Human G&MD Final

Seccular trend

long term trends

Secular trends are not

universal

Secular trends are

reversible

Positive secular trends

measures are increasing

Negative secular trends

measures are decreasing

Absent secular trends

measures are not changing

no change over a long period of time

Height secular trend

positive secular trend (newer data shows taller heights)

difference in height is small

Weight secular trend

positive secular trend (most recent data shows greatest weights)

difference in weight is larger (we are getting heavier more than we are getting taller)

Japanese body size secular trend

post WWII: height & weight had neg secular trend

changed to positive secular trend after end of the war

Lower body secular trend

positive secular trend

increase in leg length

Secular trend in age of menarche

negative secular trend (european, american, japanese)

adiposity speeds up onset of menarche

Secular trend in age at PHV

absent secular trend

Male secular trend in strength

upper body: positive secular trend

Female secular trend in strength

upper body: neg secular trend (more recent data shows pos)

pull strength: pos secular trend

Secular trend in performance (standing long jump)

1920-1960: absent secular trend

1960s-present: pos secular trend

Nutrition

process that concerns the relationship of food intake to the functioning of the organism

culture of eating, food preparation, eating environment

6 classes of nutrients

water

carbohydrates

fats

proteins

vitamins

minerals

Carbs, protein, and fat are

sources of energy

Breastfeeding recommendation

newborns should be exclusively breastfed for first 4-6 months of life

no data to show impact on growth

Breast milk compared to formula & cow’s milk

easier to digest, has less protein, has antibodies

Energy balance

sum total of energy intake minus energy expenditure

Positive energy balance

taking in more calories than you’re expending

necessary for growth

Negative energy balance

expending more calories than you’re taking in

negatively impacts growth

There is individual variation in

nutrition requirements

BMR (basal metabolic rate)

amount of energy expended at rest in a neutrally temperate climate

energy body uses for typical, normal functions

BMR & weight

BMR increase as weight increases

BMR and age

BMR decreases as we age

Energy requirements increase

each month during the 1st year

Kcal/kg during 1st year

decreases until ~7-8 months, then a continued increase

decrease is bc its between a period of rapid growth (0-6 months) and lots of activity (9 months)

Girls & Boys total calories needed per day

steady increase until growth stops

infancy, childhood, and adolescence

Kcal/kg decreases

in both males and females as they age

As body weight increases

energy intake also increases

% calories used for growth

decreases over time

almost ¼ of all calories during 1st month of life are for growth

Mean energy intake in children & adolescents

has not increased over the last years

Obesity rate secular trend

pos secular trend in infancy, childhood, and adolescence

Highest requirement of protein/kg body weight is during

infancy

this decreases over time

Total fat intake should fall between

20-30% of calories

Saturated fat intake should be

<10%

Carb intake should be

55% of total intake

Undernutrition

lack of energy and nutrients in the diet over time

has greatest impact during infancy & childhood

Underweight

having a weight for age more than 2 SD below the international reference median

Stunting

height for age more than 2 SD below the international reference median

Wasting

weight for height more than 2 SD below the international reference median

Greatest prevalence of underweight, stunting, and wasting in

underdeveloped countries

Starvation

severe caloric restriction

Mild to moderate PEM (protein energy malnutrition)

General lack of protein in the diet

most common form of undernutrition

is characteristic for several years

seen in a whole population

With mild to moderate PEM you see

stunted growth, reduced muscle mass, delayed motor development, and lack of PA

Marasmus

inadequate energy intake in all forms

occurs during 1st year of life

With marasmus you see

significantly low weight for height

Kwashiorkor

severely restricted protein

occurs during 2nd year of life

have adequate calories, just not enough protein

associated with weaning

With kwashiorkor you see

distended abdomen, dermatosis, pitting adema

Causes of undernutrition

low birth weight due to undernutrition during pregnancy

infections & parasites

inadequate diet

cultural practices

Motor development & undernutrition

occurs at normal rate for 1st year

see lag after the 1st year

PA and undernutrition

reduced levels of PA & lack of interest

Nutrition status & growth preschool (birth-36 months)

well rounded infants are greater in length & weight more

Undernutrition & PA preschool

undernourished choose activities that minimally raise HR

reduces # of calories burned

Undernutrition & growth school age

well nourished are taller and weight more

Undernutrition & Proportions school age

undernourished have relatively shorter legs

Undernutrition & musculature school age

well nourished have greater muscle mass

Undernutrition & PA school age

reduced PA still seen

Undernutrition & motor development school age

may see lag in motor development

Adolescent growth spurt may be delayed

in undernourished individuals up to 1 year

also see delay in sexual maturation

Undernutrition & performance school age

well nourished M&F are significantly stronger, faster, & can jump further (still see difference when data is normalized)

VO2 max is greater in well nourished children

Long term consequence of undernutrition into adulthood

• shorter stature

  • in females can be linked to higher rates of infant mortality

• reduced physical performance

• have higher BMI as adults

• tend to acquire more fat in the trunk region

Overweight

moderate degree of excess weight for height

Obese

severe degree of excess weight for height

Low BMI

<18.5

Normal BMI

18.5-24.9

Overweight BMI

25-29.9

Obese BMI

>30

Downsides of BMI

doesn’t take into account tissue type, fat distribution, and PA

WHO overweight in children younger than 5

weight for height more than 2 SD above international reference median

As the prevalence of overweight increases

the prevalence of wasting within a country decreases

Overweight percentile

weight for height within 85-95th percentile

Overweight prevalence 2 yr olds

2%

Overweight prevalence 3 yr olds

4.8%

Overweight prevalence 4 yr olds

5%

Overweight prevalence 5 yr olds

11%

big jump between 4&5

Obese percentile

over the 95th percentile

Adiposity rebound

overweight & obese cutoff decrease until 4-5 then increases

switch from decreasing to increasing

Obesity is most prevalent in

SE US

Factors associated with overweight & obesity

age

biological sex

parental overweight/obesity

socioeconomic status

PA levels

television watching

smoking

RMR

blood leptin level

GH level

sex steroid levels

skeletal muscle

Age and overweight/obesity

childhood obesity is risk factor for adult obesity

mid to late adulthood (55-65) has the max rate of obesity

Biological sex and overweight/obesity

females have greater risk

Parental overweight/obesity & overweight/obesity

if parents are overweight/obese, likely to have children that are overweight/obese

Socioeconomic status & overweight/obesity

obesity rates are higher in families of high SES in developing countries

obesity rates are higher in families of low SES in developed countries

PA & overweight/obesity

PA levels are lower in overweight/obesity individuals

Television watching & overweight/obesity

the greater the # of hours in front of a screen, the greater the likelihood of being overweight/obesity

Smoking & overweight/obesity

when individuals quit smoking there tends to be weight gain

RMR & overweight/obesity

RMR is higher in those that are overweight/obese

Blood leptin levels & overweight/obesity

high levels in overweight/obesity

GH level & overweight/obesity

lower levels in overweight/obesity

Sex steroids & overweight/obesity

males: low androgen levels in overweight/obese individuals

females: high androgen levels in overweight/obese individuals

Skeletal muscle & overweight/obesity

Type I fibers: no impact

Type IIx fibers: higher in those that are overweight/obese (higher amount of fast twitch fibers)

Low & high birth weights are associated with

being overweight/obese in adulthood

Breast feeding during infancy has been suggested to

prevent the development of overweight/obesity in childhood

Adiposity rebound is the

rise in BMI cutoff after it reaches its low (4-5)

the earlier it occurs, the greater the likelihood of having a higher BMI (continues into adulthood)

Effects of obesity on growth & maturation in children

larger overall body size (especially stature)

advanced skeletal maturity (does not continue into adulthood)

stature difference is insignificant in later adolescence

Effects of obesity on performance

lean individuals outperform their obese peers

except in upper body strength (obese outperform lean)

Obesity during childhood & adolescence can result in

high BP

elevated blood lipids

increase risk of type 2 diabetes (in adulthood)

high cholesterol