WEEK 11 NOTES Human Variation II


I. Human Energetics, p 479.

The human digestive system utilizes only the plant parts where they concentrate energy in the form of carbohydrates, fats, and proteins. These include the seeds, fruits, certain tuberous roots and some plant leaves. Humans are unable to digest most of plant mass; to access those sources of energy, we depend upon large domesticated herbivores.

Energy requirements are higher during growth, pregnancy, and lactation. Unduly hot and cold climates add additional energy requirements. The prime energy sources in human food are fat, carbohydrate, and protein.

We take availability of a balanced diet as an entitlement. This is not so for many who depend upon starchy foods as the mainstay in their diet. The abundance and variety of our supermarkets are not found everywhere.


Two diseases of undernutrition will be mentioned here.

Kwashiorkor is a protein deficiency disease when a child lives off of starchy yams, cassava and plantains....but no protein. The term literally means child displaced from its mother by a subsequent pregnanacy. Kwashiorkor occurs most often following weaning when children get food deficient in protein. There is edema, muscle wasting and apathy (McElroy and Townsend p 217).

Mother's milk contains an adequate amount of protein until an infant is six months old; after this time, and additional source of protein is needed even if the infant continues to nurse (Jamison p 208).

Another disease that is closely related is marasmus, which occurs in New Guinea groups who use the starch of the Sago palm (see McElroy and Townsend). These children suffer from both protein and calorie deficiency. Emaciation, growth retardation and apathy result from inadequate breast feeding. (Also see Jamison p 208.)


II. Energy Input and Food Production (Harrison et al p 486; see Peoples and Bailey Ch 19)

The agricultural abundance produced in North America, Europe and other countries with mechanized agriculture is a modern miracle. We take it for granted. We shouldn't. Mechanized agriculture is enormously energy expensive.

From a LABOR standpoint, modern mechanized agriculture is very productive. In a food foraging or subsistance agricultural society, nearly everyone works to produce food (with little surplus). This has enormous cultural implications for a society

Urbanization and all that goes with it is utterly dependent upon intensive agriculture. Indeed, modern civilizations rests on the top few inches of its topsoil. What makes so much possible in the industrialized world?

In North America or Great Britain, a single mechanized worker feeds about 70 people. That is why some of us have the luxury of being orthodontists or anthropologists. We take food for granted because someone else produces it for us.


Now, consider productivity as energy input, usually from oil and gasoline. In a 1970 study it was shown that to raise one acre of corn it tood the energy equivalent of 80 gallons of gasoline. It takes more energy to produce food than we get as caloric energy out of food.

In the United States, we feed much of our grains and other proteins to livestock. These herbivores in the food chain only extract and pass on to us only about 10% of the energy in their diet.

Let us say it differently: for every hundred food calories put it, we get back only 10 in meat or milk products. (Imagine the inefficiency if we ate carnivores who ate herbivores who were corn fed!)


It gets worse. Much more energy is needed before meat and milk products get to us by way of the pizza delivery man, fast food outfit, vending machine or as convenient microwave-ready frozen food.

Much of our food is processed, canned, frozen, cut up, and put in containers. It has to be shipped, stored, purveyed in supermarkets with blazing lights and open freezers. Home refrigerators consume 20% of a typical resident's electric bill.

We spoke about the energy input to cultivate, plant, and harvest corn. Three times more energy is consumed after it leaves the farm in shipping, processing, packaging, and marketing.

Preindustrial food systems are probably 50 to 200 times more efficient than our own from an energy standpoint. (My note: Do understand, I don't want to live that way any more than you do. I've brought all this up to bring home a point: Americans like to share their ways of doing things. But mechanized agriculture won't work in the tropical areas of the world: rainforest soils are thin and very poor and the folks there don't have the oil or machinery to do it the industrialized agricultural way.)


III. Comparative Dietary and Nutritional Adequacy (Harrison et al p 494)

The diets of our early ancestors are only speculation. Gibbons, gorillas, and orangutan offer few insights. The chimp diet is basically seeds and fruits, insects, and a limited amount of raw meat (often other primates).

Studies of the few foragers who survived into this century shows that most of their food was from plants; meat was usually less than a third of the caloric intake.

Some have argued that we need to copy this diet because it was how we evolved. These views were popularized in a book a few years ago, The Paleolithic Prescription. The authors claimed that we are 'stone agers in the fast lane'. (My note: in the literature, this is one of several discordance hypotheses. Another one says this: we evolutionarily ill-equipped for living in modern day crowded societies--in isolation. If discordance hypotheses interest you, see Eaton et al and the Time article by Wright listed in the bibliography.)


Nutritional deficiency diseases first became common when populations depleted their supplemental foods--and came to depend upon one or a few domesticated crops. Mom was right when: eat a balanced diet. For more on this theme, see Cohen Health and the Rise of Civilization.


IV. Lactase Deficiency (Harrison et al p 502)

A major portion of the world's population cannot digest lactose contained in fresh milk. Infants and young children in all populations have the lactase enzyme, In most people--and other mammals as well, the lactase enzyme disappears after weaning.

The productions of yoghurt and most diseases breaks down the lactose to a digestible form. It appears that the very high frequencies of lactose intolerance occurs in populations who are traditional non-users. Whether this is genome plasticity or true evolution is unknown.


V. Adult Body Size and Shape Variation, (Harrison et al p 503 (see Helmuth pp 164-165)

Thus, the combination of Bergmann's and Allen's rules predicts that in a cold climate, humans and other warm-blooded animals will tend to be more round in shape, be larger in mass, and have shorter appendages. In a hot climate, the opposite will be true. (Note that both Bergmann's and Allen's rules refer to all warm-blooded animals and not only to humans. See Jamison p 200}


The next three are less well known but are worthy of mention here.



Human variation reflects adaptation in environmental settings. On the long term level, it reflects evolution and natural selection. For the individual, certain variations represent human plasticity. This was vividly illustrated in the section on life at high altitude-one of many environmental stresses that humans have encountered..

In this concluding section, we look at the biological response to wealth, culture, and the mind. This section is eclectic in style, but is fully referenced. Everything cited is mainstream science.



We often think of placebos as intentional deception. They are inactive substances used in double blind studies of pharmaceuticals. In practice, the term can be extended to any type of therapy, including surgery and psychiatric care.

Before you dismiss them, do understand that there are treatment successes with them and there are even reports of side effects from placebos.

There is a large body of literature on placebos and their effect. Briefly, the placebo effect is present in hope, transference, encouragement, and in the doctor-patient relationship. The placebo effect is often at work when a patient has full trust in his/her practitioner.

In scientific study, placebos frequently achieve treatment success and patients have experienced side effects with them. Medical researchers usually dismiss the placebo effect as a nuisance.

(See Sherman, M. "The Placebo Effect" American Druggist January, 1992 pp 39-41.)


Pills are one thing. How about cold steel and surgery? Is there a placebo effect in surgery? In fact, yes. A surgical placebo effect is documented in the next section. In anthropology, belief is considered important in symbolic healing.



Coronary arterial bypass surgery is so commonplace today that the public in general has a fairly clear perception of the basic mechanics of the procedure. Before that technique was perfected, another surgical procedure was used in an attempt to improve blood flow into the heart musculature.

Bilateral Internal Mammary Artery Ligation was done to direct more blood toward the heart by collateral circulation. The operation was easy and patients generally improved. The Veterans Administration arranged for a double blind study of the procedure.

In the double-blind study of the procedure, all patients had surgery. The control group had the wound simply closed with no artery ligation.

The experimental group had ligation followed by wound closure.


Results of the study showed that there was no difference between the experimental group and the control group. The surgery worked but not for the reasons it was performed. Patients get better because they believed in it!

Shamans in aboriginal societies use rattles, song, dance, and lots of symbolism. Surgeons have symbolism, too. Green gowns, masks, towering buildings that bristle with technology are modern day healing symbols.


How effective is today's coronary arterial bypass surgery? It is highly effective; the mortality rate is only 1.5% About 85% of patients have a dramatic-or complete relief of symptoms.

At the end of one year, 85% of grafts remain open. Exercise tests show a positive correlation between patency (open vessels) and exercise tolerance. What about patients where graft closure is verified? Some of these continue to report improvement in spite of graft closure!

What about nitroglycerine tablets? Their mode of action is as a smooth muscle relaxer and a vasodilator. When a placebo for these is administered, the placebo give relief for 70-90% of enthusiastic people, 30-40% for sceptics.

(See Freund, P. and McGuire, M. Health, Illness and the Social Body. Englewood Cliffs: Prentice Hall, 1991; Moerman, D. "Physiology and Symbols: The Anthropological Implications of the Placebo Effect" in The Anthropology of Medicine, Romanucci-Ross, L., Moerman, D., and Tancredi, L., eds. Westport: Bergin & Garvey, 1997 pp 240-253.)



In Mexico today there is a non-medical health care delivery system known as Mexician Spiritualist Temples. Some are in the American Southwest. The temples are strongly anti-Catholic, usually headed by women, and are a sectarian movement outside of Western-style allopathic biomedicine. Who goes to them? Many are people disaffected with biomedical doctors but don't get results.

What do they do? There is no diagnosis. The temple curer who wears white robes does a light message amidst a smell of incense. The curer finishes with a prescription for healing and a direct order: "Do as I say!"

Does it work? About a quarter of the time, based on the patient's perception of the result. The definitive study of Mexican spiritualism is Finkler, K. Spiritualist Healers in Mexico. Salem: Sheffield Publishing Company, 1985.



Over thirty years ago, medical researchers were drawn to the tight-knit Italian community of Roseto in eastern Pennsylvania. Its late middle-age citizens seemed nearly immune to heart disease, seemingly in defiance of medical logic.

The men of the town smoked, and drank wine freely. They worked in slate quarries 200 feet down in the earth. At home their tables were laden with Italian food modified in a way that would horrify a dietitian. To save money, they had replaced olive oil with....lard! Yet their hefty body contained healthy hearts. Why?

Every aspect of their health was examined in a comprehensive series of tests, observations, and interviews; however, traditional medical science did not offer any answer.

The answer lay in social science, not medicine. Stated simply, it was found that people nourish other people. Households contained three generations; everyone had a place. The community had stability and predictability. Everyone had a part in their society. Similar 'Rosetto Effects' have been documented in Israel and Borneo.

The researchers who came to study it also predicted that the 'Rosetto Effect' would disappear. Indeed, as suburbs appeared with fences and satellite dishes, the rate of heart attacks in time came to reflect the national averages. (From "A new 'Rosetto Effect', Chicago Tribune October 11, 1996.)



In the mid-1970s, David Spiegel, a psychiatrist at Stanford University led support groups for women being treated for advanced breast cancer that had metastasized to other sites in the body. With breast cancer, if it recurs later after treatment of the initial site, it tends to spread to the lungs, liver, brain, and most frequently-bone. Prognosis is more serious with spread to distant sites.

The focus of Dr. Spiegel's study was to affirm the importance of support groups in dealing with day to day problems. Short term findings demonstrated that the support groups were a success; the participation in support groups did improve the quality of their lives.

Years later, he went back to these women's records to disprove a popular contention that emotional factors could influence the course of cancer. To his surprise, the women in support groups had survived twice as long as non-support group women. It was evident that states of mind can affect physical health.

(My note: being successfully married helps, too. Married people live longer than persons who are single, widowed or never married. Beyond marriage, it was found that women with supportive women friends do better than loners. Women gain more support from other women than they do from their husbands. Men gain more from female companionship than they do from their male cronies. Pets are helpful-especially dogs. Persons who are religious tend do better than the non-religious. Being socially connected influences health favorably.) See Goleman, D. and Gurin, J. Mind-Body Medicine. Yonkers: Consumers Union, 1993.



The major risks for coronary heart disease are well known: high blood pressure, smoking, and elevated blood cholesterol. In recent years, however, epidemiological research has identified specific psychosocial risk factors such as hostility, lack of social support, and job strain that set the stage for the disease to develop, and once diagnosed, contribute to a poor prognosis.

Three specific aspects of Type A behavior: hurriedness, competitiveness, and hostility are significant in coronary heart disease. The last, hostility, seems to be the most harmful. In a study of physicians with a 25 year follow-up period, doctors with high hostility scores were four to five times more likely to develop coronary disease than those with low scores. Fourteen percent of the doctors with high hostility were dead by age 50. In contrast, two percent of doctors with low scores for hostility were dead by age fifty years.

The precise physiological connections are not known. The importance of social support in reducing coronary heart disease was apparent in the Roseto effect. Next we will see that how we feel about life has an impact on the incidence of coronary heart disease.

(Williams, B. "Hostility and the Heart" in Mind Body Medicine. Yonkers: Consumer Reports, 1993.)



The highly respected Whitehall study in Britain has followed thousands of British civil servants for nearly two decades, accumulating an extensive array of information on each of the individuals in the study. The data, therefore, is person specific and is longitudinal. This is elegant, long term research..

Why British civil servants? The hierarchy of income and rank in civil service is clearly defined. There is good record keeping. Britain has state medicine, presumably egalitarian in access. (My note: pay attention to the term hierarchy.)

Early on, Whitehall bound that mortality for males ages 40 - 64 was about three and one-half times as high for low ranking clerical and manual workers as it was for senior administrative grades. This is a clear correlation between status and health, but this is only the beginning of the story.

There was an obvious gradient in mortality from top to bottom in the civil service hierarchy. Even among the upper ranks there was a clear gradient of coronary heart disease incidence.

Why? Top people smoked less than folks at the bottom. Strangely, people at the top who did smoke were less effected by it.. People at the lower grades had higher cholesterol and blood pressure levels. Even when the effects of the triad of smoking/cholesterol/high blood pressure are factored in, the established risk factors accounted for less that half of the gradient. Something else powerfully influences health and is correlated with hierarchy.

Even when factors such as low social support, hostility, and sedentary life style were factored in, the gradient still remained.

Reports by Marmot et al published in 1997 demonstrated that a lack of control was the largest single factor in the increased incidence of coronary heart disease at the lowest ranks in the hierarchy. A lack of control was felt by 8% of respondents in the highest ranks, while 75% of lowest ranking respondents reported a sense of no control. Clearly, the social environment has a biological effect.

Three specific findings about health and social conditions among British bureaucrats in the Whitehall study merit mention here.

(1) High ranking British civil servants are less likely to take their problems home.

(2) Risk factors for coronary heart disease in British civil servants is least in the highest grades

Has the effect of hierarchy been examined in animals? Free ranging olive baboons in Kenya (who have dominance hierarchies in their social structure) reveal that low ranking baboons have higher stress than high ranking baboons.

In macaque monkeys fed high cholesterol diets, low ranking monkeys have four times more stenosis (narrowing) of coronary arteries than did high ranking monkeys. Rank matters in issues of health.

(See Evans, Barer, and Marmor Why Are Some People Healthy and Others Not? NewYork: Aldine de Gruyter, 1994; Marmot, Bosma, Hemmingqay, Brunner and Stansfeld "Contribution of job control and other risk factors to social variations in coronary heart disease incidence" The Lancet Vol 350: July 26, 1997 pp 235-239.)



Disease is not distributed evenly through the population. Certain groups of people get sick more often than others. Some populations have premature deaths at a higher rate than other. The study of disease in populations is the work of epidemiology. Through such population studies, the connections between society and the individual appear. Such connections have important implications for social policy.


Money matters! If you want to have a long and healthy life, it is advisable to be wealthy. More specifically, don't be born into poverty. In the United States, the poorer you are, the more likely you are to contract and succumb to heart disease, rheumatoid diseases, psychiatric diseases or a number of types of cancer. Being sick of course affects your money situation. The number one cause of bankruptcy in the United States today is overwhelming medical expense. Sophie Tucker summed it up well when she said "I've been rich and I've been poor. Rich is better!"

Why is there a socioeconomic gradient? It seems so unfair. How does money exert its influence on health?


The socioeconomic gradient seems to leave an indelible mark on life. In a study of elderly nuns who have shared similar religious lives for decades ultimately have disease patterns and longevity that correlates with their childhood socioeconomic status. The lack of money in youth left a life-long scar upon their lives.


Strangely, some diseases run counter to the gradient. The wealthy are more prone to autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, melanoma, and endometriosis. Some medical experts are skeptical. They say that these results are an artifact of detection: many problems in the poor go undetected.

(Start with Conrad, P. and Kern, R. The Sociology of Health and Illness, 4th ed. New York: St. Martin's Press, 1994.)



At present, with the exception of the antimicrobial agents (such as penicillin, streptomycin, sulfonamides, antimalarial agents, and antiprotozoan agents) there are no therapeutic agents capable of removing the causes of most diseases. The vast majority of diseases aren't cured; their course is altered with ongoing management. The most spectacular example is diabetes.

Disease rates and mortality have changed. People live longer and in better health. Many fewer people (especially children) die of infectious disease; chronic disease such as heart disease, cancer, and stroke are now the major causes of death in the United States. Is the medical establishment due all the credit?

Infectious diseases such as measles, tuberculosis, scarlet fever, typhoid, and pneumonia were in long secular declines long before vaccines or antibiotics became available. Apparently, social changes in the environment seem primarily responsible for those beneficial declines in disease. The most obvious of these were sanitation, improved housing and nutrition, and the general rise in the standard of living. Was some individual suffering prevented or cured? Of course! But the introduction of specific medical services were generally not responsible for most of the modern decline in mortality.

In 1997, health care costs in the U.S. passed a thousand billion dollars. This is some serious money. As this is written in 1999, an 11% increase in health costs are predicted. The system seems able to absorb any amount of money made available to it.

Japan spends significantly less on its older citizens than does the United States, yet in the last 30 years, it has experienced the greatest increase in life expectancy of five major industrial countries.


You may disagree with it, but at least consider this idea: supposing you are a political leader in a rapidly modernizing culture and your chosen goal is the combat type II diabetes. What would be the most effective way to combat the problem? Doctors and hospitals? Not necessarily.

Will more opulent hospitals, high paid administrators and cutting edge equipment do as much as public nurses in schools and clinics? Preventing disease is overwhelmingly less expensive that treating diseased people. (See Conrad, P. and Kern, R. The Sociology of Health and Illness, 4th ed. New York: St. Martin's Press, 1994.)



I. CULTURE CHANGE (Harrison et al p 529)

When people move from one culture to the next, that transition can have a significant effect on health. Studies of migrants show that when they take on the social patterns of a culture, they take on that culture's diseases too. Many themes we have already discussed are latent in the text: the development of agriculture and urbanization led to epidemic diseases and nutritional specialization that had major health consequences.

Transportation has tied together large populations that were formally isolated. This has serious implications for public health when fearsome diseases such as Ebola are just an international flight away from major populations centers.


II. DEMOGRAPHIC CHANGE (Harrison et al p 530)

World population growth has greatly accelerated, particularly since 1800. We have noted already that this seems to be (recently) leveling off in many areas.

A phenomenon called the demographic transition occurs when a decline in mortality is followed by decreased fertility. This is seen in western Europe, Japan, and the United States. This may occur in societies when fewer children is more economically advantageous than many children.

If you thought Isaac Asimov's calculation was bizarre, consider this: Populations in many countries are becoming increasingly older as less children are born and people live longer. According to one prediction, Italy in the next century would achieve an average age of 58 years. One cynic deemed this possibility 'a nation of wheelchairs!' Who will pay for astronomically escalating medical and nursing costs? (from 15.3 Population Growth II)



Following the voyages of discovery after Columbus, domesticated plants and animals were dispersed worldwide. Rice came to America (but 90% of rice today is grown in Asia; 10% of what is grown in America--is used to make beer). Potatoes, a gift of the Andean peoples spread across the globe.

Large herbivore domesticates including horses, donkeys, cattle, and sheep were introduced into the Americas. The net effect world wide was expanding populations and occasional disasters such as the Irish potato blight.

Domestic crops have led to nutritional disorders such as goitre (I2), pellagra, and beriberi. Science has made inroads against those problems.

We have earlier noted the phenomenon of the secular (generational) growth trends. Virtually every society that has undergone modernization has witnessed weight increases. Much of that increase is fat, not muscle. The author suggests that this have been harmful for some populations, especially for populations with a history of seasonal deprivation (such as Pima Indians who as a group have the highest incidence of type II diabetes in the United States today.).

The trend has been for calorie dense foods, such as Whoppers and Big Macs. Incidentally, according to the Tribune (7/28/97), the most successful market penetration anywhere on Earth by McDonalds is in Hong Kong. Traditional foods are much less 'calorie dense' and have more non-nutritious bulk which some argue is the food for which we are designed (The Paleolithic Prescription).

..... CJ'99


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