Nutrition Lecture 4

Pre-Pregnancy Nutrition

• Optimal pre-pregnancy nutrition improves chances of a healthy baby, mother, and future for both.
• Adequate nutrition before conception supports fetal growth.
• Inadequate intake can prevent the fetus from reaching its genetic potential.
• Excessive weight gain is linked to maternal and fetal complications.
• Diet should provide adequate, not excessive, calories and nutrients.

Key Recommendations for Women Capable of Becoming Pregnant

• Iron: Prioritize heme iron (animal sources). Enhance absorption with vitamin C-rich foods.
• Folic Acid: Consume 400 mcg synthetic folic acid daily + natural folate sources.
• Weight Management: Maintain a healthy pre-pregnancy weight.
• Alcohol Avoidance: Avoid alcohol completely, especially early in pregnancy.

Key Nutrients Required Before Pregnancy

1. Folic Acid (Vitamin B9)

• Function: Prevents neural tube defects (anencephaly, spina bifida) by supporting fetal brain and spinal cord development.
• Sources: Synthetic (multivitamins, fortified foods); Natural (leafy greens, citrus fruits, dried beans).
• Medical Note: Neural tube defects often occur before a woman knows she's pregnant.

2. Iron (Heme and Non-Heme Iron)

• Function: Supports increased blood volume & oxygen supply, reduces risk of iron deficiency anemia.
• Sources: Heme Iron (meat, poultry, fish); Non-Heme Iron (spinach, legumes - enhanced with vitamin C).

3. Calcium

• Function: Supports bone health for both mother and baby.
• Sources: Dairy products, fortified plant-based milk, leafy greens.

4. Omega-3 Fatty Acids

• Function: Crucial for fetal brain & eye development.
• Recommendations: Consume 8-12 oz of various seafood weekly.
• Limit: Albacore tuna to 6 oz weekly due to mercury.

5. Iodine

• Function: Prevents fetal hypothyroidism & supports cognitive development.
• Sources: Iodized salt, seafood, dairy products.

Weight Considerations Before Pregnancy

• Obesity Risk: Maternal risks: gestational diabetes, hypertension, preeclampsia, birth defects, cesarean delivery, postpartum anemia, long-term obesity. Fetal risks: higher birth weight (macrosomia), increased perinatal death risk.
• BMI Recommendations:
  • Overweight (BMI 25-29.9): Moderate weight loss recommended if two or more risk factors are present.
  • Obesity (BMI ≥ 30): Substantial long-term weight loss advised.
  • Underweight (BMI ≤ 18.5): Evaluate for eating disorders or body image issues.

Nutrition and Lifestyle During Pregnancy

• High-Risk Pregnancy: Pregnancy more likely to result in low birth weight infants, delivery complications, or long-term issues. Assessment during prenatal visits identifies risk factors.
• Weight Gain During Pregnancy:
  • Normal BMI (18.5-24.9): 25-35 lbs total.
  • Excessive Weight Gain Risks: Maternal risks: gestational diabetes, hypertension, preeclampsia, postpartum weight retention; Fetal risks: hypoglycemia at birth, large for gestational babies, low Apgar scores, long-term obesity risks.
  • Inadequate Weight Gain Risks: Fetal risks: low birth weight (LBW), increased postnatal complications like cardiovascular disease, type 2 diabetes, and childhood obesity.
• Calorie Needs During Pregnancy:
  • First trimester: No extra calories.
  • Second trimester: Increase by 340 calories/day.
  • Third trimester: Increase by 452 calories/day.
  • Total: 2,200-2,900 calories/day depending on pre-pregnancy BMI and activity.
• Nutrient Requirements During Pregnancy:
  • Iron: Increases by 50% due to expanded blood volume. Sources: red meat, fortified cereals, beans, spinach.
  • Vitamin B12: Increases by 10% for nerve function. Sources: animal products, fortified foods.
  • Folic Acid: Essential for preventing neural tube defects.

Substances to Avoid During Pregnancy

• Alcohol: Dehydrates fetal cells, may cause fetal alcohol syndrome (facial abnormalities, intellectual disabilities, developmental delays). Avoid completely.
• Caffeine: High consumption potentially linked to low birth weight (LBW). Safe limit: 300 mg/day or less.
• Herbal Supplements: Lack of scientific testing on safety during pregnancy, potential teratogenic (birth defect causing) effects.
• Fish and Seafood: Mercury contamination from some fish can harm the fetus' brain and nervous system.
  • Safe choices: Low mercury fish (8-12 oz/week). Limit albacore tuna to 6 oz/week. Avoid high mercury fish (shark, swordfish).
• Foodborne Illnesses: Avoid unpasteurized dairy, raw/undercooked foods, and refrigerated deli meats/pâtés (unless heated).

Foodborne Illnesses to Avoid During Pregnancy

1. Listeriosis:

• Cause: Listeria monocytogenes bacteria.
• Impact: Miscarriage, stillbirth, premature delivery, neonatal infections.
• High-risk foods to avoid: Unpasteurized dairy, raw/undercooked meat, deli meats (unless heated thoroughly).

2. Toxoplasmosis:

• Cause: Toxoplasma gondii parasite.
• Impact: Mental retardation, blindness, epilepsy (if contracted during first trimester).
• Prevention: Thoroughly cook meat, wash fruits/vegetables, avoid cross-contamination, avoid changing cat litter.

3. Pica (Non-Food Cravings):

• Definition: Craving and consuming non-food items.
• Potential causes: Cultural beliefs, hunger, medicinal purposes.
• Risks: Iron deficiency anemia, premature birth, developmental delays (due to toxic metal ingestion).

Nutrition for Lactation and Breastfeeding

• Breastfeeding Recommendations:

  • WHO & AAP/ADA: Exclusive breastfeeding for first 6 months; continue breastfeeding with complementary foods.

• Benefits for Infants/Mothers: Reduces mortality & morbidity; faster postpartum recovery, reduced risk of postpartum depression, breast/ovarian cancer, type 2 diabetes, heart disease.

• Barriers: Hospital policies, lack of knowledge, cultural attitudes.

• Factors Impairing Lactation:

  • Impaired letdown (milk ejection reflex): stress, fatigue, negative attitudes, caffeine/alcohol.
  • Failure to establish lactation: delayed/infrequent feedings, weak infant sucking, nipple discomfort, lack of support.
  • Decreased demand: early introduction of formula/solids, supplemental bottles, infant's reduced interest.

• Calorie Requirements During Breastfeeding: 500 extra calories/day (100-150 from stored fat, 350-400 from food). First 6 months: +330; Second 6 months: +400.

• Fluid Intake: Drink water when thirsty. Overhydration does not increase milk production.

• Nutrient Needs: Many nutrients increased during lactation; thiamin, riboflavin, B6, B12, vitamin A, iodine.

• Other Considerations:

  • Alcohol: Passes into breast milk, reduces milk production. Wait 4 hours after drinking.
  • Caffeine: Moderate intake generally safe.
  • Seafood: Follow pregnancy guidelines.

Infant Nutrition (0-1 Year)

• Growth: Rapid physical growth. Birth weight doubles by 4-6 months, triples by 1 year. Length increases ~10 inches.
• Nutritional Needs: Infants need more calories per kg than adults due to rapid growth.
• Breast Milk Composition:
  • Protein (whey): Easy digestion, supports growth, minimizes kidney stress.
  • Fat: Easily digested, essential fatty acids (linoleic acid), cholesterol.
  • Enzymes (e.g., amylase): Aid starch digestion.
  • Minerals: Balanced for infant needs. Iron absorption from breast milk is significantly higher than formula.
  • Vitamins: Provided via breast milk, levels vary with mother's diet.
  • Immune Factors: Antibodies & protective factors, Bifidus factor (promotes healthy gut bacteria).

Infant Formulas

• Types: Standard, specialty (preterm, enriched, soy, lactose-free, hypoallergenic/non-allergenic, antireflux, metabolic disorder).
• Feeding Guidelines: Adjust quantity and frequency based on infant's age, weight, needs. Avoid overfeeding, don't force infants to finish, prevent nursing bottle caries.

Infant Feeding and Obesity

• Risk Factors: Early feeding patterns (overfeeding, early complementary foods), parental practices (ignoring hunger cues, using food as reward/comfort).
• Obesity Prevention Strategies: Breastfeeding (slower weight gain, appetite regulation, varied tastes). Healthy feeding practices (introduce complementary foods after 6 months, balanced diet, portion control).

Introducing Complementary Foods

• Optimal Timing: Around 6 months (developmental readiness). Avoid before 4 months.
• Developmental Readiness: Sitting with support, head/neck control, disappearance of tongue-thrust reflex, interest in food.
• First Foods: Iron-fortified infant cereal, pureed meats, pureed vegetables/fruits.
• Introducing New Foods: One food at a time, 5-7 days apart, monitoring for allergic reactions (rash, fussiness, vomiting...).
• Feeding Guidelines: Start with small amounts, allow self-regulation, avoid empty-calorie foods, avoid common allergens (cow's milk, eggs, wheat, citrus), honey, fruit juice (limit to 4-6 oz).

Nutrition for Toddlers and Preschoolers (1-5 Years)

• Early Childhood Nutrition: Dietary habits persist.
• Parental Role: Decide what's offered, when it's offered, and where they eat. Children decide if/how much they eat.
• Toddler Guidelines: Whole grains, fruits, vegetables, low-fat dairy, lean protein; limit solid fats, added sugars, sodium.
• Portion sizes: 1 tablespoon per year of age. (Ages 4-6 approach smaller adult servings)
• Feeding Challenges:
  • Physiological anorexia (decreased appetite): Offer small, frequent meals.
  • Food jags (temporary preferences): Continue providing a variety of foods.
  • Picky eating: Encourage exploration without pressure/force feeding.
  • Role modeling: Parental habits heavily affect children's eating habits.

Nutrition for School-Age Children (6-12 Years)

• Growth rate: Slower than infancy and adolescence (2-3 inches in height, ~5 lbs per year).
• Nutritional Needs: Increased calories with age, activity, and growth spurts; calories per kg decrease.
• Dietary Guidelines: Follow MyPlate guidelines; whole grains, vegetables, fruits, low-fat dairy, lean protein.
• Nutritional Concerns: Excessive sugar/sodium (sugary drinks, processed snacks, fast food), inadequate nutrient intake (calcium, potassium, vitamin D, fiber).

Nutrition for Adolescents (12-18 Years)

• Physical Growth: Significant growth spurt; girls (10-11 years, peak at 12); boys (12-13, peak at 14 years).
• Weight Gain: Girls tend to gain body fat; boys tend to gain muscle mass.
• Bone Growth: 50% of adult bone mass formed during adolescence, high calcium requirement (1,300 mg/day).
• Caloric Requirements: Moderately active females: ~2,000 calories/day; males: 2,200-2,800 (based on activity).
• Key Nutrients: Calcium, vitamin D, iron, protein, fiber.

Overweight and Obesity in Children and Adolescents

• Causes: Calorie imbalance (overeating, sugary drinks), lack of physical activity.
• Health consequences: Physical (short-term: insulin resistance, prediabetes; long-term: type 2 diabetes, CVD, stroke, kidney failure); Psychological (social stigma, self-esteem issues, depression).
• Prevention strategies: Healthy eating, active lifestyle, parental support, school-based programs.