Lecture 2 Flashcards
What are exchange systems and when would they be useful?
Foods are in “exchanges”
Portions/servings listed in “grains & starches,” “fruits,” “milk & alternatives” and “other” contain approx 15g of carbohydrate
¼ large bagel
1 medium apple
1 cup milk
½ cup chocolate milk
Can choose alternatives to diversify diet while also maintaining blood sugar.
Exchange systems can be useful for diet planning
For calorie control – ex. Weight Watchers
For controlling carbohydrate intake. Ex. Diabetes
What are the two ways nutrition facts tables present information?
Absolute quantities (such as grams)
Percentages of standards (% Daily Values)
What do daily values do, and what are the two types?
Give context to the actual amount of a nutrient
Recommended daily intakes for vitamins and minerals or reference standards for carbs, protein, fats, fibre, sodium
The Daily Values are of 2 types:
- Some suggest an intake goal to strive for, such as those for fibre, protein, vitamins & most minerals
- Others constitute healthy daily maximums, such as those for cholesterol, total fat, the sum of saturated fat & trans fat & sodium
What type of diet are calculations for daily value based on?
The calculations used to determine the “% Daily Value” figure for nutrient contributions from a serving of food are based on a 2,000-calorie diet
What is a lot and a little of a nutrient?
Allow one to see if a food contains a little (5% DV or less) or a lot (15% DV or more) of a nutrient.
What are the two types of nutrition claims?
Nutrient content claims and health claims
What is a nutrient content claim?
May highlight a nutrition feature of a food such as light, low, less, free.
Must meet criteria for specific claims defined by Canada’s Food and Drug Regulations (e.g., free, low, etc.)
What is a health claim?
Include two different types of claims: disease reduction claims and function claims (e.g., 7% of this nutrient helps with this)
Nutrient function claims are a subset of function claims
What is an example of nutrient content claims?
Excellent source of vitamin C; good source of potassium; source of folate (Tropicana Orange juice)
A very high source of fibre; low in fat; excellent source of iron, thiamin and folate; source of riboflavin and niacin (Catelli Healthy Harvest Rotini)
What are some examples of disease reduction claims?
Sodium and potassium, and the link to high blood pressure;
Calcium and vitamin D, and the link to osteoporosis
Vegetables and fruit reduce the risk of heart disease and some types of cancer
plant sterols help reducecholesterol
All highlight a relationship between the consumption of a food or ingredient and a person’s health.
What are function claims?
Describe the roles of a food or food constituent has on the normal functions or biological activities of the body.
What is an example of a function claim?
Consuming 7 grams of fibre from coarse wheat bran promotes regularity or consuming 3.5 grams of fibre from psyllium seed dailypromotes regularity
What is a nutrient function claim?
a subset of function claims and describe the well-established roles of energy or nutrients that are essential for the maintenance of good health or for normal development and growth
What is an example of a nutrient function claim?
Carbohydrate supplies energy, protein helps build and repair muscle or DHA, an omega-3 fatty acid, supports the normal physical development of the brain, eyes and nerves primarily in children under two years of age.
When did the nutrition facts table change?
Started in 2017 but the food industry had 5 years plus 1 year for COVID-19 (deadline: Dec 14, 2022)
What are some of the changes made to the food labels?
- Making serving sizes more consistent – easier comparison that is realistic for the amounts Canadians eat
- Revising the % daily value
- Adding a new % daily value for total sugar
- Adding potassium to the list of required nutrients - especially important for those w kidney disease
- Removing vitamin A and C (scurvy is not a concern)
- Adding mg for calcium, potassium and iron
- Adding a footnote at the bottom about % daily value
- Serving size and Calories stand out more
How are ingredients sorted on the ingredient list?
From most to least by weight
What changed for the ingredient list?
Grouping sugar-based ingredients in brackets after the name ‘sugars’
Listing food colours by their individual common names
What does “sugars” include?
White sugar, beet sugar, raw sugar or brown sugar
Agave syrup, honey, maple syrup, barley malt extract or fancy molasses
Fructose, glucose, glucose-fructose (also known as high fructose corn syrup), maltose, sucrose or dextrose
Fruit juice concentrates and puree concentrates that are added to replace sugars in foods
What foods are usually exempt from carrying a Nutrition Facts table *?
- Beverages with an alcohol content over 0.5%***
- Foods that contain very few nutrients, such as spices and vinegar
- Raw single ingredient meat, marine or freshwater animal product
- Foods sold only in the retail establishment where the product is prepared and processed from its ingredients
By Jan 1, 2026, a new front-of-package symbol will be required on foods high in at least one of what?
Sodium, sugars, saturated fat
Why will this front-of-package label be implemented?
- Frequent intake in foods high in sodium, sugars or sat fat linked to increased health risks such as: stroke, obesity, heart disease type 2 diabetes, high blood pressure, some cancers.
- Help shoppers make fast, informed choices
- Support health professionals in educating Canadians
What foods will be exempt from front-of-package labelling?
- Packaged individual portions that are only intended to be served by a restaurant or other commercial enterprise to accompany meals or snacks (for example, individually portioned crackers served with soup or creamers served with a cup of coffee)
- Milk and cream sold in refillable glass containers
foods in very small packages - Raw, single ingredient whole cuts of meat, poultry and fish that do not carry a nutrition facts table
- Foods with a protective effect on health, such as fruits and vegetables without added sodium, sugars, or saturated fat
- Certain dairy products, such as plain milk, plain yogurt and cheese because they are important sources of calcium that is needed to promote bone health and reduce the risk of osteoporosis
- Raw, single ingredient ground meats and poultry to avoid giving the impression that they are nutritionally inferior to whole cuts that do not carry a nutrition symbol
- Butter, sugar, salt and other products used for the same purpose as butter, sugar or salt, such as honey, celery salt, maple syrup, vegetable oils, seasoning salt
When did the change for Calories on menus of chains with 20+ locations in Ontario get made?
January 1, 2017
What did the Calorie change entail?
Amount per menu item
Statement about average Calorie requirement, however, individual calorie needs may vary
Some phytochemicals have significant effects on the body through actions such as?
Sensory properties
Acting as antioxidants
Mimicking hormones
Altering blood constituents in ways that may protect against some diseases.
What are some foods that are high in phytochemicals, that may promote health?
Whole foods
Wine
Tea
Chocolate
Soybeans
Flaxseed
Tomatoes
Garlic
What makes dark chocolate helpful, even though it can be rich in sugar and saturated fat?
Dark chocolate contains a flavonoid antioxidants that could potentially lower the risk of blood-clotting.
What is the recommendation for chocolate, then?
Obtain antioxidant phytochemicals with a focus on nutrient-packed, low-calorie fruits and vegetables, as well as calorie-free green or black tea and only on occasion, choose the chocolate.
Black tea - blocks iron absorption
What is helpful in tomatoes?
Eating five tomato-based meals weekly lowers risks of esophageal, prostate, and stomach cancers compared to avoiding tomatoes.
Lycopene, may inhibit cancer cell reproduction and protect against sun rays
Lycopene is found in tomatoes (especially cooked & products), papaya, watermelon, pink grapefruit
What is helpful about garlic?
Garlic has organosulfur compounds that may inhibit cancer in lab animals.
Ongoing research explores garlic’s potential benefits for allergies, heart disease, and ulcers caused by bacteria.
Studies on garlic supplements (powders and oils) have yielded disappointing results.
What are the basic chemical tastes?
Sweet
Sour
Bitter
Salty
Unami (the taste of MSG – meaty flavour, added)
What is the difference between flavour and taste?
Flavour is the total sensory impression when a food is eaten (aroma, texture, temperature, taste)
Why do people like sugar, fat, and salt?
Most people seem to like sweet, salty & fatty foods - sodium & chloride for salty, energy for fatty and sweet (brain).
People generally have aversions to bitter & sour tastes in isolation – turnip, coffee
The preference for sweet, salty and fatty tastes seems to be inborn and can lead to overconsumption of foods that offer them (now a marketing technique).
What is Ghrelin?
Basically the hunger hormone - tells your body to eat something & your taste buds guide you in judging whether foods are acceptable.
Enjoyment of sugars and fats encourage adequate energy intake (sometimes overconsumption) in what ways?
Sugars: provide energy for the brain
Fats: provide energy and essential ingredients – provide most energy/g
Enjoyment of salt: assures the consumption of sodium and chloride
Aversion to bitterness: discourages consumption of foods containing bitter toxins
The digestive system does what, overall?
Digests the food (break molecules of food into smaller molecules)
Absorbs the components (movement of nutrients into intestinal cells after digestion)
What is the digestive tract (overall)?
A flexible muscular tube extending from the mouth to the anus.
Swallowed food is not inside your body until you absorb it & some things pass through unabsorbed.
What is the mechanical aspect of digestion and where does it begin?
The mouth: chewing shreds food into small pieces to swallow. Saliva softens rough/sharp food and moistens/coats food, making it slippery. Chewing is also necessary for releasing nutrients trapped inside indigestible skins (flax seed & omega 3)
How does the mechanical aspect continue in the stomach & intestines?
Peristalsis (wave-like muscular squeezing) in the esophagus, stomach, and small intestine
Begins with the tongue’s movement, then the esophagus & pushes food along the digestive tract
What is at the base of the esophagus and why is it important?
Lower esophageal sphincter (LES or cardiac sphincter)
Prevents reflux of stomach contents into the esophagus
What happens in the stomach for mechanical digestion?
The stomach holds, mashes, and liquifies food.
Chyme (liquefied food where starches have been partly split, proteins have been uncoiled and clipped, and fat has been separated from the mass – both mechanical and chemical breakdown)
What happens to the chyme?
Released into the small intestine little by little when the pyloric valve (sphincter) opens. Squirted forcefully
Where does the vast majority of absorption occur?
Small intestine with the help of segmentation
What is segmentation?
Alternating forward and backward movement allows for greater contact between partially digested food and intestinal juices and enzymes
What happens in the large intestine/colon?
- Digestion & absorption are nearly finished once intestinal contents arrive in the colon
- The colon primarily reabsorbs water but also absorbs some minerals
- Fibre & undigested materials make up the feces
- The rectum stores fecal material that is later excreted
So what is primarily absorbed in the colon?
Water and some minerals
And what makes up the feces?
Fibre and undigested materials
How long does transit from mouth to rectum take?
1 to 3 days
How does chemical digestion take place in the mouth?
Enzymes in saliva
What is salivary amylase and what does it do?
An enzyme which breaks down starch
What is lingual lipase?
Lingual lipase begins the digestion of fat (very minor role but more important in infants who are being breast fed)
How does saliva help maintain the teeth?
Neutralizes acids produced by oral bacteria and washes away food particles that would promote tooth decay
Where does protein digestion begin?
Stomach
What does the stomach release?
Gastric juice (a mixture of water, enzymes, hydrochloric acid (HCl)
What is gastric juice used for?
The acid is needed to activate a protein-digesting enzyme (pepsin). Acid also begins the denaturation of proteins
How is the digestive tract protected from the acid?
Mucus
What is bile?
An emulsifier produced in the liver and stored in the gallbladder. Not an enzyme, an emulsifier.
What stimulates the gallbladder to release bile into the intestine?
Hormonal messengers – CCK (cholecystokinin), whose release is stimulated by fat or protein in the small intestine
What stimulates the pancreas to release pancreatic juice?
Hormonal messengers – secretin, which contains enzymes to digest carbs, protein, and fat
Bicarbonate neutralizes stomach acid
What cannot be digested by human enzymes?
Fibre. Some are digested by bacteria living in the digestive tract which results in short chain fatty acids that can be absorbed.
Once pancreatic & intestinal enzymes break down carbohydrates, proteins and fats, and pieces are small enough for nutrients to be absorbed, what remains in the digestive tract?
Only water, fibre, and some minerals.
What can be said about those who claim the body can’t handle a number of foods at the same time?
“Food-combining” diets underestimate the abilities of the GI tract.
Some foods are actually handled better in combination (e.g., vitamin C helps with iron absorption)
Why variety is important.
The digestive system adjusts to whatever mixture of foods is presented to it.
In the stomach, what happens to starch and proteins?
Starch digestion is stopped by the pH of the stomach
Acid denatures proteins, and enzymes then break them down
Nutrients are often not absorbed in the stomach, but some absorption of what occurs in the stomach?
Alcohol and drugs – why drinking on an empty stomach causes you to feel the effects earlier
What is a summary of what happens in the small intestine?
- Some sugars are absorbed soon after they enter the small intestine
- Bile emulsifies fat
Pancreatic enzymes break down starch, fat and protein (ex. pancreatic amylase, pancreatic lipase and proteases) - Cells of the small intestine also produce enzymes that complete chemical breakdown
- Small fragments are then absorbed into blood & lymph via the cells of the small intestine’s wall
- Vitamins & minerals are also absorbed
What is a summary of what happens in the large intestine (colon)
Fibre fragments, fluid, and some minerals are absorbed
Fibres are partly digested by bacteria in the colon
Most fibre is not absorbed and is excreted as feces
How many microbes are in a healthy digestive tract?
Up to 100 trillion
What are microbiota?
The mix of microbial species of a community for example those in the digestive tract.
What body systems might the intestinal bacteria affect?
Products of the bacteria may communicate with muscle, adipose tissue, the brain, immune system, etc.
What are prObiotics?
Consumable products containing live microorganisms in sufficient numbers to alter the bacterial colonies of the body in ways believed to benefit health (yogurt)
What are prEbiotics?
Substances that may bot be digestible by the host, such as fibre, but serves as food for probiotic bacteria and thus promotes their growth (or feeding good bacteria already in the body)
What is the small intestine lined with?
Projections called villi and microvilli (which extend from the villi)
They serve to increase the absorptive surface area
Provide an example of how absorption in the intestine is selective
When calcium is in short supply, calcium absorption increases (e.g., when a woman is pregnant)
How does absorption happen?
Nutrients pass through the cells of the villi
The blood and lympth then transport nutrients to the body’s cells
What do the blood vessels do with products that have passed through the cells of the villi?
Transport most of the products of carbohydrates and protein digestion, most vitamins and minerals to the liver
What do the lymphatic vessels do with products that have passed through the cells of the villi?
Transport most of the products of fat digestion (large components). These are later delivered to the bloodstream.
How does poor nutrition affect the digestive system?
- Absorptive surface of the small intestine atrophies (shrinks) with severe undernutrition
- Without adequate fibre (basically exercise), the digestive tract’s muscles become weak.
- Malnutrition (undernutrition) itself impairs digestion & thus becomes self-perpetuating – vicious cycle.
Describe belching, gas and hiccups
Hiccups are spasms of the vocal cords & the diaphragm which can be caused by irritation of the diaphragm, indigestion, etc.
Gas may be caused by air swallowed during eating, some vegetables, beans, and milk products (for those with a lactose intolerance)
Describe heartburn (GERD)
The reflux of acidic stomach contents into the esophagus
Acid burns the unprotected surface of the esophagus
Lying down after a meal can open the muscular sphincter allowing acid into the esophagus
Excess body fat can squeeze the stomach causing acid to back up.
What might help heartburn?
Limit/avoid problem foods
Eat smaller meals
Drink liquids an hour before or after eating, but not during meals
Wear reasonably loose clothing
Relax, but sit up, after eating
What can be said about antacids?
They provide only temporary relief by neutralizing stomach acidity.
Body responds by producing more acid to restore the normal acid conditions
Antacids can also interfere with ability to absorb nutrients
Acid reducers can cause indigestion and diarrhea
Acid reducers can mask the symptoms of an ulcer or GERD
Define gastroesophageal reflux disease
Severe & chronic exposure of the esophagus, throat, mouth, or airway to stomach acid & enzymes, causing inflammation & injury.
Untreated GERD may increase the risk of what?
Esophageal cancer
What is an ulcer?
An erosion of the layers of cells that form a lining
The bacterium that causes stomach ulcers may also have a role in stomach cancer
Treatment involves antibiotics
What is a hernia?
A protrusion of an organ or body part through the wall of the body chamber that normally contains the organ. Can cause food to back up into the esophagus
May require surgery
What is choking and how do you prevent it?
When food is lodged in the trachea and blocks the passage of air
Cut food into small pieces
Chew food until crushed and moistened with saliva
Don’t talk or laugh before swallowing
Never attempt to eat when you are breathing hard
Learn the Heimlich manoeuvre.
What is dysphagia?
Difficulty in swallowing
Sometimes seen in individuals with ALS, Parkinson’s disease, or following a stroke
What is constipation, its treatment, and cause?
Infrequent difficult bowel movements
Often caused by diet, inactivity, dehydration, or medication
Chronic constipation associated with risk of colon cancer
Treatment/prevention:
- Defecate when needed (harder as water is extracted)
- Consume sufficient fibre
- Drink fluids
- Be physically active
What is diarrhea?
Frequent watery bowel movements
Often caused by diet, stress, or irritation of the colon
Severe prolonged diarrhea causes dehydration & mineral imbalances
Important to drink plenty of fluids
What is IBS or irritable bowl syndrome?
Frequent bouts of diarrhea and constipation. An intermittent disturbance of bowel function. May be associated with diet, lack of physical activity, or psychological stress. Low FODMAP diet – proven to be successful in helping with discomfort
What should IBS not be confused with?
Inflammatory bowel disease (IBD – Chron’s and Colitis) – inflammation of varying degrees.
How is waste eliminated?
Some wastes are pulled out of the blood by the liver. The liver (does the detoxing) processes these wastes & either sends them to the digestive tract with bile, to leave the body with feces or prepares them to be sent to the kidneys for disposal in the urine
How are the kidneys waste and water removal specialists?
- They filter blood
- Waste becomes concentrated in the urine which travels through tubes to the bladder, which is periodically emptied.
What else do kidneys do (2)?
- The excretion or retention of sodium is a vital part of the body’s blood pressure-controlling mechanism
- Regulate fluid volume & concentrations of substances in the blood & extracellular fluids
What regulates kidney function?
Hormones
When I eat more than my body needs, what happens to the extra nutrients?
Excess energy-containing nutrients are stored in two forms:
- Glycogen (storage of some excess carbohydrate)
- Fat (storage of excess fat, protein and carbohydrate)
What happens with excess fat?
The liver ships out fat in packages to be picked up by cells that need it
Excess fat is stored in the cells of adipose tissue
Due to these storage systems, we don’t need to eat fat at every meal. How about carbohydrates?
The liver has less than one day’s supply of glycogen.
It can be effectively depleted within as few as three to six hours.
Gone within an hour of exercise, or a day with no exercise. Do need it more throughout the day, while fat is stored more.
Body stores also exist for many other nutrients. What are the two types?
Nutrients stored without limit, even if they reach toxic levels (vitamin D)
Other nutrients are stored in only small amounts & can readily be depleted (vitamin C)
Which of the following indicate the correct order food moves through the GI tract?
Stomach, small intestine, large intestine
Which of the following is a micronutrient?
A) minerals
B) vitamins
C) carbohydrates
D) a and b
E) a, b, and c
Note: water is a macro, but it is not energy yielding
D
Food label in Canada began changing Jan 1, 2017. Which is required on new food labels?
A) Manganese
B) Magnesium
C) Potassium
D) Phosphorus
E) a, b, and c
C
What are the three main parts of the small intestine, in order?
Duodenum, Jejunum, Ileum
