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Study Notes — Food Choices and Nutrient Intake

Learning Objectives and Chapter Structure

  • Learning Objectives (from Chapter 1):
    • Define Nutrient density
    • Compare fortified foods and dietary supplements
    • List the 6 classes of nutrients
    • Discuss the 3 functions of nutrients in the body
  • Activities: Do the Learning Objectives at the beginning; Concept Checks at the end of the chapter

Food Choice: Personal and External Factors

  • Personal factors (priority):
    • Influence of other people
    • Appetite
    • Mood/Emotion
    • Meaning/attachment to food
    • Habits
    • Time
    • Sustainability
    • Convenience
  • Physiological factors:
    • Age
    • Sex
    • Physiological changes
    • Nutrient needs
  • Extrinsic factors:
    • Environmental situation
    • Advertising
    • Trends
    • Seasonal variation
  • Sensory factors:
    • Taste
    • Appearance
    • Aroma, flavor, texture, temperature, quality, quantity
    • Preparation method, presentation
  • SES (Socioeconomic) factors:
    • Family income
    • Food cost
    • Social status
    • Society norms
  • Educational factors:
    • Education level
    • Nutrition education
  • Cultural, religious, and regional factors:
    • Cultural origin
    • Religious background
    • Beliefs and traditions
    • Geographical region

Nutrients from Foods

  • Nutrients are substances in food that provide:
    • Energy (kcals)
    • Structure to the body
    • Regulation of body processes
  • Some nutrients provide energy; others do not
  • Any food you eat adds some nutrients to your diet
  • Foods over supplements; emphasis on good food vs bad food

Nutrients & Their Functions: The Nutrients List

  • Carbohydrates
  • Protein
  • Lipids (Fats)
  • Water
  • Vitamins
  • Minerals

Essential Nutrients

  • Essential = need to obtain from food
  • All six classes of nutrients are essential
  • Humorous aside for illustration:
    • Beer? 30+ cans days worth of protein; 14 cans for days worth of phosphorus
    • Essential Oils are essential (playful note)

Chemical Composition of Nutrients

  • Inorganic nutrients (do not contain carbon):
    • Minerals (e.g., ext{Fe}, ext{Na}, ext{Ca}, ext{K})
    • Water (chemical formula: ext{H}_2 ext{O})
  • Organic nutrients (contain carbon):
    • Vitamins
    • Carbohydrates
    • Protein
    • Lipids
    • Note: Organic = carbon-containing; Organic = often described as "alive" in simple terms

Macro- and Micronutrients

  • Macronutrients — needed in large quantities; provide energy (kcals)
    • Examples: Carbohydrates, Protein, Lipids (fats)
    • Water is often considered a macronutrient for intake purposes; measured in grams
  • Micronutrients — needed in smaller quantities; do not provide kcals
    • Examples: Vitamins, Minerals
    • Common units: mg or mcg

Nutrients in Detail

  • Carbohydrates
    • Include sugars, starches, and fiber
  • Lipids (Fats)
    • Include saturated fats, monounsaturated fats, omega-3 and omega-6 fatty acids; cholesterol
  • Proteins
    • Found in most food groups; many proteins perform diverse roles in the body
  • Vitamins
    • Examples: Vitamin B12, Vitamin C, Niacin, Vitamin D
  • Minerals
    • Examples: Iron, Magnesium, Calcium, Zinc
  • Water
  • Energy concepts:
    • kcal = kilocalorie = 1000 calories
  • Calories per gram for energy-yielding nutrients:
    • Carbohydrates: 4\ \text{kcal/g}
    • Proteins: 4\ \text{kcal/g}
    • Lipids (Fats): 9\ \text{kcal/g}
    • Alcohol: 7\ \text{kcal/g}

The Energy-Yielding Nutrients

  • The energy-yielding nutrients provide Calories to the body:
    • \text{Carbohydrates} \rightarrow 4\ \text{kcal/g}
    • \text{Proteins} \rightarrow 4\ \text{kcal/g}
    • \text{Lipids (Fats)} \rightarrow 9\ \text{kcal/g}
    • \text{Alcohol} \rightarrow 7\ \text{kcal/g}
  • Additional notes:
    • 1 Calorie (with capital C) = 1 kilocalorie (kcal) = 1000 calories
    • 1\ \text{Calorie} = 1\ \text{kcal} = 1000\ \text{cal}

Practice Questions (Basic kcal Calculations)

  • 1. A food has 20 g carbohydrate, 8 g protein and 11 g fat. How many kcals are in this food?
  • 2. A food has 15 g CHOs, 10 g protein, and 5 g saturated fat. How many kcals are in this food?
  • 3. A food has 10 g CHOs, 10 g protein, 10 g fat, 10 mg calcium and 10 IU of vitamin D. How many kcals are in this food?
  • 4. How many grams of fat were consumed if a person received 405 kcal from fat in a day?
  • 5. If a food product contains 10 g of protein and another food item contains 10 g of carbohydrate, how many kcals are provided from each and which item is more fattening?

Nutrient Density vs Energy Density

  • Nutrient Density = Amount of a nutrient per unit of energy (kcals)
    • Example: Food A: 300 mg Ca and 100 kcals
    • Example: Food B: 100 mg Fe and 50 kcals
  • Energy Density = Amount of kcals per unit of nutrient (or per serving/gram relative to nutrients)
    • Concept: kcals/nutrients
  • Why it matters:
    • Choosing foods with higher nutrient density can improve micronutrient intake without excessive kcals
  • Illustrative examples:
    • Food A (higher calcium per kcal) vs Food B (lower calcium per kcal) would differ in nutrient density
    • Similar comparison can be made for iron, etc.

Nutrients from Fortified Foods

  • Fortified foods add nutrients beyond those originally present
  • Fortification vs Enrichment:
    • Fortification = adding nutrients to foods that may not have contained them originally
    • Enrichment = restoring nutrients that were lost during processing (e.g., grains)
  • Examples:
    • Vitamin D added to milk (recent updates)
    • B vitamins and iron added to grains (enrichment of grains with Thiamin, Niacin, Riboflavin, Folic Acid, Iron)
  • Purpose: helps to eliminate nutrient deficiencies in population groups

Nutrients from Dietary Supplements

  • Dietary supplement = a product sold to supplement the diet
  • Examples are not specified here, but commonly include vitamins, minerals, herbals, amino acids, etc.
  • Important distinctions:
    • Supplements are not regulated like food products in all respects
    • Supplements provide nutrients but do not necessarily provide benefits that come from whole foods
    • Reason for use: to fill gaps in intake, not to replace a healthy diet

Foods Provide More Than Nutrients

  • Beyond nutrients, foods contain bioactive substances that can benefit health
  • Phytochemicals in plants are bioactive compounds that can affect cells and tissues
  • These substances are not technically essential nutrients but may influence health outcomes
  • Example discussion: Soylent as a modern food/meal replacement reference (URL: https://www.soylent.com/)

Additional Notes on Terms and Concepts

  • Essential vs nonessential components:
    • Essential nutrients must be provided by the diet to prevent deficiency
  • Organic vs inorganic classification has practical implications for digestion, metabolism, and energy provision
  • The role of context (cultural, economic, educational) in dietary choices is crucial for understanding nutrient intake patterns
  • Ethical and practical implications:
    • Access to fortified foods and supplements can reduce deficiency risks, but overreliance may overshadow whole-food benefits
    • Marketing and trends can influence choices, emphasizing the need for nutritional literacy