Nutrition- Ch 1-3 INCOMPLETE Flashcards
1
Q
six major nutrients
A
water, lipids, carbs, proteins, minerals, vitamins
2
Q
five principles of healthy diet
A
adequacy, balance, calorie control, moderation, variety
3
Q
major types of research study
A
4
Q
malnutrition
A
poor nutrition that leads to diseases and issues that come from deficiencies and imbalances
5
Q
two common lifestyle habits most influential
A
smoking/tabacco and alcohol
6
Q
nutritional genomics
A
study into how nutrittion influences genes
7
Q
essential nutrients
A
body cant make self/without you will have deficiencies
8
Q
calories
A
unit of heat
9
Q
494 rule
A
4 cal/g of protein+ carb, 9 cal/g of fat
10
Q
elemental diets
A
diets with a precise chemical composition that are lifesaving for people in the hospital who cannot eat ordinary food
11
Q
nonnutrients
A
12
Q
phytochemicals
A
nonnutrient compounds that exert biological effects on the body.
13
Q
fast foods
A
restaurant foods that are available within minutes after customers order them—traditionally, hamburgers, french fries, and milkshakes; more recently, salads and other vegetable dishes as well. These foods may or may not meet people’s nutrient needs, depending on the selections made and on the energy allowances and nutrient needs of the eaters.
14
Q
processed foods
A
foods subjected to any process, such as milling, alteration of texture, addition of additives, cooking, or others. Depending on the starting material and the process, a processed food may or may not be nutritious.
15
Q
functional foods
A
a term that reflects an attempt to define as a group the foods known to possess nutrients or nonnutrients that might lend protection against diseases. However, all nutritious foods can support health in some ways;
16
Q
basic foods
A
milk and milk products; meats and similar foods, such as fish and poultry; vegetables, including dried beans and peas; fruits; and grains. These foods are generally considered to form the basis of a nutritious diet. Also called whole foods.
17
Q
enriched/fortified foods
A
foods to which nutrients have been added. If the starting material is a whole, basic food such as milk or whole grain, the result may be highly nutritious. If the starting material is a concentrated form of sugar or fat, the result may be less nutritious.
18
Q
natural foods
A
a term that has no legal definition but is often used to imply wholesomeness.
19
Q
nutraceutical
A
a term used to describe a product that has been isolated from food, often sold in pill form and believed to have medicinal effects
20
Q
organic foods
A
understood to mean foods grown without synthetic pesticides or fertilizers. In chemistry, however, all foods are made mostly of organic (carbon-containing) compounds.
21
Q
partitioned foods
A
foods composed of parts of whole foods, such as butter (from milk), sugar (from beets or cane), or corn oil (from corn). Partitioned foods are generally overused and provide few nutrients with many Calories.
22
Q
staple foods
A
foods used frequently or daily, for example, rice (in East and Southeast Asia) or potatoes (in Ireland). If well chosen, these foods are nutritious.
23
Q
why is variety important in a diet
A
One reason is that variety increases the likelihood that diet will be adequate in nutrients.Footnote In addition, some nonnutrient food components are probably important to health; some foods may be better sources of these than others. Another reason is that a monotonous diet may deliver large amounts of toxins or contaminants. Each such undesirable item in a food is diluted by all the other foods eaten with it and is even further diluted if the food is not eaten again for several days.
24
Q
ABCVM of diet
A
adequacy, balance, calorie count, variety, moderation - five aspects of healthy diet
25
scientific method steps
26
Studies of whole populations (epidemiological studies)
27
correlation the simultaneous change of two factors, such as the increase in weight with increasing height (a direct or positive correlation) or the decrease in cancer incidence with increasing fibre intake (an inverse or negative correlation). A correlation between two factors suggests that one may cause the other but does not rule out the possibility that both may be caused by chance or by a third factor.
28
A cohort study is one in which the investigators do not manipulate the study variables of interest; instead, they monitor them over time (thus, the study is prospective in nature, a longitudinal study in which data are collected at more than one point in time). For example, such a design could be used to monitor the relationship between milk product consumption and growth in a cohort of children (often a single group of individuals with similar characteristics, for example boys or girls within a defined age range).
29
The type of study chosen for research depends upon what sort of information the researchers require. Studies of individuals (case studies) yield observations that may lead to possible avenues of research. A study of a man who ate gumdrops and became a famous dancer might suggest that an experiment be done to see if gumdrops contain dance-enhancing power
30
A case-control study (case-comparison, an epidemiological study) is one in which the investigators do not manipulate the study variables of interest. Cases are the individuals with the condition of interest, for example, some form of cancer, and the controls are cancer-free individuals and are usually matched with cases in terms of age, gender, and other characteristics. For example, such a design could be used to study the association between past whole-grain food consumption and colon cancer. These studies are most often conducted by looking back in time, which means that the outcome for the subjects is already known, thus, retrospective.
31
Studies in which researchers actively intervene to alter people’s eating habits (intervention studies) go a step further. In such a study, one set of subjects (the experimental group) receives a treatment, and another set (the control group) goes untreated or receives a placebo or sham treatment. If the study is a blind experiment, the subjects do not know who among the members receives the treatment and who receives the sham. A double-blind experiment is one in which neither the experimenter nor the subjects know who receives the treatment and who receives the placebo. If the two groups experience different effects, then the treatment’s effect can be pinpointed. For example, an intervention study might show that withholding gumdrops, together with other candies and confections, reduced the incidence of tooth decay in an experimental population compared with that in a control population.
32
Finally, laboratory studies can pinpoint the mechanisms by which nutrition acts. What is it about gumdrops that contributes to tooth decay: their size, shape, temperature, colour, ingredients? Feeding various forms of gumdrops to rats might yield the information that sugar, in a gummy carrier, promotes tooth decay. In the laboratory, using animals or plants or cells, scientists can inoculate with diseases, induce deficiencies, and experiment with variations on treatments to obtain in-depth knowledge of the process under study.
33
Finally, laboratory studies can pinpoint the mechanisms by which nutrition acts. What is it about gumdrops that contributes to tooth decay: their size, shape, temperature, colour, ingredients? Feeding various forms of gumdrops to rats might yield the information that sugar, in a gummy carrier, promotes tooth decay. In the laboratory, using animals or plants or cells, scientists can inoculate with diseases, induce deficiencies, and experiment with variations on treatments to obtain in-depth knowledge of the process under study.
34
randomized controlled trials (RCT) sometimes also referred to as clinical trials, studies in which the subjects are selected in such a way that they have an equal chance of being included in the experimental/treatment group or the control group. This type of study is considered the gold standard in research.
35
placebo
sham treatment often used in scientific studies; an inert harmless medication. The placebo effect is the healing effect that the act of treatment, rather than the treatment itself, often has.
36
laboratory studies studies that are performed under tightly controlled conditions and are designed to pinpoint causes and effects. Such studies often use animals as subjects.
37
intervention studies studies of populations in which observation is accompanied by experimental manipulation of some population members—for example, a study in which half of the subjects (the experimental subjects) follow diet advice to reduce fat intakes while the other half (the control subjects) do not, and both groups’ heart health is monitored.
38
experimental group the people or animals participating in an experiment who receive the treatment under investigation. Also called experimental subjects. See also control group and intervention studies.
39
epidemiological studies studies of populations; often used in nutrition to search for correlations between dietary habits and disease incidence; a first step in seeking nutrition-related causes of diseases.
40
control group a group of individuals who are similar in all possible respects to the group being treated in an experiment but who receive a sham treatment instead of the real one. Also called control subjects. See also experimental group and intervention studies.
41
case studies studies of individuals. In clinical settings, researchers can observe treatments and their apparent effects. To prove that a treatment has produced an effect requires simultaneous observation of an untreated similar subject (a case control).
42
blind experiment an experiment in which the subjects do not know whether they are members of the experimental group or the control group. In a double-blind experiment, neither the subjects nor the researchers know to which group the members belong until the end of the experiment.
43
Here’s what you can expect to find inside a research article:
Abstract. The abstract provides a brief overview of the article.
Introduction. The introduction clearly states the purpose of the current study.
Review of literature. A review of the literature reveals what science has uncovered on the subject to date.
Methodology. The methodology section defines key terms and describes the procedures used in the study.
Results. The results report the findings and may include summary tables and figures.
Conclusions. The conclusions drawn are those supported by the data and reflect the original purpose as stated in the introduction. Usually, they answer a few questions and raise several more.
References. The references list relevant studies (including key studies several years old and current ones).
44
Nutritional assessment of individuals is an essential component of their nutritional care. These assessments are conducted by registered dietitians or other health-care professionals and may include the client’s/patient’s (a) health and diet history (e.g., a person’s medical record/food intake records); (b) anthropometric measurements (e.g., weight, height, skinfold measurements); and (c) laboratory test data (e.g., blood iron, glucose levels). This information is then interpreted in relation to current standards for the person’s age, gender, life stage, and so on.
45
6 stages of change, and eachs characteristics or actions
Precontemplation
Not considering a change; have no intention of changing; see no problems with current behaviour.
Collect information about health effects of current behaviour and potential benefits of change.
Contemplation
Admit that change may be needed; weigh pros and cons of changing and not changing.
Commit to making a change and set a date to start.
Preparation
Preparing to change a specific behaviour, taking initial steps, and setting some goals.
Write an action plan, spelling out specific parts of the change. Set small-step goals; tell others about the plan.
Action
Committing time and energy to making a change; following a plan set for a specific behaviour change.
Perform the new behaviour. Manage emotional and physical reactions to the change.
Maintenance
Striving to integrate the new behaviour into daily life and striving to make it permanent.
Persevere through lapses. Teach others and help them achieve their own goals. (This stage can last for years.)
Adoption/Moving On
The former behaviour is gone, and the new behaviour is routine.
The former behaviour is gone, and the new behaviour is routine.
46
Misinformation Terms
advertorials lengthy advertisements in newspapers and magazines and their websites that read like feature articles but are written for the purpose of touting the virtues of products and may or may not be accurate.
anecdotal evidence information based on interesting and entertaining, but not scientific, personal accounts of events.
fraud or quackery the promotion, for financial gain, of devices, treatments, services, plans, or products (including diets and supplements) that alter or claim to alter a human condition without proof of safety or effectiveness. (The word quackery comes from the term quacksalver, meaning a person who quacks loudly about a miracle product—a lotion or a salve.)
infomercials feature-length television commercials that follow the format of regular programs but are intended to convince viewers to buy products and not to educate or entertain them. The statements made may or may not be accurate.
urban legends stories, usually false, that may travel rapidly throughout the world via the Internet, gaining strength of conviction solely on the basis of repetition.
47
Dietitians of Canada (DC), the professional association of dietitians, asserts that nutrition education should be part of the curriculum for health-care professionals.
48
Terms Associated with Nutrition Advice
dietetic technician a person who has completed a two-year academic degree from an accredited college or university and an approved dietetic technician program.
dietitian a person trained in nutrition, food science, and diet planning. See also registered dietitian.
Dietitians of Canada (DC) the professional organization of dietitians in Canada.
medical nutrition therapy nutrition services used in the treatment of injury, illness, or other conditions; includes assessment of nutrition status and dietary intake and corrective applications of diet, counselling, and other nutrition services.
nutritionist someone who engages in the study of nutrition. Some nutritionists are registered dietitians, whereas others are self-described experts whose training is questionable and who are not qualified to give advice.
In U.S. states with responsible legislation, the term applies only to people who have a master of science (M.S.) or a doctor of philosophy (Ph.D.) degree from a properly accredited institution
public health nutritionist a dietitian or other person with an advanced degree in nutrition who specializes in public health nutrition.
registered dietitian (RD) a dietitian who has graduated from a university or college after completing a program of dietetics. The program must be approved or accredited by Dietitians of Canada. The dietitian must serve in an approved internship, coordinated program, or preprofessional practice program to practise the necessary skills.
registration board a professional organization that requires specific course work, experience, and passing of an examination.
49
Terms Describing Institutions of Higher Learning, Legitimate and Fraudulent
accredited approved; in the case of universities, certified by an agency such as provincial ministries of education or Dietitians of Canada.
correspondence school a school that gives home study/career course instruction by mail, sending lessons and exams to the student’s home.
diploma mill an organization that awards meaningless degrees without requiring its students to meet educational standards.
50
cause of death is directly related to
nutrition
51
Explain how RDA, AI, EAR, and UL serve different functions in describing nutrient values, and discuss how each is used.
52
Dietary Reference Intakes (DRI) a set of five lists of nutrient intake values for healthy people in Canada and the United States. These values are used for planning and assessing diets:
53
recommended dietary allowances (RDA)
nutrient intake goals for individuals; the average daily nutrient intake level that meets the needs of nearly all (97% to 98%) healthy people in a particular life stage and gender group.a Derived from the estimated average requirements (EAR; see below).
54
adequate intakes (AI) nutrient intake goals for individuals are set whenever scientific data are insufficient to allow establishment of an RDA value; the recommended average daily nutrient intake level based on intakes of healthy people (observed or experimentally derived) in a particular life stage and gender group and assumed to be adequate.a
55
estimated average requirements (EAR) the average daily nutrient intake estimated to meet the requirement of half of the healthy individuals in a particular life stage and gender group; used in nutrition research and policymaking and the basis upon which RDA values are set.
56
tolerable upper intake levels (UL) the highest average daily nutrient intake level that is likely to pose no risk of toxicity to almost all healthy individuals of a particular life stage and gender group. Usual intake above this level may place an individual at risk of illness from nutrient toxicity.
57
chronic disease risk reduction (CDRR) a new DRI category based on chronic disease risk; for example, keeping the sodium intake below the CDRR is expected to reduce the risk of chronic disease for the otherwise healthy population, while intakes above it will increase risk.
58
acceptable macronutrient distribution ranges (AMDR) values for carbohydrate, fat, and protein expressed as percentages of total daily caloric intake; ranges of intakes set for the energy-yielding nutrients that are sufficient to provide adequate total energy and nutrients while reducing the risk of chronic diseases.
59
Daily Values (DV) nutrient reference standards used on food labels, in grocery stores (and on some restaurant menus and websites in Canada and the United States). The DV allow comparisons among foods with regard to their nutrient contents.
60
The DRI committee also sets healthy ranges of intake for carbohydrate, fat, and protein known as acceptable macronutrient distribution ranges (AMDR). Each of these three energy-yielding nutrients contributes to the day’s total Calorie intake, and their contributions can be expressed as a percentage of the total. According to the committee, a diet that provides adequate energy nutrients for healthy individuals in the following proportions can provide adequate nutrients while reducing the risk of chronic diseases:
45 to 65 percent from carbohydrate
20 to 35 percent from fat
10 to 35 percent from protein
61
On average, you should try to get 100 percent of the DRI recommended intake for every nutrient to ensure an adequate intake over time.
62
Canada’s Food Guide, 2019 differs from the United States Department of Agriculture (USDA) MyPlate in the number of food groups/categories, images of food proportions, and the graphic presentation.
63
Discretionary Calories are distinguished from the Calories of the nutrient-dense foods of which they may be a part. A fried chicken leg, for example, provides discretionary Calories from two sources: the naturally occurring fat of the chicken skin and the added fat absorbed during frying. The Calories of the skinless chicken underneath are not discretionary (unless consumed in excess of need)—they are necessary to provide the nutrients of chicken.
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Unprocessed or lightly processed foods are generally best because some processes strip foods of beneficial nutrients and fibre, while others add many Calories in the form of sugar or fat.
65
75 g of meat = the size of the palm of a woman’s hand or a deck of cards
1 medium piece of fruit or potato = the size of a regular (60-watt) light bulb
50 g of cheese = the size of a nine-volt battery
30 g of lunch meat or cheese = 1 slice
1 pat (1 teaspoon) of butter or margarine = a slice from a quarter-pound stick of butter about as thick as 280 pages of this book (pressed together)
66
To judge the quality of a diet, researchers use an assessment tool known as the Healthy Eating Index 2015 (HEI-2015), developed by the USDA.5 A Canadian adaptation of the HEI (HEI-C) has been used to assess the 2004 Canadian Community Health Survey (CCHS) data set, which revealed a score of just under 60 (58.8) out of a possible score of 100 (https://www150.statcan.gc.ca/n1/pub/82-003-x/2009003/article/10914-eng.htm).
67
According to the law, most packaged food must state the following:
The common or usual name of the product
The name and address of the manufacturer, packer, or distributor
The net contents in terms of weight, measure, or count
The nutrient contents of the product (Nutrition Facts label)
Then the label must list the following in ordinary language:
The ingredients, in descending order of predominance by weight. (Readers should note that as part of the Healthy Eating Strategy for Canada, Health Canada will be updating the Ingredients List in a number of ways, including grouping various sugars, identifying colours by their common name, making it easier to identify allergens and so on; see Figure 2–11.)
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nutrient function claims a carefully worded, prescribed statement on a food that meets strict criteria that outline the role a nutrient may have in our biological system. For example, an acceptable claim for the “carbohydrate” in foods is that it “supplies energy.”
health claims claims linking food constituents with disease states; allowable on labels within the criteria established by Health Canada.
nutrient content descriptors claims using approved wording to describe the nutrient values of foods, such as a claim that a food is “high” in a desirable constituent or “low” in an undesirable one.
Nutrition Facts on a food label, the panel of nutrition information required to appear on almost every packaged food. Grocers may also provide the information for fresh produce, meat, poultry, and seafood. Readers should note that as part of the Healthy Eating Strategy for Canada, Health Canada is updating the Nutrition Facts label; see Figure 2–11.
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In addition, the label must state the contents of these nutrients expressed as percentages of the Daily Values:
Vitamin A
Calcium
Vitamin C
Iron
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antioxidants (anti-OX-ih-dants) compounds that protect other compounds from damaging reactions involving oxygen by themselves reacting with oxygen (anti means “against”; oxy means “oxygen”). Oxidation is a potentially damaging effect of normal cell chemistry involving oxygen (more in Chapters 5 and 7).
bioactive compounds defined by Health Canada as the naturally occurring chemical compounds contained in or derived from a plant, animal, or marine source that exert the desired health/wellness benefit (e.g., omega-3 fatty acids in flax or fish oils and beta-glucans from oats and barley).
broccoli sprouts the sprouted seed of Brassica italica, or the common broccoli plant, believed to be a functional food by virtue of its high phytochemical content.
conjugated linoleic acid (CLA) a type of fat in butter, milk, and other dairy products believed by some to have biological activity in the body. Not a phytochemical but a biologically active chemical produced by animals.
drug any substance that when taken into a living organism may modify one or more of its functions.
flavonoid (FLAY-von-oyd) any member of a chemical family of yellow pigments in foods; phytochemicals that may exert physiological effects on the body. Flavus means “yellow.”
flaxseed small brown seed of the flax plant; used in baking, cereals, or other foods; valued by industry as a source of linseed oil and fibre.
functional foods defined by Health Canada as foods that appear similar to conventional foods, consumed as part of the usual diet, with demonstrated physiological benefits or with the ability to reduce chronic disease risks beyond basic nutrient functions. Also defined in Chapter 1.
genistein (GEN-ih-steen) a phytoestrogen found primarily in soybeans that both mimics and blocks the action of estrogen in the body.
kefir (KEE-fur) a liquid form of yogurt, based on milk, probiotic microorganisms, and flavourings.
lignans phytochemicals present in flaxseed, but not in flax oil, that are converted to phytosterols by intestinal bacteria and are under study as possible anticancer agents.
lutein (LOO-teen) a plant pigment of yellow hue; a phytochemical believed to play roles in eye functioning and health.
lycopene (LYE-koh-peen) a pigment responsible for the red colour of tomatoes and other red-hued vegetables; a phytochemical that may act as an antioxidant in the body.
miso fermented soybean paste used in Japanese cooking. Soy products are considered to be functional foods.
natural health products (NHP) defined by Health Canada to include homeopathic preparations; substances used in traditional medicines (e.g., herbal remedies); minerals or trace elements; vitamins; amino acids; essential fatty acids; or other botanical-, animal-, or microorganism-derived (e.g., probiotics) substances. These products are generally sold in medicinal or “dosage” form to diagnose, treat, or prevent disease; restore or correct function; or maintain or promote health. As a product group, NHPs include nutraceuticals. Readers should note that the Natural Non-prescription Health Products Directorate is proposing to introduce a risk-based approach for non-prescription drugs including vitamins and minerals; see https://www.canada.ca/en/health-canada/services/drugs-health-products/natural-health-products/activities/activity-calendar/natural-non-prescription-health-products-directorate-nnhpd-upcoming-activities.html.
nutraceutical defined by Health Canada as a product isolated or purified from foods that is generally sold in medicinal forms not usually associated with foods. A nutraceutical is demonstrated to have a physiological benefit or to provide protection against chronic disease.
organosulphur compounds a large group of phytochemicals containing the mineral sulphur. Organosulphur phytochemicals are responsible for the pungent flavours and aromas of foods belonging to the onion, leek, chive, shallot, and garlic family and are thought to stimulate cancer defences in the body.
phytochemicals (FIGH-toe-CHEM-ih-cals) biologically active compounds of plants believed to confer resistance to diseases on the eater, also defined in Chapter 1. Phyto means “plant.”
phytoestrogens (FIGH-toe-ESS-troh-gens) phytochemicals structurally similar to mammalian hormones, such as the female sex hormone estrogen. Phytoestrogens weakly mimic hormone activity in the human body.
probiotics consumable products containing live microorganisms in sufficient numbers to alter the bacterial colonies of the body in ways believed to benefit health. A prebiotic product is a substance that may not be digestible by the host, such as fibre, but serves as food for probiotic bacteria and thus promotes their growth.
soy drink a milklike beverage made from soybeans, claimed to be a functional food. Soy drink should be fortified with vitamin A, vitamin D, riboflavin, calcium, and vitamin B12 to approach the nutritional equivalency of milk. Also called soy milk.
sterol esters compounds derived from vegetable oils that lower blood cholesterol in human beings by competing with cholesterol for absorption from the digestive tract. The term sterol esters often refers to both stanol esters and sterol esters.
tofu a white curd made of soybeans, popular in Asian cuisines, and considered to be a functional food.
Capsaicin
may modulate blood clotting; may reduce the risk of fatal clots in heart and artery disease
Hot peppers
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A Sampling of Phytochemicals—Possible Effects and Food Sources
Name
Possible Effects
Food Sources
Capsaicin
may modulate blood clotting; may reduce the risk of fatal clots in heart and artery disease
Hot peppers
Carotenoids (including beta-carotene, lutein, lycopene, and hundreds of related compounds)a
Act as antioxidants; possibly reduce risks of heart disease, age-related eye disease,b cancer, and other diseases
Deeply pigmented fruit and vegetables (apricots, broccoli, cantaloupe, carrots, pumpkin, spinach, sweet potatoes, tomatoes)
Curcumin
May inhibit enzymes that activate carcinogens
Turmeric, a yellow-coloured spice
Flavonoids (including flavones, flavonols, isoflavones, catechins, and others)c,d
Act as antioxidants; may scavenge carcinogens; bind to nitrates in the stomach, preventing conversion to nitrosamines; inhibit cell proliferation; flavonoids of blueberries may improve memory
Berries, black tea, celery, chocolate, citrus fruits, green tea, olives, onions, oregano, purple grapes, purple grape juice, soybeans and soy products, vegetables, whole wheat, wine
Indoles
May trigger production of enzymes that block DNA damage from carcinogens; may inhibit estrogen action
Broccoli and other cruciferous vegetables (Brussels sprouts, cabbage, cauliflower), horseradish, mustard greens
Isothiocyanates (including sulphoraphane)
May inhibit enzymes that activate carcinogens; trigger production of enzymes that detoxify carcinogens
Broccoli and other cruciferous vegetables (Brussels sprouts, cabbage, cauliflower), horseradish, mustard greens
Monoterpenes (including limonene)
May trigger enzyme production to detoxify carcinogens; may inhibit cancer promotion and cell proliferation
Citrus fruit peels and oils
Organosulphur compounds (including allicin)
May speed production of carcinogen-destroying enzymes or slow production of carcinogen-activating enzymes
Chives, garlic, leeks, onions
Phenolic acidsd (including ellagic acid)
May trigger enzyme production to make carcinogens water soluble, facilitating excretion
Coffee beans, fruit (apples, blueberries, cherries, grapes, oranges, pears, prunes, strawberries), oats, potatoes, soybeans
Phytic acid
Binds to minerals, preventing free-radical formation, possibly reducing cancer risk
Whole grains
Phytoestrogens (members of the flavonoid family, genistein and diadzein)
May inhibit estrogen and produce these actions: inhibit cell replication in gastrointestinal tract; reduce risk of breast, colon, ovarian, prostate, and other estrogen-sensitive cancers; reduce cancer cell survival; may reduce risk of osteoporosis; may also alter blood lipids favourably and reduce heart disease risk when consumed in soy foods
Soybeans, soy flour, soy milk, tofu, textured vegetable protein, other legume products
Phytoestrogens (lignans)
Block estrogen activity in cells, possibly reducing the risk of cancer of the breast, colon, ovaries, and prostate
Flaxseed, whole grains
Protease inhibitors
May suppress enzyme production in cancer cells, slowing tumour growth; inhibit hormone binding; inhibit malignant changes in cells
Broccoli sprouts, potatoes, soybeans and other legumes, soy products
Resveratrole
May offset artery-damaging effects of high-fat diets
Red wine, peanuts
Saponins
May interfere with DNA replication, preventing cancer cells from multiplying; stimulate immune response
Alfalfa sprouts, other sprouts, green vegetables, potatoes, tomatoes
Tanninsd
May inhibit carcinogen activation and cancer promotion; act as antioxidants
Black-eyed peas, grapes, lentils, red and white wine, tea
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low in fat ranges - high in this ranges compared to DV needed
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Nutrient Content Claim
Compositional Criteria (per reference amount and serving of stated size)a
CALORIES
Calorie-free
fewer than 5 Calories
Low in Calories
40 Calories or fewer
Reduced or lower in Calories
at least 25% less energyb
Source of Calories
at least 100 Calories
PROTEIN
Source of protein
protein rating of 20 or morec
Excellent source of protein
protein rating of 40 or morec
More protein
protein rating of 20 or more,c at least 25% or more protein,c and 7 g or more protein
FAT
Fat-free
less than 0.5 g fat
Low in fat
3 g or less fat
Reduced or lower in fat
at least 25% less fatb
100% fat-free
less than 0.5 g fat per 100 g, no added fat, and “free of fat”
(naming the %) fat-free
“low in fat”
SATURATED FATTY ACIDS
Saturated fatty acid-free
less than 0.2 g saturated fatty acids and less than 0.2 g trans fatty acids
Low in saturated fatty acids
2 g or less saturated fatty acids and trans fatty acids combined and 15% or less energy from saturated fatty acids plus trans fatty acids
Reduced or lower in saturated fatty acids
at least 25% less saturated fatty acids and trans fatty acids not increasedb
TRANS FATTY ACIDS
Free of trans fatty acids
less than 0.2 g trans fatty acids and “low in saturated fatty acids”
Reduced or lower in trans fatty acids
at least 25% less trans fatty acids and saturated fatty acids not increasedb
POLYUNSATURATED FATTY ACIDS
Source of omega-3 polyunsaturated fatty acids
0.3 g or more omega-3 polyunsaturated fatty acids
Source of omega-6 polyunsaturated fatty acids
2 g or more omega-6 polyunsaturated fatty acids
CHOLESTEROL
Cholesterol-free
less than 2 mg cholesterol and “low in saturated fatty acids”
Low in cholesterol
20 mg or less cholesterol and “low in saturated fatty acids”
Reduced or lower in cholesterol
at least 25% less cholesterolb and “low in saturated fatty acids”
SODIUM
Sodium-free or salt-free
less than 5 mg sodium or salt
Low in sodium or salt
140 mg or less sodium or salt
Reduced or lower in sodium or salt
at least 25% less sodium or saltb
No added sodium or salt
no salt or other sodium salts added during processing
Lightly salted
at least 50% less added sodium or saltb
SUGARSd
Sugar-free
less than 0.5 g sugars
Reduced or lower in sugar
at least 25% less sugarsb
No added sugar
no sugars added in processing or packaging, including ingredients that contain added sugars or ingredients that functionally substitute for added sugars (e.g., concentrated fruit juice), and sugars not increased through some other means
FIBRE
Source of fibre
2 g or more fibre or of each identified fibre
High source of fibre
4 g or more fibre or of each identified fibre
Very high source of fibre
6 g or more fibre or of each identified fibre
More fibre
at least 25% more fibreb and at least 2 g fibre
LIGHT
Light
“reduced in energy” or “reduced in fat”
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Glands secrete hormones that act as messengers to help regulate body processes
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The nervous system joins the hormonal system to regulate body processes through communication among all the organs. Together, the hormonal and nervous systems respond to the need for food, govern the act of eating, regulate digestion, and call for the stress response.
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Phagocytes. These scavenger cells travel throughout the body and are the first to defend body tissues against invaders. When a phagocyte recognizes a foreign particle, such as a bacterium, the phagocyte forms a pocket in its own outer membrane, engulfing the invader. Then the phagocytes may attack the invader with oxidative chemicals in an “oxidative burst” or may otherwise digest or destroy it. Phagocytes also leave a chemical trail that helps other immune cells to join the defence against infection.
T cells. Killer T cells recognize chemical messages from phagocytes and “read” and “remember” the identity of an invader from the messages. The killer T cells then seek out and destroy all foreign particles with the same identity. T cells defend against fungi, viruses, parasites, some bacteria, and some cancer cells (see the photo). They also pose a formidable obstacle to a successful organ transplant—the physician must prescribe immunosuppressive drugs following surgery to hold down the T cells’ attack against the “foreign” organ. Another group, helper T cells, does not attack invaders but helps other immune cells do so. People suffering from the disease AIDS (acquired immune deficiency syndrome) are rendered defenceless against other diseases because the human immunodeficiency virus (HIV) that causes AIDS selectively attacks and destroys their helper T cells.
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B cells. B cells respond rapidly to infection by dividing and releasing invader-fighting proteins, antibodies, into the bloodstream. Antibodies travel to the site of the infection and stick to the surface of the foreign particles, killing or inactivating them. Like T cells, the B cells also retain a chemical memory of each invader, and if the encounter recurs, the response is swift. Immunizations work this way—a disabled or harmless form of a disease-causing organism is injected into the body so that the B cells can learn to recognize it. Later, if the real, live infectious organism invades, the B cells quickly release antibodies to destroy it.
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ghrelin
a hormone secreted by the stomach that is thought to be a “hunger hormone.”
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On the surfaces of the taste buds are structures that detect four basic chemical tastes: sweet, sour, bitter, and salty. A fifth taste is sometimes included on this list: the taste of monosodium glutamate, sometimes called savoury or umami (ooh-MOM-ee), its Asian name. Aroma, texture, temperature, and other flavour elements can also affect a food’s flavour. In fact, the human ability to detect a food’s aroma is thousands of times as sensitive as our sense of taste. The nose can detect just a few molecules responsible for the aroma of frying bacon, for example, even when they are diluted in several rooms full of air.
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The enjoyment of sugars and fat encourages people to consume ample energy, especially in the form of foods containing sugars, which provide energy for the brain. Likewise, foods containing fats provide energy and essential nutrients needed by all body tissues. The pleasure of a salty taste prompts eaters to consume sufficient amounts of two very important minerals—sodium and chloride. The aversion to bitterness discourages consumption of foods containing bitter toxins and also affects people’s food preferences. People born with great sensitivity to bitter tastes are apt to avoid foods with slightly bitter flavours, such as turnips and broccoli.
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Once you have eaten, your brain and hormones direct the many organs of the digestive system to digest and absorb the complex mixture of chewed and swallowed food. A diagram showing the digestive tract and its associated organs appears in Figure 3–8. The tract itself is a flexible, muscular tube extending from the mouth through the throat, esophagus, stomach, small intestine, large intestine, and rectum to the anus, for a total length of about eight metres. The human body surrounds this digestive canal. When you swallow something, it is not inside your body—it is only inside the inner bore of this tube. Only when a nutrient or other substance passes through the wall of the digestive tract does it actually enter the body’s tissues. Many things pass into the digestive tract and out again, unabsorbed. A baby playing with beads may swallow one, but the bead will not really enter the body. It will emerge from the digestive tract within a day or two.
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peristalsis
(perri-STALL-sis) the wavelike muscular squeezing of the esophagus, stomach, and small intestine that pushes their contents along.
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chyme
(KIME) the fluid resulting from the actions of the stomach upon food.
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pyloric (pye-LORE-ick) valve
the circular muscle of the lower stomach that regulates the flow of partly digested food into the small intestine. Also called pyloric sphincter.
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large intestine
the portion of the intestine that completes the absorption process.
colon
the large intestine.
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Digestive juices contain enzymes that break nutrients down into their component parts. The digestive organs that release digestive juices are the salivary glands, the stomach, the pancreas, the liver, and the small intestine. Their secretions were listed previously in Figure 3–8.
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Cells in the stomach release gastric juice, a mixture of water, enzymes, and hydrochloric acid. This strong acid mixture is needed to activate a protein-digesting enzyme (pepsin) and to initiate digestion of protein—protein digestion is the stomach’s main function. The strength of an acid solution is expressed as its pH. The lower the pH number, the more acidic the solution; solutions with higher pH numbers are more basic. As Figure 3–11 demonstrates, saliva is only weakly acidic, while the stomach’s gastric juice is much more strongly acidic. Notice on the right side of Figure 3–11 that the range of tolerance for the blood’s pH is exceedingly small.
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students often wonder how the tract’s own cellular lining escapes being digested along with the food. The answer: specialized cells secrete a thick, viscous substance known as mucus, which coats and protects the stomach and the rest of the digestive tract lining.
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bile
a cholesterol-containing digestive fluid made by the liver, stored in the gallbladder, and released into the small intestine when needed. It emulsifies fats and oils to ready them for enzymatic digestion (described in Chapter 5).
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emulsifier
(ee-MULL-sih-fire) a compound with both water-soluble and fat-soluble portions that can attract fats and oils into water, combining them.
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pancreatic juice
fluid secreted by the pancreas that contains both sodium bicarbonate, a neutralizing agent, and enzymes to digest carbohydrate, fat, and protein.
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Other hormones (e.g., secritin) notify the pancreas to release pancreatic juice containing the alkaline compound bicarbonate in amounts precisely adjusted to neutralize the stomach acid that has reached the small intestine. All these actions alter the intestinal environment to perfectly support the work of the digestive enzymes.
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pathway of chemical digestion
Chemical digestion begins in the mouth, where food is mixed with an enzyme in saliva that acts on carbohydrates. Digestion continues in the stomach, where stomach enzymes and acid break down protein. Digestion then continues in the small intestine; there the liver and gallbladder contribute bile that emulsifies fat, and the pancreas and small intestine donate enzymes that continue digestion so that absorption can occur. Bacteria in the colon break down certain fibres.
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pg 92 in textSummary of Chemical Digestion
Mouth
Stomach
Small Intestine, Pancreas, Liver, and Gallbladder
Large Intestine (Colon)
Sugar and Starch
The salivary glands secrete saliva to moisten and lubricate food; chewing crushes and mixes it with a salivary enzyme (salivary amylase) that initiates starch digestion.
Digestion of starch continues while food remains in the upper storage area of the stomach. In the lower digesting area of the stomach, hydrochloric acid and an enzyme of the stomach’s juices halt starch digestion.
The pancreas produces a starch-digesting enzyme (pancreatic amylase) and releases it into the small intestine. Cells in the intestinal lining possess enzymes on their surfaces that break sugars (e.g., sucrase) and starch fragments into simple sugars, which are then absorbed.
Undigested carbohydrates reach the colon and are partly broken down by intestinal bacteria.
Fibre
The teeth crush fibre and mix it with saliva to moisten it for swallowing.
No action.
Fibre binds cholesterol and some minerals.
Most fibre is excreted with the feces; some fibre is digested by bacteria in the colon.
Fat
Fat-rich foods are mixed with saliva. The tongue produces traces of a fat-digesting enzyme that accomplishes some breakdown, especially of milk fats. The enzyme is stable at low pH and is important to digestion in nursing infants.
Fat tends to rise from the watery stomach fluid and foods and float on top of the mixture. Only a small amount of fat is digested. Fat is last to leave the stomach.
The liver secretes bile; the gallbladder stores it and releases it into the small intestine. Bile emulsifies the fat and readies it for enzyme action. The pancreas produces fat-digesting enzymes (pancreatic lipase) and releases them into the small intestine to split fats into their component parts (primarily fatty acids), which are then absorbed.
Some fatty materials escape absorption and are carried out of the body with other wastes.
Protein
Chewing crushes and softens protein-rich foods and mixes them with saliva.
Stomach acid works to uncoil protein strands and to activate the stomach’s protein-digesting enzyme (pepsin). Then the enzyme breaks the protein strands into smaller fragments.
Enzymes released into the small intestine by the pancreas (e.g., proteases) split protein fragments into smaller fragments or free amino acids. Deoxyribonuclease enzymes split the DNA molecules in food. Enzymes on the cells of the intestinal lining break some protein fragments into free amino acids; nucleotidases continue the breakdown of the building blocks of DNA, which are then absorbed. Some small protein fragments (e.g., tripeptides or dipeptides) are also absorbed.
The colon carries undigested protein residue out of the body. Normally, almost all food protein is digested and absorbed.
Water
The mouth donates watery, enzyme-containing saliva.
The stomach donates acidic, watery, enzyme-containing gastric juice.
The liver donates a watery juice containing bile. The pancreas and small intestine add watery, enzyme-containing juices; pancreatic juice is also alkaline.
The colon reabsorbs water and some minerals.
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microbiota
the mix of microbial species of a community; for example, all of the bacteria, fungi, and viruses present in the human digestive tract. The term microbiome refers to the collective genes of such a community.
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Bacterial Activities Digestive tract bacteria harvest energy from undigested food substances and use it to sustain themselves and to proliferate. In the process, they yield smaller molecules that the body can absorb and use.4 For example, bacteria:
Ferment many indigestible fibres, producing short fatty acids that provide many colon cells with most of their needed energy.
Break down any undigested protein or unabsorbed amino acids that reach the colon, producing ammonia and other compounds.†
Break down and help to recycle components of bile.
Chemically alter certain drugs and phytochemicals, changing their effects on the body.
Bacteria also produce several vitamins but in amounts insufficient to meet the body’s needs, so these vitamins must be obtained from the diet.
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A substantial population of intestinal bacteria scavenge and break down fibres and other undigested compounds.
The colon absorbs and uses products of bacterial metabolism; the bacteria and their products also interact with other organs and tissues.
Diet strongly influences the composition and metabolism of the intestinal bacteria.
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The healthy digestive system is capable of adjusting to almost any diet and can handle any combination of foods with ease.
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stopped for chapter 3
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