Nutrition, Study Review

• A healthy diet is composed of five main building blocks: carbohydrates (energy), proteins (tissue building), fats (energy storage), vitamins (body process support), and minerals (bone/nerve support).
• A nutrient is considered "essential" if the body cannot produce it on its own and it must come from food.
• Nutrient density refers to the concentration of essential nutrients relative to calorie content.
• Foods with high nutrient density provide more nutrients per calorie.
• A gene is a DNA segment with instructions for making proteins and determining body traits/functions.
• A whole grain contains the bran, germ, and endosperm, making it more nutritious than refined grains.
• A fortified food has added nutrients not originally present in it (vitamin D in milk, iodine in salt).
• An enriched food has nutrients added back after processing removed them (B vitamins and iron in white flour).
• Epigenetics studies how environment and lifestyle choices influence gene activity without altering the DNA sequence.
• Recommended Dietary Allowance (RDA) is the daily nutrient amount needed for healthy individuals in a specific age/gender group.
• Daily Value (DV) on nutrition labels indicates how much a nutrient contributes to the total daily recommended intake, based on a 2,000-calorie diet.
• Acceptable Macronutrient Distribution Range (AMDR) is the recommended percentage of daily calorie intake for macronutrients.
  • Carbohydrates: 45–65% of total calories
  • Proteins: 10-35% of total calories
  • Fats: 20-35% of total calories

RDA/DRI for Protein and Carbohydrate

• Protein: 0.8 grams per kilogram of body weight each day
• Carbohydrates: At least 130 grams each day for brain function

Basal Metabolic Rate (BMR)

• BMR is the number of calories needed for basic functions at rest (breathing, circulation)

Estimated Energy Requirement (EER)

• EER is the estimated daily calorie needs to maintain energy balance, considering age, gender, weight, height, and activity level.

Central Fat

• Central fat is the fat stored around the abdomen and internal organs, known as "abdominal fat," and is associated with a higher risk of chronic diseases.

Visceral Fat

• Visceral fat surrounds internal organs and is more harmful than subcutaneous fat due to its metabolic effects.

Subcutaneous Fat

• Subcutaneous fat is stored under the skin and is less harmful than visceral fat.

Glucagon

• Glucagon is a hormone released by the pancreas that raises blood sugar levels by signaling the liver to release stored glucose.

Insulin

• Insulin is a hormone produced by the pancreas that lowers blood sugar levels by helping cells absorb glucose for energy or storage.
• Hemoglobin transports oxygen from the lungs to the rest of the body via red blood cells.
• Myoglobin stores and delivers oxygen to muscles during activity via muscle cells.
• Anemia occurs when there are insufficient red blood cells or hemoglobin, leading to symptoms like fatigue/weakness.

Stages of Behavior Change

• Precontemplation: No intention to change behavior.
• Contemplation: Aware of the need for change but not ready to act.
• Preparation: Planning to change soon and taking small steps.
• Action: Actively making lifestyle changes.
• Maintenance: Sustaining new habits and preventing relapse.
• Termination: Behavior change fully integrated into daily life.

Nutrient Categories and Energy-Yielding Nutrients

• Macronutrients (provide energy): Carbohydrates (4 kcal/g), Proteins (4 kcal/g), Fats (9 kcal/g, most energy-dense).
• Micronutrients (do not provide energy): Vitamins and Minerals.
• Water is essential but provides no energy
• Non-Nutrients: Substances like phytochemicals and fiber provide health benefits but are not essential nutrients.
• Energy in food is measured in kilocalories (kcal).
  • Carbohydrates: 4 kcal/g
  • Proteins: 4 kcal/g
  • Fats: 9 kcal/g
• The digestive system includes the mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, and gallbladder.
• Mechanical digestion involves physical breakdown (chewing), while chemical digestion uses enzymes/acids.
• Nutrients are absorbed primarily in the small intestine and transported through the blood/lymph.
• Digestive tract cells replace themselves every 3-5 days.

Types of Carbohydrates

• Monosaccharides (single sugar units): Glucose, Fructose, Galactose.
• Disaccharides (two sugar units): Sucrose, Lactose, Maltose.
• Polysaccharides (many sugar units): Starch, Glycogen, Fiber.

Soluble vs. Insoluble Fiber

• Soluble fiber dissolves in water, slows digestion, regulates blood sugar, and lowers cholesterol (oats/beans/apples).
• Insoluble fiber increases stool bulk, prevents constipation, and supports digestive health (whole grains/nuts/vegetables).
• Whole grains contain bran, germ, and endosperm, but refining removes the bran/germ, reducing fiber/vitamins/minerals.
• Carbohydrates break down into glucose, and excess glucose stores as glycogen in the liver/muscles.
• Glycogen stores deplete in about 24 hours if not replenished.
• Insulin lowers blood sugar by helping cells absorb glucose.
• Glucagon increases blood sugar by signaling the liver to release stored glucose.
• Lipids are broken down by bile/lipases, absorbed in the small intestine, and transported via the lymphatic system, and stored in adipose tissue for energy.

Types of Lipids and Fat Classifications

• Triglycerides (main form of fat storage), Phospholipids (cell membranes), Sterols (cholesterol).
• Saturated fats (solid at room temp, found in animal products).
• Monounsaturated & Polyunsaturated fats (liquid at room temp, found in oils/nuts/fish).
• Trans fats (artificially hydrogenated, harmful to health).
• Proteins consist of amino acids linked by peptide bonds.
• Essential amino acids must come from food.
• Foods can be complete (all essential amino acids, animal products) or incomplete (missing some amino acids, legumes/grains).
• Complementary foods (rice/beans) can form a complete protein.
• Proteins function in muscle structure, enzymes, hormones, immune function, and fluid balance.

Nutrient Storage in the Body

• Carbohydrates are stored as glycogen in the liver and muscles.
• Fats are stored in adipose tissue.
• Proteins are not stored; excess converts to either fat or is used for energy.
• Vitamins and Minerals: Some store (fat-soluble vitamins, iron); others do not (water-soluble vitamins).
• Canada's Food Guide encourages a balanced diet:
  • Vegetables/fruits (50% of the plate).
  • Whole grains (25%).
  • Protein-rich foods (25%).
  • Water as the drink of choice
• Fat-soluble vitamins (A, D, E, K) store in fat and can build up in the body.
• Water-soluble vitamins (B-complex/C) are not stored, and excess is excreted in urine.

Vitamin Deficiencies and Related Diseases

• Vitamin D deficiency causes Rickets (weak bones).
• Vitamin C deficiency causes Scurvy (bleeding gums).
• B12 deficiency causes Pernicious anemia (nerve damage, fatigue).
• Iron deficiency causes Iron-deficiency anemia (low oxygen transport).

Functions of Micronutrients

• Calcium promotes bone health
• Iron facilitates oxygen transport
• Vitamin A supports vision and immunity
• Vitamin C aids collagen production as an antioxidant
• B vitamins assist in energy metabolism
• Iron-deficiency anemia is when there is not enough iron to make hemoglobin.
• Pernicious anemia is when the lack of B12 affects red blood cell formation.
• The difference is due to the intake: Iron deficiency is due to low iron, while B12 deficiency is due to poor absorption or lack of intake.
• Body Mass Index (BMI) = weight (kg) / height² (m²). - Underweight: <18.5 - Normal: 18.5-24.9 - Overweight: 25–29.9 - Obese: ≥30
• Total energy expenditure includes: BMR (60-70% of total energy use), physical activity (~20-30%), and thermic effect of food (TEF, ~10%). Factors affecting BMR include age, sex, muscle mass, hormones, and genetics.
• Estimating Energy Requirements (EER) is based on age, sex, weight, height, and activity level to determine daily calorie needs which maintain weight.

Test your understanding of essential nutrition concepts. Questions cover topics like essential nutrients, nutrient density, Canada's Food Guide, fortified vs enriched foods, fat-soluble vitamins, epigenetics, scurvy, and macronutrient distribution.