. There was no obvious explanation, but the cats showed signs of nutritional deficiencies. Many had problems reproducing, and many kittens born in the laboratory pens had skeletal malformations and internal malfunctions.

Pottenger had a keen interest in nutrition; a high-protein and fat natural-food diet was an important part of treatment at the sanatorium. Liver, tripe, brains, sweetbreads, and heart were fed to patients; scraps, all cooked, were fed to cats. When the cat population grew because Pottenger’s neighbors donated so many, he began securing raw meat scraps for some cats.

These cats were, before long, in plainly better health than cats consuming cooked meat. Their postoperative mortality markedly decreased, they reproduced more easily, and their kittens were healthier.

This inspired Pottenger to embark on a series of controlled experiments. Because pathological problems in cats eating cooked meats were similar to those in his patients, he believed a controlled-feeding experiment with animals would isolate variables of importance in human nutrition as well.

The experiments met the most rigorous scientific standards of his day. Pottenger’s outstanding credentials earned him the support of prominent physicians. Alvin G. Foord, M.D., professor of pathology at the University of Southern California and pathologist at the Huntington Memorial Hospital in Pasadena, co-supervised with Pottenger all pathological and chemical findings of the study.

The technology of science has grown more sophisticated since Pottenger’s study, as the search for causes of disease has moved to the intracellular level. But because of the strength of his insights, Pottenger’s inquiries and observations provide demonstrations about fundamentals of nutrition and disease.

Two areas of inquiry in particular address questions modern science has largely ignored. First, what is the nutritive value of heat-labile elements—nutrients destroyed by heat and available only in raw and undercooked foods? Second, what determines the difference in nutritional value between one animal and another, one egg and another, one glass of milk and another? Pottenger’s ten-year study answers these questions through an inquiry into the difference between raw and cooked meat, raw milk and pasteurized milk, and fresh greens versus dry greens. We will examine these areas of study in further detail next.

Raw Meat versus Cooked Meat

Effects of a raw-meat diet fed to one group of cats versus those of a cooked-meat diet fed another were measured in the initial experiment, begun in 1932. The raw-meat diet consisted of raw meat, including bones and organs such as liver, heart, brains, kidneys, and pancreas; raw milk; and cod-liver oil. The cooked-meat diet was exactly the same except for the fact that the meats were cooked. In both diets, raw milk was “marketgrade”—milk available commercially. A high-grade raw milk from cows kept at pasture or fed fresh-cut greens was later used in select experiments.

Cats were kept in large outdoor pens, and successive generations were followed. The raw-meat group reproduced easily, and as each generation developed there was, for each sex, striking uniformity in size and skeletal development. A broad face with wide dental arches and no crowding of teeth was the rule. Fur was uniform, with good sheen and little shedding. Inflammation and diseases of the gums were rare.

These animals were resistant to infections, fleas, and other parasites. They were friendly, even tempered, and well coordinated—when dropped from up to six feet or thrown, they always landed on all four feet. Miscarriages were rare, and litters averaged five kittens. Cause of death was generally old age, or occasionally fighting among males. Autopsies invariably revealed normal internal organs.

The cooked-meat group showed many contrasts to the raw-meat group, contrasts that grew with successive generations. Litter mates varied greatly in size and skeletal structure, particularly in dental and facial pattern. Often by the third generation bones had become so soft as to be actually rubbery. Vision problems, infections of internal organs and bones, arthritis, heart problems, underactivity of the thyroid gland, inflammation of the joints and nervous system, skin lesions, allergies, intestinal parasites and vermin, and a host of other pathologies were common. Coordination was poor—when tossed a short distance, the cats had trouble landing on all four feet. Pneumonia and lung abscesses were the most usual causes of death in adults; pneumonia and diarrhea were the usual causes in kittens.

At autopsy, analysis of the bones of cooked-meat animals determined calcium and phosphorous content for second- and third-generation kittens to be one-third to one-half that of raw-meat kittens. A marked difference between the two groups was also found in the average calcium to phosphorous ratio (2.08 to 1 for raw-meat kittens versus 2.63 to 1 for cooked-meat kittens).

Many cooked-meat kittens exhibited behavioral changes; females were irritable and aggressive, while males were often docile and unaggressive with little interest in females but keen interest in other males (an interest never seen in males fed the raw-meat diet). Abnormal sexual activities also were seen between females in the cooked-meat group. At autopsy, females often showed small ovaries with a congested uterus; males frequently showed testes that had failed to develop the ability to produce sperm.

Cats born outside the Pottenger Sanatorium, donated to the study and placed on the cooked-meat diet, were called first-generation deficient cats. Kittens born of them and fed the cooked-meat diet were called second-generation deficient cats. Kittens born of second-generation deficient cats and fed the cooked-meat diet were called third-generation deficient cats.

The miscarriage rate among first-generation deficient females was about 25 percent, among second-generation deficient females, about 70 percent. Many cats died in labor; deliveries were difficult; many kittens were born dead or too frail to nurse. The kittens born of cooked-meat mothers weighed an average of nineteen grams less than those of raw-meat mothers.

No fourth-generation deficient kittens were ever born in the ten years of the study. Third-generation deficient kittens always died before reaching six months of age, terminating the strain.

Raw Milk versus Pasteurized Milk

Four groups of cats were used in this part of the study. For one-third of the diet, all of them received raw meat, which included organs and cod-liver oil. The other two-thirds were either raw milk, pasteurized milk, evaporated milk, or sweetened condensed milk. The rawmilk, raw-meat diet produced many generations of healthy cats, while the various heat-processed milk and raw-meat diets produced successively sicker cats unable to reproduce by the third generation. The inclusion of one-third raw meat in the cooked-milk diets did not prevent severe problems.

The most degeneration occurred in cats fed sweetened condensed milk; they became extremely irritable and nervous and developed heavy fat deposits and marked skeletal deformities. Cats fed evaporated milk were nearly as damaged. Those fed pasteurized milk showed lesser damage, similar to that seen in the animals of the prior experiment that ate cooked meat—that is, skeletal changes, decreased reproductive capacity, and infectious and degenerative diseases (problems that were among those seen in the sweetened condensed-milk and evaporated-milk groups).

In a variation of this experiment, the effects of raw milk from cows fed fresh greens versus those of raw milk from cows fed dry feed were compared. Cats fed cooked meat and raw milk from fresh-feed cows did significantly better than cats fed cooked meat and raw milk from dry-feed cows. The latter produced deficient kittens and had difficulty nursing. Deficiencies were much less marked for animals fed cooked meat and also fed raw milk from fresh-feed cows.

The fresh greens apparently contained critically important nutrients that were lost when the greens were dried.

Fresh Greens versus Dried Greens

Guinea pigs were used to compare the effects of fresh greens versus dried greens directly. A group of these animals was fed grains, cod-liver oil, and field-dried alfalfa. Deficiency symptoms appeared—loss of hair, diarrhea, pneumonia, paralysis, and high infant mortality. Fresh-cut greens were then introduced (grass cut after sundown, sacked, and delivered before sunrise). The animals gained weight, infant deaths decreased, loss of hair decreased, and no new cases of paralysis developed.

Some guinea pigs that had developed severe symptoms initially and had not fully recovered were then allowed to feed on grass and weeds growing outside their pens. Within a few weeks, all diarrhea and loss of hair stopped, and their hair was soft, shiny, and velvety; the animals appeared even healthier than those kept inside the pens on fresh-cut greens. Seeking an explanation, Pottenger discovered that the temperature inside sacks of cut grass used for feed was from five to thirty degrees warmer than the outside air. The grass had become somewhat cooked in the sacks, and heat-labile nutrients apparently had been altered. The health of the animals suffered as a result.

THE WORK OF DR. ROBERT MCCARRISON

Pottenger was not the first to maintain experimental animals for extended periods on natural food. From 1902 until 1935, Robert McCarrison, a British physician in the Indian Medical Service and founder of the Nutrition Research Laboratories at Coonoor, India, studied goiter and other health problems of the Indian people. He did extensive experiments with large populations of laboratory animals and in 1933 published a report containing statistics about several studies.

In conjunction with those studies, McCarrison kept a control colony of about one thousand white rats for more than three years. The animals were killed and autopsied when they were two years old. In more than fifteen hundred autopsies, no sign of disease was ever found. In the three years, there was no illness, no death from natural causes, and no infantile mortality. The animals were fed whole-wheat-flour cakes of unleavened bread lightly smeared with raw butter, sprouts, raw carrots, cabbage, raw milk, raw meat, and bones once a week. All foods were fresh; the animals lived in large, airy, clean rooms, and were exposed to the sun daily.

PARALLELS BETWEEN POTTENGER’S AND PRICE’S WORK

While the experiments of McCarrison and Pottenger show the value of raw foods in keeping animals remarkably healthy, one might wonder about relevance to human needs. Cats are carnivores, humans omnivores, and while the animals’ natural diet is raw, humans have cooked some foods for hundreds of thousands of years. But humans, cats, and guinea pigs are all mammals. And while the human diet is omnivorous, foods of animal origin (some customarily eaten raw) have always formed a substantial and essential part of it.

Problems in cats eating cooked foods provided parallels with the human populations Weston Price studied; the cats developed the same diseases as humans eating refined foods. The deficient generation of cats developed the same dental malformations that children of people eating modernized foods developed, including narrowing of dental arches with attendant crowding of teeth, underbites and overbites, and protruding and crooked teeth. The shape of the cat’s skull and even the entire skeleton became abnormal in severe cases, with concomitant marked behavioral changes.

Price observed these same physical and behavioral changes in both native and modern cultures eating refined foods. These changes accompanied the adoption by a culture of refined foods. In native cultures eating entirely according to traditional wisdom resulted in strength of character and relative freedom from the moral problems of modern cultures. In modern cultures, studies of populations of prisons, reformatories, and homes for the mentally delayed revealed that a large majority of individuals residing there (often approaching 100 percent) had marked abnormalities of the dental arch, often with accompanying changes in the shape of the skull.

This was not coincidence; thinking is a biological process, and abnormal changes in the shape of the skull from one generation to the next can contribute to changes in brain functions and thus in behavior. The behavioral changes in deficient cats were due to changes in nutrition. This was the only variable in Pottenger’s carefully controlled experiments. As with physical degenerative changes, parallels with human populations cannot help but suggest themselves, although the specific nature of the relationship is beyond the scope of this discussion.

Human beings do not have the same nutritional requirements as cats, but whatever else each needs, there is strong empirical evidence that both need a significant amount of certain high-quality raw foods to reproduce and function efficiently.

THE NEED FOR A UNIFIED BIOLOGICAL THEORY

Beginning with Albert Einstein, theoretical physicists have sought a single encompassing theory uniting the theories of relativity, electromagnetism, and gravity. Although details of such a theory may remain elusive, many believe an encompassing explanation for the physical phenomena of the universe will indeed be found.

Such a theory, however, will not explain the biology of the degenerative physical and mental changes that have accompanied the abandonment of humanity’s traditional primal foods and the adoption of the refined foods of modern industrial society. To explain our modern predicament—and guide us out of it—we need a unified biological theory, based on an understanding of humanity’s roots; one that attempts to work in harmony with forces inexorably shaping us. Physics seeks an understanding of physical forces affecting the universe; human health requires an understanding of biological forces in foods that affect human destiny.

THE BENEFITS OF RAW FOODS

Enhanced Calcium Metabolism

Pottenger maintained inpatient facilities and an outpatient practice for more than thirty years, giving him an opportunity to study the effects of his nutritional programs on many patients. He observed problems with calcium metabolism in a majority. Poor development of the teeth is the first and most obvious sign. Later, arthritis appears; nearly all older people in America today show symptoms of it.

Other problems commonly connected with faulty calcium metabolism include back problems and other skeletal disorders. These include spondylitis; gallstones and kidney stones; atherosclerosis, often leading to coronary heart attacks; hardening of the arteries of the brain, often leading to strokes; cataracts; and bursitis. Deposition of calcium in abnormal places is their common denominator.

Though many people develop these problems eating diets deficient in calcium, so too do others consuming diets rich in calcium. A diet rich in calcium (including calcium supplements and vitamin supplements to aid in the assimilation of calcium) does not prevent or reverse these problems unless the diet contains adequate amounts of fresh raw foods.

Pottenger found clues about calcium problems in X-ray studies documenting changes in the skeletal system of his patients (the dangers of X-rays were little understood in his time). One study compared skeletal structures and bone age (the development of the growth center of bones in relation to the standard for a child of that age) in 150 children drinking four different types of milk—breast milk, raw-certified milk, pasteurized milk, and canned milk.

The only group with consistently excellent development of the bones and skeleton and with normal bone age was the group drinking raw-certified milk. Nearly all of the children drinking pasteurized milk or canned milk developed either very fine small bones, disturbances in the calcification of bones, or marked weaknesses in joints and ligaments. Bone age in a majority of these children was below normal.

Among children fed breast milk, development of bones was dependent on the diet and state of health of the mother. Children of mothers using high-quality foods, including raw-certified milk and raw greens, had well-developed bones displaying normal bone age. Children of mothers using diets including the cooked milks had bones with delayed development of growth centers and poor calcification, and weak joints. Breast milk is superior to raw-certified milk only if the diet of the mother is of proper quality.

Chronic Disease Deterrent

Dr. Josef Romig told Weston Price that modernized Eskimos and Indians with tuberculosis usually recovered when returned to their native villages and native diets. Native Eskimo and northern Indian diets were similar to the diet Pottenger successfully used for patients with tuberculosis and other diseases. Liberal amounts of liver, heart, pancreas, kidney, brain, tripe, meat, fish and shellfish, fertile eggs, and raw milk were used; organs were emphasized.

Much of this diet, including the organs, was served raw, in a variety of recipes. Much of the food, including the meat, was ecologically produced. Food was cooked as lightly as was palatable for the patient. Raw vegetable salads with sprouts were served twice daily. Breads made from sprouted whole grains were baked at low temperatures, minimizing the destruction of nutrients. Bone meal and marrow were also prepared at low temperatures. Small quantities of fruit and sesame seeds were consumed, and the use of vegetable oils was minimized. This type of diet, carefully individualized for each patient and usually including some fish and shellfish, is integral to the approach to chronic disease that I have used successfully for many years.

RAW FOODS AND THE DIGESTIVE SYSTEM

The digestive system adapts well to raw foods introduced at a rate appropriate for the individual. An acute inflammation in the digestive tract—gastritis, ulcers, colitis, certain types of diarrhea, for example—may be easily irritated by raw vegetables or fruits, which should in such cases be slowly introduced only when the acute problem has resolved and healing has begun.

But for most people, becoming accustomed to more raw foods in the diet involves mental more than physical obstacles. While cooking or fermentation does indeed make many foods more digestible, the healthy human digestive system is fully capable of digesting a wide variety of foods raw. Many foods may be more easily chewed when cooked, but for the fully functioning human digestive tract, many foods are most easily digested when they are eaten raw or lightly cooked. This is particularly true of most animal foods, salad greens, and fruits. But many people really cannot digest raw vegetables and some of these vegetables—kale, spinach, cabbage, potatoes—should not be eaten raw.

Colloidal cellulose and pectins in plants can withstand greater temperatures than can proteins; this is why cooking has a less pronounced effect on the digestibility of most plants than on that of animal-sourced foods. In fact, uncooked pectins and certain other fiber can be harmful, and cooking makes many vegetables more digestible. While cats indeed thrive on an all-raw diet, humans do best on a modern primal diet that includes a balance of cooked and raw foods.

In the ten-year cat study, the cats that had cooked foods were consistently found at autopsy to have much longer intestines than the cats that had been fed raw food. Intestines of the former had many distensions and a general lack of tone; the length was often up to twice that of the raw-food cats. The argument has been made that the length of the human digestive tract demonstrates that humans are best suited for a vegetarian diet; remains of the digestion of animal flesh may putrefy when stagnant in the rather long human intestines. I believe that the eating of overrefined and overcooked foods contributes to that length; problems that are due to flesh being in the intestines for an extended length of time are partly due to intestines that are too long. The low fiber content of refined foods further contributes to this problem.

SAFETY, PERSONAL TASTE AND CONVENTIONS

Evolution, anthropology, animal experiments, and clinical experience aside, the usefulness of information about raw foods justifiably hinges on questions of safety, personal taste, and convention. This pertains more to animal-sourced foods than to plant-sourced foods. In either case, however, and as mentioned earlier, the amount of raw or slightly cooked food in the diet should be increased rather slowly, allowing the body to adapt gradually. The mind also requires time to grow used to new and changing ways. Occasionally, individuals highly motivated by a desire to recover from serious health problems or to prevent them succeed in making these changes more rapidly.

Safety

In terms of animal-sourced food, there are two other primary considerations about the safety of its consumption raw or lightly cooked: the health of the source animal and the health of the individual eating the food. Both healthy animals and healthy people are highly resistant to disease. And by definition, healthy animals do not carry disease.

Be this as it may, most animals are raised today in a manner that raises questions about their health and desirability as food for human beings. Consider a steak ordered rare—in many restaurants served nearly raw in the middle. That meat has passed through an inspection system of sorts. The steer was fed hormones, antibiotics, and grains containing residues of a variety of chemical poisons; varying amounts of each are in the meat, be it well-done or raw. Government inspection supposedly guarantees that the meat contains no harmful organisms; it is accepted as safe. But mistakes, oversights, and occasionally corruption occur in the inspection system.

Meat and organs from pasture-fed, naturally raised cattle must also be inspected. Such meat is more desirable than the usual commercial varieties. Though available in many areas now, meat of this quality in much of the country is still hard to find.

It has been reported that brucellosis, or undulant fever, may be contracted by eating the meat or drinking the raw milk of infected animals, but this is debatable. Although modern commercial meat and dairy animals rarely contract this disease, their health is often poor as a result of overcrowded quarters, a lack of fresh grass and exercise, overuse of chemicals in their management, and perhaps due to a diet comprised of GMO corn and soy. These animals are best kept at least partly at pasture and in uncrowded conditions. With exercise and proper feeding, they produce milk and meat that is healthy and safe.

Occurrence of brucellosis in cows was correlated with trace-mineral deficiencies in Pottenger’s article “Brucella Infections” (The Merck Report, July 1949). Minerals present in tissues of healthy cows were found on spectrographic analysis to be missing in tissues of cows with brucella infections. Cows fed the trace minerals manganese, cobalt, copper, and iodine were immune to brucellosis when exposed to the disease in other animals.

In subsequent work with more than eighteen hundred patients with brucellosis, Pottenger found that supplements of these minerals (together with his dietary program) consistently resulted in significant improvements in blood picture, visible symptoms, and the patient’s sense of well-being. The previous diet of nearly every patient indicated a state of malnutrition long before symptoms of brucellosis first came to attention. This underscores the susceptibility of weakened individuals to infection from contaminated foods.

The corollary of increased susceptibility of weakened individuals to the spread of disease from animals is that healthy individuals are resistant to such spread. This is why primitive Africans were resistant to organisms causing so much disease among whites in Africa, and it is why traditional people everywhere ate animal life without fear of infection. The animals were by and large healthy, but the first line of defense was the superior resistance of the people consuming them. That this resistance was in part the result of eating the animal life—much of it lightly cooked, some of it raw—completed the circle of cause and effect.

Most Caucasian Americans are descendants of people from western, northern, and central Europe and Russia; a smaller number are of southern European and Middle Eastern origin. Foods have been cooked in northern regions since early explorations by prehistoric hunters. In southern Europe, the Middle East, and African regions where ancestors of African-Americans originated, cooking played a smaller but still significant role in the traditional preparation of food. Every culture Weston Price visited used at least some cooked foods. To eat an entirely raw-food diet is to ignore this heritage.

Personal Taste and Conventions

Socially, the consumption of an all-raw diet may put an individual on the fringe; eating is a social event, and the strictly raw-food person may find his or her diet quite limiting in this respect. One can, however, eat in a somewhat unconventional manner—if done with flair—and still be accepted by one’s friends. Indeed, some interesting conversations may result.

In terms of social convention, very rare meat is socially acceptable, and so too is certain raw flesh—carpaccio, steak tartare, oysters, and clams. (This obviously has nothing to do with safety. Taste as well as convention is served by cooking; a charcoal-grilled very rare steak has considerably more flavor than raw meat.) The consumption of raw fish has been accepted in America, though sushi here is deep-frozen for at least fourteen days. Most sushi is derived from oceangoing fish, and while most oceangoing fish do not harbor organisms that are harmful to humans, some do. Deep-freezing kills any such harmful organisms.

Most other fish may be lightly cooked to the point of flaking apart, which is undercooked by most standards—many individuals prefer it cooked a bit more. Restaurants generally overcook fish; by ordering it “a bit undercooked,” one may avoid having it served overcooked.

In any event, for the unconventional eater, compromise is required in social situations as well as with one’s own taste buds. Raw and lightly cooked foods simply cannot be forced. As with all food, it must be enjoyed if lasting habits are to develop. While one may strive to try new things, let the first consideration be the selection and preparation of natural foods that are enjoyed. Upon this base may be built a long lifetime of refinements.