Study Guide 5a – Introduction to Lipids
Nutr 12
Describe the roles of triglycerides, sterols, and phospholipids. Which lipid is the "fat" in
foods and in our body fat?
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Explain why it is helpful to include some fat in the diet.
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What are some general roles of lipids in the body?
Define: adipose tissue. Compare the amount of stored energy from glycogen and fat.
Describe the structure of triglycerides. How do the various fatty acids differ from one
another?
Compare the structures and properties of saturated, monounsaturated, and
polyunsaturated fats. How does the degree of saturation affect the physical qualities of fat?
List the foods that are significant sources of each type of fat. Be able to categorize different
foods in terms of their predominant fats, including:
• Animal fats, including meats, milk products, fish oils
• Vegetable oils such as corn, canola, olive, soybean oils, flaxseed
• Peanut butter and peanut oil
• Avocados
• Prepared foods such as margarine and mayonnaise
• “Tropical oils” such as coconut, palm, and palm kernel oils
What are the predominant sources of saturated fat in the U.S. diet? Explain why
nutritionists often suggest replacing meat with plant protein sources in order to reduce
dietary saturated fat.
Describe “hydrogenation”. Why is this process used by food manufacturers? List some
foods that are often high in hydrogenated fats.
What is the connection between hydrogenation and “trans fats”? Contrast cis- and transfatty acids. Would FULLY hydrogenated fats contain any trans fat? Why or why not?
How can you avoid foods that contain significant amounts of trans fats? Are trans fats found
in natural foods, or only in foods that contain hydrogenated fat?
Describe the current recommendations for saturated fat and trans fats. What are the
possible adverse effects of these fats when they are consumed in excessive amounts?
Essential Fatty Acids:
Identify the "essential" fatty acids (EFA). Are the EFA saturated, monounsaturated, or
polyunsaturated? Define: linoleic acid, linolenic acid
Explain the conversion between the 18-carbon omega-3 and omega-6 fatty acids and the
longer-chain members of their families. What are some general roles of eicosanoids in the
body? Define: eicosanoids, arachidonic acid, prostaglandins, leukotrienes, thromboxanes,
EPA, DHA.
Which essential fatty acids may have “pro-inflammatory” effects, and which have “antiinflammatory effects? Which omega-3 fatty acids have the most potent anti-inflammatory
effects?
Which chronic diseases are associated with chronic inflammation?
Give examples of food sources of linoleic acid, linolenic acid, EPA, and DHA.
Identify some specialty products that contain omega-3 fatty acids. (Are the fatty acids in
plant foods as effective for suppressing inflammation as DHA and EPA?)
How are fatty fish and fish oils protective against heart disease? About how much fish is
recommended weekly for a person with heart disease? Explain why eating more fish is
sometimes better advice than recommendation fish oil supplements.
Phospholipids:
Describe the general structure of phospholipids, and explain how their structure allows
them to function in cell membranes and lipoproteins. Which nutrient is a component of the
lecithin molecule? Define: polar, nonpolar, monoglyceride, diglyceride, choline
Are phospholipids essential nutrients?
Explain why lecithin is used in food products. What are the main sources of commercial
lecithin? Can lecithin supplements improve health or mental ability in most individuals?
Sterols:
List the main functions of cholesterol in the body. Does cholesterol provide Calories
(energy)? Give examples of hormones made from cholesterol.
Is cholesterol an essential nutrient? If not, where in the body is most of it made?
Which foods supply substantial cholesterol? Do plant foods contain significant amounts?
Which part of the egg contains cholesterol; which part contains no cholesterol?
Explain why plant sterols or stanols are added to certain types of food products. Are plant
sterols, such as sitosterol, useful for the body’s cells?