Nutritional Requirements across the Lifespan
Understanding how nutritional needs change from infancy to old age is essential. This blog post offers a comprehensive breakdown of nutrient requirements across different life stages, complete with recommended dietary allowances (RDAs), food sources. Whether you're teaching or learning Applied Nutrition, this guide will enhance your knowledge and practice.
HEALTH EDUCATION
Dr Qazi Fahim Shezad ( MD, DMRD, MSc, M.Phil Fellow HU)
4/26/20252 min read
I. Introduction
Nutritional needs vary across the human lifespan due to differences in growth, development, activity level, and health status. You must understand these changes to provide effective nutritional guidance and support to individuals and families.
II. Nutritional Requirements by Life Stage
1. Infancy (0–12 Months)
Key Features:
Rapid physical growth.
Immature digestive and immune systems.
Nutritional Requirements:
Breastfeeding: Exclusive breastfeeding is recommended for the first 6 months; continued breastfeeding with complementary foods up to 2 years.
Formula Feeding: Used when breastfeeding is not possible.
Key nutrients: Iron, calcium, vitamin D.
Key Nutrients, Sources & RDA ( required dietary allowance)
Nutrient
RDA (0–6 monts)
Food Sources
Protein
9.1 g/day
Breast milk, formula
Iron
0.27 mg/day
Breast milk, fortified formula, cereals
Calcium
200 mg/day
Breast milk, fortified infant formula
Vitamin D
10 mcg/day
Sunlight, fortified formula, supplements
2. Toddlerhood (1–3 Years)
Key Features:
Slower growth than infancy.
Developing taste preferences and independence.
Nutritional Requirements:
Small, frequent meals rich in nutrients.
Emphasis on iron, Protein, calcium, zinc.
Limit sugary foods and beverages.
Key Nutrients, Sources & RDA:
Nutrient
RDA
Food Sources
Protein
13 g/day
Eggs, milk, legumes, chicken
Calcium
700 mg/day
Milk, cheese, yogurt
Iron
7 mg/day
Red meat, spinach, iron-fortified cereals
Zinc
3 mg/day
Meat, beans, dairy
3. Preschool and School-Age Children (4–12 Years)
Nutritional Focus:
Balanced intake from all food groups.
Nutrients of concern: Vitamin A, calcium, iron.
Nutrient
RDA (4–8 yrs)
Food Sources
Protein
19 g/day
Fish, dairy, lentils
Calcium
1000 mg/day
Milk, yogurt, tofu
Iron
10 mg/day
Eggs, meat, cereals
Vitamin A
400 mcg/day
Carrots, mangoes, green leafy vegetables
4. Adolescence (13–19 Years)
Key Features:
Growth spurts and hormonal changes.
Increased risk of poor eating habits and body image issues.
Nutritional Requirements:
Higher demand for calories, protein, calcium, iron, zinc.
Girls: Increased iron needs due to menstruation.
Nutrient
RDA (Girls)
RDA (Boys)
Food Sources
Protein
46 g/day
52 g/day
Chicken, fish, milk, eggs
Calcium
1300 mg/day
1300 mg/day
Milk, cheese, leafy greens
Iron
15 mg/day
11 mg/day
Liver, red meat, spinach, dates
Zinc
9 mg/day
11 mg/day
Beef, legumes, nuts
5. Adulthood (20–60 Years)
Nutritional Considerations:
Nutrient needs stabilize; focus on health maintenance and disease prevention.
Key nutrients: Fiber, calcium, antioxidants.
Nutrient
RDA (Men)
RDA (Women)
Food Sources
Protein
56 g/day
46 g/day
Meat, legumes, dairy
Fiber
38 g/day
25 g/day
Whole grains, fruits, vegetables
Calcium
1000 mg/day
1000 mg/day
Milk, fish with bones, sesame seeds
Antioxidants
—
—
Berries, green tea, colorful veggies
6. Pregnancy and Lactation
Key Features:
Increased nutritional needs to support fetal development and milk production.
Nutritional Requirements:
Additional 300 kcal/day during 2nd and 3rd trimesters.
Critical nutrients: Iron, folic acid, calcium, iodine, protein.
During lactation: +500 kcal/day.
Nutrient
Pregnancy RDA
Lactation RDA
Food Sources
Energy
+300 kcal/day
+500 kcal/day
Whole grains, lean protein
Iron
27 mg/day
9 mg/day
Liver, meat, leafy greens
Folic Acid
600 mcg/day
500 mcg/day
Citrus fruits, spinach, lentils
Calcium
1000 mg/day
1000 mg/day
Milk, yogurt, cheese
Iodine
220 mcg/day
290 mcg/day
Iodized salt, seafood
7. Older Adults (60+ Years)
Physiological Changes:
Decreased appetite, altered taste and smell, slower digestion.
Higher risk of nutrient deficiencies and chronic diseases.
Nutritional Needs:
Focus on calcium, vitamin D, vitamin B12, fiber, hydration.
Nutrient-dense, easy-to-chew foods.
Nutrient
RDA
Food Sources
Calcium
1200 mg/day
Milk, fortified soy, sardines
Vitamin D
20 mcg/day
Sunlight, fortified milk, egg yolks
Vitamin B12
2.4 mcg/day
Meat, eggs, fortified cereals
Fiber
30 g/day (men)
21 g/day (women)
Fruits, oats, whole wheat