Nutrition Flashcards
What is DRI?
Dietary Reference Intake
How much energy is derived from carbohydrates, lipids/dietary fats, protein, an dalochol?
Carbohydrates: 4 kcal/g
Lipids/dietary fats: 9 kcal/g
Protein: 4 kcal/g
Alcohol: 7 kcal/g
What are the current national dietary guidelines for fat, protein, and carbohydrates?
Fat: <30% kcal from fat (<10% saturated fats, <1% trans fats)
Protein: 15% kcal
Carbohydrate: 55-60%
What is energy requirement?
Amount of food energy needed to balance energy expenditure in order to maintain body size, body composition, and a level of necessary and desirable physical activity consistent with long-term good health.
What are the components of daily energy expenditure for weight-stable adults?
- Basal metabolic rate (resting metabolic rate) - 60-70%
- Dietary-induced thermogenesis - 10%
- Physical activity - 20-30%
What are the components of daily energy expenditure for special stages of growth?
- Growth (tissue development and energy in new tissue)
- Pregnancy (maternal and fetal tissue deposition)
- Lactation (milk production and energy in milk)
True or False: overweight and obese individuals have relatively low metabolic rates.
False; BMR is comprised of organ mass and tissue - fat mass is relatively inert.
True or False: low metabolism contributes significantly to obese individuals’ excess weight gain.
False; no association between BMR and weight gain (for most populations)
True or False: there are diets available to increase a person’s metabolic rate thereby inducing weight loss.
False (unless that diet contains compounds like caffeine or ephedrine - short term); the only way to increase your BMR is to add muscle mass.
True or False: a person’s metabolic rate decreases during caloric restriction inhibiting the rate of weight loss.
True
When does decreased BMR occur?
Hypothyroidism
Anorexia nervosa
Individuals with Down syndrome
Very-low-calorie diets and starvation states
When does increased BMR occur?
Hyperthyroidism
Parkinson’s disease
Asthma
Any type of hypermetabolic state (burns, injury, sepsis)
BMR is suppressed in situations of severe ___.
Caloric restrictions
Energy Intake = ?
Energy Expenditure + Change in Energy Stores
What are the BMI ranges for Underweight (Chronic Energy Deficiency III, II, I), Healthy Weight, Overweight, and Obese?
CED III: <16.0 CED II: 16.0-16.9 CED I: 17.0-18.4 Healthy Weight: 18.5-24.9 Overweight: 25.0-29.9 Obese: 30.0+
BMI is highly correlated with ___ in most populations.
Adiposity
Describe situations in which BMI does not correlate to adiposity.
1.
What are “normal” levels of body fat? Note that there is no consensus
Women: 20-35%
Men: 5-20%
What are consequences of low levels of body fat? High levels?
Low levels: amenorrhea, cold intolerance, excessive use of protein stores for energy
High levels: Type 2 diabetes, all organ systems affected
When energy expenditure exceeds energy intake, what occurs?
Protein energy malnutrition and being underweight
Chronic mild protein energy malnutrition (PEM) leads to ___.
Stunting (linear growth failure)
Acute PEM can lead to ___ or ___.
Underweight; Wasting (Marasmus)
Is severe marasmus reversible?
Yes (calories + appropriate micronutrients)
What are symptoms of kwashiorkor (linked to low protein intake rather than low calorie intake)?
Edema, pigment changes
PEM increases risk of death from ___.
Concomitant infections
When energy expenditure is excessive (energy expended in metabolic functions), ___ results.
Hypermetabolism
Lipids and dietary fats are ___ in organic solvents.
Soluble
Dietary lipids include ___, ___, and ___.
TAGs, cholesterol, phytosterols
What is the majority of lipids consumed by humans?
Triglycerides (>95%)
Saturated fatty acids have ___ double bonds.
NO
Saturated fatty acids are ___ at room temperature.
Solid
Saturated fatty acids are associated with ___.
Hypercholesterolemia
Mono-unsaturated fatty acids are at least 12 C long and have one double bond at ___.
n-9
Are mono-unsaturated fatty acids associated with hypercholesterolemia or decreased HDL?
NO
Polyunsaturated fatty acids have ___ double bonds.
Multiple
What are the two essential fatty acids?
Linoleic and alpha-linolenic acid
Oils high in polyunsaturated fatty acids are generally ___ at room temperature.
Liquid
Essential fatty acid (EFA) deficiency can result from…
…very low fat diets (10-20% of calories coming from fat)
Omega-3 fatty acids are likely critical for neural and retinal tissue development. They have also been shown to reduce CVD risk in people at ____.
High risk
Hydrogenation turns liquid oils to solid fats and reduces the rotational mobility of the fatty acyl chain in ___.
Trans fats
Trans fats are associated with increased ___ levels, CHD, and atherosclerosis (to the same degree or more than saturated fats).
LDL
Soluble fibers are implicated in ___ lowering.
Cholesterol
What are the dietary sources of soluble fibers?
Legumes, oats, some fruits, some vegetables, nuts
What are the dietary sources of insoluble fibers?
Whole grains, wheat bran, some vegetables, potato skins
How do soluble fibers help lower cholesterol?
- Act as a bile-acid sequestering agent
- Reduce rate of insulin rise by slowing CHO absorption and slowing hepatic cholesterol synthesis
- Stimulate production of short-chain fatty acids in the gut which inhibit cholesterol synthesis
What are the 4 fat-soluble vitamins?
- A (retinol)
- D (cholecalciferol)
- E (tocopherols)
- K (phylloquinone)
Which type of vitamin (fat or water soluble) is stored in the body?
Fat-soluble (water-soluble tend to be excreted)
What are the 9 water-soluble vitamins?
- Thiamin (B1)
- Riboflavin (B2)
- Niacin (B3)
- Pantothenic acid (B5)
- Pyridoxine (B6)
- Biotin (B7)
- Folic acid (B9)
- B12
- Vitamin C (ascorbic acid)
Beta-carotene is a water-soluble pigment that can be cleaved to ___.
Retinaldehyde
Retinaldehyde can then be converted to ___ or ___.
Retinol and retinoic acid