Transcript Nutrition: Class Content, Student Questions

Nutrition: Class Content, Student
Questions
Fall 2011
Nutrients
• Nutrients are substances the body needs to
live
• Humans need six nutrients
– Three contain energy (calories)
– Three do not contain energy
Energy-Containing Nutrients
• Carbohydrates
– 4 calories per gram
• Protein
– 4 calories per gram
• Fat
– 9 calories per gram
Image source: public domain
Nutrients Without Energy
• Vitamins
– Organic substances found in
plant and animal sources
– A, C, D, E, K, & B
vitamins (8 of them)
• Minerals
– Inorganic substances found
in many of the body’s
structures (teeth, bones,
muscles, blood cells, etc)
– Examples: calcium, sodium,
iron, chromium, potassium
Student Question: Do we need all
vitamins? A combination?
• A: We need all vitamins. What one person
needs, however, will differ from another
person based on their dietary behaviors.
– Example: person who consumes many fruits &
vegetables vs “fast food” eater
– Example: a person with nutrient absorption
issues may need larger doses than average
individual
Student Question: Do we need all
vitamins? A combination?
• Common dietary needs are those vitamins
found in fruits & vegetables since many of
us do not consume enough
• Recommendations:
– RDA = Recommended Dietary Allowances
– AI = Adequate Intake, if no RDA value set
– UL = Upper Limit (highest intake without
negative side effects)
Student Question: What kinds of fruits
& vegetables are most beneficial?
• Generally, brightlycolored produce
– Vitamins
– Minerals
– Antioxidants
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Variety
Green, leafy vegetables
Bright berries
Tomatoes
Sweet potatoes
Photo: Scott Bauer, public domain
Student Question: What are the nutritional
differences in fruits and vegetables?
• Both have nutrients
• Generally, vegetables
are favored over fruits
– Sugar content in fruits
• Fructose
• Too much = fat storage
– Slower absorption rate
Student Question: What are the nutritional
differences in fruits and vegetables?
• Both have nutrients
• Generally, vegetables
are favored over fruits
– Sugar content in fruits
• Fructose
• Too much = fat storage
– Slower absorption rate
Student Question: Is a vegetarian
diet healthy?
• Vegetarian diets can
be “healthy” or
“unhealthy”
– Whole foods: grains,
vegetables, fruits,
herbs
– Fried tofu, mashed
potatoes with butter,
mac and cheese, candy
Student Question: What foods are
low-calorie but also filling?
• Carbohydrate-based foods are usually
digested more quickly, resulting in hunger
– Since the body needs carb as its primary energy
source, cutting isn’t terribly helpful
– Complex carbohydrates take longer to digest
than simple carbohydrates
• Brown (instead of white) rice
Student Question: What foods are
low-calorie but also filling?
• Foods higher in fiber tend to take longer to
digest
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Whole grains (barley, bran flakes, oatmeal)
Nuts & seeds (almonds, flax seeds, pistachios)
Fruit (raspberries, pear, strawberries, prunes)
Legumes (lentils, black beans, split peas)
Vegetables (peas, greens, corn, artichoke)
Student Question: What foods are
low-calorie but also filling?
• Water-based foods: soups/broths
• Leafy green vegetables
• Including protein and healthy fats with
carbohydrate at meals can slow digestion
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Eggs
Fish
Chicken
Tofu
Almond butter/peanut butter
Avocado
Student Question: What Harms
Might Vitamins Cause the Body?
• WebMD shows RDA
or AI, and UL values
for vitamins and
minerals
• Dangers are usually
associated with
megadoses
– Besthealth
Student Question: What food chemicals should
we look out for?
• Challenge: People have varying sensitivities
• Challenge: Often, the issue is accumulation
rather than one dose at a given time
• Challenge: Combinations of chemicals
• Challenge: chemicals used for a variety of
attractive purposes
• Challenge: some chemicals are naturally
occurring (estrogenic foods)
Student Question: What food chemicals should
we look out for?
• Challenge: Chemicals used for a variety of
purposes attractive to consumer
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Preservatives
Sweeteners, flavorings
Fat replacers
Emulsifiers, thickeners
Color additives
List at FDA
Student Question: What food chemicals should
we look out for?
• Guideline: the more
processed the food, the
more chemicals
present
• Guideline: shopping
around the perimeter
of a grocery store
usually the healthiest
approach
Student Question: What food chemicals should
we look out for?
• Per Center for Science in the Public Interest
• Sodium nitrite
– Found in meat salty, processed meat products
– World Cancer Research Fund, May 2011: processed
meats too dangerous for human consumption
(totalhealthbreakthroughs.com)
• Saccharin, aspartame, Acesulfame-K
• Beverages, snack foods, dairy products, gums, soups, snacks
• Increased cancer risk
Student Question: What food chemicals should
we look out for?
• Caffeine
– Addictive
– Stimulant properties
• Olestra
– Fat substitute in snack chips
– Digestive problems
– Reduce absorption of some fat-soluble vitamins
• Food dyes
• Blue 2, Green 3, Orange B, Red 3, Yellow 5, et. Al.
• Candy, baked goods, beverages
Student Question: What food chemicals should
we look out for?
• High fructose corn syrup
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Beverages, cereals, candy, cookies, condiments
Increases sweetness of food products
Consumers not consuming less sugar
Connection to corn allergies?
Metabolic problems? (insulin resistance)
• Bisphenol A in cans, plastics (cancer,
reproductive health, CV disease)