Chapter 5 Lipids: Fatty Acids, Digestion, and Cardiovascular Health

What is a common property of lipids?

Lipids do not readily dissolve in water.

What is the chemical composition of lipids primarily high in?

Carbon and hydrogen, with some oxygen.

How many kilocalories do lipids yield per gram?

9 kcal per gram.

What are the two physical forms of lipids?

Fats (solid) and oils (liquid).

What are the main functions of lipids in the body?

Regulate cellular processes, provide energy, maintain temperature, produce hormones, and aid in nutrient absorption.

What percentage of energy used by the body at rest comes from fatty acids?

About half.

What are the three forms of lipids?

Triglycerides, phospholipids, and sterols.

What are triglycerides composed of?

Three fatty acids bonded to glycerol.

What is the primary role of phospholipids?

They make up the cell membrane.

What is a sterol?

A multi-ringed structure that can act as chemical messengers.

What type of fatty acids are saturated fatty acids?

Fatty acids with single bonds in the carbon chain.

What is the state of saturated fatty acids at room temperature?

Solid.

What is the difference between monounsaturated and polyunsaturated fatty acids?

Monounsaturated have one double bond; polyunsaturated have two or more.

What are essential fatty acids?

Fatty acids that must be supplied by the diet, such as alpha-linolenic acid and linoleic acid.

What is the role of cholesterol in the body?

Regulates cell membrane structure and hormone synthesis.

What is an emulsifier?

A substance that helps mix two liquids that do not normally mix, such as fat and water.

What is lecithin?

A phospholipid used as an emulsifier in food products.

What is the significance of essential polyunsaturated fatty acids?

They are crucial for normal cell development and healthy skin.

How do trans fatty acids differ from naturally occurring fatty acids?

Trans fatty acids are straight and tend to be solid at room temperature, often resulting from hydrogenation.

What health risks are associated with trans fatty acids?

Increased risk for coronary heart disease.

What is the role of lipids in food?

They provide high energy, contribute to texture and taste, and promote satiety.

What is the primary source of energy from lipids during light activity?

Fatty acids.

What is the composition of a phospholipid?

Glycerol, two fatty acids, and a phosphate group.

What is the function of myelin sheath in the nervous system?

It surrounds nerve cells and is composed of phospholipids and cholesterol.

What is the caloric density of lipids?

High caloric density.

What is the importance of fat for infants and growing children?

It supports normal growth and development.

What role do fats play in satiety?

Fats slow the process of digestion, helping you feel full after a meal.

How do fats improve the flavor of foods?

Fats carry flavors in foods, enhancing taste and texture.

What is fat rancidity?

The decomposition of oils due to the breakdown of double bonds in unsaturated fatty acids, leading to unpleasant odors and flavors.

What factors contribute to fat rancidity?

UV light, oxygen, and the susceptibility of polyunsaturated fatty acids.

How can fat rancidity be prevented?

By adding antioxidants, hydrogenating oils, reducing light exposure, storing oils in cool, dark places, and decreasing oxygen exposure.

What is hydrogenation?

A process that saturates liquid oils, making them solid or semisolid, and increases their smoking point.

What are trans fats?

Fats resulting from the partial hydrogenation of unsaturated fatty acids, linked to increased heart disease risk.

What did the FDA ban in 2018 regarding fats?

The use of partially hydrogenated oils (PHOs) in most processed foods.

What are common fat replacement strategies in reduced-fat foods?

Using sugar, engineered fats, water, starch derivatives, protein, and fiber.

What are some food sources high in fat?

Salad oils, butter, margarine, mayonnaise, peanut butter, cheese, and ice cream.

What are the three types of fatty acids?

Saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA).

What is linoleic acid?

An omega-6 fatty acid found in safflower oil, sunflower oil, corn oil, and nuts.

What is alpha-linolenic acid?

An omega-3 fatty acid found in flaxseeds, walnuts, and canola oil.

What do dietary guidelines recommend for omega-3 fatty acids?

Consume two servings of fatty fish per week for optimal cardiovascular health.

What are phospholipids and where are they found?

Phospholipids are emulsifiers found in wheat germ, lecithin, peanuts, and egg yolks.

Is there an upper limit for dietary cholesterol?

No, dietary cholesterol does not significantly influence plasma cholesterol values.

What is the relationship between saturated fats and heart disease?

Saturated fats, found in animal products, are linked to heart disease; it's recommended to limit them to 10% of total calories.

How is fat digested in the mouth?

Through mechanical digestion and the action of lingual (salivary) lipase.

What role does bile play in fat digestion?

Bile emulsifies fats in the small intestine, aiding in their digestion.

What percentage of dietary fat is absorbed?

95% of dietary fat is absorbed.

How are chylomicrons involved in fat absorption?

Chylomicrons are transport vehicles for dietary lipids formed from triglycerides in small intestinal cells.

What are some hidden sources of fat in foods?

Nutrition Facts labels and ingredient lists can reveal hidden fats; controlling portion size is also important.

What is the caloric value of fat?

13 grams of fat equals 117 kcal, which can represent a high percentage of total calories.

What are chylomicrons?

Transport vehicles for dietary lipids.

Where are most dietary fats absorbed?

Into the lymphatic system, which eventually empties into the bloodstream.

What is the function of lipoprotein lipase?

An enzyme that breaks down triglycerides in lipoproteins.

What is a lipoprotein?

A transport vehicle for lipids in the blood, consisting of a core of lipids and a shell of protein, phospholipids, and cholesterol.

How are lipoproteins classified?

By their density; higher density lipoproteins have higher protein content.

What is LDL commonly known as?

Bad cholesterol.

What is the primary risk associated with high LDL levels?

Promotes atherosclerosis and increases the risk of cardiovascular disease.

What role do HDLs play in cholesterol management?

They scavenge cholesterol from blood vessels and transfer it to other lipoproteins or the liver.

What is the desired LDL level for heart health?

Less than 100 mg/dL is ideal.

What dietary component can help reduce cholesterol levels?

Omega-3 fatty acids.

What foods are high in soluble fiber that can reduce cholesterol absorption?

Oatmeal, oat bran, kidney beans, apples, pears, citrus fruits, barley, and prunes.

What are some practical ways to reduce blood cholesterol?

Consume fatty fish, unsaturated fatty acids, and replace butter with olive oil.

What is the recommended fat intake for adults?

20% to 35% of total calories from fat.

What is the recommended intake of alpha-linolenic acid for men and women?

1.6 g/day for men and 1.1 g/day for women.

What are signs of essential fatty acid deficiency?

Hair loss, flaky skin, slow wound healing, and increased vulnerability to infections.

How often should seafood be consumed for omega-3 fatty acids?

1 to 2 times per week.

What is atherosclerosis?

The buildup of plaques in blood vessels due to oxidized LDL and white blood cells.

What are some non-modifiable risk factors for cardiovascular disease?

Genes, age, and gender.

What effect does trans fat consumption have on heart disease risk?

Increases the risk of coronary heart disease by 23% for every extra 2% of calories from trans fat.

What is the ideal HDL level for heart health?

HDL level should be greater than 40 mg/dL in men and greater than 50 mg/dL in women.

What is the effect of saturated and trans fats on LDL levels?

They increase LDL levels.

What is the significance of the balance between omega-6 and omega-3 fatty acids?

An imbalance may lead to pro-inflammatory conditions.

What is the recommended LDL level to avoid being classified as high?

LDL level greater than 160 mg/dL is considered high.

What are the benefits of high HDL levels?

May block oxidation of LDL and reduce formation of atherosclerotic plaque.

What is the relationship between dietary guidelines and fat intake?

Less than 10% of kcal should come from saturated fat, and trans fats should be limited or eliminated.