PUBHLTH 310 Exam 1

what are macronutrients? list the classes.

they yield energy

1. carbohydrates

2. lipids

3. proteins

what are the 6 nutrient classes?

1. carbohydrates

2. lipids

3. proteins

4. vitamins

5. minerals

6. water

what are micronutrients? list the classes?

need in smaller amounts

1. vitamins

2. minerals

what are carbohydrates, what are some sources, and what are their 2 types?

- ready source of energy, make up the majority of calories in typical u.s. diet

- sources: table sugar, fruits, grains, some dairy products

- 2 types are unrefined and refined

unrefined v. refined carbs

- unrefined: : carb-based food in natural state

- refined: carb-based food undergone processing to remove various components of original food

how do grains and their parts play into this?

- grain has 3 parts: bran, endosperm, germ

- unrefined is whole grain w all parts but refined is white grain with just the endosperm

what are proteins, what are some sources, and what are some body proteins?

- made of amino acids, dietary proteins get broken down into AAs to then build body proteins

- sources: animal products, legumes, vegetables, some dairy products

- body proteins include: hormones, enzymes, transporters, structural, etc.

what are lipids, what are some sources, and what are some dietary lipids?

- concentrated source of energy

- sources: animal foods, oils, nuts, avocados, some dairy

- dietary lipids include: triacylglycerides, saturated fatty acids, unsaturated fatty acids, cholesterol, etc.

where is the main storage site of fats?

adipose tissue

what do vitamins do? give an example?

- they help with bodily processes

- example: carb metabolism -- B vitamins are important as co-enzymes for enzyme function

what do minerals do?

- regulatory and structural roles

- bone strength (e.g., calcium, phosphorus)

- transport of oxygen (e.g., iron)

- transmission of nerve pulses

- muscle contractions

what are some functions of water in the body?

- lubricant

- transporter

- regulates body temperature

- structural component of cells

- helps rid wastes

what 3 things make something a public health issue?

1. is it prevalent?

2. is it serious?

3. is it preventable and/or treatable?

what is homeostasis? list some things it contributes to?

physiological state of internal stability

- blood pressure

- blood sugar levels

- body temperature

- hormone status

- energy stores

what are some things that contribute to an increase in overweight and obesity prevalence (overnutrition) in the U.S.?

- dietary intake

- physical inactivity

- lack of sleep

- environmental exposures

- longer commuting time / sedentary jobs

what is a consequence of undernutrition? explain it. :)

- kwashiorkor - protein deficiency with adequate caloric intake

- with low protein in diet, the body can not produce transporter proteins (to transport fat and water)

what are dietary reference intakes (DRIs)?

- average amount of energy or nutrients individuals should consume per day to stay healthy, for 40+ nutrients

what are 3 things DRIs cater to?

1. age

2. conditions (pregnancy, lactation)

3. sex

what do DRIs help with in their overall purpose?

overall purpose: stay healthy by

1. reduce risk of chronic disease

2. prevent deficiencies and excesses (malnutrition)

3. support health when nutritional needs are altered

what are the 4 nutrient intake recommendations?

1. estimated average requirement (EAR)

2. recommended daily allowance (RDA)

3. adequate intake (AI)

4. tolerable upper intake level (UL)

what are the 2 energy intake recommendations?

1. estimated energy requirement (EER)

2. acceptable macronutrient distribution range (AMDR)

what is the estimated average requirement (EAR)?

- meant to estimate needs of populations

- meets needs of 50% of people in same sex and life-stage group; if a pop. eats this amount, only 50% would get sufficient amounts

what is the recommended dietary allowance (RDA)?

- add 2x the standard deviation to EAR

- RDA = EAR x 1.2

- meet needs for about 97% of population

- risk of deficiency in a population will be low

what is the adequate intake (AI)?

- used when scientific evidence is insufficient or high individual variability

- set by observational intake by healthy individuals in a population

- ex: choline is good for brain dev and transport of fat out of liver; some people make a lot or little choline w their body; set by observing median intake of people free of non-alcoholic fatty liver disease; e.g. adult male AI is 550 mg/day

what are the tolerable upper intake levels (UL)?

- maximum level of intake unlikely to pose toxicity

- not necessarily beneficial

- going over UL poses a risk to toxicity

what are the estimated energy requirements (EER)?

- average dietary energy intake to maintain energy balance

- EER (kcal/day) = total energy expenditure + energy deposition

what does total energy expended include?

- thermic affect of food

- basal metabolic rate

- thermoregulation

what does energy deposition depend on?

- age

- sex/gender

- physical activity levels

- tissue deposition (growth)

- milk production and secretion (lactation)

what are acceptable macronutrient distribution ranges (AMDR)?

- expressed as percentage of total energy intake from macronutrients

- associated with decreased risk of chronic disease, yet meeting micronutrient intake levels

- recs: 45-65% calories from carbs, 20-35% from fat, 10-35% from protein

what are the goals of the dietary guidelines for americans (DGA)?

- promote health

- prevent chronic disease

- provide tools for individuals to monitor food intake

what is the upside down food pyramid?

- 2025-2030 DGA develop under RFK Jr., released Jan 2026

- emphasizing meat intake and high fat dairy; less emphasis on grains

- considers red meats and plant sources for good protein

- saturated fats enouraged

- avoid ultra processed foods and added sugars

what is myplate?

- nutritional guide for the general public to monitor food intake per meal, divides food into groups

dietary guidelines for americans are reviewed every _ years

5

what is preconception?

before a woman's pregnancy, multiple factors affect fertility status in females and males

fertility v. fecundity v. infertility v. sub-fertility

- fertility: actual production of children, nutrition and malnutrition can impact

- fecundity: biological capacity

- infertility: difficulties to conceive (>1 year), repeated pregnancy losses, 7-15% of U.S. population considered infertile

- sub-fertility: generalized term, reduced ability to conceive

what factors affect preconception for people of reproductive age?

- genetic disorders: chromosomal abnormalities

- environment: stress, exposures

- biological/anatomical: reproductive structural problems

- age

- behavioral: diet, physical activity

give examples of how nutrition can affect reproduction status.

- adipose tissue levels affect hormone production

- amino acid status to support body protein levels (hormones)

- nutrients are needed to support normal cell functioning (including cells of reproductive tract organs)

many processes that affect fertility are due to ________________________________?

abnormal hormonal production

- conditions affecting hypothalamus, pituitary gland, ovary, testes, and adipose tissue

- protein synthesis

hormone imbalance affects:

- menstrual cycle, ovulation

- sperm production, integrity

adipose tissue is:

an endocrine organ

list the 5 female reproductive hormones and their functions.

1. estrogen - increase blood supply in endometrium, trigger release of gnrh, lh, fsh

2. progesterone - prepare endometrium for pregnancy; allows fertilization to occur; prepares uterus for implantation; decreases maternal immune response at implantation

3. fsh - stimulates production of estrogen, maturation of follicles

4. gnrh - stimulates productions of fsh, lh

5. lh - triggers ovulation, stimulates production of progesterone

list the 3 male reproductive hormones and their functions.

1. testosterone - production of sperm

2. gnrh - stimulates production of lh

3. lh - stimulates production of testosterone

what is body mass index (BMI)?

an indirect indicator using a person's weight and height to help screen for health

what is undernutrition and what can it cause?

- 10-15% below usual body weight, loss of body fat

- decrease in estrogen, lh, fsh (female)

- decrease in sperm viability and motility, testosterone (male)

what is the minimum threshold to trigger menarche? what's menarche?

- 17% body fat

- first menstruation

what bmi can cause amenorrhea? what's amenorrhea?

- < 20

- absence of menstruation for 3 months or longer

what body fat percentage is required to obtain stable menstrual cycling?

22%

what are the 3 parts of the female athlete triad?

1. disordered eating

2. amenorrhea

3. osteoporosis (loss of bone mass density)

what can cause female athlete triad? what all does it encompass?

- calorie restrictive, disordered eating (ex. anorexia or bulimia)

- usually in peak of athletic performance in teenage through young adult years

- can happen in sports w/ emphasis on lean body type (ex. gymnastics, ballet, etc.)

- undernutrition and loss of body fat, suppresses gnrh and leads to decreased estrogen, lh, fsh --> can lead to amenorrhea, late onset menarche, osteoporosis

what percent of bone mass development occurs by age 18?

92%

what can cause osteoporosis?

- undernutrition -> decreased estrogen, which alters normal bone turnover

- increased function of osteoclast results in loss of mineral bone mass w/ addition of consistent vigorous exercise, increased susceptibility to bone fractures

how are menstrual cycles and bone density correlated?

a regular menstrual cycle indicates normal bone density

how can we increase awareness of the female athlete triad?

fellow athletes and coaches should be educated on the signs of disordered eating

- light headedness, fatigue

- rapid weight loss or wide fluctuations in weight

- preoccupation with food and exercise

- avoiding social outings (meals)

- depressive states

what is the first goal in clinical treatment for female athlete triad (or general undernutrition)?

return of menstruation

- also support bone density

what is relative energy deficiency in sports (RED-S)?

awareness of adverse effects on immunity, cardiovascular health, metabolic rate, protein synthesis, mental health in both females and males

what does obesity/overnutrition or having excess adipose tissue lead to?

abnormal hormonal states resulting in subfertility

what does obesity cause in females and males?

- females: anovulation (absence of ovulation), delayed time to contraception

- males: damaged dna of sperm, altered production and testosterone levels

what are the 2 types of fat?

1. subcutaneous fat - directly under skin

2. visceral fat - surrounds vital organs

what is a common consequence of visceral fat accumulation?

insulin resistance (high blood levels of insulin)

what does insulin normally do? what happens during insulin resistance?

- signals glucose into organs

- glucose remains in blood --> increased circulating insulin and glucose

in females, body fat is inversely associated with:

fertility potential

- increased insulin production decreases sex hormone-binding globulin (SHBG) -> accumulated testosterone in ovaries -> interfering w/ egg release -> anovulation

how are males affected by body fat?

- decreased semen count, motility, etc.

- increased DNA damage in semen

- decreased gnrh, lh, testosterone

- increased estrogen

--> matter of elevated aromatase due to excess adipose tissue creating a pro-inflammatory environment, triggering increased expression of the aromatase gene

how can hormone levels be improved in people who are obese?

weight loss (5-10% body weight)

with a 5-10% loss of body weight in people who are obese _____

fertility is increased (ovulation recovered, sperm integrity increases)

natural folate food sources

spinach, legumes, lentils, avocado, asparagus, peanuts

glutamate in natural form of folate

polyglutamate (many glutamate molecules)

- requires enzymatic activity to get to absorbable form

- less efficient absorption, ~50% bioavailability

folic acid food sources

cereals, bread, granola bars, pasta, rice

glutamate in folic acid form

monoglutamate (one glutamate)

- increases bioavailability

- passively diffused through small intestine to bloodstream in original form

- more efficient absorption, ~85-100% bioavailability

does the term folate cover both food folate and folic acid?

yes

what is the purpose of folate (B9)?

critical in synthesis of DNA and cell division, important for closure of spinal cord

- rapid cell division first few weeks of life (first 21 days), CNS and heart developed by day 21

what is spina bifida?

- improper closure of spinal cord

- form of a neural tube defect (NTD)

- can cause: difficulty walking, fluid build up in brain, learning impairment, tethered spine, uncontrolled bowel movements

folate is inversely associated with

neural tube defects (like spina bifida)

what public health act was taken to increase folate intake?

mandatory fortification of cereal grains and wheat flour by FDA, led to decline in NTDs by about 1300 births/year

which ethnicity has the highest prevalence for neural tube defects (NTDs)?

hispanic births

- lower awareness of folate dietary sources

- less apt to supplement

- genetic factors

- dietary choices

what is gestational age and menstrual age during pregnancy / prenatal period?

- gestational age: 38 weeks from conception to birth

- menstrual age: 40 weeks if measured from first day of last menstruation

what happens after fertilization of egg by the sperm?

- forms single-cell (zygote)

- zygote travels along fallopian tube, dividing along the way

- resulting blastocyte implants into the uterine wall

what is the embryonic period?

weeks 3-8, when all rudimentary organs are formed

what is histotrophic nutrition?

- nutrient source for embryo

- nutrients are exchanged via uterine glands and uterine arteries

what do uterine glands do?

secrete nutrients, growth factors, cytokines into uterine capillaries / arteries

what is the amniotic sac?

fluid-filled membrane that provides fetus with constant source of liquid

what is the placenta?

- network of blood vessels and tissue, fully developed week 9

- nutrient and oxygen exchange between mother-fetus

- hormone production

- immune function

- waste elimination

what is the pathway in which nutrients/oxygen/wastes from mother travel to fetus?

mother's circulation --> placenta --> umbilical cord --> fetus

what 4 hormones are produced by the placenta? what are their roles?

1. human chorionic gonadotropin (hCG) - immune component, suppresses pregnant person's immune response to not reject placenta

2. estrogen - 30x levels of non-pregnant, helps muscle and ligament relaxation, supports growth of breasts and uterus

3. progesterone - placenta hormone, muscle relaxation to prevent pre-term labor by inhibiting muscle contractions

4. human placental lactogen (hPL) - maintains metabolic homeostasis between pregnant person and fetus

between week 9 and 30 there is an increase in which maternal nutrient stores?

- increased glucose and fat storage

- fetal nutrient demands increase

- increase in placental exchange

-> 30 weeks: fetal energy demands at peak

how does blood volume change during pregnancy?

increases 30-50%

why does blood volume increase during pregnancy?

- response to increased vascular capacity for exchange at placenta, uterus, fetus, breasts

- increased RBC production to support oxygen needs and compensate for blood loss at birth

how does the digestive tract change during pregnancy?

progesterone and estrogen cause muscle relaxation --> slower motility to increase nutrient absorption

what are the adverse consequences of hormone-related relaxation in digestive tract during pregnancy?

- gastric emptying slows --> nausea

- sphincter relaxation --> heartburn during pregnancy

what is normal weight gain for pregnancy? what % of that is the fetus?

- 25-35 lbs

- 25%

should obese people gain more or less weight during pregnancy than a normal weight person?

less

how many additional calories should be eaten in the first trimester (end ~12th week)? what about the second and third?

1. none

2. additional 300 calories

3. additional 450 calories

-> basically nutrient needs for fetal growth are in most demand in last half of pregnancy

in what ways does the pregnant body undergo metabolic shifts?

- increase storage

- increase nutrient flux

what is the main fuel source for the fetus?

glucose

what are the hormone mediated alterations to ensure high levels of glucose for fetus?

1. enhanced storage of glucose to glycogen (1st and 2nd trimester) - increased storage allows glycogen to be released and converted back to glucose for fetal use when demands increase, around week 30

2. state of insulin resistance (2nd and 3rd trimester) - human placental lactogen (hPL) stimulated stage of insulin resistance, blocks insulin receptors on maternal organs inhibiting glucose flux

a pregnant person's body relies on ____ as main source of energy for second half of pregnancy?

fat

-> lipids are accumulated between weeks 10-30, up to 3.3 kg of fat deposition, gain 4-11 lbs of fat by end

-> fat stored in 1st half of pregnancy essentially until needed later

during pregnancy, cholesterol is needed for:

- estrogen and progesterone synthesis

- cell and nerve membrane development in fetus

what are essential fatty acids?

- needed through the diet

- omega-6

- omega-3

metabolic derivatives (arachadonic acid, eicosapentaenoic acid, docosahexaenoic acid) of essential fatty acids play important roles in

immunity, eye, and neural development of fetus

are humans able to convert omega-6 and omega-3 fatty acids to derivatives?

no due to enzyme competition

how can humans eat omega-6 and 3 derivatives?

by eating marine animals, plants, poultry, and cows that contain the derivatives

- marine animals, fish have omega-3 -> EPA and DHA

- poultry and cows have omega-6 -> AA

- omega-6 and -3 FAs in plant sources like grains, nuts, legumes, vegetable and nut oils, etc.