Nutrition Chapter 5 (Exam 2)

What is the AMDR for fat intake?

20-35%

What are the health benefits and/or health risks of consuming saturated and unsaturated fatty acids?

A diet high in saturated fats is associated with high risks for cardiovascular disease. Saturated fat causes the body's blood lipids to shift towards an unhealthy profile, whereas a diet high in unsaturated fats lowers the risk of cardiovascular disease and shifts the blood lipid profile to a healthier range.

Which describes a polyunsaturated fatty acid? A fatty acid with numerous acid groups A fatty acid with two or more double bonds A fatty acid with numerous hydrogen atoms A fatty acid with two or more carbon atoms

A fatty acid with two or more double bonds

What are the functions of fat in the body?

Fat is the major source of energy for the body, both for immediate use and stored in adipose tissue for later use. Adipose tissue provides padding and protection for internal organs as well as insulation from extreme temperatures. They are the carriers for the fat soluble vitamins and they proved the two essential fatty acids

Which is accurate about the lipid composition of foods? In general, plant oils contain no saturated fat. Coconut oil is high in saturated fatty acids. Almost all the fat in beef and pork is saturated.

Fats in foods are always a mixture of saturated, monounsaturated, and polyunsaturated fatty acids. Plant oils are usually important sources of monounsaturated and polyunsaturated fatty acids, but coconut oil is an exception to that rule and contains a very high proportion of saturated fatty acids.

What is the main structure of fatty acids?

Fatty acids are carbon chains of different lengths, with an acid group at one end.

Which function of fats allows a person to ride a mountain bike for many hours without harming their internal organs? Muscle fuel Insulation Energy stores Padding

Padding

What foods are sources of saturated fats? Monounsaturated fats? Polyunsaturated fats?

Animal fats tend to contribute substantial amounts of saturated fats, with some notable exceptions. Coconut oil is very high in saturated fat, and palm oil also is a contributor. (These are sometimes called tropical oils.) Olive oil and canola oil are notable for their monounsaturated fat content. Other plant seed oils such as safflower, sunflower, corn, soybean, and cottonseed oil all are high in polyunsaturated fats.

Which is accurate about food sources of lipids? Beef fat (tallow) is a significant source of saturated fat. Legumes are a significant source of omega-3 fatty acids. Olive oil is a significant source of saturated fat. Stick margarine is a significant source of cholesterol.

Beef fat (tallow) is a significant source of saturated fat.

What foods are high in omega-3 fatty acids? In omega-6 fatty acids?

Canola oil is a plant source of omega-3 fatty acids, and fatty fish from cold, deep water are an even richer source. (But fast food fish, fried fish, and many frozen fish products come from varieties of fish that are not particularly rich in omega-3 fatty acids, and frying usually only adds more omega-6 fatty acids from the oils used in frying.) Omega-6 fatty acids come from most vegetable oils.

What are the structural characteristics of cholesterol? What compounds in the body are formed from a cholesterol precursor?

Cholesterol has a completely different chemical structure from triglycerides: it consists of interconnected rings of carbon atoms with side chains of carbon, hydrogen, and oxygen attached. Bile, vitamin D, and sex hormones are all made in the body from cholesterol. Cholesterol is also part of the cell membrane.

What foods are sources of cholesterol? What is the relationship between dietary intake and blood cholesterol?

Cholesterol is only found in foods of animal origin, so it is found in meat, poultry, fish, eggs, milk, cheese, and butter, but not in margarine, nuts, avocados, olives, and legumes. For most people dietary cholesterol has little relationship to blood levels of cholesterol. Except for some people who have a genetic predisposition toward high blood cholesterol, high intakes of saturated and trans fats are much more important in affecting blood cholesterol.

What are the various kinds of lipoproteins? What does each transport, to where?

Chylomicrons deliver recently-absorbed dietary fats to tissues, via the lymph and blood. VLDL (very low density lipoproteins) carry triglycerides and other lipids made in the liver to cells throughout the body. LDL (low-density lipoproteins) deliver cholesterol and other lipids to tissues. HDL (high-density lipoproteins) pick up cholesterol from cells and deliver it to the liver for disposal.

Which is consistent with recommendations for fish or fish oil intake? Consume fish twice a week to increase intake of EPA and DHA. Use fish oil supplements to maximize omega-3 fatty acid intake safely Eat fish raw to get the maximum benefit from the fatty acids. Choose fried fish in fast food restaurants often.

Consume fish twice a week to increase intake of EPA and DHA.

What health problems are linked with trans-fatty acids formed during hydrogenation of plant oils? What foods are most likely to contain trans fats?

Consuming trans-fatty acids poses a risk to the heart and arteries by raising blood LDL cholesterol and lowering beneficial HDL cholesterol. It may also increase tissue inflammation. Hydrogenation of unsaturated fats produces some trans-fatty acids, so they are found most often in commercially fried foods and in baked goods and other commercial foods made with partially hydrogenated vegetable oils.

Which recommendation is consistent with recommendations for fish or fish oil intake? Eat two meals each week of fatty cold water fish. Frying fish in vegetable oil improves the fatty acid profile by contributing omega-6 fatty acids. Consume fish oil supplements instead of fish because they are a more concentrated source of omega-6 fatty acids.

Eat two meals each week of fatty cold water fish.

What are the health advantages of increasing the proportion of omega-3 fats in the diet, relative to omega-6 fats?

Eicosanoids are regulatory compounds made from certain fatty acids. The omega -3 fatty acids EPA and DHA, found mainly in fatty fish, make eicosanoids that appear to lower blood pressure, prevent blood clot formation, and protect against irregular heartbeats. These are beneficial effects related to several chronic diseases. On the other hand, if most of the eicosanoids are made from omega-6 fatty acids, they have some negative effects. For health, people need the right balance of omega-3 and omega-6 fatty acids in the diet. The balance between the two fatty acids can be improved by eating fatty fish several times each week.

What is the function of bile?

Emulsify fat so it can be more easily digested

What are essential fatty acids?

Essential fatty acids are fatty acids that the body needs but cannot make in amounts sufficient to meet physiological needs. These fats must be obtained from food.

What benefits are associated with eating fish twice a week?

Fish, especially fatty cold-water fish, are high in the omega-3 fatty acids DHA and EPA. These omega-3 fatty acids help prevent heart disease by lowering blood pressure, preventing blood clot formation, and protecting against irregular heartbeats. Eat fatty fish, preferably grilled, baked, or broiled: the varieties of fish most often prepared this way contain more EPA and DHA than species used for frying or in frozen fish products.

What are the recommendations regarding fat intake?

Generally the total fat intake should between 20-35% of total calories,, mostly from mono- and poly-unsaturated fats. Saturated fat intake should be less than about 7-10% of total calories. Increase the ratio of omega-3 fatty acids to omega-6 fatty acids. Keep trans fat intake as low as possible, and minimize cholesterol intake.

What transports cholesterol away from body cells to the liver for disposal?

HDL

What is the recommendation concerning the ratio of saturated fat to unsaturated fat in the diet?

High unsat and low sat

Why are plant oils hydrogenated?

Hydrogenated fats are less likely to develop rancid flavors and they are easier to spread, contributing pleasing textural characteristics to foods

What does hydrogenation do to fatty acids?

Hydrogenation is the process of adding hydrogen atoms to an unsaturated fatty acid to produce a more stable fat which is less subject to oxidation and rancidity. Because the fat is now more saturated, any health benefits associated with the original plant oil are actually decreased.

What happens to lipids after they are absorbed from the small intestine?

In the cells lining the small intestine, triglycerides are reassembled from the parts. The small molecules of short-chain fatty acids and glycerol are absorbed into the blood stream and delivered to the liver. The triglycerides are combined with protein to from lipoproteins which are absorbed into the lymph system and eventually delivered into the blood stream.

Generally speaking for the population, which contributes most to high blood cholesterol?

Intake of saturated and trans fats

Which statement is consistent with Dietary Guidelines and USDA Food Patterns recommendations? It's OK to have 30% of your calories from fat. Fat replacers should be used whenever possible as this will decrease chronic disease risks. You should eliminate saturated fat completely from your diet. Eat fried fish about twice a week to get enough omega-6 fats. Eat mild-flavored cheeses more often to increase intake of omega-3 fats.

It's OK to have 30% of your calories from fat.

What combines with cholesterol so it can be delivered to all the cells of the body?

LDL

How can someone increase their HDL values?

Lipid intake has little influence on blood HDL levels. Regular physical activity helps increase blood HDL levels.

What are lipoproteins?

Lipoproteins are clusters of lipids and protein. They make it possible for fats to be transported in watery lymph and blood.

What are the steps of lipid digestion? Where do they occur?

Little digestion occurs until the lipids reach the small intestine. There bile (produced by the liver and stored in the gall bladder until needed) is released into the small intestine and emulsifies fat so that it can be mixed with the watery fluids. Fat-digesting enzymes break down triglycerides into free fatty acids, glycerol, and monoglycerides which can be absorbed by the cells lining the small intestine.

Which suggestion is consistent with the Dietary Guidelines and USDA Food Patterns recommendations? Minimize the use of shortening and other solid fats. Minimize intake of nuts, olives, avocados and other fatty plant foods. Keep total fat intake below 10% of calories

Minimize the use of shortening and other solid fats.

What is the difference between saturated and unsaturated fatty acids? Between monounsaturated and polyunsaturated fatty acids?

Most of the carbon atoms in a fatty acid are connected with single bonds. When there are no double bonds between carbon atoms, it is called a saturated fatty acid (the carbon chain is "saturated" with hydrogen atoms). If there is one double bond between carbon atoms, it is called a monounsaturated fatty acid, and if there are 2 or more double bonds it is called polyunsaturated fatty acid.

Holly has decided she wants to lose fat and so she decides to eliminate as much fat from her diet as possible, aiming for a fat intake of less than 10% of her calories. Is this a wise approach? Why or why not?

No, she would not have the recommended amount of calories coming from fat.

What are other names for omega-3 and omega-6 fatty acids and what is the difference between the two?

Omega- 3 is also known as linolenic acid and omega-6 is also known as linoleic acid. Unsaturated fatty acids, such as omega-3 and omega-6, are named after the location of the first double bond (counting from the non-acid end) between carbon atoms in the carbon chain. In omega-3 fatty acids the first double bond is between the third and fourth carbons and in omega-6 the first double bond is between the sixth and the seventh carbons. The difference in structure changes the way these fatty acids are used in the body.

How does a phospholipid differ from a triglyceride? What is the role of phospholipids in the body?

Phospholipids are composed of a glycerol backbone with 2 fatty acids and a phosphorus-containing molecule attached in the third spot. Because of its structure, phospholipids are soluble in both fats and water. This allows it to act as an emulsifier, or a substance that mixes with both fat and water and permanently disperses the fat in the water. This ability to dissolve in both fats and water is important in cell membranes, to allow fats to travel back and forth across the lipid-containing cell membranes into the watery liquids on both sides.

What benefit is associated with increasing the proportion of dietary fats coming from omega-3 sources and reducing the proportion coming from omega-6 sources? (Select all that apply.) Reduced inflammation Longer endurance during exercise Lower blood pressure Decreased formation of undesirable blood clots

Reduced inflammation Lower blood pressure Decreased formation of undesirable blood clots

What determines how hard or soft a fat is at room temperature?

Shorter chain fatty acids and fatty acids that are unsaturated tend to be softer and melt more easily at lower temperatures. Longer chain and saturated fatty acids tend to be hard at room temperature.

Which food is most likely a source of trans-fatty acids? Ground beef Yogurt Stick margarine Cheese

Stick margarine

How does a traditional Mediterranean diet help meet recommended fat intakes? What are the limitations in applying its benefits to Americans?

The main fat in the traditional Mediterranean diet is olive oil. This cuisine also includes generous intakes of pastas and whole grain breads, nuts, fruits, greens, and other vegetables. Legumes, cheeses, yogurt, and some fish and poultry are included. This diet is also low in red meats. The limitation of this diet is that it was eaten by people living a labor-intensive but less rushed lifestyle than is available to most Americans, Some of the dietary benefits attributed to the diet may come from the total lifestyle pattern that accompanied it - a lifestyle which is not followed by most Americans.

How does hydrogenation change the structure of fatty acids? What are trans-fatty acids?

The process of hydrogenation breaks some of the fatty acids' double bonds and adds hydrogen atoms to the molecule. This makes the oil more saturated, and more solid at a lower temperature. Not all of the double bonds are broken during this process, and some of the remaining double bonds have a shift in their chemical structure: instead of the normal bend in the 3-dimensional configuration at double bonds, the molecules are straightened out. This straightening out is a result of the hydrogen atoms being on opposite sides of the carbon bond, thus they become trans-fatty acids.

What are the main categories of lipids?

The three classes of lipids are triglycerides, phospholipids, and sterols. Fatty acids are not a main category, but they constitute an important part of triglycerides.

Which is accurate about triglycerides? All the fatty acids in the molecule will be identical. Triglycerides are found in plant oils but not in animal fats. Each triglyceride has one saturated, one monounsaturated, and one polyunsaturated fatty acid. The types of fatty acids determine the hardness or softness of the fat.

The types of fatty acids determine the hardness or softness of the fat.

In general, how can one recognize saturated fats?

They are solid at room temperature.

What are the functions of fat in foods?

They contribute to the energy value of foods and to satiety after eating. They provide flavors, aromas, and smooth and moist textures. They carry the fat-soluble vitamins and assist in their absorption.

What are the structural characteristics of triglycerides?

Triglycerides consist of 3 fatty acids attached to a 3-carbon glycerol molecule. A triglyceride can have any three fatty acids attached to the glycerol -- they do not have to all be the same. The types of fatty acids determine the hardness or softness of the fat.

What is a major difference between triglycerides and phospholipids?

Triglycerides have three fatty acids attached to the glycerol whereas phospholipids have one of the fatty acids replaced by a phosphate group.