Study Notes for BIO 1023 - Chapters 12 & 13

Chapters 12 & 13 Overview

Learning Objective 1: Differences Between Vitamins & Minerals

  • Micronutrients: Needed in small quantities, essential, not a source of energy.
      - Organic Micronutrients (Vitamins): Substances that typically contain carbon and are derived from living organisms.
      - Inorganic Micronutrients (Minerals): Elements that originate from the earth and are required by the body.
Micronutrients: General Functions
  • Blood Health:
      - Key Vitamins: B-6, B-12, Folate, K
      - Minerals: Iron, Copper
  • Nerve Impulses:
      - Key Vitamins: B-6
      - Minerals: Sodium, Potassium, Calcium, Magnesium
  • Cell Metabolism:
      - Key Vitamins: Thiamin, Riboflavin, Niacin, B-12, etc.
      - Minerals: Zinc, Chromium, Iodine
  • Bone Health:
      - Key Vitamins: A, D, K, C
      - Minerals: Calcium, Phosphorus, Magnesium
  • Immune Function:
      - Key Vitamins: A, B-6, C, D
      - Minerals: Zinc
  • Gene Expression:
      - Key Vitamins: A, D, Folate
      - Minerals: Zinc
  • Antioxidant Defenses:
      - Key Vitamins: E, C
      - Minerals: Selenium, Copper, Manganese
  • Fluid and Ion Balance:
      - Key Minerals: Sodium, Potassium, Chloride
  • Growth and Development:
      - Key Minerals: Calcium, Phosphorus, Zinc

Vitamins

  • Classification:
      - Fat Soluble Vitamins: A, D, E, K
      - Water Soluble Vitamins: B vitamins (B1, B2, B3, B5, B6, B7, B9, B12), Vitamin C
  • Sources: Some vitamins are synthesized in the body while others must come from the diet and supplements.
      - Note: “Natural” vitamin supplements isolated from foods are not healthier than lab-synthesized versions.
  • Absorption:
      - Primarily occurs in the small intestine; fat-soluble vitamins require dietary fat for absorption.
  • Transport:
      - Fat-soluble vitamins are transported via chylomicrons through the lymphatic system and bloodstream.
  • Storage:
      - Fat-soluble vitamins are stored in the liver/adipose tissue, while water-soluble vitamins are excreted quickly, with exceptions for B-12 and B-6.
Vitamin Toxicity
  • Likely to occur with fat-soluble vitamins due to their storage in the body.
Food Sources of Vitamins
  • MyPlate Sources: Dairy, Fruits, Grains, Vegetables, Protein. Examples include:
      - Dairy: Vitamin A, D, B-12
      - Fruits: Vitamin C, Folate
      - Grains: Thiamin, Niacin
      - Vegetables: Vitamin K, Folate
  • Preservation Tips for Vitamins in Fruits & Vegetables:
      - Refrigeration with high humidity, avoid prolonged exposure to heat, light, and air, minimize cooking time, avoid adding baking soda.

Minerals

  • Classification:
      - Major (Macrominerals): Needed in amounts of 100 mg or more daily; include Sodium, Potassium, Calcium, etc.
      - Trace (Microminerals): Needed in smaller amounts; include Iron, Zinc, Copper, etc.
  • Essential Functions: Cannot be synthesized in the body, play critical roles in various physiological processes.
Mineral Sources
  • Major food sources encompass all food groups, especially:
      - Grains, Dairy, Fruits, Vegetables, Protein.
Mineral Absorption
  • Depends on the body’s need, bioavailability, and competition for absorption.
      - Enhancers of Absorption: Vitamin C for iron, Vitamin D for calcium and phosphorus.
      - Inhibitors: Oxalic acid found in leafy greens can hinder mineral absorption.

Learning Objective 2: Coenzymes, Cofactors, and Enzyme Activity

  • Enzymes are proteins that facilitate chemical reactions, often requiring cofactors for activity.
  • Cofactors enhance enzyme function.
  • Coenzymes: Specific organic molecules that serve as cofactors, derived from vitamins.

Learning Objective 3: Food Sources, Functions, and Deficiencies of Micronutrients

B Vitamins Overview
  • Function primarily as coenzymes in energy and amino acid metabolism.
Individual Vitamin Details:

  1. Thiamin (B-1):
       - Sources: Pork, legumes, whole grains, enriched cereals.
       - Deficiency: Beriberi.
       - Toxicity: None known.

  2. Riboflavin (B-2):
       - Sources: Dairy, eggs, liver, leafy greens.
       - Deficiency: Inflammation of mouth and tongue; cracks at mouth corners.
       - Toxicity: None known.
       - Note: Degraded by light; milk sold in opaque containers.

  3. Niacin (B-3):
       - Sources: Meat, fish, poultry, enriched grains.
       - Deficiency: Pellagra.
       - Toxicity: Skin flushing.

  4. Pyridoxine (B-6):
       - Sources: Animal proteins, potatoes, spinach, bananas.
       - Deficiency: Dermatitis, anemia, convulsions.
       - Toxicity: Skin lesions, irreversible nerve damage from supplements.

  5. Folate:
       - Sources: Leafy greens, liver, legumes.
       - Deficiency: Anemia, neural tube defects.
       - Toxicity: High doses can mask B-12 deficiency.
       - Note: Folic acid is synthetic, important in pregnancy.

  6. Cobalamin (B-12):
       - Sources: Animal foods, fortified cereals.
       - Deficiency: Pernicious anemia, neurological symptoms.
       - Toxicity: None known.
       - Note: Stored in the liver; vegans at risk for deficiency.

  7. Pantothenic Acid:
       - Sources: Widely in foods (meat, milk, veggies).
       - Deficiency: Rare; may cause weakness, fatigue.
       - Toxicity: None known.

  8. Biotin:
       - Sources: Whole grains, egg yolks, nuts.
       - Deficiency: Rare, may cause dermatitis and hair loss.
       - Toxicity: Unknown.

  9. Choline:
       - Vitamin-like substance.
       - Sources: Eggs, meat, fish, self-synthesis.
       - Function: Precursor for acetylcholine.
       - Deficiency: No disease; lab-induced effects.
       - Toxicity: Fishy odor, low blood pressure.

Learning Objective 4: Chemical Symbols of Micronutrients

Noteworthy Micronutrients:

  1. Iodine (I):
       - Sources: Iodized salt, seaweed.
       - Function: Thyroid hormone synthesis.
       - Deficiency: Goiter, cretinism.
       - Toxicity: Inhibits thyroid function.

  2. Chromium (Cr):
       - Sources: Eggs, liver, whole grains.
       - Function: Enhances insulin action.
       - Deficiency: Glucose intolerance, nerve damage.
       - Toxicity: Unknown.

  3. Manganese (Mn):
       - Sources: Nuts, leafy greens.
       - Function: Cofactor in metabolism.
       - Deficiency: Poor growth, skeletal issues.
       - Toxicity: Nervous system disorders.

  4. Sulfur (S):
       - Sources: Protein foods.
       - Function: Stabilizes proteins.
       - Deficiency: None known.
       - Toxicity: None known.

Learning Objective 5: Dietary Supplements

  • Definition: Products intended to supplement the diet, may contain vitamins, minerals, amino acids, etc.
  • Industry Overview: Over $60 billion annually in the USA with unregulated claims.
  • Safety Issues: Not monitored by the FDA (except for folic acid).
  • Risks: Vitamin and mineral toxicity, interactions with other nutrients.
  • Ineffectiveness: Cannot resolve nutritional deficiencies from poor diets.
  • Consultation Recommended: Advisable to discuss with healthcare professionals regarding supplements.

Learning Objective 6: Nutrients, Diet, and Cancer

What is Cancer?
  • Defined as altered cells that divide abnormally, leading to tumors that can be benign or malignant.
Risk Factors for Cancer
  • Non-Modifiable: Genetics.
  • Modifiable Factors: Environment, tobacco, diet, obesity, physical inactivity.
Dietary Factor Associations
  • Increased Risk: Low fruit/vegetable intake, excessive energy intake, consumption of fried, red, and processed meats.
  • Decreased Risk: Increased intake of whole grains, dairy, plant-based foods.
  • Note: Supplements do not appear to lower cancer risk.
Recommendations
  • Nutrition Strategies: Increase plant foods, maintain healthy weight, engage in physical activity, limit consumption of alcohol, processed foods, sugary drinks, and red meats.