12 A

⭐MODULE 12 STUDY GUIDE — Nutrition Across the Lifespan (Ch. 16 & 17: Insel)

Pregnancy → Lactation → Infancy → Childhood → Adolescence → Older Adults

📘 PART 1 — VOCABULARY DEFINITIONSColostrum

The thick, yellow, early milk produced in the first ~2–4 days postpartum; rich in antibodies (IgA), immune cells, and protein to protect newborns.

Complementary foods

Foods or beverages (other than breastmilk or formula) introduced to an infant’s diet around 6 months to meet increasing nutrient needs.

Extrusion reflex

The automatic tongue-thrust reflex that pushes solid food out of an infant’s mouth; disappears around 4–6 months when they are ready for solids.

Hypervitaminosis

Toxicity caused by excessive vitamin intake—usually fat-soluble vitamins (A, D, E, K) because they are stored in body tissues.

Lactation

The physiological process of producing and secreting breast milk from the mammary glands.

Let-down reflex

The reflex where milk is released from the breast in response to infant suckling; triggered by oxytocin.

Oxytocin

A hormone released from the posterior pituitary that causes milk ejection (“let-down”) during breastfeeding and stimulates uterine contractions.

Prolactin

A hormone from the anterior pituitary that stimulates milk production in the mammary glands.

📘PART 2 — GUIDED QUESTIONS ANSWER KEY

PREGNANCY & PRECONCEPTION1. What should women looking to become pregnant be screened for?

• STIs

• Genetic conditions (e.g., sickle cell, Tay-Sachs depending on ethnicity)

• Rubella immunity

• Chronic disease control (diabetes, hypertension)

• Nutrient deficiencies (especially iron, folate, vitamin D)

• Weight/BMI assessment

2. How does weight impact fertility & pregnancy?

• Underweight: risk of infertility, low-birth-weight infants.

• Overweight/Obese: increased risk of infertility, gestational diabetes, hypertension, C-section, neural tube defects.

3. What vitamins are important before conception & why?

4. Maternal physiological changes during pregnancy + purpose

• Blood volume ↑ 50% → supports placenta, fetal growth

• Cardiac output ↑ → increased nutrient/oxygen delivery

• Respiratory rate ↑ slightly → higher oxygen needs

• GI motility ↓ → increased nutrient absorption (but can cause constipation)

• Kidney filtration ↑ → removes fetal wastes

• Fat storage ↑ → supports lactation

• Uterus/breast enlargement → prepares for fetal growth and lactation

5. What does recommended maternal weight gain depend on?

Pre-pregnancy BMI + number of fetuses + maternal age (teen vs adult).

6. Maternal weight-gain recommendations (Insel)

NUTRIENT NEEDS DURING PREGNANCY7. How do calories, protein, vitamins, minerals change?

• Calories:

  • +340 kcal/day (2nd trimester)

  • +452 kcal/day (3rd trimester)

• Protein: +25 g/day (total ~71 g/day)

• Carbs: Minimum 175 g/day to support fetal brain

• Fat: Same %, but ↑ essential fatty acids (DHA)

• Iron: 27 mg/day

• Folate: 600 mcg/day

• Iodine: 220 mcg/day

8. Why increased energy intake?

Supports fetal growth, maternal tissue expansion, placenta, and increased metabolic rate.

9. How do pregnant macro/micronutrient needs compare to adults?

• Higher: calories, protein, folate, iron, iodine

• Similar: carbohydrate % and fat % of total calories

10. Foods women should avoid during pregnancy

• Raw or undercooked meats, sushi

• Unpasteurized dairy (risk of Listeria)

• Deli meats unless heated

• High-mercury fish (shark, swordfish, king mackerel)

• Alcohol

• Limit caffeine (<200 mg/day)

11. Why avoid alcohol, tobacco, drugs?

• Alcohol → fetal alcohol spectrum disorders

• Tobacco → low birth weight, premature birth

• Drugs → birth defects, SIDS, developmental delays

LACTATION12. Breast tissue changes enabling lactation

• Mammary glands enlarge

• Alveoli develop milk-producing cells

• Ductal system develops for milk transport

• Increased blood flow supplies nutrients for milk production

13. What is colostrum & how it differs?

• Higher protein

• High in antibodies (IgA)

• Lower fat and lactose

• Acts as the infant’s first immune protection

14. Roles of prolactin vs oxytocin

15. Energy & nutrition needs of lactating women

• +330–400 kcal/day above normal

• Protein needs remain elevated

• Many vitamin and mineral needs stay high (A, C, E, B vitamins, zinc, iodine)

• Higher than pregnancy for several nutrients because milk production continues daily.

16. Practices to avoid during lactation

• Alcohol (wait 2–3 hrs after 1 drink if consumed)

• Smoking (reduces milk & exposes infant)

• Certain medications

• Excess caffeine

17. Benefits of breastfeeding (min. 3 each)

For infants:

• Immunity boost

• Lower risk of infections & SIDS

• Reduced allergies, asthma, and obesity risk

For mothers:

• Faster uterine shrinking

• Lower risk of breast & ovarian cancers

• Burns calories → aids postpartum weight loss

18. Contraindications to breastfeeding

• Maternal HIV (in high-income countries)

• Untreated tuberculosis

• Galactosemia in infant

• Mothers on certain chemotherapy or illicit drugs

INFANCY19. How do nutrition needs compare to adults?

Infants have the highest energy needs per kg compared to any life stage.

20. Infant growth measurements

• Weight

• Length

• Head circumference

• Growth charts (percentiles)

21. Infant energy needs vs adult

• Infants: ~100 kcal/kg/day

• Adults: ~25–35 kcal/kg/day

22. Infant macro distribution vs adult

23. Do infants need water? Why/Why not?

No.
Breastmilk/formula provides adequate hydration; extra water can cause electrolyte imbalance.

24. When to introduce solid foods (readiness signs)

• Loss of extrusion reflex

• Ability to sit with support

• Good head/neck control

• Interest in food

• Reaching ~6 months of age

25. Why introduce new foods one at a time?

To identify allergies or intolerances.

CHILDHOOD26. Three childhood age groups

• Toddlers: 1–3 years

• Preschoolers: 4–5 years

• School-age: 6–11 years

27. Total energy & protein needs

• Energy needs per kg decrease as growth slows

• Total energy ↑ slightly as body size ↑

• Protein needs ↑ slightly for growth but lower per kg

28. Minerals children may lack

• Iron

• Calcium

• Zinc

29. When to give supplements?

• Limited food variety

• Vegan diets

• Low dairy intake (need Ca, Vit D)

• Iron deficiency risk

30. Factors influencing childhood diet

• Parental habits

• Media/advertising

• School environment

• Culture

• Food availability

31. Main nutritional concern of childhood

Childhood obesity
Programs include:

• School Lunch Program

• WIC

• SNAP-Ed

• Let’s Move (policy initiatives)

32. Food effects on behavior

• Hyperactivity: not caused by sugar; lack of sleep & environment more likely

• ADHD: diet changes may help some (omega-3s, iron)

• Caffeine: overstimulation, irritability, sleep disruption

33. Childhood obesity risks & contributors

Risks:

• Type 2 diabetes

• Hypertension

• Fatty liver disease

• Low self-esteem

Contributors:

• Sugary foods

• Sedentary lifestyles

• High screen time

• Family food environment

Management:

• Balanced meals

• Physical activity

• Family involvement

• Behavioral counseling

ADOLESCENCE34. Physical changes in boys vs girls

• Girls: puberty earlier, ↑ fat mass, menarche

• Boys: later puberty, ↑ muscle mass, ↑ height growth spurt

35. Nutrient needs

• Energy: high due to growth

• Protein: increased for muscle/bone growth

• Calcium: 1300 mg/day

• Iron: ↑ for both sexes; girls after menarche

• Vitamin D: bone development

36. Nutrition-related concerns

• Eating disorders

• Irregular meals

• Fast food reliance

• Iron deficiency (especially girls)

37. Obese adolescents are at risk for:

• Type 2 diabetes

• Heart disease

• Hypertension

• Depression

• Orthopedic problems

OLDER ADULTS (Mature Adults)38. Age-related changes

• Weight: lean mass ↓, fat mass ↑

• Activity: generally ↓

• Immunity: weakens

• Taste/smell: ↓ → lower appetite

• GI: slower motility, less stomach acid

39. Nutrient needs

• Energy: ↓ due to lower metabolism

• Protein: ↑ or maintained to prevent muscle loss

• Carbs: 45–65%

• Fats: same; focus on healthy fats

• Water: ↑ risk of dehydration

40. Vitamin needs of mature adults

• Needs for vitamin D, B12, B6 ↑

• Energy needs ↓, so nutrient-dense foods are crucial

41. Importance of key vitamins/minerals

• Vitamin D: bone health, immunity

• B vitamins: cognition, energy metabolism

• Antioxidants: reduce oxidative stress

• Calcium: prevents osteoporosis

• Zinc: immunity

• Iron: usually lower needs after menopause unless deficiency exists

42. Reasons to add supplements

• Low appetite

• Malabsorption

• Chronic disease

• Medication interference

• Limited sun exposure (Vit D)

43. Factors affecting nutrient needs in older age

• Drug interactions: alter absorption/metabolism

• Depression: decreases appetite

• Anorexia of aging: appetite naturally declines

• Arthritis: difficulty preparing meals

• Bladder issues: restrict fluids

• Dental issues: difficulty chewing

• Vision problems: reduced ability to shop/cook

• Osteoporosis: increased Ca/Vit D needs

44. Why is overweight/obesity a concern in older adults?

Increases risk for:

• Heart disease

• Diabetes

• Mobility issues

• Joint pain

• Disability

• Shortened lifespan