Nutrition Quiz #2: Lipids
Omega-3 fats:
Animal sources: mackerel, herring, salmon, sardines, and tuna. Plant sources: chia seeds, hemp seeds, flaxseeds, walnuts, and soybeans.
Cholesterol:
Best known sterol, found in every cell in the body. Helps with numerous body processes. Precursor to vitamin D, sex steroids and adrenal corticoids.
Linoleic acid:
Converted to arachidonic acid.
Alpha-linoleic acid (ALA):
Converted to eicosapentanoic acid (EPA). Elongated to docosahexanoic acid (DHA).
True or False: taking fish oil supplements is the best way to consume adequate omega-3 fatty acids.
False. Consuming too much fish oil can be unhealthy. The best source of omega-3 fatty acids is fresh fish.
True or False: fat-free cookies tend to have half the kilocalories of full-fat varieties.
False. Fat-free foods often have added carbohydrates, which add back kilocalories. The savings in fat kilocalories is usually not much of a savings in total kilocalories.
True or False: the LDL cholesterol present in foods is harmful to the heart.
False. LDL cholesterol is a lipoprotein carrier found in the blood and not in foods.
True or False: nuts are high in cholesterol.
False. Nuts are plant foods, they do not contain cholesterol, but are instead rich sources of essential fatty acids and plant sterols.
True or False: only commercially made fried foods and snack items contain trans fats.
False. Though the majority of trans fats are Mae from hydrogenated oils that are found in commercially prepared, processed foods, trans fats also occur naturally in food such as meat and dairy products.
True or False: a healthy diet is very low in fat.
False. Whereas too much dietary fat may cause weight gain, eating too little isn't healthy either. A diet low in fat, but high in added sugars may increase the level of triglycerides in the blood.
Arachidonic acid and eicosapentaenoic acid are a. used to manufacture hormone-like substances called eicosanoids b. stored as part of the subcutaneous tissue needed to insulate the body c. the main fatty acids used to manufacture bile in the liver d. used by the body to manufacture the essential fatty acids linoleic acid and alpha-linolenic acid
a. used to manufacture hormone-like substances called eicosanoids
The major dietary compound that raises blood LDL cholesterol is a. viscous soluble fiber b. C-reactive protein c. saturated fat d. plant sterols
c. saturated fat
Monounsaturated fats:
Excellent sources: avocado, olive oil, canola oil, nuts (almonds esp.), and seeds.
True or False: butter is a healthier choice than margarine.
False. Although a limited number of stick margarines still contain heart-unhealthy trans fats, most margarines are now formulated to be heart-healthy. In contrast, butter is high in cholesterol-raising saturated fats, making it less healthy.
Functions of dietary fat:
-Add texture to baked goods -Make meats tender -Preserve freshness -Flavor enhancer
Functions of triglycerides:
-Add texture to baked goods -Make meats tender -Preserve freshness -Stored as adipose tissue for energy
Saturated fatty acids:
-All the carbons on the fatty acid are bound to hydrogen -There are no double bonds -They are solid at room temperature -They have a higher melting point
Several essential nutrients are required for dietary fat absorption:
-Fat-soluble vitamins -Carotenoids -Cholesterol -Phospholipids
What are the functions of lipids in the body?
-Lipids serve several critical roles in the body. -Used as a source of energy -Form body structures (including cell membranes) -Regulate metabolism -Enhance the absorption of fat-soluble vitamins -Provide a layer of insulation to help regulate body temperature -Help cushion the major organs
Fats:
-Powerful source of fuel -Preferred by the heart, liver, and resting muscle -Spares glucose so it is only used by the central nervous system and red blood cells -Provides a backup source of energy between meals -Cannot sustain life during prolonged starvation (glucose is needed to metabolize fat)
Length of fatty acids:
-Short: 2-4 carbons -Medium: 6-10 carbons -Long: 12+ carbons
Basic functions of lipids:
-Store and provide energy -Provide insulation -Help manufacture steroids and bile -Play a role in transporting fat-soluble nutrients in the blood -Used to manufacture major sex hormones -Key to the structure of cell membranes
Cholesterol used for making:
-Vitamin D -Sex hormones like estrogen and testosterone -Bile acid
Omega-6 fatty acid:
First double bond is between the sixth and seventh carbons from the omega end. Ex: linoleic acid.
Omega-3 fatty acid:
First double bond is between the third and fourth carbons from the omega end. Ex: alpha-linolenic acid.
Avoid saturated fats:
Food sources: beef, pork, poultry skin, poultry dark meat, cheese, ice cream, whole milk, cream, chocolate, coconut oil, butter, and palm oil.
Trans fatty acids:
Food sources: margarine, chips, crackers, cookies, frozen foods, candy bars, and coffee creamers.
Dietary cholesterol:
Food sources: organ mets, eggs, beef, pork, shell fish, poultry, butter, cheese, cream, and dairy.
Polyunsaturated fats:
Food sources: sunflower oil, safflower oil, walnut oil, flaxseed oil, corn oil, walnuts, most nuts and seeds, and margarine.
Monounsaturated fatty acid (MUFA):
Has one double bonded carbon group.
What are lipids and how do they differ in structure?
Lipids refer to a category of compounds that include: triglycerides, phospholipids, and sterols. They contain carbon, oxygen, and hydrogen. They are hydrophobic.
EPA and arachidonic acid:
Make eicosanoids, which are hormone -like substances that regulate blood clotting, immune system, inflammation, blood pressure.
ALA is needed for:
Making of healthy cell membranes, particularly in the nerve tissues and retina.
Phospholipids:
Phospholipids are synthesized by the liver. Functions: used as emulsifiers in food, major component of cell membranes.
Hydrogenation:
Replacing saturated fat with hydrogenated fat.
Unsaturated fatty acids:
Some carbons on fatty acid form a double bond with each other instead of binding to hydrogen.
Rancidity:
Spoiling of fats through oxidation. Double bonds are less stable than single bonds.
Sterols:
Sterols are made of four connecting rings of carbon and hydrogen. Do not contain glycerol or fatty acids, and don't provide energy. Phytosterols and phytostanols are major plant sterols.
Saturation of fatty acids:
The degree of saturation of a fatty acid is determined by whether the carbons are held together by a double or single bond.
The ADMR for dietary fat intake is a. <10% of daily kilocalories b. 20-35% of kilocalories c. 40-45% of kilocalories d. as low as possible
b. 20-35% of kilocalories
Triglycerides:
A triglyceride molecule has three fatty acids connected to a glycerol backbone. Most common lipid in both foods and the body, makes up about 95% of lipids in foods.
True or False: cholesterol should be consumed daily to meet the body's needs.
False. While the body does need cholesterol for important functions, it can be synthesized in the liver in sufficient amounts. Thus, consuming dietary cholesterol is not necessary.
Daily intake recommendation for triglycerides and cholesterol:
Fat intake is within 33% of total kilocalories. AMDR recommends 20-35% of daily kilocalories.
Polyunsaturated fatty acid (PUFA):
Has two+ double bonded carbon group.
True or False: a diet high in saturated fat is a risk factor for elevated blood cholesterol.
True. A diet high in saturated fat can raise blood cholesterol.
True or False: a high level of HDL cholesterol in the blood is considered heart healthy.
True. High concentrations of HDL cholesterol can help reduce the risk of heart disease.
Which of the following foods are good sources of the essential fatty acids linoleic acid and alpha-linolenic acid? a. ground flaxseeds b. cheese c. butter d. oranges
a. ground flaxseeds
To raise the level of HDL cholesterol, a. increase the viscous, soluble fiber in the diet b. increase exercise c. maintain a healthy body weight d. do all of the above
b. increase exercise
Which statement best describes the characteristics of foods high in unsaturated fatty acids? a. they are solid at room temperature b. they are more stable than saturated fatty acids and resist oxidation c. they tend to be liquid at room temperature d. they are higher in kilocalorie content than a saturated fatty acid
c. they tend to be liquid at room temperature
The type of lipoprotein that carries absorbed dietary fat and other lipids through the lymph system is called a. a micelle b. a VLDL c. an LDL d. a chylomicron
d. a chylomicron
Which of the following foods does not contain dietary cholesterol? a. steak b. chicken c. low-fat milk d. peanut butter
d. peanut butter
Fatty acids vary in structure based on all the following except a. shape b. degree of saturation c. length of carbon chain d. presence or absence of hydrogen
d. presence or absence of hydrogen
