BIOS 5445: Human Ecology
Dr. Stephen Malcolm, Department of Biological Sciences
•  Lecture 7. Mortality Malnutrition:
–  Lecture summary:
•  Nutritional problems:
–  Malnutrition.
–  Proteins & Calories.
–  Effects.
•  Vitamin deficiencies.
•  Mineral deficiencies.
American Gothic by Grant Wood, 1930
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 1
2. Malnutrition:
•  Any type of poor nutrition:
–  Undernutrition.
–  Overnutrition (lecture 8).
–  Improper nutrient balance.
•  Based on failures of behavior & culture:
–  Economic & sociopolitical problems.
–  We can feed everyone a balanced diet:
•  Nevertheless malnutrition is common.
•  Problems of food distribution.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 2
3. Protein-Calorie malnutrition:
•  Deficiency in energy (kcal) content of food.
–  Total starvation.
–  Undernutrition
–  Sufficient caloric content & insufficient
protein:
•  Protein deficiency:
–  Necessary for growth, reproduction & daily survival.
–  20 amino acids:
»  8 essential dietary amino acids + 12 can be
synthesized.
»  Essentials must occur in sufficient proportions.
»  Protein quality represents amino acid match to
required ratios.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 3
4. Protein content of food (Fig. 9-1) - balanced Mesoamerican diet:
beans balance isoleucine & lysine deficiencies of maize &
vice versa for methionine & cystine.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 4
5. Protein deficiency in children:
•  Combination of:
–  Weaning from breast milk.
–  Rapid growth rate up to age 5.
–  Single plant food rich in
carbohydrate & low in protein.
–  Parasitic infections that exploit
protein.
•  Kwashiorkor:
–  In Ga language means disease
that occurs when displaced from
the breast by another child.
–  Protein deficiency reduces
immune system function leading
to infection.
–  Distended stomach from loss of
abdominal muscle tone due to
muscle breakdown as protein
http://www.nlm.nih.gov/medlineplus/ency/imagepages/9563.htm
source.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 5
6. The Cori Cycle (Fig. 9-3) conserves glucose
driven by energy from fat metabolism:
•  Energy reserves:
–  Fat = long-term storage:
•  US = 15 kg = 135,000 kcal
= 70 days energy/person
–  Glycogen = short-term
storage, maintains sugar
homeostasis:
•  Glycogenesis:
–  Blood sugar high >
hormone insulin
secreted:
»  Glucose > glycogen
•  Glycogenolysis:
–  Blood sugar low >
hormone glucogon
secreted:
»  Glycogen > glucose
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 6
7. Effects of protein-calorie malnutrition:
•  Loss of body weight:
–  Body fat and body protein (skeletal muscle).
•  Physical work capacity declines.
•  Child birth:
–  Labor can be extended by 5 hours & increase health risks.
•  Can reduce lactation and food availability for infants.
•  Behavioral/psychological effects:
–  Apathy & inactivity (also help to conserve energy).
•  Marasmus:
–  Children combine muscle depletion of kwashiorkor (protein
malnutrition) with loss of body fat & cessation of growth.
–  Vomiting & diarrhea common, leading to dehydration.
–  Weakened immune system & disease susceptibility.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 7
8. Vitamin deficiencies:
•  Vitamin A (retinol):
–  In green & yellow vegetables & dairy products.
–  Needed for epithelial cell function (including vision).
•  Vitamin B1 (thiamine):
–  In most foods - deficient in rice.
–  Needed for carbohydrate metabolism.
–  Severe deficiency results in beriberi disease
•  Vitamin B3 (niacin):
–  Low in maize (corn).
–  Deficiency disease is pellagra.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 8
9. Vitamin deficiencies (continued):
•  Vitamin C (ascorbic acid):
–  Occurs in fresh fruits & vegetables.
–  Hominoids, 1 bat & guinea pigs cannot
synthesize vitamin C.
–  Required for collagen synthesis
–  Deficiency results in poor wound healing &
hemorrhaging - scurvy:
•  Constrained sea voyages.
•  British sailors ( limeys ) given lime juice.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 9
10. Vitamin deficiencies (continued):
•  Vitamin D:
–  Eggs, dairy products & synthesized from dietary
steroids.
–  Needed for calcium absorption and use.
–  Deficiency leads to rickets in children &
osteomalacia in adults.
•  Can be exacerbated by clothing traditions & taboos.
–  Requires UV radiation from sunlight in skin cells.
•  Facilitated by light colored skin:
–  Northern adaptation to enhance synthesis?
»  But more prone to skin cancer from UV exposure.
»  Gloger s Rule - skin color lightens with increasing
latitude.
–  Dark skin may prevent too much vitamin D.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 10
11. Mineral deficiencies:
•  Iron:
–  Highly prevalent - anemia from lack of iron in hemoglobin.
–  Results in lowered work capacity & lowered intellectual ability.
•  Iodine:
–  In seafood, vegetables & dairy products.
–  Required for thyroid hormones.
–  Deficiency leads to goiter & hypothyroidism or myxedema and
cretinism in children:
•  Highest prevalence in mountain people (Alps, Andes & New
Guinea).
•  Calcium:
–  Linked to vitamin D.
–  High in dairy products & dark green leafy vegetables.
–  Deficiency can lead to osteoporosis or pibloktok in some
Inuits.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 11
12. Adaptation and malnutrition:
•  Nutrients are required chemicals:
–  Carbohydrates, lipids, protein, vitamins &
minerals.
•  Food is cultural:
–  Regional variation in preference can shift
with cultural change.
–  Predict links between physiological
nutritional requirements and cultural
behaviors.
•  But these links are not always adaptive.
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 7: Slide - 12
13. References:
•  Kormondy, E.J., & D.E. Brown. 1998. Fundamentals of human
ecology. Prentice Hall. 503 pp. (chapter 9).
Dr. S. Malcolm
BIOS 5445: Human Ecology
Lecture 6: Slide - 13