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Questions and Answers
What are the two main types of fatty acids found in dietary fats?
What are the two main types of fatty acids found in dietary fats?
Which vitamins require the presence of dietary fat for optimal absorption?
Which vitamins require the presence of dietary fat for optimal absorption?
Which of the following are essential fatty acids that humans must obtain from their diet?
Which of the following are essential fatty acids that humans must obtain from their diet?
What is the effect of the degree of saturation in fatty acids on their physical state at room temperature?
What is the effect of the degree of saturation in fatty acids on their physical state at room temperature?
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What process involves converting liquid oils into solid fats to create a desired texture in foods?
What process involves converting liquid oils into solid fats to create a desired texture in foods?
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Which essential fatty acid is classified under Omega-6?
Which essential fatty acid is classified under Omega-6?
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Which of the following foods is a good source of Omega-3 fatty acids?
Which of the following foods is a good source of Omega-3 fatty acids?
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What is the recommended maximum daily intake of cholesterol for healthy individuals?
What is the recommended maximum daily intake of cholesterol for healthy individuals?
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Which type of fat should represent no more than 7% of total energy intake in a healthy diet?
Which type of fat should represent no more than 7% of total energy intake in a healthy diet?
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From which sources can humans obtain EPA and DHA?
From which sources can humans obtain EPA and DHA?
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Which dietary change is recommended to reduce saturated fat intake?
Which dietary change is recommended to reduce saturated fat intake?
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What is the primary function of fat in the diet?
What is the primary function of fat in the diet?
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Which of the following is NOT a recommended strategy to meet fat intake recommendations?
Which of the following is NOT a recommended strategy to meet fat intake recommendations?
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Which of the following is NOT a major class of lipids found in our diets?
Which of the following is NOT a major class of lipids found in our diets?
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What is the primary function of triglycerides in the diet?
What is the primary function of triglycerides in the diet?
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How can essential fatty acids be best described?
How can essential fatty acids be best described?
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What percentage of energy from fat is found in a traditional Inuit diet?
What percentage of energy from fat is found in a traditional Inuit diet?
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Which type of lipid is primarily found in cell membranes?
Which type of lipid is primarily found in cell membranes?
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Study Notes
Introduction to Dietary Fat
- Dietary fat is crucial for flavor and texture in food
- Julia Childs famously said "Fat gives things flavour" and "With enough butter, anything is good."
- Fat is an important energy source, though needs vary throughout life
- Fat is essential for absorbing vitamins A, D, E, and K
- Fat provides essential fatty acids
- Fat contributes to the palatability of food, dissolving flavors and providing mouth-feel
Why Dietary Fat is Needed
- Essential for energy production (needs change through the life cycle)
- Crucial for absorbing fat-soluble vitamins (A, D, E, and K)
- Provides essential fatty acids
- Enhances palatability by dissolving flavors and giving a characteristic mouth-feel
Crisps and Cooking Oil
- Some crisps contain a substantial amount of cooking oil (up to 33% in some cases).
- The oil content translates to dietary intake.
Setting Recommendations
- Dietary needs vary based on energy needs, fat-soluble vitamin requirements, and essential fatty acids
- Dietary intake also needs to consider chronic disease risk reduction
What is Dietary Fat?
- Dietary fat is a class of naturally occurring organic compounds
- Fat is generally hydrophobic in nature
- Various types of lipids include fatty acids, triglycerides, sterols, and phospholipids
Triglyceride Formation
- Glycerol (a small, water-soluble carbohydrate derivative) plus three fatty acids constitute a triglyceride
Types of Fatty Acids
- Saturated fatty acids: Have the maximum number of hydrogen atoms attached to carbon atoms. They tend to be solid at room temperature.
- Monounsaturated fatty acids: Have one double bond between carbon atoms. They tend to be liquid at room temperature.
- Polyunsaturated fatty acids: Have more than one double bond between carbon atoms. They tend to be liquid at room temperature.
Saturated vs. Unsaturated Fatty Acids
- Saturated fats tend to be solid at room temperature
- Unsaturated fats tend to be liquid at room temperature
- Degree of saturation affects melting point
Fatty Acid Composition of Common Foods
- Animal fats and tropical oils (coconut and palm) are primarily saturated fats
- Some vegetable oils (e.g., olive and canola) are rich in monounsaturated fats
- Many vegetable oils are rich in omega-6 polyunsaturated fats
- Only a few oils contain significant omega-3 polyunsaturated fats
Hydrogenation
- Hydrogenation of unsaturated fatty acids creates saturated and trans fatty acids.
- Hydrogenation changes the physical properties of fats and can convert liquid oils into solids.
- This process can lead to the creation of trans fats which were once common in processed foods.
Trans Fat in the Canadian Food Supply
- The amount of trans fat in processed foods has decreased since 2005-2009, in comparison to 2010-2011
Replacing Trans Fats
- Alternatives to partial hydrogenation include full hydrogenation, fractionation, traditional highly saturated fats, and interesterification blends.
Interesterification
- Interesterification is a process that rearranges fatty acids in triglycerides
- It can change the melting properties of a fat
Interesterification (IE)
- Alters the melting properties of fats without generating trans fats
- Can reduce saturated fat content by approximately 10%
- Increases the proportion of saturated fatty acids in the sn-2 position.
Next Time...
- Discussion on how much fat people eat
Trends in Fat Consumption
- Fat consumption patterns over time demonstrate variations in type and quantity
- Data shows shifts in dietary fat intake over time.
Definitions
- Fat/Lipid: Naturally occurring organic compounds typically hydrophobic (repel water)
- Fatty Acids: Carboxylic acids with varying aliphatic (carbon) chain lengths
- Triglycerides: The most abundant dietary lipid, composed of three fatty acids bonded to one molecule of glycerol
- Phospholipids: Amphipathic lipids, major components of biological membranes. They have both hydrophilic (water-loving) and hydrophobic (water-fearing) properties
- Sterols: Amphipathic lipids with a four-ringed structure. Examples like Cholesterol are often associated with animal products.
Classifying Lipids
- Triglycerides, Fatty Acids, Phospholipids, Glycolipids, Sterols represent distinct lipid classes
- Each class has unique structures and functions
- Each class has different implications on health
Fat as a Source of Energy
- Fat provides 9 kcal/gram in comparison with 4 kcal/gram for protein and carbohydrates
- Fat's energy density depends on the proportion consumed in various diets
- Breast milk, Asian/African rural diets, Japanese diets, and traditional Inuit diets vary in the percentage of total energy from fat
Trends in Fat Consumption and Source
- Data from various studies reveal trends in fat ingestion and associated sources
- Graph data shows changes over various periods of time
Fats as a Function of Total Energy Consumption
- A global map reveals dietary fat intake trends per country, with region-specific differences showing the quantity of fat ingested.
Top Contributors of Saturated Fats to the Canadian Diet
- Data shows foods containing a high proportion of saturated fats, with some processed foods frequently appearing among the highest contributors.
Essential Fatty Acids
- Omega-6 fatty acids (linoleic acid) and Omega-3 fatty acids (linolenic acid, EPA, and DHA) are essential for human health, but can be derived from specific food sources
- Omega-3 and 6 fatty acids play various critical functions, impacting heart health to developing brain function in infants
Cholesterol
- Cholesterol is a sterol found only in animal products, a type of dietary fat
- Specific foods contribute a significant portion of the cholesterol consumed by humans in the North American Diet
Action of Bile in Fat Digestion
- Bile acts as an emulsifier, breaking down fats into smaller globules for more efficient enzyme action to aid digestion.
- Bile has both water-loving and fat-loving properties which allows it to break down fats for easier absorption
Process of Lipid Digestion and Absorption
- Digestion process occurs in multiple bodily components to digest and absorb lipids and fat, including in the mouth, stomach, and small intestine
- Lipids are absorbed at the intestinal lining by converting larger molecules into triglycerides and then packaged into lipoproteins for transport.
Lipoproteins
- Lipoproteins are complexes of lipids and proteins, enabling fat transport in the bloodstream
- LDL (low-density lipoproteins) contain primarily fat, with less protein
- HDL (high-density lipoproteins) contain more protein than fat
Effect of Different Fats on Cholesterol
- Monounsaturated and polyunsaturated fats tend to lower LDL cholesterol. Saturated fats and trans fats raise LDL cholesterol.
- Trans fats also tend to lower HDL cholesterol
A Fat Cell
- Fat cells (adipocytes) store lipids and are an important part of the body's energy reserve and insulative functions
Fat's Role in the Body
- Fat acts as an energy store, supplies fuel for muscles, aids as an emergency energy reserve, acts as insulation, forms the bases of certain cell membranes, and serves as a source for hormones and other essential compounds
- Fats involved in transporting vitamins A, D, E, and K, along with assisting absorption of needed products. Fats also play critical roles in satiety, senses of taste and smell of food.
Dietary Fat Recommendations
- Limit total fat to less than 30% of daily energy intake
- Limit saturated fat to less than 7% of daily energy intake
- Ensure adequate intake of polyunsaturated and monounsaturated fats while also limiting cholesterol intake
How to Meet Recommendations
- Choose foods with lower fat content
- Reduce consumption of red meat and replace with poultry and fish
- Consume fewer processed and hydrogenated foods
Food Sources of Fatty Acids
- Various foods contain different types and amounts of healthful and harmful fatty acids. Consult specific food sources for details.
Saturated Fat Debate
- The historical perception of saturated fat as harmful has been debated and reevaluated over time, with differing views and recommendations across different periods.
Calories, Fat, and Saturated Fat in Cooked Ground Meat Patties
- Specific data regarding calorie, fat, and saturated fat contents depending on different types of cooked ground meat. This analysis offers a comparison based on various types of ground meat and cooked ground meat patties
Lipids in Grain Products
- Different grain products contain various quantities of total caloric intake, fat intake, and saturated fat intake. Consult this section for details.
Food Fat, Saturated Fat, and Calories
- Specific nutritional information regarding food fat, saturated fat, and calories present in various foods including a range of cooking methods for plain and cooked potatoes, as well as estimations of caloric intake for different portions sizes in pork chops or with a portion of milk.
Food Feature: Defensive Dining
- Suggestions to reduce saturated fat in home-prepared foods include swapping ingredients for lower saturated fat alternatives
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