Key Topics in Nutrition: Study Guide

Nutrition Fundamentals

Vitamin B

Vitamins are essential micronutrients required for various metabolic processes. Vitamin B refers to a group of water-soluble vitamins that play important roles in cell metabolism.

• Key B Vitamins: Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic acid (B5), Pyridoxine (B6), Biotin (B7), Folate (B9), and Cobalamin (B12).

• Functions: Energy production, red blood cell formation, nervous system health.

• Deficiency Symptoms: Fatigue, anemia, neurological issues.

• Sources: Whole grains, meats, eggs, dairy, legumes, leafy greens.

Bone Health

Bone health is maintained by a balance of nutrients, hormones, and physical activity.

• Key Nutrients: Calcium, vitamin D, phosphorus, magnesium.

• Vitamin D: Enhances calcium absorption in the gut.

• Osteoporosis: A condition characterized by weak and brittle bones, often due to calcium or vitamin D deficiency.

Vitamin C and Iron

Vitamin C (ascorbic acid) is a water-soluble vitamin important for immune function and collagen synthesis. It also enhances the absorption of non-heme iron from plant sources.

• Iron: Essential for hemoglobin formation and oxygen transport.

• Deficiency: Can lead to anemia, fatigue, and impaired cognitive function.

Vitamin B6

Vitamin B6 (pyridoxine) is involved in amino acid metabolism, neurotransmitter synthesis, and hemoglobin production.

• Deficiency: Can cause anemia, dermatitis, depression, and confusion.

Antioxidants

Antioxidants are molecules that protect cells from oxidative damage caused by free radicals.

• Examples: Vitamin C, vitamin E, beta-carotene, selenium.

• Role: May reduce risk of chronic diseases such as cancer and heart disease.

Nutrition and Disease

Malignant Tumor

A malignant tumor is a cancerous growth that can invade surrounding tissues and spread to other parts of the body.

• Nutrition's Role: Diets high in antioxidants, fiber, and certain vitamins may reduce cancer risk.

How to Reduce Risk of Cancer

• Consume a diet rich in fruits, vegetables, and whole grains.

• Limit processed and red meats.

• Maintain a healthy weight and engage in regular physical activity.

• Avoid tobacco and limit alcohol consumption.

Energy Balance and Weight Management

Behavior Modification Techniques

Behavior modification involves strategies to change eating and activity habits for better health outcomes.

• Examples: Self-monitoring, goal setting, stimulus control, cognitive restructuring.

How to Estimate Caloric Needs

Caloric needs depend on age, sex, weight, height, and physical activity level.

• Basal Metabolic Rate (BMR): The number of calories required to maintain basic physiological functions at rest.

• Total Energy Expenditure (TEE): $\text{TEE} = \text{BMR} + \text{Physical Activity} + \text{Thermic Effect of Food}$

BMI – What is Overweight, etc.?

Body Mass Index (BMI) is a screening tool for categorizing weight status.

• Formula: $\text{BMI} = \frac{\text{weight (kg)}}{\text{height (m)}^2}$

• Categories: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), Obese (≥30)

Weight Loss – How Can a Person Lose 1 lb. in a Week?

To lose 1 pound of body weight, a caloric deficit of approximately 3,500 kcal is needed.

• Strategy: Reduce daily intake by 500 kcal or increase physical activity to achieve a 3,500 kcal deficit over 7 days.

Weight Theories (Ideal Weight, etc.)

Several theories exist to determine ideal body weight, including BMI, waist-to-hip ratio, and body fat percentage.

• Ideal Body Weight (IBW) Formula (Hamwi method):

• For men: $\text{IBW} = 106 \text{ lbs} + 6 \text{ lbs for each inch over 5 feet}$

• For women: $\text{IBW} = 100 \text{ lbs} + 5 \text{ lbs for each inch over 5 feet}$

Macronutrients and Metabolism

Aerobic and Anaerobic Metabolism for Each Nutrient

Metabolism refers to the chemical processes that convert food into energy. Aerobic metabolism requires oxygen, while anaerobic metabolism does not.

• Carbohydrates: Can be metabolized both aerobically and anaerobically.

• Fats: Metabolized aerobically only.

• Proteins: Primarily metabolized aerobically.

How Much Protein Does an Average Adult Need per kg?

The Recommended Dietary Allowance (RDA) for protein is:

• $0.8 \text{ g protein/kg body weight/day}$ for healthy adults.

• Needs may increase for athletes, pregnant women, or during illness.

When Do Nutrient Requirements Increase?

• During periods of growth (childhood, adolescence)

• Pregnancy and lactation

• Illness, injury, or recovery

• Increased physical activity

Micronutrients

Chromium

Chromium is a trace mineral involved in carbohydrate and lipid metabolism, and it enhances insulin action.

Vitamin A

Vitamin A is a fat-soluble vitamin important for vision, immune function, and cell growth.

• Deficiency: Night blindness, increased infection risk.

• Sources: Liver, dairy, orange and green vegetables.

Iodine

Iodine is essential for thyroid hormone synthesis, which regulates metabolism.

• Deficiency: Goiter, hypothyroidism, developmental delays in children.

• Sources: Iodized salt, seafood, dairy.

Promoters

Promoters are substances that enhance the absorption or utilization of nutrients. For example, vitamin C promotes iron absorption.

Protein and Amino Acids

Amino Acid Structure

Amino acids are the building blocks of proteins, each containing an amino group, a carboxyl group, and a unique side chain (R group).

• General Structure: $\text{NH}_2-\text{CHR}-\text{COOH}$

Amino Acid Processing in Liver

The liver plays a central role in amino acid metabolism, including deamination, transamination, and urea synthesis.

Protein Deficiency Diseases

• Kwashiorkor: Protein deficiency with adequate energy intake; symptoms include edema, fatty liver, and skin changes.

• Marasmus: Severe deficiency of both protein and energy; symptoms include wasting and stunted growth.

Vitamins and Minerals

B Vitamins

B vitamins are a group of water-soluble vitamins that play important roles in cell metabolism and energy production.

Calcium

Calcium is essential for bone health, muscle contraction, nerve transmission, and blood clotting.

• Deficiency: Osteoporosis, muscle spasms.

• Sources: Dairy, leafy greens, fortified foods.

Copper and Zinc

Copper and zinc are trace minerals important for immune function, enzyme activity, and growth.

• Deficiency: Impaired immunity, growth retardation, anemia (zinc), and neurological issues (copper).

Blood and Anemia

Microcytic and Macrocytic Anemia – Causes

Microcytic anemia is characterized by small red blood cells, often due to iron deficiency. Macrocytic anemia features large red blood cells, commonly caused by vitamin B12 or folate deficiency.

• Microcytic: Iron deficiency, chronic disease.

• Macrocytic: Vitamin B12 or folate deficiency.

Folate and Neural Tube Defects

Folate is a B vitamin essential for DNA synthesis and cell division. Adequate folate intake before and during early pregnancy reduces the risk of neural tube defects in infants.

• Sources: Leafy greens, legumes, fortified grains.

Metabolic Rate

BMR (Basal Metabolic Rate)

BMR is the amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state.

• Factors Affecting BMR: Age, sex, genetics, body composition, hormone levels.

• Formula (Harris-Benedict Equation):

• For men: $\text{BMR} = 66 + (13.7 \times \text{weight in kg}) + (5 \times \text{height in cm}) - (6.8 \times \text{age in years})$

• For women: $\text{BMR} = 655 + (9.6 \times \text{weight in kg}) + (1.8 \times \text{height in cm}) - (4.7 \times \text{age in years})$

Table: Types of Anemia

Type	Red Blood Cell Size	Main Cause	Key Nutrient Deficiency
Microcytic	Small	Iron deficiency, chronic disease	Iron
Macrocytic	Large	Impaired DNA synthesis	Vitamin B12, Folate

Additional info:

• Some topics (e.g., "Promoters") were expanded with academic context for clarity.

• Where only a term was listed, standard textbook definitions and explanations were provided.