Macro & Micro Nutrients Lecture Notes

Classification and Basics of Nutrients

Nutrients are classified based on the quantity required by the human body into two main categories: Macronutrients and Micronutrients.
Macronutrients constitute the majority of an individual's diet and are essential for growth and energy. These include carbohydrates, proteins, fats, and oils.
Micronutrients are required in very small amounts and consist of vitamins and trace minerals.
While needed in small quantities, micronutrients are essential for bodily functions; a lack of these leads to deficiency diseases.

# Macronutrients: Energy and Growth
Carbohydrates, proteins, and fats are interchangeable as energy sources.
Energy yield per gram:
Fats: $9\, \text{calories/gram}$ ($9\, \text{kcal/g}$).
Proteins: $4\, \text{calories/gram}$.
Carbohydrates: $4\, \text{calories/gram}$.
These nutrients are present in large quantities in food and are required in similarly large amounts by the body.

# Carbohydrates: Energy and Metabolism
Composition: Composed of carbon, hydrogen, and oxygen.
Function: According to (Masby 260), they constitute the main source of energy for all body functions, particularly brain functions, and are necessary for the metabolism of other nutrients.
Forms after ingestion:
Glucose: Circulates in the bloodstream for immediate availability.
Glycogen: Stored in the liver and muscle cells for later use.
Types of Carbohydrates:

1. Available Carbohydrates: present as starch in cereals, legumes, pulses, and potatoes, and as simple sugars in honey, milk, fruits, and sugar.

2. Unavailable Carbohydrates (Dietary Fiber): consist of cellulose and hemicelluloses which the body cannot digest.
   Functions:
   Primary source of energy.
   Spare proteins for body-building functions.
   Dietary fiber increases stool bulk and aids in defecation.
   Food Sources: Cereals (wheat, rice, Bajra, Maize), Pulses (Rajma, Channa, all dhals), sugars, and tubers (potatoes, sweet potatoes).

   Protein Characteristics and Ratings

   Composition: Large combinations of amino acids containing carbon, hydrogen, nitrogen, and oxygen.
   Growth and Maintenance: Broken down into peptides and amino acids vital for growth, development, and building tissues (muscles, skin, hair, nails).
   Amino Acid Types:
   Essential: Cannot be manufactured by the body; must be supplied via diet.
   Non-essential: Can be manufactured by the body.
   Categories:
   Complete: Contain essential amino acids; found in meat, poultry, fish, eggs, milk, and cheese.
   Incomplete: Found in nuts and legumes.
   Functions: Growth/repair of tissues, production of enzymes, hormones, antibodies, and hemoglobin, blood clotting, and providing energy if needed.
   Protein Ratings (Relative Biological Value):
   Eggs: $100$ (Highest rating).
   Fish: $70$.
   Lean beef: $69$.
   Milk: $60$.
   Brown rice: $57$.
   White rice: $56$.
   Soybeans: $47$.
   Peanuts: $43$.
   Dried beans: $34$.
   White Potato: $34$.
   Animal proteins are generally considered superior to vegetable proteins.

   Fats and Oils

   Composition: Carbon, hydrogen, and oxygen (connected differently than carbohydrates).
   Physical States: Oils are liquid at room temperature; fats are solid.
   Functions: Major source of stored energy ($9\, \text{kcal/g}$), cushioning/protection of major organs, insulation to preserve body heat, flavor retention, and satiety (prolongs feeling of fullness).
   Fatty Acids:
   Saturated: Typically found in solid fats.
   Unsaturated: Typically found in oils.
   Sources: Ghee, butter, oilseeds, nuts, meat, poultry, fish, eggs, whole milk, and cheese.

   Balanced Diet and The Food Pyramid

   Definition: Getting the right types and amounts of foods and drinks to supply nutrition and energy for maintaining cells, tissues, and organs, and supporting growth.
   Physical Activity Recommendations:
   Adults: At least $30\, \text{minutes}$ most days.
   Children: $60\, \text{minutes}$.
   Weight management: $60-90\, \text{minutes}$ daily.
   USDA Food Pyramid Guidelines (Based on a $2,000\, \text{calorie}$ diet):
   Grains: $6\, \text{oz}$ (Half should be whole grains).
   Vegetables: $2.5\, \text{cups}$.
   Fruits: $2\, \text{cups}$.
   Dairy: $3\, \text{cups}$ (Low-fat or fat-free).
   Meat/Beans: $5.5\, \text{oz}$ (Lean cuts, seafood).
   Fats/Oils: Most fat should be from fish, nuts, and vegetable oils. Limit solid fats (butter, lard).

   RDA for Major Nutrients

   Carbohydrates: $65\%$ of total diet.
   Proteins: $1\, \text{g/kg}$ of body weight.
   Fats: $3-4\, \text{tsp}$ oil and $1\, \text{tsp}$ ghee.
   Daily Intake Targets:
   Calcium: $1-2\, \text{g/d}$.
   Iron: $28-30\, \text{mg/d}$.
   Vitamin A: $2400-3000\, \text{IU/d}$.
   Vitamin E: $10-15\, \text{mg/d}$.
   Vitamin D: $400-500\, \text{IU/d}$.
   Vitamin K: $50-80\, \text{µg/d}$.
   Vitamin C: $40\, \text{mg/d}$.
   Vitamin B12: $3-2\, \text{mcg/d}$.
   Sodium: $2-3\, \text{g/d}$.

   Comprehensive Mineral Profiles

   Calcium ($Ca$): For bones, teeth, and blood serum. Deficiency: Osteoporosis. Toxicity: Kidney dysfunction. Sources: Milk, dates, broccoli, spinach.
   Phosphorus ($P$): Combines with calcium for bone/cell energy. Deficiency: Osteoporosis. Toxicity: Calcification of tissues. Sources: Avocados, eggs, whole grains.
   Potassium ($K$): Regulates fluids, heart, and nerves. Deficiency: Irregular heart action. Toxicity: Muscular weakness. Sources: Bananas, oranges, potatoes, leafy greens.
   Sodium ($Na$): Fluid regulation. Excess: High blood pressure (Hypertension). Sources: Salt, cured meats, packaged foods.
   Iron ($Fe$): Hemoglobin and oxygen transport. Deficiency: Iron deficiency anemia. Toxicity: Constipation. Sources: Dates, red meats, dark leafy greens.
   Zinc ($Zn$): Growth and maintenance. Deficiency: Growth failure, poor wound healing. Sources: Dairy, poultry, fish, nuts, legumes.
   Fluorine ($F$): Teeth and bones. Deficiency: Tooth decay. Toxicity: Discoloration of teeth, nausea. Sources: Fluoridated water, seafood.
   Copper ($Cu$): Hemoglobin formation. Toxicity: Liver damage. Sources: Organ meats, nuts, egg yolks.
   Iodine ($I$): Thyroid regulation (metabolic rate/growth). Deficiency: Goiter. Sources: Iodized salt, salt-water fish.

   Comprehensive Vitamin Profiles

   Vitamins categorized as Fat-soluble ($A, D, E, K$) and Water-soluble ($C$ and $B$-complex).
   Fat-Soluble Vitamins:
   Vitamin A: Promotes vision and healthy skin. Adult RDA: $1000\, \text{RE}$. Deficiency: Night blindness (nyctalopia), xerophthalmia, Bitot's spots. Toxicity: Liver damage, birth defects. Food Sources: Carrots, sweet potatoes, spinach, liver.
   Vitamin D: Bone formation. Deficiency: Rickets in children (soft bones, bow legs), osteoporosis. Toxicity: Calcium build-up/bone spurs. Food Sources: Fatty fish, fortified dairy products, egg yolks.
   Vitamin E (Tocopherol): Antioxidant, anti-aging. Deficiency: Cellular degeneration. Toxicity: Blurred vision, dizziness. Food Sources: Nuts, seeds, spinach, and broccoli.
   Vitamin K: Blood clotting and bone healing. Deficiency: Hemorrhaging. Food Sources: Leafy green vegetables, fish, meat, eggs.
   Water-Soluble Vitamins:
   Vitamin C (Ascorbic Acid): Immune support, collagen formation. Deficiency: Scurvy (weakness, bleeding gums, loose teeth). Toxicity: Acid sores. Food Sources: Citrus fruits, strawberries, bell peppers, broccoli.
   Vitamin B1 (Thiamine): Nerve/muscle function. Deficiency: Beriberi (means "I can't, I can't" in Singhalese; cripples victims). Food Sources: Whole grains, nuts, and seeds.
   Vitamin B2 (Riboflavin): Energy metabolism. Deficiency: Cheilosis (scaling/fissures at corners of mouth), premature aging. Food Sources: Dairy products, eggs, green leafy vegetables, and lean meats.
   Vitamin B3 (Niacin): Healthy skin and nerves. Deficiency: Pellagra (Characterized by the 4 D's: Dermatitis, Diarrhea, Dementia, Death). Food Sources: Meat, fish, poultry, and whole grains.
   Vitamin B6 (Pyridoxine): Brain function, red blood cell formation. Food Sources: Chickpeas, bananas, potatoes, and fortified cereals.
   Vitamin B9 (Folic Acid): Neural tube birth defects prevention, Red blood cells. Deficiency: Vitiligo (white skin patches), anemia. Food Sources: Leafy greens, legumes, seeds, and fortified grains.
   Vitamin B12 (Cobalamin): Nervous system, sperm production, mental energy. Deficiency: Pernicious anemia. Food Sources: Meat, fish, dairy, and fortified plant-based milks.

   Malnutrition and Hidden Hunger

   Malnutrition (Protein Energy Malnutrition - PEM): Lack of major nutrients. In Madhya Pradesh, $53\%$ of children are malnourished.
   Hidden Hunger: Insidious deficiency caused by cheap, filling food lacking essential vitamins/trace minerals. Strikes health and vitality without necessarily causing a "hungry belly."
   Global Impact: Affects $2\, \text{billion}$ people ($1$ in $3$). High prevalence in Africa; caused by high intake of starchy staples (rice, maize) and low intake of nutrient-rich foods.

   Nutritional Status and Assessment

   Definition: Nutritional status is the current body status of a person/population related to nourishment.
   Interaction Factors:
   Internal: Age, sex, behavior, physical activity, diseases.
   External: Food safety, cultural, social, and economic circumstances.
   Assessment Methods:

3. Direct Methods (ABCD):

• Anthropometric: Measurements of height, weight, BMI, circumferences (MAC, HC).

• Clinical: Physical signs (skin, eyes, tongue, nails) associated with deficiencies.

• Dietary: Evaluation of food intake (Recall, FFQ, Diary).

• Biochemical: Laboratory tests (Blood, Urine).

1. Indirect Methods: Vital health statistics (infant mortality, morbidity), ecological variables (crops), and economic factors (income, food prices).

   Anthropometric Standards and BMI

   Body Mass Index (BMI) Formula: $\text{BMI} = \frac{\text{Weight (kg)}}{\text{Height (m)}^2}$.
   Adult Status Categories:
   Below $18.5$: Underweight.
   $18.5 - 24.9$: Normal.
   $25.0 - 29.9$: Overweight.
   $30.0$ and Above: Obese.
   Children BMI Interpretation: Uses age- and sex-specific percentiles (Underweight if < 5\text{th} percentile; Overweight if $\geq 95\text{th}$ percentile). Waist Circumference: Predicts mortality. Males: Level 1 > 94\, \text{cm}; Level 2 > 102\, \text{cm}.
   Females: Level 1 > 80\, \text{cm}; Level 2 > 88\, \text{cm} (Note: Page 89 mentions 83cm, but standard table shows higher).
   Waist/Hip Ratio (WHR): High risk if > 0.80 for females and > 0.95 for males.

   Dietary and Laboratory Evaluation

   24 Hours Dietary Recall: Quick but depends on memory.
   Food Frequency Questionnaire (FFQ): Around $100$ food items; representative of patterns.
   Diet History: Hour-long interview discovering usual patterns over long periods.
   Observed Food Consumption: Most accurate (meals are weighed) but expensive and time-consuming.
   Laboratory Assessment:

• Hemoglobin estimation: Index of overall nutrition and anemia.

• Urine Dipstick: Checks for sugar, albumin, blood.

• Stool Examination: Presence of parasites.

• Individual Nutrient Measurement: Serum retinol, serum iron, urinary iodine.