NOTES for WEEK 7

READER pp 46-51

The first article "Beyond the Thrifty Gene . . . " follows in the footsteps of the 'discordance hypothesis' discussed earlier. In brief, it says that we live in an environment today quite different from that of our food forager forebears.

We are all familiar with diabetes. There are two general types of this disease.

• Type I is juvenile diabetes. This is the failure of the pancreas to produce insulin. Measures for management are familiar: diet and regular injections of insulin. Best and Banting won the Nobel Prize for their work in this field early in this century. It is one of the triumphs of twentieth century medicine.
• Type II is adult onset diabetes. The authors use the acronym NIDDM for it in this article.

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In this country, Type II diabetes varies in different ethnic groups. We will see the epidemiology later in this course in a unit specifically on diabetes. TEXT discusses the issue on page 233.

Persons of Native American Indian ancestry seem most susceptible to type II diabetes; the highest incidence is among Pima Indians (A'a'tam pronounced 'autumn' means "people").

• Weiss has called the high incidence of disease among these folks the "New World Syndrome."
• Neel was the first to argue that these folks had a 'thrifty genotype' that was advantageous for the food forager lifestyle but was harmful in a sedentary lifestyle with an abundance of calorie-dense foods.

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Unless you are really into nutrition, this article is going to be slow going. Read it. THESE NOTES ARE NOT ENOUGH!

Now, let us here display the content of tables I, II, and III side-by-side for comparison.

(My Comment: One of the problems with this article is what you see in the bibliography. The sources are old!)

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READER pp 52-57

The second article "Genetic Prophecy . . . " examines the problem of genetic testing at the individual level and by insurance companies. Genetic testing is new legal ground and science is creating legal and ethical problems unimaginable a generation ago. See "genes' below as a separate NOTES topic.

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MEDICINE IN THE NEWS

This past week a study was released that suggested obesity can shorten life.

"Fatter you are, shorter your life, study hints" Chicago Tribune October 8, 1999.

The figures are based on the Body Mass Index (BMI). The recommended BMI is between 20 and 25. To calculate, multiply your weight in pounds by 700, divide by your height in inches, then divide by height again for your BMI.

White women and white me with a BMI of 40 or over (that is nearly double their ideal weight) had a significantly higher rate of death for a given age. An intriguing exception was for black women, for whom overweight was not a significant risk.

One other health trivia tidbit: Are you an apple or a pear? Divide your waist size by your hip size. The healthiest are .80 for women, .95 for men. (See Annual Editions Health 96/97.)

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DISEASES FIND EASY PATHWAYS INTO U.S.

This is the title of the Chicago Tribune article October 7, 1999 that was an update on the newest disease in the news (as I write this 10/9/99), West Nile encephalitis.

The Ebola outbreaks in Africa and the best seller in 1994 The Hot Zones have heightened our consciousness of disease outbreaks and their potential to come here.

The outbreak of encephalitis in the New York metropolitan area, which has resulted in at least 50 confirmed cases and five deaths have been traced to a virus similar, if not identical, to the West Nile encephalitis virus found in Africa, the Middle East, and Australia.

The pathogen has never been seen in this country before. It is spread from birds to people by mosquitoes. How West Nile enchephalitis got to the United States in unknown. Hundreds of birds (crows in particular) have died, as have some prize rare birds in the Bronx zoo.

North America is home to several encephalitis viruses. The most common is the St. Louis encephalitis (SLE), a germ that mosquitoes can transmit from birds to people. The birds are unharmed by it. Outbreaks of it occur periodically in the Midwest and the Southeast. The victims are usually elderly.

It is the newest and most current 'emerging disease.' Other potential ones in the news are cholera, and a drug-resistant form of tuberculosis now raging in prison populations in Russia.

Sources:

Cowley, G. and Kalb, C. "Anatomy of an Outbreak" Newsweek October 11, 1999.

Manier, J. "Illinois on alert for African virus" Chicago Tribune October 5, 1999.

"Reemerging diseases threaten Americas" The Kankakee Journal September 29, 1999.

Swanson, S. "Diseases find easy pathways into U.S." Chicago Tribune October 7, 1999.

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ARE WE IN EMINENT DANGER?

Preston's The Hot Zone came out in 1994 when I first did this course at IUN. The students loved it and so did I. A year later, Garrett's The Coming Plague was published. It is wonderfully authoritative with lots of citations. I've used it throughout this course. It is a true reference work.

Both books are riveting and scary. They both have an underlying tone of crisis, of doomsday waiting to happen. The premises in each are as follows:

• Major U.S. population centers are but a day away from any major city on Earth.
• We are invading ever deeper into rainforests and other wild habitats, thus releasing new diseases.
• A disease could appear from nowhere and overwhelm us if the circumstances are right.

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Is it going to happen? This is a contrary view from an interview with science writer Ed Regis.

Van, Jon "On the Record" Chicago Tribune:

He says that in the 20 year record for Ebola is 750 deaths. In comparison, 1,000 people choke to death in this country each year.

Ebola requires direct person-to-person contact with blood, vomit and other fluids. When CDC workers wear gloves, gowns, masks, and goggles-they don't get sick.

Are the microbes winning? Are we having 'a revenge of the microbes?' Probably not. Human life expectancy in nearly every country is increasing. In most infant mortality rates have been decreasing. If anything, we're becoming less vulnerable than more vulnerable.

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TEXT CH 5 pp 169-179 ECOLOGY AND ECONOMICS OF NUTRITION

Nutrition is a hard sell. Lectures on this topic were among the worst that I can recall from dental school in the 1960s.

This week's reading is short, intentionally so to allow time for other topics. When you read pp 170 through 179, be sure to acquire mastery of these ideas-they are integral to medical anthropology:

• Central to every culture is its way of obtaining food. A culture's way of getting food is called its subsistence strategy. Many ways of food-getting are discussed in this chapter.
• Humans are unable to synthesize eight amino acids (read the exception on page 172). All eight must be present in the diet simultaneously for protein synthesis.
• Many staple plant foods are deficient in one or more essential amino acids. People make it up by "protein complementarity." This means they eat two or more veggies to get a balanced diet.
• Diets lacking in essential nutrients result in nutritional diseases-topics we cover later.

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The remainder of the reading is about subsistence by hunting and gathering, our oldest subsistence strategy. Pay attention to their short work day and how they achieve a balanced diet. The Ju/'hoansi profiled had periodic food shortages.

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THE EVOLUTION OF HUMAN NUTRITION From the article of that name by Barry Bogin in The Anthropology of Medicine 2^nd ed. Romanucci-Ross, Moerman, & Tancredi eds.

These notes are an adjunct to the class lecture.

1. We need 45-50 essential nutrients. We know those as proteins, carbohydrates, fat, vitamins, minerals, and water.

2. Wild animals seek out and eat foods with essential ingredients. Humans, particularly infants, do also. Yet, we overeat as we saw in the video fat. Later, we will meed animals that eat dirt. They do it for nutritional reasons as we will see.

3. Every culture has a cuisine. If it has a long history, it tends to be nutritious and well balanced. They may explain it mythologically (ethnoscience); we explain it scientifically (biomedically).

4. Why do we need some nutrients that other animals can synthesize? It is widely accepted that primates (including humans) had their origins in forested environments rich in seeds, fruits, vegetables, and insects which they ate freely. (Incidentally some people eat insects. Grasshoppers for supper anyone?) With certain nutrients freely available in the environment, our ancestors lost the ability to synthesize them.

5. Plants also product toxic substances called secondary metabolites. Some are the basis of medicinals, such as quinine. Others are downright toxic. Why? They are the plant's biochemical defense.

6. Human feces reveal much about ancient human dietary practices. The oldest know are from Homo erectus at Terra Amata (France) that may date to 300,000 ya. "Fossilized feces" are called coprolites. How can you tell if they are human? Human coprolites soaked in trisodium phosphate solution for 72 hours turn brown to black. No other species produces this effect.

7. Food preparation techniques such as cooking, grinding, soaking, and fermenting has broadened the human food base. Some foods such as acorns are not edible without having a toxic component such as tannin removed from them.

8. Industrialization, sedentism, and contemporary living have increased the incidence of heart disease, obesity, and diabetes.

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GENETICS RESHAPING MEDICINE These remarks are a supplement to the second article in READER for this week.

"In the next five to 10 years, everyone who's interested will have the opportunity to undergo some form of DNA testing to predict their future risk," said Dr. Francis Collins, director of National Human Genome Research Institute which seeks to map all human genes.

As of November, 1998, 30,261 of 80,000 to 100,000 of the human genome has been mapped. The 15 year $3 billion federal program will finish its job by 2003, two years ahead of schedule.

"Fixing" human genes has been less than successful thus far.

More successful is genetic testing. In the near future it will be possible to test for 20 to 30 common ailments including cancer, heart disease, diabetes, and Alzheimer's.

• Practical question: would you want to know? Supposing the test was false positive? Did you read the READER article?
• Legal question: should your insurance company have the right to test your genes and thereby deny you coverage-and share that information with others? Personal privacy advocates are up against well-financed lobbyists from the insurance industries who want genetic testing. Supposing your employer wants to test you in order to keep health costs down?
• Ethical question: A couple who are carriers of the sickle cell trait want to have their fertilized ovum tested for sickle cell disease. IS a fertilized egg life?

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Item: Genetic engineering has become big business in agriculture and a big publicity issue in Europe. Genetic engineering of seed crops in the United States has increased yields and improved disease resistance. Europeans want no part of it! Many foods are now advertized as not genetically altered. This is a major threat to American agricultural exports. As of this year (1999), one-half of the soybean crop and one-third of the corn plant contains transplanted genes. No ill effect have been reported.

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Item: Virginia Tech has produced genetically engineered pigs that will produce factor VIII in their milk which can be then used by type A hemophiliacs.

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• Should the government maintain a national DNA data base? Should newborns be DNA 'fingerprinted?' The FMI opened a DNA database of people convicted of certain serious offenses last year. England already has a DNA data base of everyone convicted of a crime since 1995-as well as suspects. My question is: how accurate is this stuff?

..... CJ'99

Resources

Kotulak, R. "Genetics reshaping medicine" Chicago Tribune February 21, 1999.

Lagnado, L. "Group Sows Seeds of Revolt Against Genetically Altered Foods in U.S." Wall Street Journal October 12, 1999

Shreeve, J. "Secrets of the Gene" National Geographic October, 1999 pp 42-75.