Nutrition in Infants/Children Flashcards
How is growth regulated?
Growth and body composition is controlled mainly at the level of long bone growth.
Bone growth
Long bone length growth- primary driver of whole body growth.
Genetic determination of rate/time course (canalization)
Adequate nutrition required for genotypic height attainment
Skeletal muscle growth
Growth rate/target weight controlled by bone length growth.
Passive stretch= pyshiological stimulus for growth
Muscle activity and adequate nutrition are required for maximum phenotypic mass
Visceral organ growth
Driven by functional demand: food intake and metabolic work.
Infant growth
IGF-1 mediated
Insulin is main driver of IGF-1 production at this stage
Childhood growth
IGF-1 mediated
Growth Hormone main driver of IGF-1 at this stage
Puberty growth
Primarily driven by sex-steroid
Activators of endochondral ossification
IGFs, IGFBPs, T3, 25OH2 VitD, FGFs, IHH, PtHrP, BMPs, WNTs, VEGFs
Growth Faltering
Primary and Secondary malnutrition and weight loss due to:
Primary insults- Inadequate diet, or disease. That cause:
Interactions: anorexia, malabs, decr immunity, mucosal damage, nutrient loss
Stunting and wasting
Wasting: low weight for height
Stunting: low height for age.
Stunting more common, and is a cyclical syndrome w serious co-morbidities. It decreases the psychosocial development
Both caused by:
- Poor diet after weaning, lacking specific nutrients
- Infection/Inflammation: major inhibitory influence.
Where is long bone growth regulated?
at the level of endochondral ossification in the growth-plate
When does stunting begin?
In childhood- breast feeding protects the infant, so occurs after weaning.
Considered an inflammatory disease assoc w poor sanitation and hygiene: Environmental enteric dysfxn.
Environmental Enteric Dysfunction
Caused by intestinal inflammation–> innate and acquired immune activation:
Chronic villous atrophy
Crypt hyperplasia
Inflammatory cell infiltrate
EED then leads to:
-increased intestinal permeability –> inflammation (increased TNFa, IL1, IL6, corticosteroids, insulin resistance, and decreased IGF1/IGFBP3)
- malabs and malnutrition –> increased susceptibility to infection.
These all cause inhibition of bone growth and STUNTING
Vegan Children
Can have near-normal growth but need some supplementation (lacks in developing countries)
Milk and growth
Milk intake is the main determinant of serum IGF-1 and height. Those who have high intake of milk become taller and achieve their growth potentials better than those who don’t.
Main nutrient deficiencies assoc w stunting
Iodine, Protein and Zinc
Type I nutrient deficiencies
VitA def: blindness, but no effect on growth.
Fe def: anemia, but no effect on growth
Iodine def: goiter/cretinism, and depressed growth.
Type II nutrient deficiencies
Prot def: depressed growth.
Zinc def: depressed growth
- happens with nutritionally poor staples (starchy root-crops) and foods with high phytate content (cereals and legumes), and low intake of animal foods.
Foods assoc with Zinc deficiency
Starchy root-crops as diet staples
High phytate content foods: cereals and legumes
Low intake of animal source foods.
Iodine and bone length growth
Iodine–> T4/T3 –> promotes GH secretion and modulated IGF-1 activity
Directly regulates chondrocyte maturation.
Severe Iodine def: Impaired mental fxn, delayed physical development
Zinc and bone length growth
Needed for the anabolic effect of IGF-1 in the growth plate, when deficient–> stunting.
EED and linear growth
Causes release of inflammatory inhibitors of endochondral ossification: Cortisol FGF21 IL1, IL6, IL8 TNF IFNy
Nutritional components that stimulate chondrocyte proliferation
Milk AAs Zn Iodine These increase linear bone growth
Major reason of global stunting problem
Inflammation through EED- reflecting poor sanitation and hygiene
