Human Adaptability
ANT 475/575
Dr. Bindon
[Home | Discussion | Paper]
[ Department of Anthropology | College of Arts and Sciences | University of Alabama ]

Nutrition and Adaptation

Nutritional Requirements

As with all heterotrophs, we have to ingest foods to provide several different categories of nutrients:

Energy

Protein, Lipids, and Carbohydrates

Vitamins

Minerals

Trace Elements

However, unlike other heterotrophs, Homo sapiens does not feed, he dines

We imbue our eating with social and symbolic significance

Meals are family and social affairs

Solidify alliances, incur indebtedness

Many foods have special meaning

Totems, taboos, preferences, health

Energy

We require energy from our foods to support the maintenance of our body and our activities

Basal Metabolic Rate (BMR) is the energy expended by an individual who is reclining in a thermoneutral state, at least 12 hours post-prandial

Activity energy requirements are defined by the physical activity performed by the individual

Protein

Required amino acids

Nine that we don’t synthesize

Three more that premies require

Timing of ingestion is critical for protein synthesis

Non-specific nitrogen

Gluconeogenesis

Requirements difficult to determine in adults because of turnover in body

Lower the intake, the more efficient the body becomes at supplying need

Critical needs for normal growth

Pregnancy, lactation

Healing from trauma, illness

Carbohydrates

Glucose is most important form for storage, transportation, utilization in the body

Efficient formation of ATP for cellular work

Active transport into peripheral cells requires insulin--defects produces diabetes

Lipids

Important source of energy

Essential fatty acid: linoleic acid

Should comprise less than 30% of total caloric intake

Micronutrients

Vitamins function as enzymes and coenzymes in various metabolic processes, and diverse other bodily activities

Minerals: Serve as structural elements of bone, tooth, muscle, connective tissue, receptor site, binding sites, etc.

Vitamins

Vitamins are nutritional requirements either because we lack the ability to synthesize them, or we fail to synthesize them in sufficient quantity for normal metabolism

Vitamins fall into two broad categories depending on intrinsic chemical properties: water soluble vitamins and fat soluble vitamins

Water soluble vitamins are present in all body fluids, and are subject to normal excretion

Storage is minimal, and daily or near daily intake is necessary to prevent deficiency conditions

Fat soluble vitamins form lipoprotein complexes and can be stored by the body

Excesses are only slowly metabolized out and excreted

B-1 or Thiamin

Sources: Pork, organs, whole grains, legumes

Functions: Oxidative decarboxylation of ketones for TCA cycle. Coenzyme in reactions removing CO2 in Pentose Phosphate shunt

Deficiency: Beriberi with symptoms of peripheral nerve changes, edema, heart failure

Excess: Not Reported

Polished Rice Disease: Shipboard beriberi known from Japanese navy--addition of meat to normal rice ration reduced occurrence

B-2 or Riboflavin

Sources: Dairy, meat, fish, cereals

Functions: Coenzyme in energy metabolism (electron transport system), aiding in synthesis of ATP

Deficiency: Reddened lips, cracks at mouth corner (cheilosis) eye lesions

Excess: Not reported

Requirement increases with increasing caloric intake.

Niacin

Sources: Liver, grains, legumes

Functions: Hydrogen acceptor as Nicotinamide Adenine Phosphate (NAP and NADP)

Deficiency: Pellagra (skin, g.i. lesions, nervous, mental disorder)

Excess: Flushing, burning, tingling around neck, face, hands

Synthesized from tryptophan

Lime processing in maize is necessary to breakdown glutelin, make tryptophan available

Maize Processing

The rise of maize (Zea mays) as a major cultivar in the New World from 7,000 b.p. in Mexico was not without a biological price

Corn is of limited nutritional benefit without appropriate processing or treatment to enhance availability of nutrients

90+% of the protein in the corn kernel comes in four forms

Albumins, available, low quality

Globulins, available, low quality

Zein, relatively available, low lysine, low tryptophan, high leucine to isoleucine ratio

Glutelin, soluble in alkaline solution, high lysine, moderate tryptophan, low leucine to isoluecine ratio

Nutritional deficiencies of corn when not appropriately processed:

Low in essential amino acids lysine and tryptophan

High leucine to isoleucine ratio

Low availability of niacin

Thought to be bound by an insoluble substance

Can be synthesized from excess tryptophan

Synthesis of niacin is inhibited by leucine

Leucine inhibition is removed by isoleucine

Most severe nutritional problem with a high maize diet is the potential for Pellegra from niacin deficiency

Symptoms:

Dermatitis: Skin inflamation where exposed to sunlight

Diarrhea: Loss of acidity may allow bacterial growth, causing a decreased ability of the intestinal mucosa to facilitate absorption

Depression: Irritability, headaches, sleeplessness, loss of memory hallucinations, delusions of persecution, and severe depression

Death through organ failure

Historically Pellegra has been the only endemic nutritional disease native to the U.S.

In 1918, there were an estimated 10,000 pellegra deaths and 100,000 cases, primarily in the cotton growing regions of the Southern U.S.

Pellegra became a public health issue in the South during the depression

Families growing corn and eating mostly non-alkaline processed grits

Alkalai processing changes the nutritional quality of maize

Tortilla manufacture in MesoAmerica

Heat dried corn to boiling in 5% lime-water solution

Cool, discard liquid, wash corn, grind into a dough

Form pancake shape and cook on hot clay griddle

Sources of alkalai (turning the water to a base pH, higher than 7.0) include the mineral lime from bedrock in many areas, commercial lye and soda preparations, and wood ash

Lime has the added benefit of increasing dietary calcium

Alkalai processing increases the bioavailability of niacin and glutelin, while decreasing availability of Zein

The net effect is to decrease the likelihood of pellegra on a high corn diet

The populations most likely to experience pellegra historically are those that relied heavily on it

Native Americans

Many New World Societies were very heavily reliant on maize cultivation and alkalai processing

Katz and colleagues used the HRAF files to assess processing technique (alkalai or not), and cultivation and consumption of corn on 4 point scale (none to high)

They found a good association between level of cultivation, consumption, and alkalai processing

Modified from Katz et al., 1975:203.

^aCrow (Plains): use alkalai, but have no cultivation of corn, and little consumption of maize

Their use of maize historically comes from the Hidatsa

Crow split from Hidatsa to become nomadic buffalo hunters, but maintained the food habit of alkalai processing corn (with wood ashes)

^bPaez (Andean): Most Andeans don't process, but the Paez do

Archaeological evidence suggests that the Colombian area where the Paez live did not develop corn cultivation like others in the Peruvian Andes

The Maize complex, complete with alkalai processing was introduced into Colombian Andes late (like in Southwest U.S.), influencing the Paez and others

^cPapago (Southwest U.S.): don't use alkalai, but are moderate producers and consumers of corn

Limits of the arid environment prohibits year-round cultivation and high reliance on corn

Papago don't store maize nor allow it to fully ripen--they eat it in the roasting ear stage, gorging at a time when other food is abundant (Thrifty Genotype)

B-6 or Pyridoxine

Sources: Meats, vegetables, whole grains

Functions: Coenzyme in amino acid metabolism

Deficiency: Convulsions, skin rash, anemia

Excess: Not reported

Requirement increases with increasing protein intake

Pantothenic Acid

Sources: Liver, yeast, whole grains

Functions: Part of CoAcetoacetyl-TCA cycle (energy metabolism)

Deficiency: Fatigue, sleep disturbances, rare in man

Excess: Not reported

Folic Acid

Sources: Legumes, green vegies, whole wheat

Functions: DNA synthesis

Deficiency: Megalocytic anemia, diarrhea; Rats show spontaneous abortion

Excess: Not reported

May be involved in distribution of skin color

Denatured by UV light

B-12

Sources: Muscle, eggs, Not in vegies

Functions: DNA synthesis

Deficiency: Pernicious anemia, neurological disorders

Excess: Not reported

Pernicious anemia shows Megaloblastic cells, defective RBC production, deterioration of spinal cord tissue, tingling of extremities

Biotin

Sources: Legumes

Functions: Fat synthesis, amino acid metabolism, glycogenesis

Deficiency: Fatigue, depression, nausea, dermatitis, muscle pain

Excess: Not reported

Choline

Sources: Phospholipids, egg yolk, liver, grains, legumes

Functions: Acetylcholine precursor

Deficiency: Not reported

Excess: Not reported

C or Ascorbic Acid

Sources: Citrus, tomatoes, green peppers, salad greens

Functions: Connective tissue synthesis

Deficiency: Scurvy: skin, teeth, blood vessel degeneration

Excess: Diarrhea, kidney stones

1780: Limeys discovered importance of citrus fruits to prevent scurvy on long sea voyages

Scurvy was the cause of more deaths than anything else during voyages of exploration

A or Retinol

Sources: Green or yellow vegies, dairy foods, liver and liver oils, especially concentrated in predator’s livers

Function: Part of visual pigment rhodopsin, epithelial cell differentiation, cell membranes, mucopolysaccharides

Deficiency: Xeropthalmia including night blindness to corneal ulcerations

Excess: Headache, vomit, anorexia, long bone swelling, lysosome membrane breaks down, cells self-digest

Acute toxicity has occurred in Arctic explorers who consumed large quantities of polar bear liver

Polar bear liver contains 600 mg retinol (2,000,000 I.U.) per 100 gm

A taboo on polar bear liver consumption among Eskimos may be because of toxicity

Or may be due to fact that polar bears are mean mothers

D or Cholecalciferol

Sources: Eggs, dairy products, cod liver oil, fortified milk

Functions: Calcium absorption, promotes bone growth

Deficiency: Rickets, Osteomalacia

Excess: Vomit, diarrhea, kidney damage, soft tissue calcification

Synthesized in dermis with UV exposure

May play a role in the distribution of skin color

E or Tocopherol

Sources: Seeds, leafy greensvegetables

Functions: Antioxidant, maintains cell wall integrity

Deficiency: Hemolysis, anemia

Excess: Gastrointestinal disturbances

Increased polyunsaturated fatty acid intake requires increased E

Has been claimed as wonder drug: prevent heart attack, increase sexual potency

Recent findings support an anti-oxidant role

K or Menaquinone

Sources: Green leafies

Functions: O2 and C02 combine with K to liberate energy used to activate the blood clotting cascade

Deficiency: Only seen when induced by antibiotics or gall bladder disease, produces internal hemorrhage

Excess: Not very toxic, although the possibility exists of internal clots

Is synthesized by bacteria in intestine, in addition to dietary sources

Calcium

Sources: Dairy goods, lime salts

Functions: Bone, tooth formation and growth; nerve transmission

Deficiency: Stunted growth, rickets, osteoporosis, convulsions

Excess: Not well absorbed without additional Vitamin D

Andeans chew coca with burnt lime and fat

Hypothesized association with arctic hysteria and possession cults

Controversy about calcium deficiency causing osteoporosis versus inactivity effects on bone density

Calcium absorption decreases with age

An increase in protein intake leads to an increase in Ca requirement, while an increase in phosphorus intake leads to a decrease in Ca needs

Both effects mediated by kidney tubular reabsorption

Iron

Sources: Eggs, meat, whole grains, leafy greens

Stored in the spleen, liver and bone marrow

Functions: Hemoglobin constituent, also functions in energy metabolism

Deficiency: Iron-deficiency anemia

Excess: Hemosiderosis, cirrhosis-like illness

Heme iron (from animal sources) is highly absorbable

Non-heme iron absorption is increased by presence of animal tissue, Vitamin C, low iron stores

Absorption decreased by phytates, bran, tea, CaPO4

Popeye myth based on a typo in early food tables suggesting spinach had 10 times as much iron as it does

Known toxicity from taking supplements and among Africans cooking in iron pans and storing beer in iron containers

Menstruating females have increased iron requirements

Iodine

Sources: Marine foods, dairy products, vegetables where soils contain iodine

Function: Constituent of Thyroxin

Deficiency: Goiter, cretinism in children born to goiterous mothers

Excess: Depress thyroid activity, goiter

Cretinism among the Maring due to non-iodized trade salt

Deficiency can by induced by goitrin present in Cruciferae (e.g., cabbage, rutabagas)

Thiocyanate contained in cassava also suppresses absorption

Zinc

Sources: Widely distributed, most absorbable from animal foods

Functions: Constituent of DNA polymerase necessary for cell division

Deficiency: Hypogonadic dwarfism, stunting

Excess: Fever, nausea, diarrhea

Deficiency can be induced by calcium or cadmium which may be obtained through geophagia and which selectively suppress zinc absorption

Also, phytates present in whole-grain bread (e.g., in Shiraz, Iran) can complex the zinc, making it unabsorbable

Sources

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Date this page last edited: August 20, 2002
e-mail me at: jbindon@tenhoor.as.ua.edu