Carbohydrates

three essential elements for life

• Energy to do work

• building materials to main form and function

• control agents to regulate processes

Carbohydrates as a basic fuel source

• Solar energy →photosynthesis→carbohydrates for human body

• used interchangeable with cal, kilocal and kcal

• energy from digestion and metabolism needed for voluntary and involuntary movements

How is energy produced from a fuel source

• change basic fuel to fefined fuel

• carry refined fuel to its needed place

• burn the refined fuel

why are carbohydrates important in the global diet?

• widely available

• low cost

• foods are easily stored

Carbohydrate composition

Carbon, hydrogen and oxygen

Monosaccharides

• smallest unit

• doesn’t require digestion (quickly absored in intestine →liver)

• either used for immediate energy or stored as glycogen

three simple sugars

glucose (corn syrup), Fructose (fruits, honey), Galactose (lactose)

Disaccharides

• double sugar unit

• the three diaccharides that are important for human nutrition
  →Sucrose (Glucose+Fructose) -table sugar

  →Lactose (Glucose +Galactose)-sugar in milk

  →Maltose (Glucose +Glucose)- found as imtermediate between startch and glucose

Polysaccharides

• Many sugar units

• types: Startch, Glycogen, Dietary Fiber

Starch

• Grains, legumes, other vegetables

• found as small amounts in fruits

• grinding helps to break it →better for digestion

• most important dietary carbohydrate

Whole grain vs refined grain

whole grain: retains outer layer, inner germ and endosperm (holds nutrients better)

Refined grains: some nutrients were removed during the process

Glycogen

• not a significant source

• carb formed in body tissues—>important for metabolism and energy balance

• quickly available source of energy stored in the liver and muscles

Dietary Fiber

• cellulose, lignin, noncellulose and polysaccharides

• humans lack enzymes to digest these carbs

• beneficial to prevent diseases like cardiovascular and gastrointestinal problems

cellulose

• component of cell walls in plants

• undigested in GI tract →add bulk

• stimulates muscle action and forms feces to eliminate waste products

• main source are the stems of leaves and covering of grains

Lignin

• main sources = stem and leaves of vegetables

• non-carb dietary fiber

• forms woody part of certain plants

• binds the cellulose fibers = strengthens plant walls

• combines with bile acids and cholesterol in intestine to prevent absorption

Non-Cellulose polysaccharide

• Hemicellulose, pectin, gums, mucilages, and algal

• absorb water and swell to empty mass from stomach

• provide fermentation on which colon bactera can work

Sugar Alcohols

• Nutritive sweeteners

• 2-3kcal/g (normal = 4kcal/g)

• absorbed slower than normal carbs

eamples of sugar alcohols

xylitol, sorbitol, and mannitol.

what lowers the risk of dental caries?

sugar alcohol -b/c oral bacteria cannot feed off of alcohol

what can cause osmotic diarrhea

too much sugar alcohol ( unabsorbed in the intestines)

Nonnutritive sweeteners

• little too no kcals

• acesulfame-k, aspartame, neotame, saccharin and sucralose

how do carbohydrates function as fuel supply reserves

glycogen is stored in the liver and maintaining bgl and ensures brain function

the following are the special functions of which tissue?

• glycogen in ____ provides a constant echange with the bodies overall energy balance

• protects cells from depressed metabolic function and injuries

Liver

the following are special functions of ____
carbs help to regulate both ___ and ___ metabolism

protein and fat

the following is the primary energy function of ____

• supplying energy to the brain av it does not have its own reserve of glucose and depends on the supply of glucose from the blood

central nervous system (CNS)

____ % of an adult total caloric intake should come from carbohydrate foods

45%-65%

how much grams of carbs are reccomended for an adults total caloric intake for 2000kcal/day

225-325g

sugar should be limited to no more than ____ of total calories consumed

25%

what are the dietary guidelines for Americans in regards to carb rich foods

• limit calories from added sugars

• limit consumption of refined grains (solid fats, added sugars and sodium)

• half of grains consumed should be whole grains - replace refined grains

• increase intake of dark green, red and organge veggies, fruits and beans and peas

• choose foods with more potassium, dietary fber, calcium and Vit D (e: veggies,fruits,wholegrains and milk products)