Unit 2: Section 4 - Diet and Food Production

Question 1

Define Balanced Diet.

Answer 1

A balanced diet should include all the major food groups but in the correct proportions to provide us with the right amount of nutrients, including fibre and water. The five important nutrients include carbohydrates, proteins, fats, vitamins and mineral salts.

Question 2

Each nutrient has different functions in the body. What is the function of Carbohydrates?

Answer 2

To provide energy - they are the main source of energy.

Question 3

Each nutrient has different functions in the body. What are the functions of Fats (Lipids)?

Answer 3

Fats (lipids) act as an energy store, provide insulation, make up cell membranes, and physically protect organs.

Question 4

Each nutrient has different functions in the body. What are the functions of Proteins?

Answer 4

Proteins are needed for growth, the repair of tissues (e.g. muscles) and to make enzymes.

Question 5

Each nutrient has different functions in the body. What are the functions of Vitamins?

Answer 5

Vitamins are important in the chemical processes of cells. Different vitamins have different functions, e.g. vitamin D is needed for calcium absoprtion, vitamin K is needed for blood clotting.

Question 6

Each nutrient has different functions in the body. What are the functions of Mineral salts?

Answer 6

Mineral salts are inorganic elements essential for normal body function. Different mineral salts have different functions, e.g. iron is needed to make haemoglobin in the blood, calcium is needed for bone formation.

Question 7

Each nutrient has different functions in the body. What is the function of Fibre/roughage?

Answer 7

Fibre/roughage is the indigestiable part of food, especially cellulose. It is essentail for healthy functioning of the digestive system - aids movement of food through gut.

Question 8

Each nutrient has different functions in the body. What are the functions of Water?

Answer 8

Water is essential - it is used in chemical reactions and to transport substances in and around cells. We need a constant supply to replace water lost through urinating, breathing and sweating.

Question 9

What do the Recommended Daily Allowance (RDA) and Guidline Daily Amounts (GDA) give?

Answer 9

RDA and GDA give an indication as to normal/healthy levels of nutrients.

Question 10

State 3 reasons why the Recommended Daily Allowance (RDA) and Guidline Daily Amounts (GDA) are given as a range of values?

Answer 10

1. Every person is an individual (have their own metabolism rate).
2. Every person is at a unique state of health.
3. Every person has a different level of activity.

Question 11

State the 3 nutrients that energy should come from (include the percentages).

Answer 11

Energy should come from:

1. 57% Carbohydrates
2. 30% Fats
3. 13% Proteins

Question 12

Define Malnutrition.

Answer 12

Malnutrition is caused by having too little or too much of some nutrients in your diet.

Question 13

What are the 3 causes of Malnutrition?

Answer 13

1. Not having enough food - you get too little of every nutrient.
2. Having an unbalanced diet: -Getting too little of a nutrient can lead to all kinds of deficiency illnesses, e.g. getting too little iron in your diet causes anaemia. -Getting too many carbohydrates or fats can lead to obesity.
3. Not being able to absorb the nutrients from digestion into your blood stream properly. E.g. coeliac disease reduces absorption of nutrients from the small intestine. This also causes deficiency illnesses.

Question 14

1. Define Obesity
2. Describe it’s causes.

Answer 14

1. Obesity is defined as being 20% (or more) over the recommended body weight. It is a common dietary condition caused by eating too much food (having an energy rich diet). This excess energy is stored as fats (lipids) and deposited under the skin in adipose tissue.
2. Over-nutrition and lack of exercise can lead to obesity:

• Too much sugary or fatty food and too little exercise are the main causes of obesity.
• People can also be obese due to an underactive thyroid gland, but this problem isn’t common.

Question 15

Obesity is a bigger problem in developed countries. What can Obesity increase the risk of?

Answer 15

Obesity can increase the risk of diabetes, arthritis, high blood pressure, coronary heat disease (CHD) and even some forms of cancer.

Question 16

An unhealthy diet can increase the risk of Cornonary Heart Disease (CHD). Describe CHD.

Answer 16

Coronary heart disease (CHD) is the result of reduced blood flow to the heart. It can lead to chest pain (angina) and heart attacks. It’s caused by **atherosclerosis **- the narrowing and hardening of the coronary arteries (the blood vessels that supply the heart).

Question 17

Explain the effect of a diet high in Saturated Fat.

Answer 17

A diet high in saturated fat raises the blood cholesterol level. This increases the build up of fatty substances that are deposited in the walls of the coronary arteries (called atheromas) which causes atherosclerosis. Narrowing of the arteries would restrict blood flow and cause possible oxygen starvation to the heart muscle.

Question 18

Explain the effect of a diet high in Salt.

Answer 18

A diet high in salt will decrease the water potential of the blood which will make the kidneys retain more water in the blood. This will increase the blood pressure (hypertension) which can then damage the inner lining of the coronary arteries. This causes atherosclerosis.

Question 19

1. Briefly describe Cholesterol.
2. Why is Cholesterol needed?
3. Explain how Cholesterol converts itself to be moved around the body in the blood.

Answer 19

1. Cholesterol is a lipid made in the body (in the liver from saturated fats). It’s found in many foods e.g. dairy products, eggs and meat.
2. Some is needed for the body to function normally. It is also used in cell membranes, to make steroid sex hormones and to produce bile.
3. Cholesterol needs to be attatched to a protein to be moved around, so the body forms **lipoproteins **- substances composed of both protein and lipid.

Question 20

There are two types of Lipoprotein. One of them are High Density Lipoproteins (HDLs).

1. State what they are composed of.
2. State what they transport.
3. State their function.

Answer 20

1. High density lipoproteins (HDLs) are mainly protein.
2. They transport cholesterol from body tissues to the liver where it’s recycled or excreted.
3. Their function is to reduce blood cholesterol when the level is too high.

Question 21

There are two types of Lipoprotein. One of them are Low Density Lipoproteins (LDLs).

1. State what they are composed of.
2. State what they transport.
3. State their function.

Answer 21

1. Low density lipoproteins (LDLs) are mainly lipid.
2. They transport cholesterol from the liver to the blood, where it circulates until needed by cells.
3. Their function is to increase blood cholesterol when the level is too low.

Question 22

Animals consist of saturated fats. We (humans) consume many animals (meats). However, a diet high in saturated fat is detrimental. Explain why.

Answer 22

A diet high in saturated fat raises LDL (low density lipoprotein) level - so more cholesterol is transported to the blood, increasing total blood cholesterol and increasing the risk of CHD (coronary heart disease).

Question 23

Plants consist of polyunsaturated fats. We (humans) consume many plants (e.g. vegetables). A diet high in polyunsaturated fat is beneficial. Explain why.

Answer 23

A diet high in polyunsaturated fat raises HDL (high density lipoprotein) level - so more cholesterol is transported from the blood to the liver, decreasing total blood cholesterol and decreasing the risk of CHD (coronary heart disease).