Flashcards in 26 - Carbohydrates, Lipids and Proteins Deck (40):
What percentage of premature deaths are caused by behavioral patterns?
Obesity, tobacco, alcohol, etc.
Nutrition and health is important
What is the difference of fat content in previous times, western and Mediterranean diets
- We have a higher fat content than previous times (pre-agricultural)
- We have lower fat content than the Mediterranean diet however
- The Mediterranean diet has less saturdated fat which is the bad fat, so it is still better
What are we currently using for a food pyramid?
What are the dietary guidelines for Americans?
- Promote health
- Reduce risk for chronic diseases
- Diet and physical activity
What are the 2010 American Dietary Guidelines?
- Balance calories/physical activity to manage weight
- ↑ fruits, vegetables, beans, and nuts
- ↑ whole grains, fat-free and low-fat dairy products
- ↑ fish and seafood
- ↓sodium, saturated fats, trans fats, cholesterol, added sugars, and refined grains
Describe food as energy
- Basic Fuels – Carbohydrate, Fats, Proteins (and ethanol)
- Fed state (storage of fat, glucose utilized, protein used)
- Non fed state (uses endogenous sources, maintain glucose, used stored glycogen, use stored protein and fat to produce glucose)
- Starvation (metabolic changes for alternative fuels)
Describe carbohydrates in the diet
- Organic compounds
- Molar ratio of C:H:O as 1:2:1
- 45-65% of daily energy
- 1 gram = 4 kcal
- Stored in liver & muscle as glycogen
Describe the difference between simple and complex carbohydrates
- monosaccharides (one sugar unit)
- disaccharides (2 sugar units)
- Multiple units of mono- and disaccharides can be joined together to form oligo- (10) (complex CHOs).
- Starch, glycogen, and fiber are examples of polysaccharides
What is the glycemic index?
- Glycemic index is a system to quantify the glucose response to CHO-containing food
- Glycemic index is defined as the area under the curve for the increase in blood glucose during the 2 hours following ingestion of 50g of food, as compared with ingestion of 50g of reference food (either glucose or white bread).
Describe high and low glycemic index foods
A food with a low glycemic index are usually more slowly digested, absorbed, and metabolized and will result in a smaller rise in blood glucose (and insulin) than one with a higher glycemic index.
The more manufactured or processed the food is, the higher the glycemic index
What happens to the reward center in the brain following a high glycemic food?
- Higher glycemic foods stimulate the reward center in the brain
- It stays stimulated for hours after
- May influence next meal choice as well
What are the potential clinical effects of high glycemic index dietary carbohydrates?
- Reduced satiety and more rapid return of hunger
- Increased prevalence of obesity
- Increased risk of type 2 diabetes (increased insulin resistance)
- Increased risk of coronary heart disease (high glucose, high insolin, high triglycerides, low HDL, small LDL, high oxidative stress, inflammatory cytokines and C-reactive protein)
Describe hyperglycemia in response to stress
- Stress hyperglycemia – elevated blood glucose in response to stress or illness
- ↑ stress hormones; ↑ production of cytokines; all oppose insulin
- Also leads to ↑ protein breakdown and ↑ fatty acid oxidation
Treatment response is decreased when blood sugars are high, so now we treat stress-induced hyperglycemia in the hospital
Describe high fructose corn syrup and fructose
***** KNOW THIS *****
- In many foods/sweetened beverages
- HFCS is actually more similar to sucrose (table sugar) than to fructose
- HFCS is 50/50 of fructose and glucose)
- Fructose absorption facilitated by glucose and other monosaccharides
- Excess fructose consumption can lead to gastric distress/diarrhea
- Fructose may impact hormone levels, satiety, & food consumption
- Type of sweetener has changed, but amount of fructose in diet has remained constant
Describe the studies on FRUCTOSE (not HFCS)
- Higher intake decreases LDL particle size in overweight children
- Increases de novo lipogenesis compared with glucose
- Increased fructose consumption is associated with fibrosis severity in patients with non-alcoholic fatty liver disease
- Increased serum uric acid – Cardiorenal
- Promotes chronic low level inflammation in young men
- However, many studies use a fructose:glucose ratio well above 1.0 or study fructose by itself (not as part of solid food)
- Overall very weak evidence that HFCS uniquely contributes to overweight/obesity
What are the types of dietary fiber?
- Oats, legumes, vegetables, fruit, Metamucil
- Slows gastric emptying (may increase insulin sensitivity); increases gastrointestinal bulk; helps lower LDL cholesterol by interfering with cholesterol absorption
- Whole grains, bran, legumes, vegetables, fruit
- Increases water in GI tract; speeds colon emptying
- Provides substrate for short chain fatty acid synthesis by colon microbiota
Describe the composition of whole grains
During processing, bran and germ are removed – removing fiber, vitamins, minerals, antioxidants, healthy fats – leaving essentially the carbohydrates and proteins
Sometimes food manufacturers will enrich the product (add the nutrients back in), although it’s still healthiest to received the nutrients in the natural form
What is the role of fiber in clinical nutrition?
- Western diet – inadequate fiber (↑ fast food, ↑ processed foods, ↓ fruit/vegetable intake)
- No disease/syndrome for fiber-deficient diet (just constipation)
- Slows gastrointestinal transit time
- Decreases lipoprotein concentration in blood
- May lower all-cause and CVD mortality
- May decrease risk of colorectal carcinomas & adenomas
What are the benefits of fat?
- Provide texture, aroma, flavor to foods
- Phospholipids and cholesterol are structural materials of cellular membranes that provide the starting materials for other molecules
- Help in fat-soluble vitamin absorption
- Insulate, cushion (protect), lubricate
- Provides energy
How does fat provide energy?
- Adipose tissue can be broken down for energy
- Excess energy as CHOs or protein can be converted to fatty acids by liver and stored as triglycerides
Describe fat as part of the diet
- Insoluble in water
- High energy (9 kcal/g)
- Component of biological membranes
- Important for development
- Source of critical metabolic products (Inflammatory mediators, gene regulators, substances that resolve inflammatory responses and regulate lipid metabolism)
What are the types of fatty acids?
- Meat, dairy products, coconut, palm, palm kernel oils, cocoa butter
- Olive oil, avocado, canola oil
- Corn, soy, sunflower, safflower oils
- Oily ocean fish, flax seed oil, 10% in canola and soy oils
Partially hydrogenated polyunsaturated ω6 (Trans fats)
- Frying and baking oils and margarine
What are the health effects of each type of fatty acid?
- Risk of CVD, ↑ LDL
- May ↓ LDL, cardioprotective
Polyunsaturated (N6) (ω6)
- Essential, ω6:ω3 important; some ↑ inflammatory cytokines
Polyunsaturated (N3) (ω3)
- Essential, ↓ TGs, cardioprotective, brain health?
Partially hydrogenated polyunsaturated ω6 (Trans fats)
- Most detrimental to health, ↑ LDL, ↓ HDL, ↑ inflammatory cytokines
What are the recommendations for fat intake?
- 20-36 g
- 12-17 g (19-50 years old)
- 11-14 g (51-70 years old)
Partially hydrogenated polyunsaturated (trans fat)
What are the results of deficiency of essential fatty acids?
- Largely non-existent in normal population (7% of total energy intake)
- Deficiency documented in 70s in patients on parenteral nutrition (PN)
- Linoleic (dry skin, rash, increased infection, impaired wound healing, decreased immune function)
- α-Linolenic (less recognized, neurologic abnormalities, numbness, parasthesia, blurred vision, difficulty walking)
What are the potential benefits of omega 3s?
- Rheumatoid arthritis
- Multiple sclerosis
- Type 1 diabetes
Don't need to memorize
Describe trans fatty acids
- Small amounts occur naturally (dairy)
- Produced during hydrogenation process
- Decrease rancidity/increase shelf life
- Labeling – allowed to list 0g if product contains
Describe animal, plant and hydrogenated fats
Animal fats – saturated; solid at room temperature
Plant fats – unsaturated; liquid at room temperature
Hydrogenation – converts unsaturated bonds into saturated
Describe the difference between cis and trans fat
Cis – natural unsaturated fatty acids (kinks)
Trans – no kinks, making it structurally similar to saturated fatty acids
Describe the regulation of artificial trans fats
June 16, 2015: FDA finalized decision to ban artificial trans fat
Mandated in 2018 - May prevent 20,000 heart attacks & 7,000 coronary deaths per year (CDC)
What are the physiological effects of consuming excess dietary trans fats?
- Abdominal fat deposition in primates
- Systemic inflammation (high interleukin 6, TNF alpha, C-reactive protein)
- Endothelial dysfunction
- Diabetes mellitus?
- Membrane properties
Describe the dyslipidemia that may result from trans fat
High LDL, high HDL, high triglycerides, high lipoprotein(a)
LDL particle sizedecrease (more atherogenic)
Describe the fat distribution when consuming trans fat
The diets produced weight gains of 1.8 and 7% respectively, and a higher proportion of the fat gain was deposited intra abdominally in the trans fat fed group.
Composed of amino acids
- Building blocks of protein (20)
- Nutritionally essential, nonessential, conditionally essential
- Body degrades its own protein if essential amino acids are lacking
- Functionally all are essential
- Not “stored”
What are the functions of proteins
- Growth, maintenance, and movement
- Regulators of gene transcription and translation
- Fluid and electrolyte balance
- Acid-base balance
- Transportation and storage
Describe the quality considerations in vegetarian/vegan diets
- May be more practical to design a lower calorie diet with animal protein than with plant protein
- Need to also consider micronutrients
- May impact weight control, reduce chronic disease, improve gut microbiome
- 3oz lean beef = 160 kcal (23 g protein)
- 6 Tbsp peanut butter = 500 kcals (24 g protein)
How do you optimize nitrogen-energy relationships
- Loss of body protein – disability and death
- Cannot store excess amino acids; N is eliminated in urine
- Critically ill have accelerated protein loss demands greater energy and protein intake (1.5g/kg/day)
- Patients with burns/multiple trauma (2g/kg/day) - VERY high
Describe the risks of losing too much protein
- Too much protein can result in pre-renal azotemia
- Increases burden to kidney due to high demands for excretion
- Kidney stones, osteoporosis
What are the physiological effects of increasing protein intake?
High calcium, uric acid and citrate in the urine