lec 6 consumer nutrition 2
TRANSCRIPT
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Community and public health nutrition 6-Consumer awareness 2
a) Food additives b) Anti nutrients
Prepared by; Dr. Siham GritlyUniversity of Bahri
"All things are poisons; nothing is without poison; only the dose determines whether there is a harmful effect“. Paracelsus (16th Century Philosopher)
Dr. Siham Gritly
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Glossary
• additives: substances not normally consumed as foods but added to food either intentionally or by accident.
• preservatives: antimicrobial agents, antioxidants, and other additives that retard spoilage or maintain desired qualities, such as softness in baked goods.
• generally recognized as safe (GRAS): food additives that have long been in use and are believed to be safe. First established by the FDA in 1958,
• Delaney Clause: a clause in the Food Additive Amendment to the Food, Drug, and Cosmetic Act that states that no substance that is known to cause cancer in animals or human beings at any dose level shall be added to foods
•
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Glossary
• margin of safety: when speaking of food additives, a zone between the concentration normally used and that at which a hazard exists. For common table salt, for example, the margin of safety is 1/5 (five times the amount normally used would be hazardous).
• intentional food additives: additives intentionally added to foods, such as nutrients, colors, and preservatives.
• indirect or incidental additives: substances that can get into food as a result of contact during growing, processing, packaging, storing, cooking, or some other stage before the foods are consumed; sometimes called accidental additives
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Glossary
• Nitrites: salts added to food to prevent botulism. One example is sodium nitrite, which is used to preserve meats.
• Nitrosamines; derivatives of nitrites that may be formed in the stomach when nitrites combine with amines. Nitrosamines are carcinogenic in animals.
• Bacteriophages; viruses that infect bacteria to prevent spoilage.
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Glossary • genotoxicant is a substance that mutates or
damages genetic material• Phytochemicals: nonnutrient compounds
found in plant-derived foods that have biological activity in the body.
• Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrients .
• carcinogen is a substance that causes cancer,
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Food additives
• Food additives are substances added to food to preserve flavor or enhance its taste and appearance.
• Most additives are preservatives that help prevent spoilage during the time it takes to deliver foods long distances to grocery stores and then to kitchens.
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Some of food additives found in food
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antimicrobial nitrites and nitrates Monosodiumglutamate MSG Emulsifiers: lecithin, mono- and diglycerides Gums: agar, alginates (brown algae), carrageenan (extracted from red seaweeds), aguar, locust bean,, pectin, xanthan gum, gum arabic, cellulose derivativesArtificial color: indigotine (blue), erythrosine (Food Red), tartrazine (Yellow) Natural: annatto (yellow), caramel (yellowish brown), carotenoids (yellowish orange), dehydrated beets (reddish brown), grape skins (red, green)
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• Some act as Antimicrobial Agents; The most widely used antimicrobial agents are ordinary salt and sugar.
• Salt has been used throughout history to preserve meat and fish;
• sugar serves the same purpose in canned and frozen fruits and in jams and jellies.
• Both exert their protective effect primarily by capturing water and making it unavailable to microbes.
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• Other antimicrobial agents, the nitrites, are added to foods for three main purposes:
• to preserve color, • to enhance flavor by inhibiting rancidity,
especially in cured meats and poultry; • to protect against bacterial growth
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• Some reduce the risk of foodborne illness (for example, nitrites used in curing meat prevent poisoning from the botulinum toxin).
• Others enhance nutrient quality (as in vitamin D–fortified milk).
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The GRAS (generally recognized as safe)
• generally recognized as safe (GRAS), based either on their extensive, long-term use in foods or on current scientific evidence.
• Several hundred substances are on the GRAS list, including such items as salt, sugar, caffeine, and many spices.
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The Delaney Clause
• a clause in the Food Additive Amendment to the Food, Drug, and Cosmetic Act that states no substance that is known to cause cancer in animals or human beings at any dose level shall be added to foods
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• the FDA prefers to believe additives (and pesticides and other contaminants) safe if lifetime use presents no more than a one-in-a-million risk of cancer to human beings.
• Thus, instead of the “zero-risk” policy of the Delaney Clause, the FDA uses a “negligible-risk” standard,
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Margin of Safety
• To determine risks of an additive, researchers feed test animals the additive at several concentrations throughout their lives.
• The additive is then permitted in foods in amounts 100 times below the lowest level that is found to cause any harmful effect, that is, at a 1/100 margin of safety.
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Risks versus Benefits
• additives would not be added to foods if they only presented risks.
• general, additives are used in foods when they offer benefits
• in the case of color additives only enhance appearance but do not improve health or safety
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• the FDA finds it worth taking the small risks associated with the use of nitrites on meat products, for example, because nitrites inhibit the formation of the deadly botulinum toxin.
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Benefit of food additivesWithout additives, bread would quickly get moldy, and salad dressing would go rancid
Ref. Ellie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition. 2011, 2008 Wadsworth, Cengage Learning
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• The FDA also requires that additives not be used:
• To disguise faulty or inferior products• To deceive the consumer• When they significantly destroy nutrients• When their effects can be achieved by
economical, sound manufacturing processes
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Intentional Food Additives
• Intentional food additives are added to foods to give them some desirable characteristic:
• resistance to spoilage,• color, flavor, texture, • stability, • nutritional value.
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Intentional Food AdditivesEllie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition. 2011, 2008 Wadsworth, Cengage Learning
Food Additive Purpose Common Examples
Antimicrobial agents)
Prevent microorganisms from growing
Salt, sugar, nitrites and nitrates (such as sodium nitrate
Antioxidants Delay or prevent rancidity of fats and other damage to foods caused by oxygen
Vitamin C (ascorbic acid, sodium ascorbate), vitamin E (tocopherol), sulfites, synthetic antioxidants butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT)
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Intentional Food AdditivesEllie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition. 2011, 2008 Wadsworth, Cengage Learning
Colors Enhance appearance
Artificial: indigotine (blue), erythrosine (red), tartrazineYellow Natural: annatto (yellow), caramel (yellowish brown), carotenoids (yellowish orange), dehydrated beets (reddish brown), grape skins (red, green)
Flavors Enhance taste Salt, sugar, spices, artificial sweeteners, MSG (Monosodiumglutamate)
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Intentional Food AdditivesFood Additive Purpose Common Examples
Emulsifiers and gums
Thicken, stabilize, or otherwise improve the consistency
Emulsifiers: lecithin, mono- and diglycerides Gums: agar, alginates (brown algae), carrageenan(extracted from red seaweeds), locust bean, psyllium, pectin, xanthan gum, gum arabic, cellulose derivatives
Nutrients (vitamins and minerals)
Improve the nutritive value
Thiamin, niacin, riboflavin, folate, iron (in grain products); iodine (in salt); vitamins A and D (in milk); vitamin C and calcium (in fruit drinks); vitamin B12(in vegetarian foods)
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Natural food coloring: annatto (yellow
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Psyllium and psyllium seeds
the combination of low fat diet, low in saturated fats and cholesterol plus psyllium, can reduce total cholesterol levels by 4% and low density lipoprotein (LDL) cholesterol by 7%. The soluble fiber in psyllium reduces absorption of blood cholesterol and bile acids from the intestine and that in turn lowers blood cholesterol levels.
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Gum Arabic
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Indirect Food Additives
• Indirect or incidental additives find their way into foods during harvesting, production, processing, storage, or packaging.
• Incidental additives may include tiny bits of plastic, glass, paper, tin, and other substances from packages as well as chemicals from processing, such as the solvent used to decaffeinate coffee.
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Example of Indirect or incidental additivesRef WHO 2013
• Acrylamide (C3H3ONH2) is a chemical that is produced naturally in certain foods when they are cooked at high temperatures.
• It is also manufactured industrially for use in the production of polyacrylamide gels, which are used for various purposes, including the treatment of drinking-water and wastewater.
• Acrylamide is known to cause cancer in animals and, in high doses, can cause nerve damage in humans.
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• Acrylamide; compound that forms when carbohydrate-rich foods containing sugars and the amino acid asparagine are cooked at high temperatures
• Common foods containing acrylamide:• French fries• Potato chips• Breakfast cereals• Cookies
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• Food Packaging • The FDA ensures the safety of food
packaging and assesses whether packaging materials might migrate into foods.
• These materials, known as “food contact substances,” include coatings on can interiors, plastics, papers, and sealants.
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• Dioxins• dioxins is a class of chemical pollutants created
as by-products of chemical manufacturing, burning, chlorine bleaching of paper pulp, and other industrial processes.
• Scientists suggested that dioxins are extremely toxic and are likely to cause cancer in humans
• Dioxins persist in the environment and accumulate in the food chain
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• Examples; Coffee filters, milk cartons, paper plates, and frozen food packages, if made from bleached paper,
• Human exposure to dioxins comes primarily from foods such as beef, milk products, pork, fish, and shellfish
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• Decaffeinated Coffee Many consumers have tried to eliminate caffeine from their diets by selecting decaffeinated coffee.
• To remove caffeine from coffee beans, manufacturers often use methylene chloride in a process that leaves traces of the chemical in the final product.
• People are exposed to much more methylene chloride from other sources such as hair sprays and paint-stripping solutions.
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• Hormones are a unique type of incidental additive in that their use is intentional, but their presence in the final food product is not.
• The FDA has approved about a dozen hormones for use in food-producing animals,
• hormone treated animals produce leaner meats, and dairy cows produce more milk.
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• Antibiotics Like hormones, antibiotics are also intentionally given to livestock, and residues may remain in the meats and milks.
• people consuming these foods receive tiny doses of antibiotics regularly, and those with sensitivity to antibiotics may suffer allergic reactions.
• To minimize drug residues in foods, the FDA requires a specified time between the time of medication and the time of slaughter to allow for drug metabolism and excretion.
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Natural Toxicants in Foods
• Plants may serve as poisons; for example, hemlock, a member of the parsley family, has been known as a deadly poison.
• Most chemicals that are natural poisons produced by the plant forms part of its defense mechanism against herbivores and pathogens.
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• A system within cells (p-glycoproteins), found especially in the mucosa of the gastrointestinal tract (esophagus, stomach and colon), protects against toxic substances in plants, bacteria and fungi
• Natural toxicants include the goitrogens in cabbage, cyanogens in lima beans, and solanine in potatoes and others
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Goitrogens
• Poisonous mushrooms are a familiar example of plants that can be harmful when eaten.
• Cabbage, turnips اللفت , mustard الخردل greens, اللفت , brussels sprouts وبراعم ,broccoli , القنبيط cauliflower بروكسلkohlrabi الكرنب , and radishes الفجل contain small quantities of goitrogens—compounds that can enlarge the thyroid gland
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Goitrogens
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Cabbage, turnipscauliflower
brussels sprouts kohlrabi
mushrooms
radishes
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Cyanogens
• Cyanogens inactive compounds that produce the deadly poison cyanide upon activation by a specific plant enzyme.
• Lima beans, cassava and fruit seeds such as apricot pits contain cyanogens
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Cyanogens
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Lima beans
apricot pits cassava
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• Dozen of seeds if eaten can be fatal to a small child.
• the most infamous cyanogen in seeds is laetrile; a compound mistakenly represented as a cancer cure.
• laetrile kills cancer, but only at doses that kill the person, too.
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Solanine; Average solanine content: 8 mg/100 g potato. Toxic solanine dose: 20 to 25 mg/100 g potato
• potato contains many natural poisons including solanine, a powerful narcotic-like substance.
• Most of a potato’s solanine is found in the sprout and in the green layer that develops just beneath the skin.
• Solanine poisoning is extremely rare, however, because the small amounts of solanine normally found in potatoes are harmless—even when the potato skin is eaten. Solanine can be toxic, when consumed in large quantities.
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• Cooking does not destroy solanine, but it can be removed by peeling the potato.
• Found also in apples, egg plants, roots and leaves of tomatoes and sugar beet roots
• Symptoms of solanine poisoning include gastrointestinal disturbances and neurological disorders.
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• Hormone disrupters are chemicals that affect human or animal health by interfering with normal hormonal processes
• Example; Oestrogens: at least 50 plants are known to contain chemicals that have oestrogenic activity, including carrots, soya beans, wheat, rice, oats, barley potatoes, apples, cherries, plums and wheat ,الشعيرgerm.
• Oestrogens are also present in vegetable oils such as cotton seed, sunflower, corn, linseed, olive and coconut oils.
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• Gossypol: this is the yellow colouring of cotton, Gossypium.
• When ingested, the results are depressed appetite and loss of body weight, cardiac irregularity and circulatory failure or pulmonary oedema.
• A major source of gossypol in the diet is cotton seed oil, which may be found in salad oil, margarine and shortening.
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Gossypolcotton seed
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• Myristicin: hallucinogenic chemical produced by, celery, parsley, parsnip, mint and nutmeg.
• It is said that as little as 500 mg of raw nutmeg may produce psychoactive symptoms,
• while 5–15 mg of powdered nutmeg may result in euphoria, hallucinations and a dream-like feeling, followed by abdominal pain, depression and stupor (coma)
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celery,
parsley
parsnip
mint
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Carcinogens A carcinogen is a substance that causes cancer, and a genotoxicant is a substance
that mutates or damages genetic material
• Safrole is a carcinogen found in several oils, including oil of sassafras, camphor and nutmeg.
• Safrole has been found in 53 plant species and in ten plant families, and has been shown to produce liver cancer when sufficient is added to a rat diet.
• Black pepper contains small amounts of safrole and larger amounts of piprine, which has been shown to be carcinogenic to mice.
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sassafras, camphor
nutmeg
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• Furanocoumarins are carcinogenic chemicals produced by celery, parsley and parsnip. The concentration in these plants is low, but may increase in diseased plants.
• Cycasin is found in cycads, which are important sources of starch for tropical and subtropical populations. Such compounds can produce liver, kidney, intestinal and lung cancers in rats.
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• Mutagens: the cooking and processing of meat and fish at high temperatures results in heterocyclic amines with mutagenic and carcinogenic effect
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• Epichloro-hydrin Carcinogens in tea bags • Some tea bags are made using a wet paper
strength reinforcing coating using epichlorohydrin, which is known to be carcinogenic.
• epichlorohydrin found also in coffee filters, sausage/salami casings have the same issues.
• use loose leaf tea or make sure the tea bags don't use epichlorohydrin
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Anti-nutrients
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Anti-nutrients are, compounds which prevent the nutritive value of foods from being effective, either; by preventing the absorption of nutrients,
Or by being toxic themselves,
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Phytate and oxalatesand their interfering with nutrients
• Oxalates and phytates belong to a group of anti-nutrients.
• phytates has a strong binding affinity to minerals such calcium, magnesium, iron, copper and zinc
• This results in precipitation, making the minerals unavailable for absorption in the intestines.
• Phytic acids are common in the nuts, seeds and grains
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• Oxalates have an adverse effect of binding to essential minerals like calcium, magnesiom and iron
• oxalic acid presents in many plants, particularly in members of the spinach family. Oxalates bind to calcium and prevent its absorption in the human body
• accumulate in body tissues, causes toxicity over time• They also bind to calcium to form calcium oxalate,
which can then easily settle out as sediments from the urine, causing kidney stones.
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short list of high oxalate foods
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Swiss Chard SpinachPlantains
AlmondsCashewsSesame Seeds
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Summary of Some of anti-nutrients compound and their effects
Antinutrient Source of food Activities in the body
Phytate and oxalic acid
spinach, broccoli inhibits mineral absorption
Flavonoids
tanninstea, coffee, wine
reduce the absorption of iron and zinc
inhibits mineral absorption
Protein, trypsin inhibitors and
Lectins
beans, wheat, Castor Beans
inhibits digestive enzymes
glucosinolatesbroccoli, brussel sprouts, cabbage and cauliflower.
prevent the uptake of iodine , affecting the function of the thyroid and thus are considered goitrogens
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Reduce phytates and oxalates effects Boiling and then discarding the water, or soaking and
discarding the soaking water, can help reduce both phytates and oxalates
other traditional methods of food preparation such as fermentation, cooking, malting reducing certain
antinutrients
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broccolispinach
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• 1997-2012 HealthCheck Systems• Sareen Gropper, Jack Smith and James Groff, Advanced Nutrition and Human
Metabolism, fifth ed. WADSWORTH
• Melvin H Williams 2010; Nutrition for Health, Fitness and Sport. 9 th ed, McGraw Hill• • Heymsfield, SB.; Baumgartner N.; Richard and Sheau-Fang P. 1999. Modern
Nutrition in Health and Disease; Shils E Maurice, Olson A. James, Shike Moshe and Ross A. Catharine eds. 9th edition
• Guyton, C. Arthur. 1985. Textbook of Medical Physiology. 6th edition, W.B. Company
• FAO/WHO/UNU expert consultation (WHO, 1985) report
• Ellie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition. 2011, 2008 Wadsworth, Cengage Learning
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• Health implications of acrylamide in food. Joint FAO/WHO consultation, Geneva, Switzerland, 25 - 27 June 2002
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• parsley البقدونس• الطيب وجوز camphor and nutmeg , الكافور• األبيض والجزر والبقدونس ,by celery الكرفس
parsley and parsnip• والخوخ cherries, plums , الكرز• الكتان linseed , بذر• sassafras• locust bean خروب