Macronutrients (Carbs, Fats, Proteins) Flashcards
proteins, carbohydrates, and fats are what type of nutrient?
macronutrient
dietary substances that are consumed in smaller amounts than macronutrients, but still essential for various needs of the body
micronutrient
- Vitamins and vitamin-like substances
- Minerals
- Essential amino acids
- Essential fatty acids
Typically (not always) not made by the body in sufficient amounts and therefore must be ingested to some degree
Energy density for proteins, carbs, and fats
carbs = 4 calories(kcal)/gram
Proteins = 4 calories(kcal)/gram
Fats = 9 calories(kcal)/gram
organic compounds consisting of carbon and water in a 1:1 ratio
Primary source of readily usable energy
Does not contain any essential components
carbohydrates
- Major staple of plant matter
– Make up 40-70% of calories in most diets
carbohydrates
6 major functions of carbohydrates
- Fuel for metabolic processes
- Especially CNS, RBCs, renal medulla - Prevent protein from being used for energy
- Enable fat metabolism/oxidation
- Taste/dietary variety
- More than other macros - Healthy gut
- Food for intestinal microflora
- Aid in nutrient absorption - Help form important cellular structures
monosaccharides and disaccharides
May be naturally occurring or added to food products
simple carbohydrates
fruits, veggies, dairy, honey, maple syrup are examples of what type of carbohydrate
Naturally occurring simple carb
table sugar, beverages, cereals/grains, HFCS
are examples of what type of carbohydrate
Additive simple carb
polysaccharides, like starches, cellulose, glycogen, gums, pectins, are examples of?
complex carbs
2 main starches in human diet
amylose and amylopectin
glucose storage in animals
Glycogen
“resistant” starch that is not absorbed/digested
fiber
2 types of fiber
- Soluble - dissolves in water to form gel-like material
- Oats, peas, beans, apples, citrus, carrots - Insoluble - stays intact; increases stool bulk
- Whole-wheat flour, bran, nuts, beans, potatoes, veggies
carbohydrates must be broken down in the ____. Can only be absorbed as ___
GI tract
monosaccharides
what begins the process of carbohydrate digestion?
amylase
Speed of breakdown depends on overall composition of food
____ → rapid breakdown → spike in blood sugar levels
simple carbs
____ → slower breakdown → more gradual rise/fall in blood sugar
complex carbs
____ → do not have clinical impact on blood sugar/energy
insoluble carbs
describe the digestion/storage of sugar
- Monosaccharides are absorbed by the small intestine
- Enter circulation and travel to liver - Liver changes sugars into glucose
- If glucose not immediately needed for energy → stored as glycogen
- Once glycogen stores are full → carbs are stored as fat (TG)
what are 2 examples of foods that are exceptions of how carbs are broken down?
fiber and protein
can impact digestion
evaluates the 2-hr postprandial curve for blood glucose values relative to a reference standard (usually glucose or white bread)
Glycemic Index (GI)
similar to glycemic index - calculates 2 hr postprandial change taking into account a standard serving size of that food
Glycemic Load (GL)
Incorporating a low GI/GL diet has been shown to have positive health effects, especially in ?
Especially in chronic disease patients - HTN, DM, cancer, CV disease, obesity
what is the recommended intake for carbs
Recommended 45-65% of overall caloric intake
what makes a “good” carb vs “bad” carb?
Good:
1. High…
- nutrients
- fiber
2. Low…
- GI/GL
- calories
- sodium
- saturated fat
- refined sugars and grains
Bad:
1. Low…
- relative nutritional content
- dietary fiber
High…
- GI/GL
- calories
- refined sugar content
- Corn syrup, white sugar, honey, juices
- refined grains
- White flour, rice, pasta
- sodium
- saturated fats
Clinical pearls of carbohydrates for pt education
- Less processed = more healthy (in general)
- “White” foods are not your friend!
- Fiber is your friend! - Avoid eating carbohydrates without protein or fat
- The type of carb is more important than the amount
- GI/GL, if your patient can understand, can be helpful
- Moderation is a big key - Avoid sugary beverages!
Provide energy and important component of many body structures, molecules
Include essential fatty acids
water-insoluble compounds, a type of lipid
dietary fats
dietary fats can come from ?
both plant and animal products
what has the lowest satiety index of any macronutrient
dietary fats
- Calorie-for-calorie, less filling
- Higher calorie/gram ratio than other macros
7 major functions of dietary fats
- Energy reserve*
- Stored fat (adipose tissue)
- A lean adult can store about 120,000 kcal in adipose
stores vs 2,000 kcal in glycogen stores - Absorb necessary fat-soluble vitamins from diet
- Provide essential fatty acids
Linoleic and alpha-linoleic acid - Component of body structures and molecules
- Cell membranes, neural tissue, hormones - Insulate the body
- Cushion and protect viscera
- Contribute to flavor and palatability of food
type of fat that contain the maximum number of carbon-hydrogen bonds
saturated
type of fat that have at least one double-bond between carbon molecules
unsaturated
2 types of unsaturated fat
- Monounsaturated fats (MUFAs) - one double-bond per molecule
- Olive, canola, peanut, avocado - Polyunsaturated fats (PUFAs) - multiple double-bonds per molecule
- Omega-3 and Omega-6 fatty acids
- Walnut, sunflower, flax, soybean, fatty fish
differences between saturated vs unsaturated fats
- saturated
- More likely to be solid at room temperature
- Often from animal sources, but can be from plants
(Coconut oil, palm oil, Animal meats, Dairy products, Processed meats, Pre-packaged snacks)
- Generally less healthy - Ideally about 5% of caloric intake - unsaturated
- More likely to be liquid at room temperature
- Often from plant sources
- Generally more healthy overall
type of unsaturated fats with an altered double bond
often produced as part of industrial food processing
More stable, less likely to spoil, inexpensive
Can withstand repeated heating without breaking down
trans fat
heating liquid vegetable oils in presence of H gas
Converts oils into solid - margarine, shortening
Hydrogenation
which fat is most associated negative health outcomes and commonly found in many processed foods
trans fat
fats must be broken down in the __
GI tract
Dietary triglycerides are broken into ___
smaller molecules (fatty acids)
enzyme made by serous glands on tongue, gastric chief cells, pancreas that begins the breakdown of fats
lipase
____ are added in the duodenum and help break down fatty acids, and prevent them from re-aggregating into larger molecules
bile salts
Short and medium chain fatty acids are absorbed in ____
upper small bowel
Longer-chain fatty acids and cholesterol are converted back to TG and transported in the lymph system in the form of ___
chylomicrons
Bile salts are largely reabsorbed in the ___ for reuse
lower small bowel
___ helps package fats into their various forms
liver
why can infants only absorb fats from milk?
human milk contains lipase to help break it down
Other milks (including cow’s milk) do not contain lipase
Capacity for fat absorption declines with ___
age
Fat malabsorption syndromes can happen in patients who have… (3)
Gastric resections
Inflammatory bowel disease
Enzyme deficiencies
what is the recommended intake for dietary fats
20-35% of overall caloric intake!
Saturated fats should be <10% of overall calories
Averages out to 44-78 g/day
what are the “good” and “bad” fats?
good - monosaturated, polyunsaturated
bad - saturated fats, trans fats
clinical pearls of dietary fats for pt education (4)
- Less processed = more healthy (in general)
- Avoid eating carbohydrates in place of fat
- The type of fat is more important than the amount
- Limit saturated and trans fats
- Moderation is a big key!
- Replacement of SFAs with PUFAs has a lot of potential health benefits! - Elimination of dietary fat is not as important
as overall well-balanced, healthful diet
what are proteins?
- organic compound consisting of carbon, water (hydrogen and oxygen), and nitrogen*
- Found in virtually every tissue
- 50% stored in skeletal muscles - Made up of amino acids
- Includes essential amino acids
what macronutrient has the highest satiety index of any macro
proteins
3 major functions of proteins
- Synthesis of structural and functional proteins
- Structural - keratin, collagen, myosin
- Functional - enzymes, hormones - May be used for energy
- Most in storage - not directly available - Need varies depending on metabolic demands
- Rate of growth
- Need for tissue repair
- Anabolism/muscle use
meats, fish, crustaceans, dairy, eggs, protein shakes are what type of protein?
animal-based
Nuts, beans, peas, seeds, tofu, lentils, chickpeas are what type of protein?
plant-based
differences between plant vs animal proteins
- Amino acid proportions in animal proteins align more closely with human needs
- Animal proteins are more easily digestible (90% vs. 80%)
pros and cons of plant-based diets
- Pros - less environmental impact, reduced risk of some diseases
- Cons - lower in some essential nutrients, must be well-balanced, affected by cooking/processing
what type of protein must be obtained from food
essential amino acids
what type of protein is normally produced by body, but not always
semi-essential
what type of protein can be produced on its own by the body
nonessential
proteins must be broken down in the ___
GI tract
____ begins the process of breaking down into amino acids
pepsin
proteases are released from the __ and ___
pancreas and small intestines
what are the two major players of proteases
Trypsinogen and chymotrypsinogen
___ absorbs amino acids into the bloodstream
small intestine
storage of amino acids is ____
limited
what is the recommended intake of protein?
Recommended 10-35% of overall caloric intake!
protein intake varies with ?
age - need more protein when younger, stabilizes out in adulthood
health
activity
what are the 3 exceptions for when protein intake stabilizes in adulthood
- If pregnant - 1.0 g/kg/d; if lactating - 1.3 g/kg/d
- If weight training - 1.2-1.7 g/kg/d
- If kidney or liver disease - decreased overall protein intake
how is too much protein a bad thing?
- Still stored as fat if too much is consumed
- Increased risk for several diseases…
- Heart disease (CAD)
- Liver disease
- Disorders of calcium/bone homeostasis
- Renal disease
- Increased risk of cancer (bowel, breast, prostate)
what makes a “good” or “bad” protein
- good
- Lower caloric content
- Prepared in a healthful manner
– Baked or grilled
– Fat was drained/removed
– Skin was removed
- Minimally processed
- Wild/free-range - bad
- Higher caloric content
- Prepared in an unhealthy manner
– Fried, deep-fried
– Fat not removed
– Skin not removed
- Processed meats (sausage, hot dogs)
- Caged/farmed
Failure to Absorb/Consume Carbohydrates are usually seen in patients with ?
dietary intolerances
lactose intolerance
gluten intolerance/celiac disease
patients on extremely low/no-carb diets have an increased risk of ?
mortality, cardio/cerebrovascular events, and cancer deaths
the most common complaint of failure to absorb/consume carbohydrates is ?
GI upset
Colonic bacteria ferment unabsorbed/digested carbs
Excess gas production
symptoms: Abdominal pain, cramping, flatulence, bloating, altered bowel habits
failure to absorb/consume fats is usually seen in patients with ?
GI illnesses - Chronic inflammation, Resection of the stomach or intestine, Pancreatic disease
the most common symptom of failure to absorb/consume fats is
greasy diarrhea
Steatorrhea - fatty stools; foul-smelling, light-colored, may float
Fat-soluble vitamin deficiencies
vision and skin changes is what type of vitamin deficiency
A
thinning bones, fatigue, muscle aches/weakness, depression is what type of vitamin deficiency
D
impaired reflexes/coordination, difficulty walking, muscle weakness is what type of vitamin deficiency
E
nosebleeds, bleeding gums, prolonged bleeding time, GI hemorrhage is what type of vitamin deficiency
K
malnourishment (inadequate dietary protein) can lead to ?
- Marasmus - lack of general nutrients, including protein
- Profound muscle wasting and emanciation - Kwashiorkor - lack of adequate protein in the presence of other nutrients
- Edema, rotund bellies
failure to absorb/consume protein can be seen in patients with:
- Prolonged fasting, liquid (weight loss) diets, limited oral intake, or TPN
- Patients with chronic liver disease
symptoms of failure to absorb/consume protein
edema, muscle weakness, muscle wasting
Low Hb, low serum albumin, impaired immune function
