Unit 9: Nutrition

Nutrition Overview

Nutrition supports tissue growth, repair, function

Digestion: process of breaking down food into smaller and smaller pieces so we can eventually absorb the nutrients from itStarts in the mouth: enzymes/chewingContinues in stomach: hydrochloric acidFinishes in small intestine: enzymes

Digestion

Nutrition Overview

• Metabolism: the sum of all the chemical reactions in your body. – Building it up (anabolism) and breaking it down

(catabolism)– Main location = liver

• Nutrition: “the act or process of nourishing or being nourished”

• Diet: “food and drink regularly provided and consumed”

Main categories of nutrients

• Fats• Carbohydrates• Proteins• Vitamins• Minerals• Water

Provide energy

The most vital nutrient

Major Categories Nutrients• Carbohydrates: metabolized to simple sugars

like glucose, a ready source of energy that circulates the body– Provide 4 kcal/ g of energy– Ex. Pastas, breads, fruits and vegetables

Major Categories of Nutrients

• Fats: essential parts of cell membranes and some hormones. Provide insulation to warm body.– Provide 9 kcal/g of energy– Ex. Canola oil, butter, meat fat

Major Categories of Nutrients• Vitamins: organic compounds our body needs

to function normally that it must obtain from the diet because it can’t make them itself

Major Categories of Nutrients• minerals: a naturally occurring solid

compound found on the periodic table• They support Biochemical processes– Both vitamins and minerals provide 0 kcal/g

Water

• Most essential nutrient• Human body ≈ 60% water by weight

(depending on size)• Many body processes require it• Maintains blood pressure• Readily available from beverages and

fruits/vegetables

Proteins

• Mostly responsible for growth and repair of tissues.– Provide 4 kcal/g of energy. However, are only

really used for energy when everything else has been used up

Protein

• Made from amino acids• The body can make most amino acids except for

a few (9) which are essential amino acids (EAA). – We have to get them from our diet!

• Proteins from plant foods are “incomplete” meaning that they only contain some EAAs but not all– But two incomplete proteins together may make a

complete protein = complementing amino acids

Modern North American Diet

• Biggest problem = nutritional excess– Affluence? – Convenience foods? – Perceived shortage of time?

Modern Canadian diet

Modern North American DietGetting too much of everything and in the improper

proportionsToo much saturated fatHalf of carbohydrates from baked goods65% of B. Columbians not eating recommended

amounts of fruits and vegetables77% not eating recommended amounts of calcium.

However, we are concerned about our fat, starch, fibre intake and are taking steps to fix it (especially women)

6 Principles of a Healthful DietABCD-MV

• Adequacy- are you getting enough of what you need?• Balance- getting a good balance of all food groups• KiloCalorie control- are your energy consumption

patterns matching your expenditure ones• Nutrient Density- for the amount of kilocalories you are

taking in, are you getting a good amount of nutrients?• Moderation-not too little or too much of anything• Variety- a range of food items from each food groups

Nutrient Density

DIETARY GOALS FOR NORTH AMERICANS

Reduce total caloric intake• One Calorie (as we know it)= 1,000 calories = 1

kcal• The key is to eat selectively, portion control– Buy smaller plates– Think of restaurant meals as 2 meals– Consume nutrient dense foods– Control hunger by consuming filling foods such as

protein/fibre, eating smaller meals throughout day

• We consume, on average, 18% more calories a day than 30 years ago

Reduce total fat intake

• Fat is associated with higher calorie intake as well as increased serum cholesterol

• Associated with some forms of cancer: breast, colon

• Often it’s not the original source of food that is high in fat, but the manner in which it is prepared

• Cut fat off meat before cooking, choose low fat cheeses/spreads, dab extra fat off pizza, avoid friend foods, fill a spray bottle with oil to grease pans, BBQ, broil, bake

Reduce proportion of saturated fat and increase the proportion of unsaturated fat

Saturated fat = solid at room temperature ( ex. Bacon fat).Animal fats typically high in saturated fat, while plant fats are

typically low in saturated fatHowever, palm-oil/ coconut oil = high in saturated fat

Unsaturated fat typically found in plant oilsIs actually “good fat”Fish oil is one of the best kinds because it also has omega-

3 fatty acids and reduces the risk of CVD

Choose a diet low in cholesterol

• Found mainly in animal products• Eggs, liver, kidney, shellfish all high in

cholesterol• However, dietary cholesterol only raises

serum cholesterol if the person is sensitive to dietary cholesterol

• Recall: for most individuals to lower serum cholesterol, they need to consume a diet low in _______________

Increase Dietary Fibre

Fibre = is a carbohydrate that we are not able to break down in our body to use for energy

It is “filler”, passing through the digestive tract without being absorbed.

Add bulk to your diet, thus possibly reducing appetite

Increase Dietary Fibre

Soluble fibre:Lowers total and LDL cholesterolRegulates blood sugar

Ex. Fruits, legumes and oats (oat bran)

Insoluble fibre: draws water into the stool making it larger and softerSpeeds passage of food through the digestive tract

Ex. Cereals, grains (wheat bran), vegetables

Increase consumption of complex carbohydrates

• Complex carbs are found in grains, cereal, pasta and potatoes• Take longer to absorb than simple carbohydrates (ex. Glucose,

fructose)– Therefore regulate blood glucose levels, which is preventative

against __________________• Contain more dietary fibre, richer sources of vitamins and minerals• Look for “100% whole wheat”, “whole grain”, “whole oats”, “whole

rye” on labels. Just because something says “whole wheat” doesn’t mean it is a complete whole grain. Check you labels!

Use Salt and Sodium in Moderation• Table salt = sodium chloride• North Americans typically consume more than 3

times the RNI for sodium!• Sodium is added to a lot of products upon

processing• Sodium may increase blood pressure, which can

cause a __________ in an artery leading to _______________

• Salty foods are a risk factor for some digestive cancers– Irritates cells lining the stomach

Ensure adequate iron intake• Iron deficiency can lead to anaemia, which is a

lowered ability of the blood to transport oxygen• Leads to decreased energy levels

Ensure adequate iron intake

Two forms of iron:• Heme iron from animal products. Ex. Beef, liver, heart

– Easier to absorb

• Non-heme iron from plants. Ex. lentils, beans– Not as easy to absorb into digestive tract

• Absorption of non-heme iron is improved if eaten together with a heme-iron source

• Overall, Iron absorption improved by vitamin C, inhibited by coffee/tea

Ensure adequate Calcium intakeMany vital processes in your body require

calciumAlso a major component of bones/teethPrevents osteoporosis, which is especially

relevant to post-menopausal womenSmoking has the opposite effect of calcium!

Increase consumption of foods containing vitamins A and C

• Vitamins C / A (beta-carotene) are powerful antioxidants– An antioxidant prevents the action of oxidizing

agents in the body that damage cells and can lead to cancer (as well as aging poorly)

• Increase consumption of dark orange and dark green veggies

• Cabbage family veggies (arugula, bok choy...) are especially good anti-oxidants

Drink Alcohol in moderation

• Contains 7 kcal/g (more than carbs and proteins!)• One regular beer = 150 kcal• One glass white wine = 100 kcal• One shot of vodka = 60 kcal• “empty calories”• Alcohol should NEVER be consumed during

pregnancy!

Eat a variety of foods

• That way if some foods aren’t providing you with the nutrients you need, others will

• Eliminates boredom!

Vegetarian Diets

• Do not contain meat• Types of vegetarians:– Vegans: eat NO animal products of any kind; this

includes milk.– Lacto-ovo-vegetarians: don’t eat fish but eat milk

products and eggs– Lacto-ovo-pesco vegetarians: don’t eat red meats

but eat fish, milk, eggs• Not really vegetarians!

Health Benefits of a Vegetarian diet

• Prevents/ reverses coronary artery disease• Lowers serum cholesterol and LDL• Lowers incidence of hypertension• Lowers mortality from type 2 diabetes• Lowers incidence of lung/ colorectal cancer• May decrease breast cancer and kidney

damage

Other Benefits of Not Eating Animal Products

– Animal products tend to be expensive– Protein rich diets may be high in fat, low in fibre– Meat/ dairy more likely to contain pathogens– Animals concentrate heavy metals such as

mercury in large fish– Better use of land resources

Nutrient Deficiencies associated with the vegetarian diet

• Typically eat less protein, however, it is often enough

• Iron is harder to absorb from plant food• B-12• Calcium• Vitamin D

Reading Labels• As of Dec 2007, all manufacturers had to conform to new and

extremely strict labelling standards in Canada.• New labels contain:

- The common name of the food- A net quantity declaration- The name and address of the dealer - The durable life date of the product- A list of ingredients (in decreasing order by weight, volume, count- A nutrition facts table (next slide)

• They can also contain:– Nutrient content claims– ex. ‘low in fat’; ‘reduced sodium’ – Health claims– ex. “a diet low in saturated fat is associated with decrease

incidence of heart disease. Product X is low in saturated fat

Nutrition Facts Table

• All labels in Canada must contain the following information

• Nutrients expressed in %Daily Value for ease

• Check to make sure the serving size matches how much you are consuming!

NUTRITIONAL CONCERNS OF THE DEVELOPING WORLD

Water

• People need approximately1 litre water/ day to survive

• In the third world, 1/3 people have access to clean drinking water

• Estimated that 17-25 diseases relating to water could be reduced by 50-100% with ample clean drinking water

Energy and Protein

• Lack of calories and protein impairs growth– Small females have more difficulty carrying/having

children• Lack of calories and protein increases

susceptibility to disease– Our immune cells need energy/protein to

function!– Malnutrition often a contributing cause of illness• Ex. measles

Nutrient Deficiency: Kwashiorkor

• Another important function of protein is to maintain water balance

• Lack of protein leads to fluid accumulation in the abdomen

Obesity in the third world• As standard of living increases, so do obesity

rates• Egypt, Mexico have very high rates of

childhood obesity– Both have a stable and growing economy