Lecture 33 Flashcards
Macronutrients
1
Q
carbohydrate
A
- 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
2
Q
galactosemia (inborn error of metabolism)
A
- 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
3
Q
lactose intolerance
A
- 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
4
Q
complex carbohydrates
A
- 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
5
Q
starch vs fiber
A
- 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
6
Q
fiber classification
A
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
7
Q
glucose homeostasis
A
glucose is primary carbohydrate in human metabolism; target range is 70 to 140 mg/dL
pg 792
8
Q
type 2 diabetes symptoms
A
- hypoglycemia: sweating, pallor, irritability, hunger, lack of coordination, sleepiness
- hyperglycemia: dry mouth, increased thirst, weakness, headache, blurred vision, frequent urination
pg 793
9
Q
carbohydrate quality
A
- 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
10
Q
carbohydrate counting for diabetes
A
- 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
11
Q
carbohydrate recommendations for health
A
- 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
12
Q
too much fiber
A
- 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
13
Q
roles of protein
A
- structural components, enzymes, transporters, fluid and electrolyte balance, acid-base balance, antibodies, hormones, energy and glucose, and others (blood clots, scars, vision)
pg 804
14
Q
essential, non-essential, and conditionally essential amino acids
A
- 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
15
Q
conditionally essential amino acids
A
- neonates: cysteine, proline
- PKU: tyrosine
- cirrhosis: cysteine, tyrosine
- trauma: arginine, glutamine
pg 806
16
Q
nitrogen balance
A
- 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
17
Q
protein intake recommendations
A
recommended value is 0.8 g per kilogram of body weight per day
pg 809
18
Q
protein quality
A
based on Digestible Indispensable Amino Acid Score (DIAAS)
pg 810
19
Q
best sources of protein
A
- 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
20
Q
complementary proteins
A
two or more proteins whose amino acids complement each other -> essential amino acids missing from one are supplied by another
pg 813
21
Q
protein-energy malnutrition (PEM)
A
- 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
22
Q
treatment for PEM
A
- 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
23
Q
protein excess
A
- 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
24
Q
protein supplements
A
- 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
25
Q
functions of fats
A
energy stores, muscle fuel, padding, insulation, cell membranes, raw materials, absorption
pg 820
26
Q
essential fatty acids
A
- 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
27
Q
essential fatty acid deficiency
A
- 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
28
Q
fat intake recommendations
A
replace saturated fats with polyunsaturated and monounsaturated fats; 10% or less of energy as saturated fats
pg 825
29
Q
sources of monounsaturated fats
A
- avocado
- oils (canola, olive, peanut, sesame)
- nuts (almonds, cashews, filberts, hazelnuts, macademia nuts, peanuts, pecans, pistachios)
- olives
- peanut butter
- seeds (sesame)
pg 826
30
Q
sources of omega-6 polyunsaturated fats
A
- margarine (NONhydrogenated)
- oils (corn, cottonseed, safflower, soybean)
- nuts (pine nuts, walnuts)
- mayo
- salad dressing
- seeds (pumpkin, sunflower)
pg 826
31
Q
sources of omega-3 polyunsaturated fats
A
- fatty fish (herring, mackerel, salmon, tuna)
- flaxseed, chia seed
- marine algae
- nuts (walnuts)
- oils (canola, flaxseed, soybean, walnut)
- yeast
pg 826
32
Q
sources of saturated trans fats
A
- 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
33
Q
sources of trans fats
A
mostly processed foods
- fried foods
- margarine
- nondairy creamers
- many fast foods
- shortening
- commercial baked goods
- many snack foods
pg 827
34
Q
medium chain tri(acyl)glyceride (MCT)
A
- 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
35
Q
very long chain acyl CoA dehydrogenase deficiency (VLCADD)
A
- 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
36
Q
orlistat (Xenical)
A
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
37
Q
blood lipids
A
- 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
38
Q
health effects of lipids
A
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
39
Q
health benefits from lipids
A
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
