Nutrition: Food Science, Macronutrients, and Dietary Guidelines

Nutrition

Science of foods and the nutrients they contain and of their actions in the body including social, economic, cultural and psychological implications of food and eating.

Taste

Biggest determinant of what we eat.

Carbohydrates

Organic, energy yielding, macronutrient, 4kcal/g.

Fats

Organic, energy yielding, macronutrient, 9kcal/g.

Proteins

Organic, energy yielding, macronutrient, 4kcal/g.

Vitamins

Organic, micronutrient.

Minerals

Inorganic, micronutrient.

Water

Inorganic.

Inorganic

Doesn't contain carbon.

Energy available from foods equation

#g x energy(kcal/g)= #energy (kcal/g) / total energy = %.

Epidemiological studies

Cross-sectional, case study, cohort studies.

Experimental studies

Lab-based animal studies, human intervention or clinical trials.

EAR

Estimated average requirement of half the healthy people of a given age and sex.

RDA

Recommended dietary allowances for practically all healthy people.

AI

Average daily amount of nutrient that appears sufficient to maintain a specific criteria.

UL

Max daily amount that appears safe for most healthy people, anything beyond it is an increased risk of adverse health effects.

CDRR

Nutrient intakes associated with a low risk of chronic disease.

Acceptable macronutrient distribution range (AMDR)

45-65% carb, 20-35% fat, 10-35% protein.

Health claims: Diet risk reduction

Established link between nutrient and reduction in risk of developing a diet related disease.

Health claims: Function

Well established benefits from consuming nutrient for normal biological function in the body.

Health claims: General

Provide dietary guidance through healthy eating.

Monosaccharides

Glucose, fructose, galactose.

Disaccharides

Maltose, sucrose, lactose.

Polysaccharides

Large chains of monosaccharides.

Glycogen

Storage of glucose in animals' skeletal muscle and liver.

Starch

Storage form of glucose in plants.

Fibre

Structural part of plants.

Insoluble fibre

Speeds up waste in digestive tract (brain, vegetables).

Soluble fibre

Lowers blood glucose and cholesterol (oats, barley, legumes, citrus).

RDA for fibre

130g is how much the brain uses.

Health Canada food labels recommendation for fibre

Females consume 25g and males consume 38g daily fibre.

longitudinal and circular stomach muscles

pushes food forward

diagonal stomach muscles

churns food over

longitudinal small intestine muscles

form outside of small intestine

circular small intestine muscles

form inside of small intestines

peristalsis

pushes food along intestine

segmentation

breaks chyme into smaller pieces

importance of segmentation

increases surface area for enzymes to break down nutrients

saliva

eases swallowing, breaks down some carbs

gastric juice

HCL uncoils proteins

pancreatic juice

bicarbonate neutralizes acidity, digests all nutrients

bile

emulsifies fat

liver

produces bile

gallbladder

stores bile

intestinal juice

digests all nutrients

pepsinogen

gastric enzyme

enteropeptidase

activates tripsin which activates trypsinogen

cholecystokinin

signals gallbladder to release bile

pancreatic lipase

breaks down emulsified fats

lipid breakdown

carboxyl and glycerol backbone bonds break

bile routes

recycled to small intestine or to large intestine

large intestine bile

for control of bacterial overgrowth or trapped by fibre and secreted

jujenum and ileum

absorb nutrients

duodenum

digests and secretes digestive enzymes

goblet cells

secrete mucous

micelles

emulsified fat droplets formed by bile, monoglycerides and long-chain fatty acids

chylomicrons

reformed triglycerides packed with lipoproteins

lipoproteins

transport vesicles

where are lipids released into bloodstream

left subclavian vein

high density lipoprotein

high protein

low density lipoprotein

low protein, more fat