KNES 337 - Unit 12 Sugars, Starches, and Fibers

enriched vs. whole grain

• On the ingredient label

  • “Enriched wheat flour” - by law means that vitamins were put back into white flour 

  • “Whole grain whole wheat flour including the germ” 

simple carbs

sugary, sweet, e.g. cereals, white bread, french fries, cookies, chocolates 

complex carbs

starchy, e.g. bread, yam, broccoli, bananas, oats

oligosaccharides

3-60 monosaccharides, short chains of monosaccharides joined by bonds that cannot be broken by human enzymes (fiber sources)

fructans and galacto-oligosaccharides

type of oligosaccharides, found in inulin, garlic, onions

also wheat, artichokes, beans

polysaccharides

• up to 1000s of monosaccharides, long chains joined by bonds, some are digestible (glycogen, starch) and some are not digestible (cellulose)

  • Found in potato, rice, pasta, bread, apple peel, seeds, nuts (very starchy foods)

polysaccharides found in

potato, rice, pasta, bread, apple peel, seeds, nuts

monosaccharides

most basic unit, e.g. glucose, fructose, galactose

• Most abundant and nutritionally relevant is glucose

• Only monosaccharides are absorbed into bloodstream

disaccharides

two monosaccharides joined by a covalent bond

sucrose

• cane sugar, beet sugar, most widely used natural sweetener

• = glucose + fructose

maltose

• formed from the partial breakdown of starch and is often used in malt beverages (e.g. beer), bacteria ferment the maltose and make alcohol as a byproduct

• = glucose + glucose

lactose

• milk sugar, one of the only animal sugars besides glucose

• = glucose + galactose 

simple sugars

refers to monosaccharides and/or disaccharides 

***Health Risk - rapidly absorbed into blood stream, increased insulin and inflammation

fiber

important because of what happens to it in the colon

the preferred fuel for gut microbiota 

colon

bacterial enzymes can break down fiber to form short chain fatty acids and gas as a byproduct

• Fiber is the preferred fuel for gut microbiota

• Short chain fatty acids - very important messenger 

• Gas - flatulence 

diet and gut microbiota

• High fiber, whole natural foods → microbiota symbiosis → healthy gut microbiota

• Processed foods, low fiber → microbiota dysbiosis → chronic disease 

processed vs. ultraprocessed foods

• If in a box, not necessarily highly processed 

  • E.g. catelli pasta - “whole grain durum what semolina” - great choice!

  • E.g. chocolate lucky charms - “whole grain corn” (sounds good), but also “sugar, modified corn starch, corn syrup, dextrose…artifical flavour…cocoa processed with alkali, colour added” - not great 

    • Significantly changed from its original state, with salt, sugar, fat, additives, preservatives, and/or artificial colours added

whole grain foods

in a grain of wheat, the outer bran layer is a rich source of dietary fiber

• Germ: contains protein, unsaturated fats, thamin, niacin, riboflavin, iron, and other nutrients

• Bran and germ are removed in the refining (i.e. making white flour)

• Endosperm primarily contains starch, the storage form of glucose in plants = white flour 

germ

• contains protein, unsaturated fats, thamin, niacin, riboflavin, iron, and other nutrients

• removed in refining

soluble fiber

food because it benefits health in several ways

• Slows down glucose absorption, lowering peak blood levels of glucose

• Reduces fat and cholesterol absorption

Found in oats, barley, psyllium, fruit pulp, peas, beans, citrus fruits, strawberries

psyllium

best place to get it is bran buds (Kellogg's All-Bran buds), reduces cholesterol absorption/lowers cholesterol (health claim)

oats

beta-glucan, oatmeal, oat flour

insoluble fiber

also benefits health in several ways

• Moves bulk through the gut, controls gut pH, removes toxic waste, prevents constipation

• Found in vegetables, wheat bran, whole grains, flax seed, popcorn, corn bran, seeds, nuts, apple peel 

how body manages glucose

1. Blood glucose rises when you eat

2. High blood glucose stimulates pancreas to release insulin

3. Insulin - stimulates uptake of glucose into cells and storage as glycogen in liver and muscle, also helps convert excess glucose into fat stores

4. As body cells use glucose, blood levels decline

5. Low blood glucose stimulates pancreas to release glucagon

6. Glucagon - stimulates liver cells to break down glycogen and release glucose into blood

7. Blood glucose begins to rise 

high blood glucose

stimulates pancreas to release insulin

insulin

stimulates uptake of glucose into cells and storage as glycogen in liver and muscle, also helps convert excess glucose into fat stores

low blood glucose

stimulates pancreas to release glucagon

glucagon

stimulates liver cells to break down glycogen and release glucose into blood

effects of nutrients on blood glucose over time

• Carbohydrate is most responsive and most exposure to glucose - short term

• Protein and fat - delayed response

• Fat affects blood glucose the least 

• Ketogenic diet is based on this - 70% of all calories coming from fat to reduce blood glucose and reduce insulin usage 

added sugars

• Major sources of simple sugars in most diets are added during processing of food

• Labels contain information on total sugars per serving but do not distinguish between naturally occurring and added sugars

• Added sugars add calories without adding nutrients 

• All sugars now required to be included together on the ingredient lists (can’t spread them all out)

• e.g. brown sugar, corn syrup, malt syrup, honey

• e.g. milk is 13% of daily value of sugar, chocolate milk is 26%

bad side of sugar

• Tooth decay

• Empty calories (calories without nutrients

• Often mixed with fats

  • Limit sweet and sticky foods, replace them with vegetables and fruits

  • Overall quality of diet decreases when sugar intake decreases

non-nutritive sweeteners

includes artificial and non-artificial zero-calorie sweeteners

• Zero-calorie or low-calorie sweeteners - either artificially synthesized or naturally derived 

• E.g. aspartame, sucralose, acesulfame K, saccharin, advantame, neotame, stevioside 

• Use a very small amount to get a very sweet taste, e.g. advantame - 20x sweeter than sucrose 

  • Reduce sugar content, but still get sweet taste 

• In pop, gum, yogurts, brownie mix, protein bars, protein powders 

  • In anything that says “zero sugar”

  • Aspartame is in 6000 products - even in toothpaste, antibiotics 

  • All approved, and in the marketplace, so not toxic - but not healthy either 

sugar intake recommendations

No more than 6 teaspoons (24 grams) for women

No more than 9 teaspoons (36 grams) for men 

• Less than 6 teaspoons per day for children - and sugary beverages should be limited to no more than 8 oz a week 

• BUT for 1 can of soft drink = 10 teaspoons of sugar - exceeds all daily amounts

aspartame

very common artificial sweetener, a dipeptide (2 amino acids = aspartic acid + phenylalanine)

• Digested by us - releases methanol, aspartic acid, and phenylalanine 

  • Methanol converted to formaldehyde and then formic acid (most concerning), not good for our body, rapid conversion (formaldehyde converted to formic acid right away)

• 200x sweeter than sucrose

• PKU (phenylketonuria) - products need to label “contains phenylalanine"

  • People with PKU unable to metabolize phenylalanine and will accumulate in their brain 

• Blue packets - Nutrasweet, Equal have aspartame, and many sodas

• Acceptable daily intake is 40 mg/kg BW

• Not compatible with high temperatures (> 30 degrees C)

  • Aspartame will start to degrade 

  • Never cook or bake with aspartame

sucralose

made from sugar, chlorinated sugar, 600x sweeter than sugar, safe when heated, used for baking, yellow packets - splenda

acesulfame K

often used in combination with other artificial sweeteners, stable at high temperature

saccharin

discovered in 1879 by accident by chemist working on coal tar derivatives (he licked it and it was intensely sweet), 300x sweeter than sucrose 

• Banned in Canada in 1977 due to bladder cancer fears (it caused it in rats), but then brought it back because it was discovered that the mechanism by which it caused cancer in rats is not present in humans 

sugar alternatives

do contribute calories, includes alcohol sugars, stevia

alcohol sugars

~2.6 kcal/g, e.g. xylitol, mannitol, sorbitol, erythritol

• Used in chewing gum and other candies and foods

• Can be used to mask the unpleasant aftertaste of some artificial sweeteners

• Are not well absorbed in the gut, large amounts can cause diarrhea

stevia

herbal alternative, GRAS-status

• initial studies with crude whole leaf extracts of stevia = reproductive, renal and cardiovascular toxicity, not initially approved

• Purified stevioside preparations show no toxic effects

  • In 2012, Health Canada approved its use in foods 

evidence in rodents

• One of the first studies to revisit artificial sweeteners 

  • So they don’t cause cancer, but are they affecting us in other ways?

  • Tested saccharin, sucralose, aspartame 

  • Control mice, and NAS (non-nutritive sweeteners) mice 

    • NAS had altered microbiota - increased glucose response (prediabetic state)

      • Used antibiotics to knock down microbiota - glucose tolerance back to normal - good but antibiotics have other bad effects

      • Also put altered microbiota into germ free mice - glucose intolerance increased as well

  • Looked at adult humans too - Some are responsive and some are non-responsive 

    • Responders - blood glucose elevated, altering microbiota, glucose intolerance increases

    • Non-responders - microbiota doesn’t change, normal glucose tolerance 

    • Not great conclusions

evidence in humans

• For 2 weeks, 120 healthy adults consumed saccharin, sucralose, aspartame, stevia packets - does lower than acceptable daily intake 

• Compared with controls receiving packets containing the vehicle (glucose) or no supplement 

• Fecal transplant into mice - people into mice → every sweetener increase blood glucose in the mice 

• None of these are good for us if we are responders 

• Bottom responders - most are good, but saccharin can still cause a bad glucose response 

• Worst of all of these is saccharin - bad for both top and bottom responders - microbiota being messed up 

erythritol

alcohol sugar, a zero-calorie sugar substitute found in Truvia, keto foods, might raise risk of stroke, death 

• Cleveland Clinic researcher found that erythritol was found in the blood of people who turned out to be at the highest risk for a bad cardiac outcome

• High erythritol blood levels seemed to lower the threshold for triggering a clot

  • Erythritol promotes blood clots

• Erythritol found in monk fruit sweeteners (white sugar replacement), not pure monk fruit extract, Splenda (ingredients: erythritol, stevia leaf extract)

  • Found in a protein bar by Dr. Reimer 

  • Now she’s handing them out 

maternal health with aspartame and stevia

• Mother rats consumed aspartame or stevia during pregnancy and lactation 

• Offspring had more fat mass

• FMT to germ free mice 

  • Higher body fat % after 14 days

  • Worse glucose intolerance 

• Maternal consumption detrimental for offspring 

  • Offspring didn’t have to consume it themselves to be obese 

WHO and non-sugar sweeteners

• WHO suggests non-sugar sweeteners not be used as a means of achieving weight control or reducing the risk of noncommunicable diseases (conditional recommendation)

  • Cut them out 

• Recommendation relevant for everyone 

• Not a homogenous class of compounds, each has a unique chemical structure

sugar and tooth decay

• Sugar is sole food for bacteria → produce acid → bacteria form sticky white plaque → acid produced by bacteria for 20 min after sugar is eaten

• Promoters of tooth decay: 

  • Increased frequency of sticky food

  • Acidic beverages - coffee, tea

  • Excessive cleaning/polishing of teeth - whitening

  • Nursing bottle syndrome - don’t send kids to sleep with milk or juice in bottle

protective foods

• Cheese - decreases acidity, increases pH of plaque

• Protein - with calcium, strengthens enamel

fluoride

• Remineralizes eroded enamel

• In water, toothpaste, dental rinses

fluorosis

• due to excess fluoride, mottled enamel during tooth development, too much fluoride, cosmetic condition that can only form in children < or = 8 years when permanent teeth are developing