63 lines
2.8 KiB
Markdown
63 lines
2.8 KiB
Markdown
- **Lipids** are a class of nutrients that do not dissolve in water.
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- They will dissolve in organic solvents
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- Oil is less dense than water, so it will rise to the top of a solution
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- Major functions of lipids in the body include
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- Providing and storing energy
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- forming and maintaining cell membranes
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- producing steroid hormones
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- insulating the body
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- cushioning the body against bumps and blows
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- forming body contours
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- **absorbing fat soluble vitamins and phytochemicals**
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## Fatty Acids
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A fatty acid is a hydrocarbon chain found in lipids; one end of the chain forms a carboxylic acid, and one end forms a methyl group.
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- Short chain fatty acids have 2 to 4 carbons
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- Medium chain fatty acids have 6 to 12 acids
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- Long chan acids have 14 to 24 carbons
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- Fatty acids are identified by:
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- The number of carbon atoms
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- The type of bond between carbon atoms
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- **Saturated fatty acid (SFA)** Every single carbon atom is filled with hydrogen atoms
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- **Unsaturated fatty acid** is a fatty acid that is missing hydrogen atoms and has one or more double bonds within the carbon chain
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- **Monounsaturated** (MUFA)
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- Has one double bond within the carbon chain
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- Sources include:
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- **Canola oil**
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- **Olive oil**
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- **Avocados**
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- Nuts
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- Seeds
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- Peanut butter
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- **Polyunsaturated** (PUFA)
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- Fatty acid that has two or more bonds within the carbon chain
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- Sources include:
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- **Soybean oil**
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- **Fatty fish**
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- **Flax seed**
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- **Walnuts**
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- Corn oil
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- Sunflower oil
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- Most naturally occurring fatty acids are cis fatty acids
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- Hydrogen atoms of the double bonded carbon are on the same side of the hydrocarbon atom
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- **Trans fats** are unsaturated fatty acids that have a trans double bond.
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- Hydrogen atoms of the double bonded carbons are on the opposite side of the hydrocarbon chain
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- **Hydrogenation** is the food manufacturing process that adds hydrogen atoms to liquid vegetable oil, forming trans fats.
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- Can be stored for longer periods because they are less likely to undergo oxidation
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- Raise "bad" cholesterol levels in the blood
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- Increases risk of heart disease
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- **Essential fatty acids** are fatty acids that must be supplied by the diet
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- **Linoleic acid** - 18 carbon omega-6 fatty acid found in vegetable oils
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- **Alpha-linolenic acid** - 18 carbon omega-3 unsaturated fatty acid, found in flaxseed, walnuts
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- Precursor for
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- Eicosapentaonoic acid (EPA) - 20 carbons
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- Docosahexaenoic acid (DHA): 22 carbons
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- Both acids are found mainly in fatty fish
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- Essential fatty acids are needed for growth and healthy cell membranes, especially in the brain.
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# Triglycerides
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A lipid that has three fatty acids attached to a three-carbon compound called glycerol
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- Comprises 95% of lipids in food and body
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- **Glycerol** is a three carbon alcohol that forms the backbone of fatty acids
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# Phospholipids
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# Sterols |