Foods and Nutrition 1021 Lecture Notes - Lecture 4: Lactose Intolerance, Dietary Fiber, Bran
11 Jun 2018
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Chapter 4 Part 1
Carbohydrates
The body’s first choice for energy needs
Used as glucose or stored as glycogen
Dietary Sources:
Grains (e.g. Breads/Cereals/Pasta/etc.), Beans/legumes
Milk and alternatives
Fruits
Starchy vegetables (e.g.Potatoes/Turnip/Corn/Carrots/etc)
Enemy is over consumption → can lead to adipose tissue
End point of carbs is Glucose!
Take carbs in morning and keep adding a bit on it during the day!
Simple Carbohydrates
Monosaccharides: glucose, galactose, fructose
Disaccharides: sucrose, lactose, maltose
Sugar Alcohols: sorbitol, mannitol
Glucose + Glucose= maltose
Glucose +galactose= Lactose
Glucose +Fructose= Sucrose(sugar)
Ose= sugar
Ol= alcohol
Monosaccharides
Glucose
Blood sugar (dextrose)
Essential CHO - main source of energy for brain & nerves
Excreted in the urine by diabetics
Fructose
Fruit sugar; sweeter than sugar
Galactose
Part of lactose (milk sugar); freed during digestion
Disaccharides
Sucrose (Fructose-glucose)
Table sugar (beet or cane)
Lactose (Galactose-glucose)
Sugar in milk → poorly digested → lactose intolerance?
Maltose (Glucose-glucose)
Malt sugar
In germinating seeds
Important in brewing
Complex Carbs
Prebiotics- food for probiotics
Probiotics- good bacteria!
find more resources at oneclass.com
find more resources at oneclass.com
Starch & fiber (3 or more polymers)
Oligosaccharides (3-9 polymers)
Malto-oligosaccharides: maltodextrins
Other oligo-saccharides: raffinose, stachyose, fructo-oligosaccharides
Polysaccharides (>9 polymers)
Starch: amylose, amylopectin, modifed starches
Non-starch polysaccharides: cellulose, hemicellulose, pectins,
hydrocolloids
Starch - Excellent source of glucose → Storage form of glucose in plants
Fiber - Indigestible parts of plant foods
Cellulose; Hemicellulose; pectin’s; gums; mucilage’s; nonpolysaccharide
lignin
Glycogen - Storage form of CHO in liver & muscles in humans & animals
Fiber
Polysaccharides; sugar units held by bonds indigestible by human enzymes
Whole grains, F&V, legumes
Supply valuable vitamins, minerals, phytochemicals, & fiber, with little or no fat
Two types:
Soluble (viscous) - Dissolve in water/viscous and form gummy gels.
- Add thickness to foods (e.g., pectin)
- Inside of apples, barley, carrots, legumes, oats, psyllium
- Help stool formation
- Have significant cholesterol-lowering effect
- Help regulate blood glucose following a CHO-rich meal
- In the colon, bacterial fermentation of soluble fibres produces small fatlike
molecules such as butyrate → soluble fibre can reduce the risk of colon cancer
- Butyrate provides energy to colon cells
- Butyrate helps the colon resist chemical injury that could lead to cancer
- Higher fibre leads to the replacement of cells in the colon lining
- cells are sloughed off before they can initiate the cancer process
Insoluble (non-viscous) - Less readily fermented
- Cellulose & hemicellulose in bran, tough, stringy, gritty
- Some legumes, wheat bran, skin on fruits and vegetables, and hull of seeds
- Helps to move our stool through the large intestine
Important to drink enough water for the fibre you eat (think of a sponge)
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find more resources at oneclass.com
Food sources
Health benefits of Fibre-
Lower blood cholesterol (2 ways)
◦ Reduced risk of heart disease
Vacuum like action: Foods rich in viscous (soluble) fibers bind with
cholesterol-containing bile in the intestine and then this is carried out in
feces
Prevention: Bacterial fermentation of fiber releases small fatty acid that
help reduce cholesterol synthesis in liver
Blood glucose control
◦ Reduced risk of diabetes
Glucose absorption slowed down when fiber traps nutrients & delays
transit to GIT
Prevents surges in blood glucose & insulin levels
Healthy weight management
◦ Foods rich in complex CHO – low in fats & added sugars
◦ Promote weight loss – less energy per intake; feeling of fullness, delay hunger
◦ Choose fresh fruit, vegetables, legumes, whole grain foods
Maintenance of GIT health
- Cellulose (in cereal bran, F&V) – enlarge & soften the stools to help prevent
constipation
- Hemorrhoids (swelling of rectal veins) – less likely to occur when stools are soft
& pass through easily
- Appendicitis – prevented with intestinal contents moving through & not
permitting bacterial growth
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The body"s first choice for energy needs. Used as glucose or stored as glycogen. Enemy is over consumption can lead to adipose tissue. Take carbs in morning and keep adding a bit on it during the day! Essential cho - main source of energy for brain & nerves. Part of lactose (milk sugar); freed during digestion. Starch & fiber (3 or more polymers) Starch - excellent source of glucose storage form of glucose in plants. Fiber - indigestible parts of plant foods. Glycogen - storage form of cho in liver & muscles in humans & animals. Polysaccharides; sugar units held by bonds indigestible by human enzymes. Supply valuable vitamins, minerals, phytochemicals, & fiber, with little or no fat. Inside of apples, barley, carrots, legumes, oats, psyllium. Soluble (viscous) - dissolve in water/viscous and form gummy gels. Help regulate blood glucose following a cho-rich meal.
