C3.7 - Choosing a Healthy Diet

Healthy Diet

• Canada’s Food Guide to Healthy Eating
  • Contains food groups that will provide all daily nutritional requirements
• 1 serving size equal to
  • medium fruit
  • 125 mL vegetables
  • half bagel / small waffle
  • 200 mL milk / yogurt
  • 30 mL peanut
  • 75 g chicken

Nutrients

Carbohydrates

• carbohydrates: compounds made up of carbon, hydrogen, and oxygen
• major source of energy for humans
• can be used directly or be stored
• 2 types
  • Simple Carbohydrates (i.e. sugars → fruit, honey, milk)
  • Complex Carbohydrates (i.e. starches → bread, rice, potatoes)
• glucose: main fuel supply for cells
  • used for cellular respiration
  • or for making larger carbs / fat molecules
• glycogen: chain of many glucose molecules
• cellulose / fibre: complex carbohydrate often found in fruits and vegetables

Proteins

• protein: complex molecule constructed from 20 kinds of amino acids
• amino acid: organic molecules that compose a protein
• Contribute to almost all day-to-day functions
  • i.e. form hair muscles
  • long-term nutrient storage
  • may defend against harmful microorganisms
  • facilitate inter-cell communication
• enzyme: protein that speed up specific chemical reactions without being consumed
• essential amino acids: 1 of 8 amino acids that our cells cannot make from other molecules

Fats

• fats / lipids: molecules formed from fatty acids and glycerol
• store energy in body and help body absorb fat-soluble vitamins
• provide body with insulation
• saturated fats: fats with single bonds between carbon atoms in fatty acids
  • has max. number of hydrogen atoms
  • high intake promotes buildup of fat deposits within blood vessel walls
• unsaturated fats: fats with at least one double bond in a fatty acid chain
  • found in
    • fruits
    • vegetables
    • nuts
    • seeds
    • fish
    • olive / sunflower seed oil
  • important part of healthy diet
• trans fat: partially hydrogenated unsaturated fat (processed to accept more hydrogen atoms)
  • solid at room temp.
  • longer shelf life than other unsaturated fats
  • often used in fast food
  • contribute to heart disease and bad health

Vitamins and Minerals

• vitamin: organic nutrient needed in small amounts to regulate body processes and perform chem. reactions
• organic nutrient: nutrient that contains carbon
• Types of Vitamins
  • water-soluble cannot be stored in body, continuous intake required
  • fat-soluble be stored in fatty tissue in small amounts
• mineral: inorganic nutrient that don’t contain carbon
  • important minerals: Ca, Fe, P, Cu, Na, Zn
• Found naturally in foods like
  • meat
  • eggs
  • dairy
  • whole-grain products
  • tofu
  • green leafy vegetables
  • some fruits

Water

• Required by every cell to complete its process
• Many of body’s chem. reactions happen in water
• dehydration: lack of enough water in body

What are calories?

• calorie: amount of energy required to raise temp. of 1 g water by 1 °C
• dietary calorie (C.): equal to 1,000 calories
  • calories often used to refer to C.
• Calories of nutrients
  • Fat: ~9 C. / g
  • Carbs and proteins: ~4 C. / g
  • More C-H bonds in fats than carbs / proteins
• Calories needed for basic maintenance + active lifestyle
  • 2,200 calories for female teens
  • 2,500 calories for male teens

Beneficial Foods

• nutraceutical: substance purified from foods and taken as medicine to give health benefits incl. disease prevention
• functional food: food that has health benefits incl. disease prevention beyond nutritional benfit
• probiotics: foods that contain substances that help promote growth of helpful intestinal bacteria

Fitness

• 2 classes: cardiovascular and muscular
• Cardiovascular fitness delivers greatest benefits
• Heart rate may indicate level of fitness
• Benefits
  • loss of excess weight
  • lower blood lipids
  • lower BP (blood pressure)
  • increased energy lvls.

Diets and Dietary Supplements

• Balance of food types must be maintained
• Vegetarians avoid meat and fish on moral or ethical grounds
• Vegans do not consume any animal products
• Diets must be specially planned to incorporate all dietary nutrients
• Vitamins and supplements may be required if diet is lacking in certain nutrients
• A balanced diet will usually not require the use of vitamins

Drugs and Other Toxins

• psychoactive drugs: drugs that affect central nervous sys. and interfere w/ normal functioning of brain
• LD50: lethal dose for 50% of test pop.

Nicotine

• Found in tobacco and its products
• Extremely toxic
  • ORL-RAT LD50 50 mg/kg
• Increases pulse rate and BP
• Interferes with vit. C absorption → impairs immune response
• Tobacco smoking may result in…
  • hardening of arteries
  • respiratory infections
  • emphysema
  • ulcers
  • cancer

Caffeine

• Found in many plants incl. coffee and tea
• Toxic
  • ORL-RAT LD50 192 mg/kg
• Acts as a diuretic (dilutes urine)
• Increases BP
• Constricts blood vessels

Alcohol

• Produced by yeast fermentation
• ORL-RAT LD50 7060mg/kg
• Excessive use problems:
  • physical
  • psychological
  • social problems

LSD

• LSD: D-lysergic acid diethylamide
• Illegal hallucinogen
• IVN-RAT LD50 16 mg/kg

Heroin

• Derived from opium poppy Papaver somniferum
• Highly addictive illegal narcotic
• Lethal dose varies among individuals
• Users have greater tolerance to the drug
• Injected intravenously
• Intense rush
• Users prone to…
  • liver disease
  • infections
  • collapsed veins
  • hepatitis and HIV infection

Ecstasy

• Both a stimulant and hallucinogen
• Illegal neurotoxin
• Increases body temp, and
• Blocks serotonin uptake
  • causing insomnia, and
  • insensitivity to pain

Anabolic Steroids

• Synthetic derivatives of the male hormone testosterone
• Builds muscle tissue in patients
• Used illegally by athletes to boost performance
• Side effects
  • liver damage
  • heart problems
  • high blood pressure
  • mood swings
  • female masculinization