THU

1.3 food components and energy

nutrients

• Nutrients are substances in food essential for the body's energy, structure, and regulatory processes.
• Six classes of nutrients are vital for maintaining overall health: carbohydrates, lipids, proteins, water, vitamins, and minerals.

essential nutrients

• Foods contain various nutrients, but not all are essential.
• An essential nutrient cannot be synthesized by the body or produced in adequate amounts, requiring dietary intake to avoid deficiency.
• Cholesterol is crucial for cell membrane structure and regulation, but is not essential as the liver can produce it from other food sources.
• Vitamin C is essential for humans and certain mammals as it cannot be synthesized by the body.

macronutrients

• Nutrients are classified by the amount required in the diet: macronutrients are needed in large amounts.
• Major macronutrients include water, carbohydrates, proteins, and lipids, typically measured in grams.
• Carbohydrates provide energy, especially for the central nervous system and red blood cells, and facilitate cellular communication.
• Lipids serve as energy sources, structural components of cellular membranes, and precursors for hormones (e.g., vitamin D, estrogen, testosterone).
• Proteins function primarily in a structural and regulatory capacity, forming enzymes and some hormones like insulin.
• Water is crucial for regulating body temperature, removing waste, and serving as a medium for body processes, although it does not provide energy.

micronutrients

• Micronutrients are essential nutrients required by the body in smaller amounts, including vitamins and minerals.
• They regulate body processes but do not provide energy themselves; instead, they assist in energy extraction from macronutrients like carbohydrates, proteins, and fats.
• Minerals contribute to bodily structure, exemplified by bones, which contain high levels of calcium and phosphorus.
• Micronutrients are measured in milligrams and micrograms; for instance, a 20-year-old female requires approximately 18 milligrams of iron and 15 micrograms of vitamin D daily.
• A comparison of nutrient requirements shows a significant difference in quantity: she consumes about 250 grams of carbohydrates daily, which is 16,666,666 times more than her vitamin D requirement when measured equivalently.

nutrients that contain energy

• Energy-containing nutrients include carbohydrates, lipids, and proteins, which can be metabolically processed into cellular energy.
• The energy originates from the chemical bonds within these macronutrients; when these bonds are broken, energy is released and transformed into ATP (Adenosine Triphosphate).
• ATP serves as the compound that fuels body functions.
• Food energy is measured in calories, defined as the energy required to raise the temperature of 1 gram of water by 1 degree centigrade.
• Food calories are commonly listed in kilocalories (kcals or Calories), with 1 kcal being equivalent to 1 Calorie, which equals 1,000 calories.
• For example, a fun size Snickers bar contains approximately 74 kcals (Calories), which would be represented as 74,000 calories in physics terms.

estimating energy

• The caloric content of food can be determined by knowing the grams of carbohydrates, proteins, lipids, and alcohol present.
• Example: A peanut butter and jelly sandwich can have its total calories calculated using energy-yielding nutrients.
• There are specific calories per gram:
- Carbohydrate: 4 calories/gram
- Protein: 4 calories/gram
- Lipid: 9 calories/gram
• Actual caloric values may vary based on the type of nutrient and interactions with other food components.
• For the example sandwich:
- 60 grams of carbohydrates contribute 240 calories (60 x 4).
- 14 grams of protein contribute 56 calories (14 x 4).
- 32 grams of lipids contribute 288 calories (32 x 9).
• The total caloric content for the sandwich is 584 calories.

estimating percent of calories

• Recommendations for energy-yielding nutrients are expressed as percentages of total calories.
• These percentages indicate the proportion of total calories recommended from each macronutrient: fat, protein, and carbohydrates.
• The percentages can be compared to Acceptable Macronutrient Distribution Ranges (AMDR).
• To calculate the percentage of calories from a specific nutrient, divide the calories from that nutrient by total calories and multiply by 100.
• An example calculation for the percentage of calories from carbohydrates is provided.

1.4 phytochemicals and nutrient density

phytochemicals

• An extraction process removing essential nutrients from food would leave behind substances that may provide health benefits.
• These compounds, called phytochemicals, are primarily found in plant foods like fruits, vegetables, whole grains, nuts, and seeds.
• Phytochemicals are not essential nutrients, as there are no specific deficiencies associated with their absence, yet they may offer various health advantages.
• Observational studies indicate that a diet high in fruits and vegetables correlates with a decreased risk of chronic diseases, such as cardiovascular disease and cancer, potentially due to phytochemicals.
• Thousands of phytochemicals have been identified, with many more likely undiscovered, emphasizing the recommendation to consume whole foods rather than rely on supplements.
• Phytochemicals may work synergistically with other food components, making it impossible to isolate and replicate their benefits entirely through supplementation.
• Various groups of phytochemicals exist, such as flavonoids, which belong to the broader polyphenols category and contain subcategories and specific compounds.
• Research is ongoing to uncover the complexity and nutritional implications of phytochemicals, particularly regarding their medical properties.

nutrient density

• Nutrient density is a key concept in achieving a healthy dietary intake, referring to the nutrient-to-calorie ratio in foods.
• The main goals in daily nutrition are to obtain sufficient calories for energy and essential nutrients (especially vitamins and minerals).
• In developed countries, the challenge lies in acquiring necessary nutrients without exceeding caloric needs for maintaining a healthy weight.
• Foods that are considered nutrient dense provide high amounts of vitamins and minerals with fewer calories.
• A comparison shows that a 150-Calorie serving of baked potato is more nutrient dense than French fries, highlighting the importance of food choice.
• Adding purified fats (e.g., butter) or sugars to foods decreases their nutrient density by increasing caloric content without enhancing nutrient value.
• The principle of nutrient density can guide choices in daily meals, including sauces or milk products, to help maintain adequate nourishment while supporting healthy weight.

1.5 promoting change

choices, accountability and change

• Nutrition experts emphasize the importance of considering short- and long-term health impacts in food choices, though it is not the primary factor for many.
• A survey of college students revealed that their food selection is mainly influenced by time, availability, cost, and taste.
• Early food preferences are shaped by parental choices, family traditions, cultural backgrounds, and religious practices.
• Research indicates that current eating patterns often mirror childhood diets.
• Certain foods may evoke positive memories or serve as comfort during stress, which can lead to habitual choices that affect long-term health if not balanced.
• Identifying and changing detrimental food habits is a significant challenge.

stages of change

• Individuals make over 200 food choices daily, influenced by habits, emotions, and external factors like advertisements and packaging.
• Promoting healthy eating requires understanding that behavior change occurs in distinct phases rather than instantaneously.
• The Stages of Change model identifies five phases:
- Precontemplation: Individuals are unaware of or uninterested in change; awareness strategies are essential to progress.
- Contemplation: Weighing benefits and barriers of change; strategies include identifying misconceptions and addressing concerns.
- Preparation: Planning actionable changes within 30 days, like increasing physical activity or purchasing healthier foods; realistic goal-setting is crucial.
- Action: Implementing the planned changes with encouragement and support.
- Maintenance: Sustaining changes as part of one's lifestyle after six months; ongoing effort is necessary for lasting change.
• The process of change parallels spiritual principles, emphasizing agency and personal responsibility in decision-making.

STUDY GUIDE

1.3 Food Components and Energy

Nutrients

• Nutrients are essential substances in food for the body's energy, structure, and regulatory processes.

• Six classes of nutrients: carbohydrates, lipids, proteins, water, vitamins, and minerals.

Essential Nutrients

• Not all nutrients are essential; essential nutrients cannot be synthesized by the body or produced in adequate amounts, requiring dietary intake.

• Example: Cholesterol is crucial but not essential since the liver can produce it; Vitamin C is essential.

Macronutrients

• Macronutrients are needed in large amounts and include water, carbohydrates, proteins, and lipids, typically measured in grams.

• Major functions include:

• Carbohydrates: provide energy and facilitate cellular communication.

• Lipids: serve as energy sources and hormone precursors.

• Proteins: structural and regulatory roles, forming enzymes.

• Water: regulates body temperature and removes waste, no energy.

Micronutrients

• Micronutrients are required in smaller amounts (vitamins and minerals), assisting in energy extraction from macronutrients.

• Example: A 20-year-old female requires 18mg of iron and 15mcg of vitamin D.

Nutrients That Contain Energy

• Energy nutrients: carbohydrates, lipids, and proteins can be metabolically processed into cellular energy (ATP).

• Food energy measured in calories; 1 kcal = 1 Calorie = 1,000 calories.

Estimating Energy

• Caloric content of food can be determined by knowing grams of carbohydrates, proteins, lipids, and alcohol.

• Example: Peanut butter and jelly sandwich total calories calculation based on nutrient composition.

• Carbs (60g): 240 calories

• Protein (14g): 56 calories

• Lipids (32g): 288 calories

• Total: 584 calories.

Estimating Percent of Calories

• Recommendations for energy-yielding nutrients expressed as percentages of total calories; can be compared to Acceptable Macronutrient Distribution Ranges (AMDR).

1.4 Phytochemicals and Nutrient Density

Phytochemicals

• Phytochemicals are compounds in plant foods that may provide health benefits (not essential nutrients).

• High fruit and vegetable diets are linked to a decreased risk of chronic diseases.

• Research ongoing; thousands exist, and many more undiscovered.

Nutrient Density

• Nutrient density refers to the nutrient-to-calorie ratio in foods, prioritizing high amounts of vitamins and minerals.

• Example: Baked potato vs. French fries, nutrient dense vs. calorically dense food comparisons.

1.5 Promoting Change

Choices, Accountability, and Change

• Importance of considering health impacts in food choices; surveyed college students prioritize time, availability, cost, and taste.

Stages of Change

• Behavior change in food choices occurs in distinct phases:

• Precontemplation: Unawareness or disinterest in change.

• Contemplation: Weighing benefits and barriers.

• Preparation: Planning changes within 30 days.

• Action: Implementing planned changes.

• Maintenance: Sustaining changes after six months.