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TODAY • Human Nutrition • Synergy between nutrition and disease • Especially vulnerable populations • Four faces of hunger • Global Hunger © T. M. Whitmore LAST TIME • Questions about local, market, or niche agriculture in the US? © T. M. Whitmore • 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 © T. M. Whitmore • • • Energy 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 © T. M. Whitmore 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 © T. M. Whitmore • • • • • Marasmus 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. © T. M. Whitmore Kwashiorkor • • • • Severe protein deficiency Bloated body Fluids stuffed in cells against wasted muscles Results in diarrhea, apathy, brain damage © T. M. Whitmore • • • • Protein 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 © T. M. Whitmore • • “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 © T. M. Whitmore “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 © T. M. Whitmore • 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 © T. M. Whitmore • • 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 © T. M. Whitmore so good with rice • • 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.) © T. M. Whitmore 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) => T. M. Whitmore increases niacin and beans have it as©well • • 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 © T. M. Whitmore • 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 © T. M. Whitmore • 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 © T. M. Whitmore • 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 © T. M. Whitmore 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 © T. M. Whitmore • 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) © T. M. Whitmore 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 © T. M. Whitmore • 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 © T. M. Whitmore • • 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) © T. M. Whitmore • 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 © T. M. Whitmore Oral Rehydration Therapy (packet for addition to water) Oral Rehydration Therapy (home made) • • • 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) © T. M. Whitmore • • 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 © T. M. Whitmore • 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© T. M. Whitmore rich enough (e.g., maize gruels) • 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 © T. M. Whitmore • 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 © T. M. Whitmore • 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 © T. M. Whitmore • • • • • • Global Hunger Global situation late 1990s Data drawn from FAO’s SOFA report 2002 http://www.fao.org/DOCREP/004/y6000e/y600 0e00.htm The International Food Policy Research Institute: http://www.ifpri.org/pubs/fpr/fpr24.pdf The concept of “food security” © T. M. Whitmore • • 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 © T. M. Whitmore 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 © T. M. Whitmore • • 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) © T. M. Whitmore Countries with food shortfalls – requiring assistance Source: FAO Source: FAO Source: FAO Number of malnourished children, 1993, 2010, and 2020 Source: IFPRI IMPACT simulations.