BPK 110_Chapter 1

BPK 110 Human Nutrition: Current Issues

Chapter 1: Introduction to Nutrition

Learning Objectives

  • Define key nutrition terms: nutrition, diet, nutrient, essential nutrient, phytochemical.

  • Distinguish between processed and whole foods.

  • Understand food additives and the concepts of organic and genetically modified foods.

  • Explore the scientific study of nutrition, recognizing its strengths and limitations.

  • Critically evaluate nutrition sources.

Nutrients and Non-nutrients

Nutrients

  • Diet: The total food a person regularly eats.

  • Nutrients: Food substances necessary for maintenance, growth, and survival.

    • Essential Nutrient: Nutrients that the body cannot synthesize, must obtain from diet.

      • Examples: Essential amino acids, essential fatty acids, vitamins, minerals, water.

  • Categories of Nutrients:

    • Macronutrients: Required in larger amounts.

      • Water

      • Carbohydrates: Sugars, starches, fiber (organic).

      • Lipids (fats): Triglycerides, fatty acids, sterols, phospholipids (organic).

      • Proteins: Composed of amino acids (organic).

    • Micronutrients: Required in smaller amounts.

      • Vitamins: Fat-soluble and water-soluble (e.g., vitamin D).

      • Major minerals: e.g., Sodium (Na), Calcium (Ca).

      • Minor minerals: e.g., Zinc (Zn), Copper (Cu).

Non-nutrients

  • Substances found in food that aren't classified as nutrients.

    • Examples: Phytochemicals, caffeine, natural toxins.

Phytochemicals

  • Definition: Chemicals in plants that may have health benefits.

  • Characteristics:

    • Hundreds of known phytochemicals.

    • Contribute to plant colors and may have positive health impacts.

  • Examples:

    • Flavonoids: Bright pigmentation and anti-inflammatory properties.

    • Carotenoids: Antioxidant effects, responsible for yellow, orange, red colors.

Toxins

  • Naturally occurring substances in plants/animals.

  • Can be harmful if consumed above a certain threshold.

  • Tips: Discard old or spoiled food to minimize toxin exposure.

Food Modifications

Fortification of Food

  • Fortified Foods: Addition of nutrients by manufacturers.

    • Mandatory: Example - Iodine in table salt.

    • Voluntary: Example - Added vitamins in cereals.

Whole Foods vs. Processed Foods

  • Whole Foods: Minimally processed, associated with lower disease risk.

  • Processed Foods: Higher processing linked to health risks (e.g., Type 2 diabetes, cardiovascular issues).

  • Classification: Use NOVA classification to differentiate foods based on processing levels.

    • NOVA Groups:

      • Group 1: Unprocessed/minimally processed foods.

      • Group 2: Processed culinary ingredients.

      • Group 3: Processed foods.

      • Group 4: Ultra-processed foods.

Food Additives

  • Substances added to enhance taste, appearance, safety, etc.

  • Must be approved and controlled in quantities, especially in processed foods.

Organic Foods

  • Defined as foods with minimal synthetic input, grown to preserve biodiversity.

  • Features: Lower pesticide levels but nutritional benefits are still being studied.

Genetically Modified Foods (GMFs)

  • Foods with altered DNA through methods like selective breeding.

  • Safety: GM foods on the market have passed assessments; concerns remain regarding biodiversity and ethics.

Why Do We Eat?

Sustenance and Enjoyment

  • Nutrients provide:

    • Body structure and function.

    • Energy: Carbohydrates and proteins = 4 kcal/g; Lipids = 9 kcal/g.

  • Enjoyment plays a substantial role in dietary choices.

Psychological Reasons

  • Psychological factors influence dietary habits and preferences.

Diet and Health

  • Relationship between diet and leading health issues in Canada, particularly chronic diseases.

Gene-Diet Interactions

  • Genetics influence nutrition (appetite, absorption) and vice versa.

  • Epigenetics: Refers to how diet influences gene expression without altering DNA.

Examples of Epigenetics

  1. Agouti Mouse Study: Diet of pregnant mice affected offspring's gene expression.

  2. Dutch Famine Study: Offspring born during the famine showed increased health risks.

Choosing a Healthy Diet

Key Principles

  • Balance: Nutrients should be consumed in proportions promoting health (e.g., 80% healthy vs. 20% less healthy choices).

  • Variety: Consuming diverse foods to minimize nutrient deficiencies.

  • Moderation: Striving for not too much, not too little.

  • Nutrient Density: Higher nutrients relative to caloric intake is preferable.

Study of Nutrition

Research Challenges

  • Difficulty in studying nutrition due to:

    • Constant dietary changes.

    • Non-manipulable variables.

    • Substantial influence of non-nutritional factors.

    • Causation is hard to prove.

  • Common research methods: Experimental studies and epidemiological studies.

The Scientific Method

  1. Define the problem.

  2. Make observations.

  3. Formulate a hypothesis.

  4. Develop a study method.

  5. Collect results (qualitative/quantitative).

  6. Analyze data.

  7. Draw conclusions.

Experimental vs Epidemiological Studies

  • Experimental Studies: Test specific variables; require ethical approval, random recruitment, controlled environments.

  • Epidemiological Studies: Observe population trends; provide insights but do not prove causation.

Limitations of Epidemiology

  • Associations do not imply causation; dietary recall methods are often flawed.

Finding Credible Nutrition Articles

  • Recommended platforms: PubMed, Google Scholar, library databases.

  • Ensure sources are evidence-based and peer-reviewed.

Evaluating Nutrition Sources

  • Assess value, relevance, and trustworthiness of information based on evidence quality, sources, and potential biases.

Nutrition Evidence Considerations

  • Nutrition research is complex and integrative; many questions remain unanswered.

Two-Eyed Seeing Concept

  • Combining Indigenous knowledge with Western scientific methods for a more holistic understanding of food and nutrition.

Recommendations for Healthy Eating

  • Favor whole foods and minimize processed food intake.

  • Practice balance, variety, moderation in food choices.

  • Aim for higher nutrient density in food selections.

  • Utilize VETO (Value, Evidence, Trustworthiness, Opinion) technique for evaluating nutrition information credibility.