BPK 110

Diet

total food a person regularly eats

Essential nutrients

one that the body requires but cannot make itself

Macronutrients

(need in larger amounts)

• Carbohydrates

  • Sugars, starches, fibre

  • Organic

• Lipids (fats)

  • Triglycerides, fatty acids, sterols, phospholipids

  • Organic

• Protein

  • Made from amino acids

  • Organic

Micronutrients

 (need less amounts)

• Vitamins

  • Fat soluble and water soluble

  • Organic

• Minerals

  • Chemical elements

  • Inorganic

Non-nutrients

• Substances found in food that are not considered nutrients

• Ex. Phytochemicals, Caffeine, toxins

Phytochemicals

• Plant chemicals

• Hundreds of them

• May have positive effects

Examples of Phytochemicals

• Flavonoids: Give plants bright blue, red or dark pigmentation

  • Anti- inflammatory, anti-tumor, antioxidant effects

• Carotenoids: Give plants yellow, orange, red pigmentation

  • Antioxidant effects

Toxins

• Naturally found in plants and animals

• Can have harmful effects on body beyond a threshold

• Throw out old, mouldy, foul smelling

 

Processed Foods

 A lot of additives, ingredients, extra sugar/sodium and often has a lot of good nutrients taken out

• Cereal, Snacks, Frozen Foods, Bacon

Whole Foods

Basically foods in the its more natural form. Nothing added to it.

• Examples: Fish, Vegetables, Meat (untouched)

NOVA

Group 1  (Unprocessed or Minimally Processed Foods)

• Unprocessed Food

Group 2: Processed Culinary Ingredients

• Oil, butter, sugar, salt

Group 3: Processed Foods

• Canned food, cheese, bread

• Usually made of both group 1 and 2

Group 4: Ultra-processed Foods

• Made mostly from group 2 and 3

• Soda, chocolate bars, candy, frozen dinners, deli meat

Organic Foods

Organic foods are foods that have minimal synthetic or artificial inputs and are grown, raised and harvested in a way that preserves biodiversity.

• Ex. manure, compost and crop rotation

Genetically Modified Foods

foods that have undergone alterations to their DNA through the process of genetic engineering.

 

Using a Vector

1. DNA of organism of desired gene

2. Desired gene is removed

3. A vector is used for gene transfer

4. Gene is incorporated into vectors

5. As it grows, the target organism takes up the desired gene from vector

6. Target organism has new gene incorporated in its DNA

Why Do We Eat?

Body Structure

• Nutrients make the body structure capable of performing its many functions

Body Functions

• Nutrients contribute to physiology by being in various reactions and processes aimed at homeostasis

Energy provision

• Body needs energy to survive and perform tasks throughout the day

• Only Carbs, lipids and protein provide energy

Enjoyment

• Food taste good

• Food has cultural meanings

Psychological reasons

• Eat due to boredom, happy, depressed etc.

 

Diet and Health

Modifiable risk factors: Smoking, stress

Unmodifiable risk factors: Gender, age , genetics

Nutrition Epigenetics

• Food changes DNA expression

  • Agouti mice experiment

• Dutch Famine

  • Increased risk in diseases for offsprings

Choosing a healthy diet

• Balance: 80% healthy, 20% less healthy

• Variety: No single food can provide all nutrients

• Moderation: Don't eat too much or less of one thing like sugar or sodium

• Nutrient density: Some things are provide more nutrients per kcals. Ex. 100kcals of Milk compared to Coke

Study of Nutrition

Uses scientific method

1.  Define the problem

2. Take observations of the phenomena

3. Make a hypothesis

4. Develop study methods

5. Take detailed results

6. Analyze data

7. Draw conclusions

Experiments studies

• Uses RCT

Epidemiological Studies

• Uses already set population to find correlation

  • Like looking for a population who consumes a lot of fibre

• Systematic reviews are good

Two-eyed seeing

is the practice of equally using both a Western science lens as well as an Indigenous ways of knowing lens to help us understand things

Determining Nutritional Status

condition of the body with respect to nutrition

Diet Analysis

1. Record what you ate

2. Compare to recommendations

3. Determine if its enough or not.

Laboratory tests

• Uses blood samples for nutritional status

Ex. Blood lipid panel

dietary reference intakes (DRIs)

• Are set scientific determined values for nutrient requirements

• Vary from gender and stage of life

Estimated average requirement (EAR)

• The amount of nutrients that will meet the needs of 50% of the population

• Other 50% would be deficient

 Recommended dietary allowance (RDA)

• The amount of nutrients that will meet the needs of 97% of the population

• RDA is set at two standard deviations so around 30% is fine

Adequate intake (AI)

• Not enough evidence for EAR or RDA

• determined by observing how much of that nutrient healthy people eat. Since these individuals do not show signs of deficiency

Tolerable Upper Limit

The excess that shows signs of toxicity

Estimated energy requirement

• estimates the total amount of energy needed to maintain a person’s current size

Acceptable macronutrient distribution range

• gives recommendations for the percentage of energy to come from each of the three energy-yielding nutrients

• Carbs: 45-65%

• Lipids: 20-35%

• Protein: 10-35%

Canada Food Guide

50% of plate is vegetables and fruits

25% of plate is whole grains

25% of plate is proteins

Key Themes

• Variety: Plate has wide range of foods

• Accessibilities: foods that are relatively cheap

• Cultural relevance: Includes many different foods

• Availability: features options that are available during the year

Be mindful of eating habits

Cook more often

Enjoy your food

Eat with others

Use Food labels

First Nations Food Guide

• Make the community healthier by working together to change nutrition environment

• Increase use of traditional foods

• Decrease sugary drinks and eat more vegetables and fruits

• Serve healthier portions and increase gardens

American Food Guide

• Follow healthy diet, variety, nutrient dense

• Limit calories from sugar and saturated fats

• Support healthy eating

Brazil Food Guide

• Use whole foods

• Limit oils, fats and salt and sugar

• Limit and avoid processed foods

• Eat food in nice environments or with others

• Shop for food

• Develop cooking skills

• Plan mealtimes

• Dining out, focus on fresh dishes with whole ingredients

• Beware of food advertisement

Food labels (Canada)

Requirements

1. Common name of food

2. Net quantity

3. Name and address of producer

4. Best before date

5. Ingredient list

6. Nutrient fact box

Food Composition Claims (Canada)

• Pure or 100% pure: can only be put for uncontaminated products

• True, real: Must be real not substitutes

• Vegetarian Claim: must have vegetarian ingredients

• Highlight ingredient claims

• Minute or trace ingredients: Cannot emphasize presence if found in minute amounts

• Negative claims: no artificial sweeteners or preservatives

Nutrient content claims

• Things like low in fat, calories, high in fibre but cannot lie

 

Disease reduction claims

• Links a food or its ingredients lower risks of developing specific disease

Function claims

• Consuming a nutrient or diet with its role in the normal biological function of the body

Front-of-package Labels

• Box in the front stating if something is high in sodium or sugar

Food Safety

• Cook to safe temp

• Defrost safely

• Refrigerate fresh animal

• Keep cold food cold and vice versa

• Wash countertops

• Prepare raw meat with different tools and surfaces

Natural Health products

• Probiotics

• Supplements

Menu Labeling

• All restaurants with 20 or more chains must have calorie labels

• Ontario was the first to enact this

Informed Dining program

Informed Dining program

• Voluntary program for menu labeling

Digestion

Digestion separates the nutrients in food and breaks larger molecules into smaller ones

Mechanical Digestion

• Chewing of food and stomach churring

Chemical Digestion

• Uses enzymes to alter chemical structures of nutrients

Enzymes

• peeds up the rate of reaction

  • Ex. Hydrolysis(breaking down) and condensation(building things)

Hormones

• Just chemical messengers that are required for many physiological processes

• They communicate information about specific parts of the digestive tract to the brain and other digestive structures

 

The digestive tract

• Long tube like structure

• Sphincters often separate different parts of the tube

• Take 2 days for material to pass through the entire tract

  • Food spends most of its time in the large intestine

  • Age, activity levels, gender, medication use affects transit time

Layer of the Digestive Tract Wall

• Lumen

• Mucosa

• Submucosa

• Muscularis

• serosa

The Mouth

• Saliva contains two enzymes: Salivary amylase and lingual lipase

• Saliva contains a antibacterial component called lysozyme

• Chewed food and mixed is called the bolus

The Pharynx (Throat)

• it is part of the conduit from the mouth to the stomach

• the mechanism in place to ensure that food moves into the esophagus and not down the wrong tube into the respiratory tract. This process involves a flap of tissue called the epiglottis.

The Esophagus

• It is merely a conduit for food from the pharynx to the stomach

• peristalsis uses waves of muscle contractations on to move a bolus of food forward

The Stomach

• Temporary reservoir for food that can last for 4-5 hours

•  For chyme to enter the small intestine, the pyloric sphincter must open.

Gastric Juice

• Mucus: provides lubrication and chemical reactions

• Hydrochloric Acid: unravels proteins and activates enzyme pepsin

• Pepsinogen is a proenzyme that is secreted by certain stomach cells

• gastric lipase: continues the breakdown of lipids that lingual lipase began in the mouth.

The Small intestine

• the primary site of digestion and absorption

• Divided into three parts:

  • Duodenum: hooked tube

  • Jejunum

  • Ileum

• This fussiness is due to millions of villi (singular = villus) – invaginations of the small intestine membrane

The Large intestine

• 1.5 M in length

• Colon is the main part

• Any unabsorbed material is either

  • Packaged for removal

  • Acted upon by bacteria

Microbiota

• all the non-human cells is found in the large intestine

  • 300-500 different species

Microbiome

• the genetic material of the non-human organism found in our body

  • Roles in Health/Disease

The Pancreas

• Endocrine function: Releases hormones into the bloodstream.

  • Produces: Insulin → lowers blood glucose levels. Glucagon → raises blood glucose levels. Helps regulate blood sugar.

• Exocrine function : Releases digestive secretions into the small intestine.

  • These secretions are called pancreatic juice.

  • Pancreatic juice contains digestive enzymes:

    • Protease → breaks down proteins.

    • Lipase → breaks down fats (lipids).

    • Amylase → breaks down carbohydrates.

  • Pancreatic juice also contains bicarbonate:

    • Chyme leaving the stomach is very acidic.

    • Bicarbonate neutralizes the acid.

    • This creates a better environment for small intestine enzymes to function.

The Liver and Gallbladder

•  digestive role relates to the production of bile. Though made in the liver, bile is stored in the gallbladder for quick secretion when needed

• Bile is a lipid emulsifier

  • The salts within bile have a hydrophilic (water-loving; lipid-hating) head and a hydrophobic (water-havng; lipid-loving) tail

• Micelle: This allows bile to arrange itself so that lipids groups together in smaller mixtures within a ring of bile salts

• Emulsification: allows hydrophobic lipids to be suspended and transported easily within the watery environment of the small intestine lumen

Probiotic

 culture of living organism

• Found in Yogurt or Kombucha

• Cannot treat or cure disease

Prebiotic

Carbohydrates that act as food for microbiota

• Found in asparagus, garlic, banana

• Supports microbiome

Ulcer

• Weakened, damaged parts of the lining of the digestive tract

  • Ex. Canker Sores or Peptic Ulcers

Gastroesophageal Reflux Disease

• When lower esophageal sphincter weakens; acidic stomach contents spill into esophagus (heart burn)

• Can lead to gastroesophageal reflux disease (GERD)

Irritable Bowel Syndrome

• Includes abdominal pain, bloating, cramping, diarrhea, constipation, flatulence

Diverticula

• Weakened walls of the large intestine from outpouchings

• Can be inflamed = diverticulitis

• Can bleed = diverticulosis

• Age, obesity, smoking, physical inactivity increases risk

• Diet low in fibre and high in animal fat increases risk

Gallstones

• Hardened bile deposits that form stones in the gallbladder

• Diets high in sugars and saturated fat and energy increase risk

Digestive tract Cancers

• Colorectal cancer has both genetic and lifestyle risk factors

• Physical inactivity and obesity increase risk

• Diets high in red and processed meats increase risk. Vegetables, fruits and fibre reduce risk

Constipation

• Bowel movements that are difficult to pass

• Stools tend to be dry

• Increases risk for hemorrhoids

• Risk factors: age, female sex, genetics, physical inactivity, the use of certain medications

Diarrhea

• Occurs when matter pass through too quickly through the large intestine

• Typically due to bacterial and viral infections

  • Can be caused by food poisoning

Delivery of nutrients to the Liver

• Nutrients that enter the blood capillaries at the villi will then enter the veins that lead to the liver

  • All nutrients except large lipids and fat-soluble vitamins

• At the liver, material is stored, used, detoxified or sent off to the rest of the system

• The material that enters the cardiovascular system can then be transported to where it is needed

Dietary Toxins and Detoxification

• Liver, kidneys and lungs removes toxins from body

• Lack of evidence to support the use of detox diets

 

Energy Metabolism

1. Glycolysis

•  first step of cellular respiration

• six-carbon glucose is broken down into two molecules of three-carbon pyruvate

• Since bonds are broken in this process, energy is released and then captured in two molecules of ATP (does not require oxygen)

1. The breakdown of Pyruvate

• Anaerobic Metabolism of Pyruvate

  • Pyruvate is oxidized to lactate, producing a acidic environment in the blood that is not sustainable

  • Process is reversible

• Aerobic Metabolism of Pyruvate

  • Pyruvate forms acetyl CoA with additional of coenzyme A

1. The citric Acid Cycle

   •  series of chemical reactions that occur under aerobic conditions

   • acetyl CoA reacts with oxaloacetate to form citrate

   •  some energy is captured within GTP, an energy currency like ATP. The waste product carbon dioxide is also produced.

   • Electrons are lost and captured within electron transporters

2. Electron transport chain

• are proteins that are embedded in the mitochondrial membrane

•  ATP synthase promotes the bonding of the phosphate group onto ADP, regenerating ATP

Lipid Metabolism

• Triglycerides are the main dietary lipids

  • has three fatty acids attached to a glycerol backbone

• To metabolize triglycerides, the glycerol and fatty acids first need to be separated

Amino Acids Metabolism

• main role of amino acids in the body is to promote the growth and repair of tissues

• The first step in using amino acids for energy is the removal of this nitrogen group through deamination

• There are 21 amino acids in the human diet

• These remaining chains can either be used to form glucose, pyruvate or certain citric acid cycle intermediates

Water Overview

• Polar molecule (H20) Oxygen (Negative), H(Positive)

• Non polar molecules not attracted to water (Hydrophobic)

Water Content in the human body

• Human body is 60-70% water by weight that is found in 2/3 of cells

  • Intercellular water

• 1/3 found outside of cells like blood, spaces between cells

  • Extracellular

Movement of Water

• Osmosis is the movement of water towards charged particles

• Blood pressure involves a force that pushed water out of blood and into the extracellular space

Functions of Water

Structure

• Water helps structures maintain their form Ex. Eyes

Solvent

• Water is the most important biological solvent because of the variety of polar substances it can dissolve

• For instance, blood can transport oxygen, nutrients and other cellular needs to the tissues while also removing harmful waste products

Hydrolysis

•  use water to split larger molecules into smaller ones

• Ex. breakdown of the double-sugar maltose into two molecules of single-sugar glucose

Defense from infections

• Water provides an environment for immune cells to fight off infections (Within the lymph)

• Mucus helps trap and gather pathogens together for removal

Protection from injury

• Water in synovial fluid protects joints from scrapping

• Mucus found in lining body tissue can protect digestive tract and respiratory systems

• Cerebrospinal fluid protects brain from forces that might cause damage

Temperature Regulation

• Body uses water to regulate body temperature through two main mechanisms

  • When sweat evaporates, it cools down our body

  • Blood is shunted to the skin's surface to help promote sweating

Sources of water

• Liquid, vegetables  and metabolism

Maintain water balance

• Main priority of body is to maintain water homeostasis

• Two different mechanism

  • Thirst

  • Kidneys

Dehydration

• Darker color of urine means dehydrated

Water intoxication

• When waters levels decrease the concentration of dissolved particles

  • Ex. Hyponatremia

• Typically due to sweating and is only replaced by water

Diuretics

• Substances that promote water loss through urination

  • Ex. Diuretic pills (water pills) promote sodium excretion in the kidney

• Coffee and alcohol are also diuretics

  • They are psychoactive drugs (affects brain)

Caffeine

• Found in leaves, nuts and seeds

• Stimulant that promotes alertness

• May increase risk of miscarriage and kidney stones

Alcohol

• 7kcals/g

• Higher levels of consumption increases risk for cancer, liver, cirrhosis, confusion, dementia, malnutrition

• Moderate amounts may provide a slightly lower risk of CVD

• Factors that affect level of intoxication

  • How much is consumed

  • Speed of absorption

  • Size

  • Gender, genetics, type of alcohol

  • Menstruation cycle

Alcohol Metabolism

• 90% of alcohol is metabolized in the liver

Hangovers

• Typically 6+ hours after drinking

• Vomit, tired, decreased attention etc.

• May be due to direct effect of alcohol, acetaldehyde buildup or congeners

Indigenous Lens of Water

• Tied to our existence

• Part of who we are and has a life of its own

Whanganui River

• After 140 years of lobbying, this river has the same rights as humans

Decolonizing Water Project (Canada)

• Aim: creating a community-based water governance system led by Indigenous individual and rooted in Indigenous law

Types of Carbohydrates

• Sugars

  • Glucose (monosaccharide) (single sugar)

    • Fructose (Fruit)

    • Galactose (milk)

  • Sucrose (disaccharide) (glucose and fructose)

    • Maltose

    • lactose

• Starches

  • Amylose

  • amylopectin

• Fibres

  • Body cannot break down bonds

Sugar types in food

• Intrinsic sugars: naturally in whole foods (fruit, milk)

• Extrinsic (added) sugars: added during processing

• Added sugars are now grouped on Canadian labels

Refined vs whole grains

• Whole grains: contain bran, germ, endosperm → higher fibre + nutrients

• Refined grains: bran + germ removed → lower fibre, less nutrients

• Health advice: choose “whole grain” as first ingredient

Digestion and Absorption of Carbohydrates

Mouth: salivary amylase begin digestion of starch

Stomach: hydrochloric acid inactivates salivary amylase, no digestion here

Pancreatic amylase is secreted into the small intestine

Microvilli of the small intestine also secrete various carbohydrate digesting enzymes

Undigested carbs pass on to the large intestine and any remaining carbs is excreted

Lactose Intolerance

• Caused by insufficient secretion of the enzyme lactase

  • Lactose cannot be digest in small intestine, bacteria in the large intestine ferments it

  • Leads to production of methane gas

• Symptoms include cramps, bloating, diarrhea, abdominal pain

Glycemic Response and Glycemic Index

• Glycemic Response = spike in blood glucose that follows a meal once glucose enters the general circulation

• Glycemic Index: relative ranking of food's potential to spike blood sugar on a 100-point scale

  • Glycemic Load

Blood Sugar Regulation

• Body regulates Blood Sugar

  • Insulin and glucagon are blood-sugar regulating hormones secreted in the pancreas

• When blood sugar is not in balance, can have negative effects

  • Hypoglycemia (low blood sugar): affects Energy levels

  • Hyperglycemia (High blood sugar): if chronic can lead to diabetes

Endocrine vs Exocrine Pancreas

• Endocrine: Pancreas secretes insulin glucagon into blood

• Exocrine: Pancreas secretes pancreatic juice into digestive tract to facilitate digestion

Glucagon and Blood Glucose

• Glucagon increase blood glucose through 3 main ways

  • Glycogenolysis: The conversion of glycogen to glucose

  • Gluconeogenesis: The conversion of certain amino acids into glucose

  • Lipolysis: The breakdown of stored lipids. The glycerol from triglycerides can then be used to make glucose

Carbohydrate Functions

• Energy Provisions

  • Role is to provide energy

  • Cells metabolize glucose to capture energy as ATP

• Spare proteins

  • If body doesn't get enough carbs, gluconeogenesis happens

• Fat burns in a Carbohydrate Flame

  • Enough dietary carbs are needed to maintain the citric acid cycle

  • If diet is low on carbs, products of lipid metabolism cannot enter the citric acid cycle and will instead form ketones

Diabetes

Diabetes is a disease characterized by chronically elevated blood glucose levels, due to the body’s inability to regulate them