The Carbohydrates: Sugars, Starches, and Fibre

Types of Carbohydrates

• Monosaccharides - Single sugars (glucose, fructose, galactose) 

• Disaccharides - Pair of monosaccharides (maltose, sucrose, lactose)

• Polysaccharides - Large chains of monosaccharides (glucose) 

Monosaccharides (examples)

• Glucose - Blood sugar, part of all disaccharides.

• Fructose - Fruits, honey. Sweetest of all sugars

• Galactose - Naturally present in all animal dairy products.

Polysaccharides (examples)

• Glycogen - A Storage form of glucose in the body. Highly branched chain. Reserved energy source.

• Starch - Storage form of glucose in plants. Long branched/unbranched chain.

Disaccharides (examples)

• Maltose (Glucose + Glucose)

• Lactose (Glucose + Galactose)

• Sucrose (Glucose + Fructose)

Condensing Reaction

Forms between hydroxyl group (OH) and H on another monosaccharide (broken by hydrolysis)

Lactose Enzyme

Required help Digest/absorb lactose and is immediately after birth.

Lactose Deficiency

Disease, some meds, prolonged diarrhea, malnutrition, genetics. 

lactose Intolerance (Dietary changes)

• Gradual increase in milk.

• Spread sources throughout the day

• Yogurt with live/active bacteria, fermented dairy products 

• Lactose-free products 

• Enzyme pills 

Glucose in Body

Glucose in body as glycogen

• The brain has a glycogen reserve 

• Liver (hydrolysis for release) 

• Muscles - Uses for only muscle uses. 

Making Glucose from Protein

• Poor use of protein/amino acid

• Gluconeogenesis 

Making Glucose From Fat

• Essentially Unable 

• Ketone bodies, ketosis. 

Diabetes

Blood glucose rise after meal, remains above normal (type 1 and 2)

Hypoglycemia

Blood glucose drops below normal range.

Added Sugars

• Enhance flavour

• Supple texture, colour to baked goods

• Provide food for yeast fermentation

• Acts as a bulking agent

• Balances the acidity of tomato/vinegar base products.

Recommended Intake of sugars

• Canadas Food Guide - Most sugar come from fruit, veg, milk/daiy

• Diabetes Canada - 10% total kcalories

• World Health Organization - Less then 10% kcal, 5% or less cause health benefits.

Alternative Sweeteners 

• Artificial sweeteners (nonnutritive sweeteners)(NO energy)

• Other high-intensity sweeteners (stevia leaves, monk fruits)

• Sugar alcohols (polyols) (naturally occurring fruits/veg)

Unable to take in enough energy/nutrients

• Feelings of fullness 

• Increase transit time 

Sudden increase can cause GI upset

• Increase fibre intake gradually 

• Drink plenty of fluids 

• Select fibre from a range of sources 

DRI for daily

Carb

• AMDR (45-65%)

• RDA (130g)

Daily Fibre

• Health Canada (food labels) - 28g

• DRI - AI 14g/1000kcal (NO UL)

• WHO - less then 25g