Transcript Dietary fiber

Nutrition Basics
Chapter 12
© 2012 McGraw-Hill Higher Education. All rights reserved.
Nutritional Requirements:
Components of a Healthy Diet

Your body requires 45 essential nutrients:
◦ Proteins, fats, carbohydrates, vitamins, minerals, water
 Macronutrients
 Micronutrients
 Body obtains nutrients through process of digestion

Energy in food is expressed as kilocalories (kcalorie)
 1 kcalorie = amount of heat it takes to raise the temperature of 1 liter of fluid 1
degree centigrade
 2,000 calories per day meets a person needs.
 1,000 calories = 1 kcalorie
 3 categories supply energy
 Fat = 9 calories per gram
 Protein = 4 calories per gram
 Carbohydrates = 4 calories per gram
© 2012 McGraw-Hill Higher Education. All rights reserved.
2
Table 12.1 The Six Classes of
Essential Nutrients
© 2012 McGraw-Hill Higher Education. All rights reserved.
3
Figure 12.1 The Digestive System
© 2012 McGraw-Hill Higher Education. All rights reserved.
4
Proteins – Basis of Body Structure

Form muscle, bone, blood, enzymes, hormones,
cell membranes
◦ Twenty common amino acids – building blocks
 Nine essential amino acids
 Eleven nonessential amino acids
◦ Complete proteins provide all essential amino acids
 Most animal proteins provide complete proteins
 Most plant proteins are incomplete
 Plants, legumes, nuts
 Combine 2 vegetables to make up missing amino acids
◦ Recommended amount
 0.36 grams per pound of body weight
 10-35% of total calorie intake
 Average is 15-16%
© 2012 McGraw-Hill Higher Education. All rights reserved.
5
Fats (or Lipids)


Essential in small amounts
Most concentrated source of energy (9 cals/gram)
◦ Stored energy, provides insulation and support for body organs
◦ Two fats are essential components of diet
 Linoleic acid
 Alpha-linolenic acid
◦ 10% from saturated fats
◦ Triglycerides - glycerol molecule with 3 fatty acid chains
 Animal fats primarily made of triglycerides






Unsaturated
Monounsaturated
Polyunsaturated
Saturated
Hydrogenation
Trans fatty acids
© 2012 McGraw-Hill Higher Education. All rights reserved.
6
Fats and Health

Cholesterol
◦ Low density lipoprotein (LDL) – “bad” cholesterol
◦ High density lipoprotein (HDL) – “good” cholesterol




Absorbs fat-soluble vitamins (A,D,E, K)
Omega-3 fatty acids – AMDR 5-10%
Omega-6 fatty acids – AMDR 0.6-1.2%
Recommended intake
◦ Adults
 Men 17 grams per day of linoleic and 1.6 grams of alpha-linolenic
 Women 12 grams per day of linoleic and 1.1 grams of alpha-linolenic
◦ Only 3-4 teaspoons (15-20 grams) of vegetable oil per day
◦ AMDRs for total fat 20-35%
© 2012 McGraw-Hill Higher Education. All rights reserved.
7
Carbohydrates
Supply energy for body cells
 Two groups

◦ Simple carbs: one or two sugar units
 Fruit, sugar, honey, malt, and milk
◦ Complex carbs: multiple sugar units
 Starches and fiber
 Grains – wheat, rye, rice, oats, barley, millet
 Legumes – dry beans, peas, lentils
 Tubers – potatoes, yams
◦ Digestion
 Mouth and small intestines
 Break down to glucose
© 2012 McGraw-Hill Higher Education. All rights reserved.
8
Refined Carbohydrates versus
Whole Grains
Refined (processed)
 Unrefined (whole grains)
 All grains before processing

◦ Inner layer: germ
◦ Middle layer: endosperm
◦ Outer layer: bran

During processing
◦ Germ and bran are removed, leaving just the
starchy endosperm
© 2012 McGraw-Hill Higher Education. All rights reserved.
9
Glycemic Index and
Glycemic Response
Insulin and glucose levels
 Quick rise in glucose and insulin levels
= high glycemic index

◦ Eating high glycemic index foods may
increase appetite
◦ May increase risk of diabetes and heart
disease
◦ Unrefined grains, fruits, vegetables and
legumes – relatively low glycemic index
© 2012 McGraw-Hill Higher Education. All rights reserved.
10
Recommended Carbohydrate Intake





Average American consumes 200-300 grams
130 grams needed to meet the body’s
requirements for essential carbohydrates
Recommended: adults 45-65% of total daily
calories (225-325 grams)
WHO recommends a limit of 10% of total
calories from added sugars
USDA recommends about 8 teaspoons of sugar
per day
© 2012 McGraw-Hill Higher Education. All rights reserved.
11
Fiber – A Closer Look

Food and Nutrition Board
◦ Dietary fiber: nondigestible carbohydrate that is present
naturally
◦ Functional fiber: nondigestible carbohydrate that has been
isolated or synthesized
◦ Total fiber is the sum of both
◦ Soluble (viscous) fiber
◦ Insoluble fiber

Sources
◦ All plant substances

Recommended intake
◦ 38 grams for adult men
◦ 25 grams for adult women
◦ Needs to come from foods, not supplements
© 2012 McGraw-Hill Higher Education. All rights reserved.
12
Vitamins
Organic (carbon-containing) substances required
in small amounts to regulate various processes
within a living cell
 13 vitamins:

◦ 4 fat soluble: A, D, E, K
◦ 9 water soluble: C and 8 B-complex vitamins (thiamin (B1),
riboflavin (B2), niacin (B3), pyridoxine (B6), folate, B-12, biotin,
pantothenic acid)

Sources:
◦ Human body does not manufacture most vitamins
◦ Abundant in fruits, vegetables, grains
© 2012 McGraw-Hill Higher Education. All rights reserved.
13
Minerals
Inorganic micronutrients (do not contain carbon)
 Help to regulate body functions, aid growth,
maintain body tissues, release energy
 17 essential minerals
◦ Major minerals: 100+ milligrams per day

 Calcium, phosphorus, magnesium, sodium, potassium,
chloride
◦ Trace minerals: minute amounts
 Copper, fluoride, iodide, iron, selenium, zinc
© 2012 McGraw-Hill Higher Education. All rights reserved.
14
Water
You are composed of about 50-60% water
 Can live up to 50 days without food, but only a
few days without water
 Food and fluids you consume provide
80-90% of your daily water intake;
the rest is through metabolism
 Food and Nutritional Board

◦ Men: 3.7 total liters of water, with 3.0 liters
(13 cups) coming from beverages
◦ Women: 2.7 total liters of water, with 2.2 liters
(9 cups) coming from beverages
© 2012 McGraw-Hill Higher Education. All rights reserved.
15
Other Substances in Food

Antioxidants
◦ React with free radicals
◦ Vitamin C, vitamin E, selenium, carotenoids

Phytochemicals
◦ Soy foods may help lower cholesterol levels
◦ Cruciferous vegetables render some carcinogenic
compounds harmless
◦ Allyl sulfides (garlic and onions) boost the cancerfighting immune cells
© 2012 McGraw-Hill Higher Education. All rights reserved.
16
Nutritional Guidelines:
Planning Your Diet

Here are several tools to help you design a
healthy diet:
◦ Dietary Reference Intakes
◦ Dietary Guidelines for Americans
◦ MyPyramid
© 2012 McGraw-Hill Higher Education. All rights reserved.
17
Dietary Reference Intakes (DRIs)

Food and Nutrition Board set standards


RDAs (recommended daily allowance)
AI (adequate intake)
Include standards for both recommended and
maximum safe intakes
 Established standards for nutrient intake




Prevent nutrient deficiencies
Promote health
Daily Values used on food labels
◦ Based on 2,000 calorie diet
© 2012 McGraw-Hill Higher Education. All rights reserved.
18
Dietary Guidelines for Americans
Reduce overall calories
 Eat a variety of nutrient-dense foods
 Limit saturated fats to less than 7% of total calories
 Limit cholesterol to less than 300 mg per day
 Choose high-quality proteins
 Choose carbohydrates wisely
 Eat less sodium
 Eat more potassium
 Reduce or eliminate alcohol
 Follow food safety guidelines

© 2012 McGraw-Hill Higher Education. All rights reserved.
19
Figure 12.3 Nutrient Density of 12-ounce
Portions of Selected Beverages
© 2012 McGraw-Hill Higher Education. All rights reserved.
20
USDA’s MyPyramid



USDA released in 2005
Reminds consumers to make healthy food choices and to
be active every day
Key messages:






Personalization
Daily physical activity
Moderation of food intake
Proportionality
Variety
Gradual improvement
© 2012 McGraw-Hill Higher Education. All rights reserved.
21
Figure 12.4
USDA’s MyPyramid
© 2012 McGraw-Hill Higher Education. All rights reserved.
22
Figure 12.5 MyPyramid
Food Intake Patterns
© 2012 McGraw-Hill Higher Education. All rights reserved.
23
Table 12.6 MyPyramid Daily Calorie
Intake Levels
© 2012 McGraw-Hill Higher Education. All rights reserved.
24
MyPyramid: Number of Daily
Servings and Serving Sizes

Grains (6): 1 slice of bread, 1 small muffin (2.5”
diameter), 1 cup ready-to-eat cereal flakes, ½ cup
cooked cereal, 1 (6”) tortilla

Vegetables (5): ½ cup cooked or raw
vegetables, 1 cup raw leafy salad greens,
½ cup of vegetable juice

Fruit (4): ½ cup fresh/canned/frozen fruit,
½ cup 100% fruit juice, 1 small whole fruit,
¼ cup dried fruit
© 2012 McGraw-Hill Higher Education. All rights reserved.
25
MyPyramid: Number of Daily
Servings and Serving Sizes
Milk/Dairy (3): 1 cup milk or yogurt, ½ cup
ricotta cheese, 1½ oz. natural cheese,
2 oz. processed cheese
 Meat and Beans (5½): 1 oz. cooked lean
meat/poultry/fish, ¼ cup cooked dry beans or
tofu, 1 egg, 1 tablespoon peanut butter,
½ oz. nuts or seeds
 Oils (6 teaspoons per day)
 Discretionary calories,
solid fats, and added sugars

© 2012 McGraw-Hill Higher Education. All rights reserved.
26
The Vegetarian Alternative



Reasons
Types:
◦
◦
◦
◦
◦
◦
Vegans
Lacto-vegetarians
Lacto-ovo-vegetarians
Partial vegetarians
Semivegetarians
Pescovegetarians
◦
◦
◦
◦
◦
Vitamin B-12
Vitamin D
Calcium
Iron
Zinc
A food plan for vegetarians
© 2012 McGraw-Hill Higher Education. All rights reserved.
27
Functional Foods
Foods to which health-promoting or
disease-preventing components have been
added
 Fortified, enriched, enhanced
 Examples





Calcium-fortified orange juice
Margarine enriched with sterols to
lower the risk of heart disease
Sports bars for energy
Vitamin B-12 enriched soy milk
© 2012 McGraw-Hill Higher Education. All rights reserved.
28
Dietary Challenges for Special
Population Groups
Children and teenagers
 College students
 Older adults
 Athletes
 People with special health concerns

© 2012 McGraw-Hill Higher Education. All rights reserved.
29
A Personal Plan: Making Informed
Choices About Food
Reading food labels
 Reading dietary supplement labels
 Evaluating functional foods

© 2012 McGraw-Hill Higher Education. All rights reserved.
30
Using Food Labels
© 2012 McGraw-Hill Higher Education. All rights reserved.
31
Protecting Yourself Against
Foodborne Illness

Causes of foodborne illnesses:
◦
◦
◦
◦
◦
◦
◦
◦

Campylobacter jejuni
Salmonella
Shigella
Escherichia coli
Listeria monocytogenes
Staphylococcus aureus
Clostridium botulinum
Norovirus
Preventing and treating foodborne illnesses
© 2012 McGraw-Hill Higher Education. All rights reserved.
32
Environmental Contaminants and
Organic Foods

Organic foods
◦ Concerned about pesticides and other environmental
contaminants
◦ Must meet strict USDA guidelines

Guidelines for fish consumption
◦ Do not eat shark, swordfish, king mackerel, or tilefish
◦ Eat up to 12 oz. a week of a variety of fish and shellfish
that is lower in mercury
◦ Limit albacore tuna to 6 oz. per week
◦ Check advisories about the safety of recreationally
caught fish
© 2012 McGraw-Hill Higher Education. All rights reserved.
33
Additives in Food



Some 2,800 substances are added to foods to
maintain or improve nutritional quality, freshness, to
help in processing or preparation, or to alter taste or
appearance
Most common: sugar, salt, corn syrup, citric acid,
baking soda, vegetable colors, mustard, pepper
Potential health concerns:
Nitrates and nitrites
 BHA and BHT
 Sulfites
 Monosodium glutamate (MSG)

© 2012 McGraw-Hill Higher Education. All rights reserved.
34
Food Biotechnology


Used to produce specific desired traits in plants,
animals, or microorganisms
Food irradiation


Genetically modified foods (GM)


Alters characteristics of a plant, animal, or microorganism
through gene manipulation
Animal cloning


Kills potentially harmful pathogens
FDA deems safe for human consumption, but
probably will be used as breeding stock
Labeling of GM foods

FDA does not require special labeling for GM foods
© 2012 McGraw-Hill Higher Education. All rights reserved.
35
Food Allergies and Food Intolerances

Food allergies
◦
◦
◦
◦
Reaction of the body’s immune system
Affect 1.5% of the adult population
Affect up to 6% of infants
90% of food allergies
 Cow’s milk, eggs, peanuts, tree nuts, soy, wheat, fish,
shellfish

Food intolerances
◦ Problem lies with metabolism rather than with
the immune system
© 2012 McGraw-Hill Higher Education. All rights reserved.
36
Nutrition Basics
Chapter 12
© 2012 McGraw-Hill Higher Education. All rights reserved.