Term | Definition |
Disaccharides | Pairs of Monosaccharides
-Maltose, Sucrose, Lactose |
Maltose | 2 glucose units |
Sucrose | glucose & frutose |
Lactose | galactose & glucose |
Condensation | links two monosaccharides together |
hydrolisis | Breaks a disaccharide in two |
Polysaccharides | Generally composed of glucose units: glycogen & starch |
Glycogen | -Storage form of energy in body
-found mostly in liver & muscle |
Starch | -Storage form of energy in plants
-2 forms: amylopectin & amylose |
Small intestine | -mostly carbohydrate digestion
-pancreatic amylase
-specific disaccharide enzymes |
Specific disaccharide enzymes | maltase, sucrase, lactase |
Large intestine | soluble fibers fermented |
Carbohydrate metabolism | -glucose most critical for energy use
-Can store glucose as glycogen in liver & muscle
-Ketone bodies made
-use glucose to make fat: unlimited production & storage |
Liver Storage | -condensation into glycogen
-hydrolysis for release of glucose when needed |
muscle storage | -glycogen stored, but only used by that specific muscle |
Ketone bodies | -made from fat fragments
-occurs when not enough carbohydrates
-can be used for energy by most tissues |
Ketosis | -disturbs acid-base balance, since acidic when production exceeds use
-Carbohydrates needed for protein sparing & prevention of ketosis |
Consistency of Blood Glucose | -must have steady supply to blood stream
-blood glucose homeostasis
-glucagon & epinephrine
-balancing within normal range
-diabetes |
Blood Glucose Levels | Too Low: dizzy & weak
Too High: Fatigue |
Blood glucose homeostasis | Insulin: glucose from blood into cells |
Glucagon & epinephrine | brings glucose out from glycogen storage |
Balancing within normal range | balancing meals at regular intervals |
Diabetes | Type 1, Type 2, "Pre-Diabetes" |
Type 1 | no insulin |
Type 2 | -insulin not effective
-Fasting blood glucose > or = 126mg/100 ml |
"Pre-Diabetes" | Fasting Blood Glucose level 100-125mg/100 ml |
Health Effects of Starch & Fibers | -Diabetes:reduce glucose surges
-GI Health: reduce damage & ample fluids improve elimination
-Weight management: feeling of fullness
-Cancer |
Effects of Starch & Fiber on Cancer | -Dietary fiber & colon cancer have inverse relationship
-Source of dietary fiber:veg., fruit & whole grains & provides phytochemicals
-Preventing Colon cancer: Diluting, binding, and removing carcinogens + Bacterial fermentation: reduces inflammation |
Dietary fiber recommendation | -FDA: DV set at 25 grams/day
-USDA: DRI set at 25-35 grams/day
-No UL set, since generally no adverse effects of high levels upon healthy people |
Fatty Acids | -often named an omega number
-Omega number is the number of carbons starting at methyl end
-most common 18 carbons |
Omegas | -Omega 3: linolenic acid
-Omega 6: Linoleic acid
-Omega 9: Oleic acid |
Triglycerides | -glycerol backbone
-three fatty acids
-Formed via series of condensation reactions
-usually contain mixture of fatty acids |
Effect of degrees of unsaturation | Firmness & Stability |
Firmness | -Polyunsaturated fats: soft
-Saturated fats: hard
-Length of carbon chain: shorter is softer |
Stability | -oxidation and spoilage of fats
-More unsaturation, more risk of spoilage
-Can protect by reducing contact with light, air and heat |
Mostly Saturated Fatty Acids | -Animal fats & tropical oils: Coconut oil, butter, beef tallow, palm oil & lards |
Monosaturated Fatty Acids | -Some Veg. Oils: Olive Oil, Canola Oil, peanut oil, safflower oil |
Polysaturated Fatty Acids | -Many Veg. oils: Flaxseed, walnut, sunflower, corn, soybean, cotton seed |
Phospholipids | -solubility in fat & water
-Emulsifiers in food industry: used in mayonnaise and candy bars
-Lecithin: most common (see Fig. 5-9)
-Food sources: eggs, soybeans
-Bio role: part of cell membrane (Fig. 5-10) |
Sterols | -Food Source: Cholesterol in animal foods & Plant sterols like soybeans + added to food like margarine
-Body compounds made from cholesterol: e.g.; vitamin D
-Found in cell membranes |
Lipid Digestion | - Small intestine:
-Cholecystokinin (CCK):Gall bladder releases bile & Bile acts as emulsifier
-Pancreatic lipase
-Hydrolysis:Triglycerides and phospholipids
-Bile use can affect blood cholesterol levels |
Lipid transport | -Chylomicrons
-Very-low-density lipoproteins (VLDL)
-Low-density lipoproteins (LDL)
-High-density lipoproteins (HDL) |
Chylomicrons | -largest & least dense
-Diet derived lipids
-Liver removes remnants from blood |
Very-low-density lipoproteins (VLDL) | -made in liver
-lipids from diets & liver synthesis |
Low-density lipoproteins (LDL) | -mostly brings cholesterol to cells |
High-density lipoproteins (HDL) | -removes cholesterol from cells
-carry cholesterol to liver for recycling
-anti-inflammatory properties |
Role of Triglycerides | -provide cells with energy: 9 kcals per gram, virtually unlimited ability to store fat energy in body
-Adipose tissue: storage
-Skin insulation, shock absorption & cell membrane composition |
Essential Fatty Acids | -Omega 6: most veg. oils
-Omega 3: mostly fish, DHA, EPA, Eicosanoid(hormones)
-Fatty Acids deficiencies |
Recommended intake of fat | 1. DRI & Dietary guidelines
-Diet low in saturated and trans fat
-Diet low in cholesterol
-20 to 35 percent of daily energy from fat
2. Daily Values (DV) on food labels
-Fat (30%); Saturated and trans fat combined (10%) and cholesterol (300 mg) |
guidelines for groceries | 1. Fat replacers
-May be derived from fat, carbohydrate or protein, Ex: Olestra
2. Read Food Labels
-Total fat, saturated fat, trans fat, and cholesterol
-Compare products
-% Daily Value vs. % kcalories from fat |
Proteins | -more complex than carbohydrates or fats
-20 amino acids
-peptides bonds link amino acids |
20 amino acids | -different characteristics
-essential amino acids
-nonessential amino acids |
Protein Digestion | 1.Mouth: Crushed & moistened
2.Stomach
-Hydrochloric acid denatures proteins
-Pepsinogen to pepsin (due to HCl)
3.Small Intestine
-Hydrolysis reactions: pancreatic enzymes
-Peptidase enzymes: breakdown of small chains of aa’s |
Role of Proteins | 1. Growth & maintenance
2.Enzymes
3.Hormones
4.Energy
5. Transporters for lipids, vitamins, ect. |
Growth & maintenance | -Building blocks for most body structures ex: Collagen
-Replacement of dead or damaged cells |
Enzymes | -Break down, build up, and transform substances
-Catalyst for many reactions |
Hormones | -messenger for molecules
-transported in blood to target tissues |
Energy | -Starvation & insufficient carbohydrate intake may result in use of protein for energy |
Protein Metabolism | Excreting Urea:
-Liver releases urea into blood: kidney filters urea out of blood
-Protein intake & urea production: water consumption necessary |
Protein Quality | -Digestibility
-Amino Acid Consumption
-Reference protein
-High Quality proteins
-Complementary proteins |
Digestibility | -Animal proteins are high (90-99%)
-Plant proteins usually lower (70-90%) |
Amino Acid Consumption | -essential amino acid levels are critical
-generally composition compared to reference protein
-Limiting amino acids: lowest level of a particular essential amino acids compared to reference protein |
Reference proteins | -amount of essential amino acids needed by pre-school age children |
High-quality proteins | -Animal proteins
-Plant proteins: none except soybean, quinoa |
Complementary Proteins | -low quality proteins combined to provide adequate levels of essential amino acids |
Protein Energy Malnutrition (PEM) | -Marasmus
-Kwashiorkor |
Marasmus | -Chronic PEM
-Children 8-16 months: poverty & "little old people"
-Impaired growth, wasting of muscles, impaired brain development, lower body temperature
-digestion & absorption |
Kwashiorkor | -Acute PEM
-Children 18 months to 2 years
-Develops rapidly
-Edema, fatty liver, inflammation, infections, skin and hair changes
-Marasmus-Kwashiorkor mix: edema and wasting |
Health Effects of protein (High protein Diet) | -Heart Disease:animal protein intake may be cause
-Cancer:Protein rich diet not shown to be a problem but Red meat linked to colon cancer incidence
-Kidney Disease:Accl of kidney deterioration & High levels of urea disposal
-Osteoporosis
-Weight contr |
Osteoporosis | -Calcium excretion increases
-Ideal ratio has not been determined
-Animal protein intake suggested by some research to result in greater bone loss |
Recommended Intakes of Protein | 1. Needed Dietary protein
-Source of essential amino acids & Practical source of nitrogen
2. AMDR=10 to 35 percent of daily energy intake
3.RDA:Adults = 0.8 grams/kg of body weight/day
-Presumes adequate energy is consumed |
Protein Supplements | -muscle work builds muscles
-may be helpful if protein intake is low |
Amino Acid Supplements | -Potential risks associated with intake: May prevent the use of other amino acids
-Branched-chain aa’s not helpful |