today next few lectures l.
Skip this Video
Loading SlideShow in 5 Seconds..
Today & next few lectures PowerPoint Presentation
Download Presentation
Today & next few lectures

Loading in 2 Seconds...

play fullscreen
1 / 45

Today & next few lectures - PowerPoint PPT Presentation

  • Uploaded on

Today & next few lectures Look through & selectively read from the “hunger/nutrition issues” links on Blackboard Today Biology of human nutrition Traditional diets & protein-calorie nutrition Vitamins, minerals, & deficiency diseases Synergies between nutrition & disease Next week

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

Today & next few lectures

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
today next few lectures
Today & next few lectures
  • Look through & selectively read from the “hunger/nutrition issues” links on Blackboard
  • Today
    • Biology of human nutrition
    • Traditional diets & protein-calorie nutrition
    • Vitamins, minerals, & deficiency diseases
    • Synergies between nutrition & disease
  • Next week
    • Malnutrition & hunger
    • The Entitlement concept
    • Causes of hunger – the Irish famine example
    • Nutrition transition
nutrition and hunger
Nutrition and Hunger
  • Biology of Nutrition
    • Active adults and growing children need most food/body weight
    • But, small children, infants, and the aged are most at risk to severe consequences of nutritional problems
    • Nutritional needs
      • Energy: commonly measured in kilocalories (kcal) or what we usually call “calories”
      • Protein: variable in “quality” for human use
  • Body “burns” carbohydrates, fats, and sugars for the energy to live
  • Proteins also can be converted by the liver to sugars for energy if necessary, but not vice versa (not very efficient)
  • Calories in excess of need => storage as fat
severely insufficient nutrition
Severely Insufficient Nutrition
  • Calorie or protein-calorie malnutrition
    • Severe forms of this in infants especially can lead to marasmus
    • Body breaks down lean muscle and tissue to produce calories
  • Severe protein malnutrition can lead to kwashiorkor
  • Stick-like limbs, bloated belly, wide eyes:
  • From Greek “to waste away”
  • Lacking calories (as well as protein), children may weight less than half of normal
  • Brings diarrhea, apathy, and brain damage
  • Bloated look as fluids are accumulated to push against wasted muscles.
  • Severe protein deficiency
  • Bloated body
  • Fluids stuffed in cells against wasted muscles
  • Results in diarrhea, apathy, brain damage
  • There are 22 amino acids needed to create the thousands of proteins humans need to create: e.g., blood, hormones, hair, muscle, antibodies, etc.
  • We make all the amino acids needed except for 9 that must be in foods:
    • leucine, valine, tryptophan, phenylaline, isoleucine, threonine, lysine, cystine, and methionine
  • Foods vary in their composition of these so vary in “quality” of protein (% protein that is usable)
  • Foods also vary in total quantity of protein per gram
quality of protein i
“Quality” of protein I
  • Animal foods:
    • Quality is relatively high
      • e.g., eggs = 98%; milk = 80%; fish = 80%; meat = 70%
    • Quantity is relatively high as well
  • Grains:
    • Quality is relatively high
      • e.g., rice, wheat, oats = 70%; millet, rye = 55-60%
    • Quantity is relatively low
      • ~ 10-15% by weight is protein
quality of protein ii
“Quality” of protein II
  • Legumes (pulses):
    • Quality is so-so – usually deficient on one or more of the 9 amino acids
      • e.g., soy beans = 60%; lima beans = 50%; lentils = 30%
    • Quantity is relatively high
  • Other vegetables
    • Quality is so-so to poor
    • Quantity frequently low also
traditional diets i
Traditional diets I
  • Traditional Mesoamerican bean burrito
    • Beans
      • Short of methionine, cystine
      • Lots of lots of lysine, tryptophan, isoleucine
    • Corn (maize)
      • Short of tryptophan & lysine (OK otherwise)
    • So the beans balance the shortage of tryptophan and lysine in the corn making the overall protein quality very good
traditional diets ii
Traditional diets II
  • Hamburger & wheat bun
    • Wheat
      • Short of lysine
      • Lots of methionine, tryptophan, isoleucine
    • Beef
      • Lots of lysine
    • So the two balance each other out
  • Rice and Soy
    • Rice is short on lysine so mixed with most beans => good
    • Soybeans have lots of lysine and tryptophan so good with rice
vitamins minerals
Vitamins & minerals
  • Chronic shortages may not show obvious effects but at the biochemical level there are problems
    • Variety in diet best solution
  • Shortages can be precipitated by some diseases (e.g., parasites such as hook worm, malaria, etc.)
historical acute deficiency diseases
Historical acute deficiency diseases
  • Beri-beri: thiamine (vitamin B1)
    • Found in rice eating pops in Asia
    • More varied diet => not a major problem now
    • Common vegetable sources are various legumes and whole grains -- polished (white) rice is deficient
  • Pellagra: niacin (vitamin B3)
    • In populations who consume maize or sorghum as main foods since both are low
    • Not in Mesoamerica, however, because of the treatment of maize (nixtamalization) => increases niacin and beans have it as well
historical acute deficiency diseases16
Historical acute deficiency diseases
  • Scurvy: vitamin C
    • Formerly a major problem for sea-going navies and explorers
      • Early 19th C British Navy solution – eating limes => Brits commonly called “Limeys”
      • Sauerkraut also works fine!
    • Periodically a problem in refugee pops who don't get enough fresh fruits and vegetables
  • Rickets: vitamin D
    • Lack of sufficient sunlight in winter
contemporary acute deficiency diseases iron
Contemporary acute deficiency diseases: Iron
  • Iron deficiency:
    • Most common single nutrient deficiency in the world
      • > 1/3 of pop in many developing countries
    • Reduces cognitive performance, energy and work ability, and resistance to infection (especially to diarrheal and respiratory diseases) even in mild cases
    • Severe forms = anemia
contemporary acute deficiency diseases iodine
Contemporary acute deficiency diseases: Iodine
  • Iodine deficiency:
    • Iodine is lacking in soils from some mountain areas and in domr highly leached soils
      • e,.g., Andes, Himalayas, C Africa, SE Asia...
    • Major consequences:
      • Swelling of thyroid (goiter)
      • Important mental deficiencies (cretinism) in kids if deficient in pregnant women
contemporary acute deficiency diseases vitamin a
Contemporary acute deficiency diseases: Vitamin A
  • Vitamin A deficiency:
    • Major consequences
      • To vision can lead to blindness
      • Also decreased immune function
      • Kids with severe protein-calorie malnutrition often have impaired sight as a result of this
synergy nutrition and disease
Synergy: nutrition and disease
  • Poor nutrition (protein-calorie or other nutrient shortages) => reduced ability to fend off new infections or makes existing ones more severe
  • Diseases interfere with nutrient absorption and/or actively deplete nutrients from our bodies
how poor nutrition disease
How poor nutrition => disease
  • Reduction in the body's innate immunities (that react to general patterns of proteins in pathogens)
    • Less effective phagocytosis (process by which microorganisms are engulfed and encapsulated)
    • Weakened epithelial barriers (protective coverings on body surfaces inside and out)
    • Lowered lysozyme production (a bodily protein that functions as an antibacterial)
how poor nutrition disease ii
How poor nutrition => disease II
  • Reduction in ability to generate acquired immunities - the specific immunities one acquires to a particular disease pathogen
    • Reduced production of humoral antibodies
    • Impaired cell-mediated immunity
how disease poor nutrition
How disease => poor nutrition
  • Most infections interfere with the body's ability to absorb nutrition and/or actively deplete nutrients
    • Reduced appetite
    • Poorer quality of diet ingested
    • Diseases deplete bodily tissue
    • Fevers => increased metabolic rate thus, the body needs more kcal but they may not be there
special case of gi tract diseases
Special case of GI tract diseases
  • 1.8 billion cases/yr of infant/weanling GI diseases
  • Predominantly diarrheas, but also intestinal parasites, cholera, & various types of dysentery
    • Impede absorption of nutrients (diarrheas just don't let food sit in gut long enough)
special case of gi tract diseases ii
Special case of GI tract diseases II
  • Many if not most deaths (perhaps 1 million/ yr in the world) can be averted with adequate treatment (called Oral Rehydration Therapy)
    • According to The Lancet (1978), ORT is "potentially the most important medical discovery of the 20th century"
    • Clean water with 60 cent packets of salts/sugars to recover health
    • Full recovery => increased nutrition above basic levels – often hard to get

Oral Rehydration Therapy

(packet for addition to water)

Oral Rehydration Therapy

(home made)

especially vulnerable populations i
Especially vulnerable populations I
  • Increased likelihood of malnutrition and more serious consequences
  • Women in general due to cultural traditions that privilege food to males
  • Pregnant women
    • Poor nutrition => low birth weight babies
    • Developmental problems for baby physically and mentally
    • Reduced resistance to diseases
    • Less able to breast feed (=> less resistance for the baby as well)
especially vulnerable populations ii
Especially vulnerable populations II
  • Lactating women
    • Poor nutrition seldom greatly interferes with ability to produce milk
    • But, poor nutrition does deplete the mother's body of necessary nutrients
    • If nutrition is not better between end of lactation and next pregnancy => spiral down to chronic anemia etc.
  • Elderly
    • Ability to fend off infections is reduced with great age and malnutrition hurts that as well
especially vulnerable populations iii
Especially vulnerable populations III
  • Children
    • Malnutrition in infants and children very problematic if timing coincides with critical growth processes
      • Up to age 5 risk is greatest
    • Especially at weaning age (approx 2 yrs)
    • Due to impure water used to make weaning foods (not sufficiently boiled due to lack of fuel) and general low hygiene =>
      • Kids die from diarrheal diseases and dehydration and malnutrition
    • Weaning foods are typically not nutrient-rich enough (e.g., maize gruels)
four faces of hunger i
Four Faces of Hunger I
  • I. Starvation/Famine
    • Widespread to complete lack of protein/calorie nutrition
    • A small percentage of global hunger – perhaps 1% at risk annually
    • Leads to increased mortality (usually to infectious diseases not starvation per se)
    • Great social disruption => increased problems with diseases and access to food
    • In any famine not all starve – the well off can buy food -- thus NOT usually only a simple shortage
four faces of hunger ii
Four Faces of Hunger II
  • II. Malnutrition/Undernutrition
    • Seasonal or periodic P/C under-nutrition
    • Most serious effects on kids and special needs adults (pregnant and lactating women, the elderly)
    • measures of malnutrition in children
      • Stunting - stature too short for age/sex (adjusted for local norms) => chronic
      • Wasting – weight too light for age/sex (adjusted for local norms) => acute
four faces of hunger iii
Four Faces of Hunger III
  • III. Micro-nutrient deficiencies
    • Vitamin and mineral shortages
    • Sometimes called “hidden hunger”
  • IV. Nutrition-depleting illnesses
    • Secondary malnutrition
    • Most common nutrient depleting diseases are infant/weanling diarrheas – 5 million deaths annually world wide
global hunger
Global Hunger
  • Global situation late 1990s
  • Data drawn from FAO’s SOFA report 2002
  • The International Food Policy Research Institute:
  • The concept of “food security”
global trajectories of hunger i
Global Trajectories of Hunger I
  • Proportions undernourished (or food insecure)
    • Late 1970s ~ 28%
    • Late 1990s ~17%
    • Thus, real progress
    • Less progress in absolute numbers
  • Micro-nutrient deficiencies
    • Iron: 40% of global south
    • Iodine: 12% of global south
    • Vitamin A: 14% of kids in global south
global trajectories of hunger ii
Global Trajectories of Hunger II
  • Absolute numbers undernourished (or food insecure)
    • 1970s ~ 900m; 2000 ~ > 800 m
    • => decrease of ~ 100m in absolute numbers (but smaller %)
  • Children 1993 ~ 200 m; now ~ 175 m
  • World food summit target in 2015 => 400m
    • Current trajectory => 475-500m by 2015
regional differences malnourished or food insecure
Regional differences malnourished or food insecure
  • Global South
    • Sub-Saharan Africa
    • E. Asia, SE Asia, & Pacific
    • South Asia
    • Latin America & Caribbean
    • Near East & N. Africa
  • Developed Economies (mostly N America)