Transcript Chapter 3

BMS208 Human
Nutrition
Topic 19: Consumer Concerns
Topic 20: World Hunger
Brian Spurrell
Objectives
1. Discuss food-borne infections and intoxications and common bacteria in each
classification.
2. List methods to prevent food-borne illness during food production and service.
3. Discuss food irradiation, including benefits and risks.
4. Identify environmental contaminants in the food supply and methods to reduce risk.
5. Discuss the health hazards associated with pesticides, pesticide monitoring
techniques, and the risks and benefits of organic foods.
6. Discuss common additives in the food supply and the risks and benefits of each.
7. Discuss intentional food additives and indirect food additives and their risks and
benefits in food.
8. Describe sources of drinking water, harmful contaminants, and methods to ensure
water safety.
9. Discuss the risks and benefits of genetic engineering.
10.Identify the role of the FDA in bioengineered foods.
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Food Allergy
• Term that is misused and misunderstood by
general public
• Reactions to food are not necessarily allergy
based!
• Adverse food reaction is probably a better term
until diagnosis is completed
• Food intolerance and food hypersensitivity are
more useful terms to use
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Food Intolerance and Hypersensitivity
• Food Intolerance: Adverse reaction to food
caused by
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Toxic,
Pharmacologic,
Metabolic or
Idiosyncratic reactions to food or chemical substances in
the food
• Food Hypersensitivity: occurs when the immune
system reacts to a food that the immune system
erroneously determines that it is harmful
– Occur very rapidly after exposure (< 2 hours)
– Cause and effect relationship
– Severity varies from mild to life threatening
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Allergic Reactions
• Combination of allergen with IgE (class of antibodies)
binding to mast cells releases chemical mediators
(including histamine, serotonin, etc)
• These inflammatory mediators cause
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itching,
contraction of smooth muscle,
vasodilation and
mucus secretion
• Wide range of symptoms attributed to allergic reactions
to food
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Some Symptoms
• Gastrointestinal
– abdominal pain, nausea, vomiting, diarrhoea, GI
bleeding, etc
• Cutaneous
– urticaria (hives), angioedema, eczema, erythema (skin
inflammation), itching
• Respiratory
– rhinitis, asthma, cough, laryngeal oedema etc
• Systemic
– anaphylaxis, hypotension
• Others (not proven?)
– behavioural, tension-fatigue syndrome, ADHD, otitis
media, psychiatric disorders, neurologic disorders,
migraine
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Urticaria
(hives)
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Anaphylaxis
 Most severe (can be fatal) and can involve a range of body
systems
 Systemic anaphylaxis
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abdominal pain,
nausea,
vomiting,
cyanosis,
hypotension,
angioedema,
chest pain,
urticaria,
diarrhoea,
shock and death
 Peanut is one of the most common
causes
◦ Epipen – to treat.
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Food Allergens
• Relatively few foods
• Usually have high protein content and often of plant or
marine origin
• Examples
– Peanuts, tree nuts, shellfish, cow’s milk, chicken eggs, soy and
wheat
– Allergic reactions to chocolate and strawberry have not been
documented
• Individual foods contain a wide range of proteins only a
few of which may be allergenic
– Cross reactivity may occur between foods that contain
related proteins (cow and goat milk)
– Allergy to one food may result in allergy to related foods
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Food Allergens
Heating may destroy allergens
◦soy bean,
◦peanuts or
◦corn oils
may be tolerated even though allergy
exists to original food
Caution must be exercised with
allergies that may lead to anaphylaxis
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Risk Factors
• Heredity
• Exposure to the antigen
– Initial exposure and sensitisation
• Gastrointestinal permeability
– Greatest in early infancy
• Environmental factors
– May increase the allergic reaction
• Inhalants
• Synergistic effects of other foods or food
components
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Most Common Food Allergens
Infants/Children
Adults
Egg
Fish
Fish
Nuts
Milk
Peanuts
Peanuts
Shellfish
Soy
Wheat
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Food Intolerances
• Adverse reactions to foods
– Non-immunological
– Toxic, pharmacologic, metabolic, idiosyncratic
– Symptoms may be the same as for allergy
• Diagnosis must exclude allergy
• Allergy skin tests not appropriate for food
intolerances
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Food Additives
• Preservatives, flavour enhancers and
colourings
• Adverse reactions are rare
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Non-Immunologic Reactions to Foods
• Lactase deficiency
– Foods containing lactose
– Bloating flatulence, diarrhoea, abdominal pain
• Cystic fibrosis
– Symptoms precipitated by many foods
– Bloating, steatorrhea
• Inborn errors of metabolism
– Phenylketonuria (PKU) (phenylalanine containing foods)
results in mental retardation etc (if untreated)
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Non-Immunologic Reactions to Foods
• Reactions to pharmacological agents in
foods
– Vasoactive amines in cheeses,
chocolate etc
• Migraines, urticaria
– Histamine releasing agents
(shellfish, chocolate, strawberries etc)
• Urticaria, eczema
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Non-Immunologic Reactions to Foods
• Reactions to food additives
– Tartrazine (yellow or yellow coloured foods,
soft drinks, medicines)
• Hives, rash, asthma
– Sulfites (shrimp, processed foods, avocado,
dried potato and fruit, vegetables, juices,
wine, beer)
• Acute asthma, anaphylaxis
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Non-Immunologic
Reactions to Foods
• Reactions to microbial toxins in foods
– Proteus causes histamine like substance to be
released (from un-refrigerated fish)
• itching, rash vomiting
• Various other types of food poisoning
– Ciguatera (tropical fish eg Spanish mackerel)
• neurological disorders
– Red tide (algae of mussels and clams)
• paralytic shellfish poisoning
– Mycotoxins
• aflatoxin, botulism, listeriosis etc
– Prion diseases – Bovine Spongiform Encephalitis
(BSE) Creutzfeldt Jakobs Disease (CJD)
– Helminth infections
• tapeworms from undercooked meat or fish
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Consumer Concerns
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Temperature
From °F to °C: subtract 32 and
multiply by 5 divided by 9 (0.56)
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Food-Borne Illnesses
• Food-Borne Infections and Food Intoxications
– Hazard vs toxicity
– Food-borne illness
• Common
• Estimated 5.4 million cases/year – OzFoodNet 2004 and can be
lethal
– Vulnerable
• Pregnant women, very young, elderly, sick, malnourished
– Contamination with pathogens
• Salmonella
• Listeria,
• E. coli etc.
– Food intoxications
• Botulism,
• Staphylococcal poisoning
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Food Safety in the Marketplace
• Pasteurization
• Undercooked foods
• Industry controls
– HACCP analysis
– Imported foods (? Quality)
• Consumer awareness
– Safety seals,
– Damaged packaging,
– Damaged cans
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Safety in Food Preparation
• Meats and poultry
– often contaminated
• Other meat concerns – BSE  CJD
– Selection of cuts
– Processed meats (eg salami)
• Seafood
– Range of parasites – worms, bacteria, bacteria
– Raw oysters  hepatitis A
– Microbial and heavy metal contamination
• Ciguatera, Mercury
• Precautions and procedures
– Not always easy to detect contaminated food
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Advances in Food Safety
• Irradiation – sterilisation of food
– Gamma rays
– Microwaves
– Beta rays
– X-rays
Kill micro-organisms etc
• Consumer concerns about irradiation
– Largely unfounded
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Environmental Contaminants
– Harmfulness of Environmental Contaminants
• Persistance – compounds resist ‘breakdown’
• Bioaccumulation – pass through the food chain.
– Examples of Environmental Contaminants
• Methylmercury (Minimata, Japan, 1953)
• PBB (polybrominated biphenyl)
• PCB (polychlorinated biphenyl)
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Bioaccumulation illustrated
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Natural Toxicants in Foods
• Potentially harmful
– Toxic mushrooms
– Goitrogens in vegetables
– Solanine in potatoes
– Aflatoxins in peanuts
– Cyanide type compounds in cassava
All the above toxicants require care in the
preparation and/or storage of food to
prevent spoilage.
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Pesticides
 Hazards of pesticides
◦ Tolerance level – maximum residual level allowed
◦ Bioaccumulation
 Pesticides from other countries
◦ Regulation difficult – caution with imported foods
 Consumer Concerns
◦ Minimizing risks
 Depends on pesticide and its persistence
◦ Alternatives to pesticides
 GMO’s, biological control (sterile fruit flies), crop rotation
◦ Organically grown crops
 May or may not be beneficial
 Foods may have reduced shelf life, be contaminated etc
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Food Additives
 Benefits:
◦ Preservatives
 Reduce risk of pathogen growth
 Prevent spoilage
◦ Fortification
 Enhance nutrient quality
◦ Enhance flavour
◦ GRAS List
 Substances exempted from approval process
◦ Margin of safety
 100x lower than experimentally determined toxicity
◦ Risks versus benefits
 Presumably added because benefits outweigh risks
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Intentional Food Additives
• Deliberately added to foodstuffs
– Antimicrobial agents
– Antioxidants
– Artificial colours
– Artificial flavours and flavour enhancers
– Texture and stability
• Nutrient additives
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Indirect Food Additives
 Additives that accumulate in food indirectly
◦ during harvest, production, processing and packaging
 Microwave packaging
◦ Active packaging – home pizza’s, safety from contamination
 Dioxins
◦ From chlorine use in paper manufacture – therefore paper packaging can
contaminate foods
◦ Carcinogenic – but minute amounts
 Decaffeinated coffee
◦ Methylene chloride used to remove caffeine, minute residues
◦ Carcinogenic, minute risk
◦ Not indicated on labelling
 Hormones
◦ Growth hormone BGH for cattle, pGH for pigs, clenbuterol, TBA, other
steroids etc
 Antibiotics
◦ Withholding period
◦ Antibiotic resistance may develop
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Consumer Concerns
about Water
 Sources of Drinking Water
◦ Surface water
 Easily contaminated – directly exposed, runoff etc
◦ Groundwater
 More slowly contaminated – more permanent
 Water Systems and Regulations
◦ Home water treatments
 Different systems to remove different contaminants
◦ Activated carbon – chlorine, heavy metals, organics
◦ Reverse osmosis – sodium, Giardia, arsenic
◦ Distillation systems
◦ Bottled water
 Treatment depends on the source
◦ filtered,
◦ sterilised,
◦ deionised etc
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Highlight: Food Biotechnology
 Genetic Engineering
◦ cf. Selective Breeding
◦ Extended shelf life
 softening enzymes in tomatoes
◦ Efficient food processing
 production of rennin by fermentation systems
◦ Improved nutrient composition
 golden rice with Vitamin A
◦ Genetically assisted agriculture
 soy bean resistant to pesticides or
 plants that produce their own pesticides
◦ leaf chewing caterpillars – corn, broccoli, potatoes;
◦ viral resistance yellow squash – etc.
◦ Other possibilities
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– Disruption of ecosystems
– Introduction of diseases
– Biological weapons
– Ethical dilemmas
Potential Problems and Concerns
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Hunger and the Global
Environment
BMS208 Topic 20
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Objectives
1. Discuss the prevalence of world hunger, populations at risk, and political
and environmental causes of hunger.
2. Describe malnutrition, nutrients most often deficient, and the health
consequences.
3. List the environmental problems that are decreasing food production.
4. Discuss solutions to the world’s hunger, poverty, and environmental
problems.
5. Identify environmental and social costs of agriculture and food industry.
6. Discuss sustainable agriculture, low-input agriculture, and precision
agriculture.
7. Describe consumer food choices to save energy in food production,
including locally grown foods.
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• The US experience.
Very low food
security
Food secure
Low food security
Food Security!
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Fig. 20-1, p. 702
• Primarily from poverty
• Food Shortages
– Political causes – Chinese political reforms resulted in up to 30 million
dead between 1959-1961 (supposed to reform agriculture)
– Armed conflicts eg. Many African nations, workforce involved in wars,
famine relief blocked etc
– Natural disasters – crop failure (drought)
• Malnutrition
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2 billion people world wide
mostly women and children
Micronutrients - iodine, iron, vitamin A
Protein energy malnutrition - marasmus and kwashiorkor
• Diminishing Food Supply
– potential problem in future, at present there is sufficient food to feed
the entire world population
World Hunger
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• Population Growth Leads to Hunger and
Poverty
• Hunger and Poverty Leads to Population
Growth
• Breaking the Cycle
Poverty and Overpopulation
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• The limitations in the production of foods reduce the
ability to feed the people of the world.
• Environmental Limitations in Food Production
– Soil erosion, compaction, and salinity caused by over-tillage and
over-irrigation
– Deforestation and desertification caused by overgrazing
– Air pollution from the burning of fossil fuels
– Ozone depletion??
Environmental Degradation & Hunger
• Environmental Limitations in Food Production
– Climate changes
• caused by deforestation
– Water pollution
• caused by sediment, salt, fertilizer, pesticide, and manure
– Water scarcity
• caused by overuse
– Extensive overgrazing
• caused by livestock needs
– Over fishing and water pollution
Environmental Degradation & Hunger
• Other Limitations in Food Production
– Irrigation, fertilizers, and improved genetic strains are reaching
their limits.
– Harvests are falling short of consumption needs.
– World agriculture produces enough foods to provide each
person with 11424 kJ per day.
– Distribution is a problem.
– Population is a problem??
Environmental Degradation & Hunger
• Governments, businesses, and all individuals have
opportunities to make environmentally conscious
choices.
• Proper choices may help to relieve hunger, improve
quality of life, and generate jobs.
• Personal choices have a great impact also.
Solutions
• Sustainable Development Worldwide
– Hunger relief, population stabilization,
environmental preservation and sustainable
resources must be considered.
– Permanently improve the lives of people by
helping them to help themselves
Solutions
• Activism and Simpler Lifestyles at Home
– Government action to promote sustainability
– Business involvement can support hunger
and food recovery programs.
– Education about hunger and advocates for
legislation
Solutions
 Activism and Simpler Lifestyles at Home
◦ IN the US, Foodservice efforts include the
American Dietetic Association (ADA)
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Conserve resources and minimize waste
Fight hunger
Conduct research on programs
Advocates to legislatures on the local, state, and national levels
Support programs that
◦ combat malnutrition,
◦ provide food security,
◦ promote self-sufficiency,
◦ respect local culture,
◦ protect the environment, and
◦ sustain the economy
Solutions
• Activism and Simpler Lifestyles at Home
– Individual Choices
• Joining and working for hunger-relief organizations
• Lobby for needed changes in economic policies for
developing countries.
• Make lifestyle choices that consider environmental
consequences.
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Food shopping
Food choices
Food packages
Gardening
Cooking food
Kitchen appliances
Food serving, dishwashing, and waste disposal
Solutions
© 2008 Thomson - Wadsworth
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The End!
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