Lecture 33

Question 1

carbohydrate

Answer 1

• hydrated carbon
• glucose is carbohydrate used by humans
• monosaccharides: glucose (blood sugar or dextrose), fructose (sweetest, occurs naturally in honey and fruits -> low glycemic index), galactose (usually in a disaccharide, approximately 40% of energy in infants -> given lactose)
• disaccharides: sucrose (table sugar, 50% glucose, 50% fructose), lactose (26 g/L in cow’s milk, 33.5 g/L in human milk)

pg 783-785

Question 2

galactosemia (inborn error of metabolism)

Answer 2

• can’t metabolize galactose
• galactose-1 phosphate uridyl transferase (GALT) deficiency -> classic galactosemia (most common and severe type, but still rare), duarte variant only reduces enzyme activity by ~75%
• deficiency of galactose kinase (GALK)
• or deficiency of galactose-6-phosphate epimerase (GALE) -> least common
• clinical presentation: refusal to eat, spitting up or vomiting, yellowing of skin, lethargy, cataracts (GALK, GALT)
• later in life (affects development): speech affected, math and reading difficulty, neurological impairments (gait, balance, fine motor tremors), early ovarian failure
• babies are given galactose free formula

pg 786-787

Question 3

lactose intolerance

Answer 3

• inability to digest individual amounts of lactose (a certain dose)
• shortage of the enzyme lactase, normally produced by the SI
• lactose is fermented by bacteria in the LI, producing CO₂ and short chain fatty acids
• nausea, cramps, bloating, gas, loose stools, gurgling sounds, diarrhea -> 30-120 minutes after eating -> severity varies
• each individual must find the dose they can tolerate

pg 788

Question 4

complex carbohydrates

Answer 4

• glycogen: in muscle, storage form of carbohydrates in the human body, highly branched chains of glucose, glycogenin protein
• starch: found in food; amylopectin (occasionally branched) and amylose (unbranched chains)

pg 789

Question 5

starch vs fiber

Answer 5

• starch α(1,4) glucose linkage -> body can break down these bonds
• fiber (cellulose) β(1,4) glucose linkage -> body canNOT break down these bonds

pg 790

Question 6

fiber classification

Answer 6

nutrient of public health concern
* soluble dietary fibers (soluble in water, fermentable): split into viscous and non-viscous
* insoluble dietary fibers (poorly or non-fermentable): non-viscous -> cellulose, lignin

pg 791

Question 7

glucose homeostasis

Answer 7

glucose is primary carbohydrate in human metabolism; target range is 70 to 140 mg/dL

pg 792

Question 8

type 2 diabetes symptoms

Answer 8

• hypoglycemia: sweating, pallor, irritability, hunger, lack of coordination, sleepiness
• hyperglycemia: dry mouth, increased thirst, weakness, headache, blurred vision, frequent urination

pg 793

Question 9

carbohydrate quality

Answer 9

• simple v. complex -> can be misleading because complex carbs can be digested rapidly and raise blood glucose (i.e. maltodextrin)
• high glycemic v. low glycemic index -> low glycemic does NOT mean a food is “healthy”; a product can be all fructose, which is low glycemic but may not be the best sugar to have at high levels
• can also be determined by the amount of processing, whole food being the highest quality and ultra processed food being the lowest quality

pg 794

Question 10

carbohydrate counting for diabetes

Answer 10

• one carbohydrate exchange is 15 g of carbohydrate, also called “1 carb choice”
• carbohydrate counting estimates the amount of carbohydrate ingested from a meal so it can be matched to the rapid insulin dose needed (in general, 1 unit of injected insulin needed to counteract 15 g of ingested carbs)
• carbs not consumed should not be counted; if insulin is given before meal, make sure to consume enough carbs to utilize it and avoid hypoglycemia

pg 795

Question 11

carbohydrate recommendations for health

Answer 11

• emphasis on whole grains, vegetables, legumes, and fruit
• limit refined grains
• helps reduce risks of obesity, cancer, cardiovascular disease, diabetes, dental caries, and GI disorders
• MAKE HALF YOUR GRAINS WHOLE GRAINS
• heart disease: diets rich in whole grains, legumes, and veggies may protect heart disease and stroke; soluble fibers (oat bran, barley, and legumes) lower blood cholesterol
• diabetes: some fibers delay passage of nutrients from stomach into small intestine; slows glucose absorption, increases satiety (from fiber)
• GI health: soluble and insoluble fibers; keep contents of intestinal tract moving easily, may protect against diverticular disease
• cancer: studies show increasing dietary fiber from foods protects against colon cancer
• weight management: fiber-rich foods tend to be low in fats and added sugars, yielding less energy per bite (promote feeling of fullness as they absorb water)

pg 797-800

Question 12

too much fiber

Answer 12

• may bind with minerals, resulting in losses with excretion
• individuals with marginal overall food intake may not meet energy or nutrient needs with high-fiber diets -> malnourished, elderly, young children on vegan diets especially vulnerable
• dehydration also a risk (fiber pulls water with it)

pg 801

Question 13

roles of protein

Answer 13

• structural components, enzymes, transporters, fluid and electrolyte balance, acid-base balance, antibodies, hormones, energy and glucose, and others (blood clots, scars, vision)

pg 804

Question 14

essential, non-essential, and conditionally essential amino acids

Answer 14

• essential: must be consumed in the diet
• nonessential: can be synthesized from other precursors (amino acids)
• conditional: cannot be synthesized due to illness or lack of necessary precursors -> premature infants lack sufficient enzymes needed to create arginine

pg 805

Question 15

conditionally essential amino acids

Answer 15

• neonates: cysteine, proline
• PKU: tyrosine
• cirrhosis: cysteine, tyrosine
• trauma: arginine, glutamine

pg 806

Question 16

nitrogen balance

Answer 16

• negatively affected by stress (trauma, ICU, disease), decreased intake (malnutrition, cancer, disease), or lack of an essential amino acid (very poor protein quality -> taking AA from muscles)

pg 807-808

Question 17

protein intake recommendations

Answer 17

recommended value is 0.8 g per kilogram of body weight per day

pg 809

Question 18

protein quality

Answer 18

based on Digestible Indispensable Amino Acid Score (DIAAS)

pg 810

Question 19

best sources of protein

Answer 19

• all meats -> generally 3 oz serving of cooked meat -> provides 21-25 g of protein (~7 g/oz)
• dairy
• mushrooms, dried beans, peanut butter, nuts, and soy

pg 812

Question 20

complementary proteins

Answer 20

two or more proteins whose amino acids complement each other -> essential amino acids missing from one are supplied by another

pg 813

Question 21

protein-energy malnutrition (PEM)

Answer 21

• marasmus: extreme loss of muscle and fat (wasting)
• kwashiorkor: edema (swollen belly) and enlarged fatty liver
• marasmic kwashiorkor: edema and wasting
• protein energy wasting (PEW) -> used in chronic kidney disease
• nutrition intervention must be cautious, slowly increasing protein

pg 814-815

Question 22

treatment for PEM

Answer 22

• medical and nutritional treatment can dramatically reduce mortality rate
• should be carefully and slowly implemented
• step 1: address life-threatening factors (severe dehydration, fluid and nutrient imbalances, medication for disease)
• step 2: restore depleted tissue (gradually provide nutritionally dense foods (liquid/puree) with high-quality protein and high in kcal)
• step 3: transition to solid foods and introduce physical activity

pg 816

Question 23

protein excess

Answer 23

• high protein intake associated with increased calcium excretion
• risk of kidney stones
• high intake of animal protein associated with an increased risk of heart disease
• risk of colon cancer
• high protein intake increases the work of kidneys

pg 817

Question 24

protein supplements

Answer 24

• not needed in healthy, well-nourished people
• may not improve athletic performance
• weight loss
• may benefit from consistently consuming protein-rich foods (protein satisfies the appetite)
• extra protein from supplements unlikely to dampen appetite further

pg 818

Question 25

functions of fats

Answer 25

energy stores, muscle fuel, padding, insulation, cell membranes, raw materials, absorption

pg 820

Question 26

essential fatty acids

Answer 26

• linoleic acid and the omega-6 (n-6) family -> can make arachidonic acid (AA) which is a conditionally essential FA
• α-linolenic acid and the omega-3 (n-3) family -> can make EPA and DHA, important for eyes, brain and heart; diets may be low in n-3
• supplied by vegetable oils, fish, and algae
• those with heart disease should consume 1 g of ω-3 FAs per day (combination of EPA and DHA)
• signaling: eicosanoids from arachidonic a. and EPA -> hormone like effects
• ω-6 MORE inflammatory than ω-3 (evens are inflammatory, odds are non-inflammatory)

pg 821-822

Question 27

essential fatty acid deficiency

Answer 27

• rare in U.S.
• infants and children with extreme fat-free or low-fat diets
• malabsorption
• insufficient parenteral nutrition
• need fat to absorb fat soluble nutrients
• biochemical signs appear before clinical symptoms
• clinical symptoms: dry, scaly rash, hair loss, hair depigmentation, poor wound healing, growth restriction in children

pg 823

Question 28

fat intake recommendations

Answer 28

replace saturated fats with polyunsaturated and monounsaturated fats; 10% or less of energy as saturated fats

pg 825

Question 29

sources of monounsaturated fats

Answer 29

• avocado
• oils (canola, olive, peanut, sesame)
• nuts (almonds, cashews, filberts, hazelnuts, macademia nuts, peanuts, pecans, pistachios)
• olives
• peanut butter
• seeds (sesame)

pg 826

Question 30

sources of omega-6 polyunsaturated fats

Answer 30

• margarine (NONhydrogenated)
• oils (corn, cottonseed, safflower, soybean)
• nuts (pine nuts, walnuts)
• mayo
• salad dressing
• seeds (pumpkin, sunflower)

pg 826

Question 31

sources of omega-3 polyunsaturated fats

Answer 31

• fatty fish (herring, mackerel, salmon, tuna)
• flaxseed, chia seed
• marine algae
• nuts (walnuts)
• oils (canola, flaxseed, soybean, walnut)
• yeast

pg 826

Question 32

sources of saturated trans fats

Answer 32

• bacon, butter, lard
• cheese, whole milk products
• chocolate, coconut
• cream, half-and-half, cream cheese, sour cream
• meats
• oil (coconut, palm, palm kernel)
• shortening

pg 827

Question 33

sources of trans fats

Answer 33

mostly processed foods

• fried foods
• margarine
• nondairy creamers
• many fast foods
• shortening
• commercial baked goods
• many snack foods

pg 827

Question 34

medium chain tri(acyl)glyceride (MCT)

Answer 34

• saturated fat
• impaired or damaged lipid (fat) metabolism: obstructive jaundice, biliary cirrhosis, pancreatitis, cystic fibrosis, celiac disease, Whipple’s disease, Crohn’s disease, very long chain acyl CoA dehydrogenase deficiency, Fabry disease, regional eneteritis, intestinal lymphangiectasia, and neonates
• MCT in infant formulat may not be necessary -> CT (C:10 and C:12) in breast milk approx 4 g/100 mL
• parenteral formulas, tube feeds -> ICU, severe injuries, burns, and infections (structured lipids in medical foods)
• in sports drinks and wellness products

pg 828-829

Question 35

very long chain acyl CoA dehydrogenase deficiency (VLCADD)

Answer 35

• cardiomyopathic: neonatal or early infancy; cardiomyopathy, pericardial effusion, hepatic dysfunction, mildly elevated serum ammonia, lactate and creatine kinase levels; severe, usually fatal without treatment; NO residual VLCAD enzyme activity
• hepatic: late infancy or childhood; recurrent hypoketotic, hypoglycemia, hepatic dysfunction; intermediate severity, may be life threatening if not diagnosed and treated; NO residual VLCAD enzyme activity
• myopathic: adolescence to adulthood; isolated skeletal muscle involvement, myalgia and rhabdomyolysis triggered by exercise or fasting; mild severity; two missense mutations or single AA deletions with residual enzyme acivity
• to treat: diet high in MCT (90%), carnitine 100 mg/kg/d, avoid fasting and excess strenuous exercise

pg 830-831

Question 36

orlistat (Xenical)

Answer 36

promoted for treatment of obesity; works by inhibiting pancreatic lipase and reducing digestion/absorption of fat in the small intestine; lower energy intake -> weight loss; leads to immediate diarrhea

pg 832

Question 37

blood lipids

Answer 37

• desirable levels: total cholesterol (< 200 mg/dL), LDL (< 100 mg/dL), HDL (> 60 mg/dL), triglycerides (< 150 mg/dL)
• factors to lower LDL and raise HDL: weight loss, replace SFA with MUFA and PUFA, soluble fiber, phytochemicals, physical activity (even without weight loss)

pg 833

Question 38

health effects of lipids

Answer 38

trans fats

• increase LDL and decrease HDL
• food sources include deep-fried foods using vegetable shortening, cakes, cookies, doughnuts, pastry, crackers, snack chips, margarine, and imitation cheese
• butter versus margarine

cholesterol

• dietary cholesterol has less effect on blood cholesterol than saturated fats and trans fat
• food sources of cholesterol include egg yolks, milk products, meat, poultry and shellfish

Conjugated linoleic acid (CLA) is naturally occurring trans fat that may be beneficial to health (found in milk)

pg 834

Question 39

health benefits from lipids

Answer 39

MUFA and PUFA (replace SFA to decrease cholesterol)

• dietary strategy to help prevent heart disease
• food sources of monounsaturated fat include olive, canola, and peanut oil, and avocados
• food sources of polyunsaturated fat include vegetable oils (safflower, sesame, soy, corn and sunflower), nuts, and seeds

Omega-3 (n-3)

• reducing risk of heart disease and stroke
• food sources include vegetable oils (canola, soybean, and flaxseed), walnuts and flaxseeds, fatty fish (mackerel, salmon, and sardines)
• mercury levels in fish and supplements
• low omega-6 to omega-3 ratio REDUCES inflammation

pg 835