Nutrition Principles Lecture 36

Lecture 36: Principles of Nutrition (2)

• Learning Objectives: Students will be able to understand acceptable macronutrient distribution ranges (AMDR) and differentiate between beneficial and harmful types of lipids.

Acceptable Macronutrient Distribution Ranges (AMDR)

• AMDRs are ranges of intake for macronutrients linked to a reduced risk of chronic disease while ensuring adequate essential nutrients.

• For adults, the AMDR is:

  • 45-65% of total calories from carbohydrates
  • 20-35% of total calories from fat
  • 10-35% of total calories from protein

Dietary Fats

• Types of fats significantly impact health outcomes more than the total amount consumed.
• Fats influence coronary heart disease (CHD), cancer risk, and obesity.

Plasma Lipids and CHD

• A strong link exists between elevated blood LDL cholesterol and heart disease.
• High HDL cholesterol levels correlate with a reduced risk of heart disease.
• Elevated plasma triglycerides also pose a risk for CHD, although the association is weaker than with LDL cholesterol.

Saturated Fats

• Consumption of saturated fats (containing no double bonds) increases total plasma cholesterol and LDL levels, augmenting CHD risk.
• Key sources include dairy, meat products, and some vegetable oils (e.g., coconut, palm).

Monounsaturated Fats

• Monounsaturated fats contain one double bond per fatty acid.
• Predominantly found in vegetables and fish.
• Lower both total plasma cholesterol and LDL levels.
• Maintain or slightly increase HDL cholesterol levels.
• Associated with low CHD incidence.
• An example is oleic acid.

Polyunsaturated Fats (PUFAs)

• PUFAs contain more than one double bond.
• The effect on cardiovascular disease varies depending on the location of double bonds.

ω-6 Fatty Acids

• Examples include linoleic acid (18:2(9,12)).
• Derived from vegetable oils.
• Lower plasma cholesterol and LDL.
• Lower HDL.
• Sources: nuts, avocados, olives, soybeans, sesame, cottonseed, and corn oil.

ω-3 Fatty Acids

• Examples include linolenic acid (18:3(9,12,15)).
• Found in plants.
• Suppress cardiac arrhythmias.
• Reduce serum triglycerides.
• Lower blood pressure.
• Decrease thrombosis tendency.
• Significantly reduce cardiovascular mortality.
• Have minimal effect on LDL and HDL cholesterol levels.
• Two fatty fish (e.g., salmon) meals per week are recommended.
• ω-3 long-chain PUFAs are present in infant formula for brain development.

Trans Fatty Acids

• Classified as unsaturated but behave like saturated fats, increasing LDL but not HDL.
• Increased risk of CHD
• Formed during hydrogenation of liquid vegetable oils (used in margarine and hydrogenated oils).
• Present in some baked goods, cookies, cakes, and deep-fried foods.

Reference Book

• Biochemistry "Lippincott's Illustrated Reviews" by Champe, Harvey, and Ferrier (2005), 5th or 6th edition.

This quiz covers the principles of nutrition discussed in Lecture 36. Focus areas include acceptable macronutrient distribution ranges (AMDR) and the impact of different types of dietary fats on health. Understand the relationship between diet and chronic diseases like heart disease.