Nutrition and Life Cycle

NUTRITION AND LIFE CYCLE undernutrition ? environmental condition that influences growth and development Determinants of Low Birth Weight in Industrialized Countries 1. ethnic differences - black infants lighter than whites at birth; mother?s ethnicity = stronger predictor 2. SES factors ? US born have lower birth weights than foreign born minorities 3. ****SMOKING ? most important determinant of birth weight!!!!!! 4. Cocaine 5. Teenage pregnancy ? mothers younger than 16 likely to have low birth weight; mothers are still growing! Competing with infant for nutrients Low Birth Weight in Developing Countries 1. Undernutrition ? 16% of all newborns 2. Teenage pregnancy ? competing for nutrients Immune System 1. leukocytes (white blood cells) and macrophages ? kill bacteria 2. lymphatic system 3. humoral immunity ? produces antibodies (proteins synthesized by plasma cells) 4. cell-mediated immunity ? T and B lymphocytes ** Fetal nutrition impacts later immunity! More vulnerable to infectious diseases! Protein energy malnutrition ? kwashiorkor and marasmus adult height = 10% less in malnourished Effects of Undernutrition stunting ? short stature (chronic) ? more boys women suffer less consequences of undernutrition because they can store more energy (have more fat); eating the same amount of food ( less effect in males because they have bigger muscles underweight ? acute wasting ? low weight and height for age (chronic) ***Females have more caloric reserves of energy! ? less vulnerable to malnutrition, more buffers against environmental stress Determinants of variability in birth weight in developing nations: 1. Socio-economic factors: blacks are usually born weighing less than whites 2. Smoking: easiest factor to control and MOST deleterious effect! Occurs because of oxygen reduction; smoking reduces oxygen, decreases appetite, increases metabolic rate usually weigh 200 grams less at birth 3. Teenage pregnancy: before 16 years = low birth weight competing for nutrients with mother because both are growing! Also after 40 years of age ? hormones less able to readily store energy Head Circumference and undernutrition: maternal undernutrition must be EXTREMELY severe to affect brain growth! Results in low birth weight BUT THE SAME BRAIN SIZE!!!!!! NO POPULATION DIFFERENCES IN HEAD CIRCUMFERENCE ( No population differences in brain size!