MedicalAnthropology, Chapters 4-6 Summary
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Chapter 4: Diet and Nutrition in Health and Disease
• diet plays a major role in health and disease
• nutrient deficiencies or surpluses can result in dysfunction across physiological systems.
• nutrition is a young science, origins in the 1910s and 1920s
Fundamentals
• nutrient deficiencies as a cause of disease were initially not considered likely.
scurby or pellagra were due to vitamin deficiencies
•
• a certain number of calories are required in a day to stay alive
• up to 20% goes to fuel the brain
• energy is derived from carbohydrates in plant foods and fat in animal and some plant foods (i.e.
nuts and seeds)
• protein is required as a source of amino acids. Used to make own body’s proteins which
helps with muscle and bone. It is a source of metabolizable nitrogen, essential for DNA
• carbohydrates, protein, and fat are referred to as “macronutrients” b/c they are needed in large
quantities
• minerals humans need in the greatest quantity is calcium.
• Dietary Reference Intakes (DRIs) for macro and micronutrients are a diverse set of standards
that are not always straightforward to interpret Basis for US Dietary Guidelines, which
translate nutrient requirements into dietary recommendations.
• result of changing health concerns
when people receive all the nutrients the need in the proper amounts, they are said to be in
•
a nutrient balance.
• if under nurished they would suffer from undernutrition
• if they receive too much nutrition it is called overnutrition.
• both conditions can be considered malnutrition, meaning bad nutrition. Most often used
for undernutrition though.
• Protein energy malnutrition (PEM) most often occurs when there are shortages of these
macronutrients.
Digestive Physiology
• humans have generalized digestive systems. We can digest both plant and animal foods.
other animals like cows and monkeys have specialized stomachs that can ferment large
•
quantities of fiber. Humans lack the gut specializations.
• Human digestion goes as follows:
1. starts at the mouth, teeth break large food particles, saliva will break down starches, carbs.
2.food goes through esophagus into the stomach, where it is subjected to strong acids that kill
potential pathogens and enzymes. This begins the process of disgesting protens.
3. after 2-3 hours, goes to small intestine where starches, fats, sugars, and proteins are absorbed
by the cells.
4. everything else goes to the large intestine/colon. The colon has large colonies of bacteria, most
of which are quite helpful in that they can ferment some fibrous material that the human body
cannot digest on their own.
• nutrients that have been absorbed are transported via the lymph system to the bloodstream then
to the liver for further process. MedicalAnthropology, Chapters 4-6 Summary
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• nutrients go to tissues that need to utilize them immediately
• body has limited capacity to store protein
fatigue is common to low-energy diets.
•
• hard to detect nutrient deficiencies except in their extremities
An EvolutionaryApproach to Nutrition
• Environment of evolutionary adaptation (EEA): the traits that organisms now possess reflect
advantages that accrued to individuals with those traits in some past environment.
• i.e. having flexible fingers, including an opposable thumb, first evolved among early
primates, 50-60 million years ago.
• Bipedalism evolved sometime around six million to eight million years ago, and the large
brain of humans began to emerge 2 million years ago.
• Most relevant for humans is considered to be the Upper Paleolithic, when humans were
biologically “modern” and lived as hunter-gatherers. 200,000-10,000 years ago
• difference among Upper Paleolithic hunter-gatherers, resulting in differences in diet, some
relying on animals and others plants. Overall pattern was similar.
• historically considered the “hand-to-mouth” existence due to the threat of starvation.
• (Blurb box) Scurvy is due to a deficiency in Vitamin C. Epidemics between 1550 and 1857.
• Transition to agriculture among populations around 10,000 years ago altered the way of life.
• lead to domestication and large-scale production, different than hunter-gatherers.
• energy expenditure increased with this transition
• Jared Diamond argued that agriculture was the worst mistake in the history of human race.
• paleolithic hunter-gatherers were very successful in acquiring good, which led to
population
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