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Slide 1

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F212 Biology ­ Food and
health…read more

Slide 2

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Diet and Food production…read more

Slide 3

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Define the term Balanced Diet
· Balanced diet: One that contains all the nutrients required for health
in appropriate proportions.…read more

Slide 4

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Explain how consumption of an unbalanced diet
can lead to malnutrition with reference to obesity
· Malnutrition is caused by an unbalanced diet. BMI CATEGORY
· The biggest form of malnutrition in the developed <18.5 Underweight
world is obesity ­ it is caused by consuming too
much energy. The excess energy is deposited as 18.5-25 Healthy
fat in the adipose tissues.
· Obesity is the condition in which excessive fat 25-30 Overweight
deposits impairs health, and is usually defined as
when a person has a Body Mass Index (BMI) of 30 30-35 Obese (Class l)
of over.
· This indicates a body weight of 20% or more 35-40 Obese (Class ll)
above the weight recommended for your height.
BMI = mass in kg / (height in m)2 >40 Morbidly obese…read more

Slide 5

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Discuss the possible links between diet and coronary heart disease (CHD)
· Some components of the diet help to reduce the risk of CHD.
· Dietary fibre, moderate alcohol consumption and eating oily fish appear to be beneficial.
· However, more is known about these components that increase the risk of CHD.
· Excess salt in your diet will decrease the water potential of your blood.
· As a result more water is held in your blood and the blood pressure increases.
· This can lead to hypertension ­ a condition in which the blood pressure, particularly the diastolic pressure is maintained at a level
that is too high.
· Hypertension can damage the inner lining of the arteries, which is one of the early steps in the process of atherosclerosis.
· Fats are an essential part of the diet.
· Animal fats tend to be saturated and plant oils tend to be unsaturated.
· In general it is recognised that saturated fats are more harmful than unsaturated fats, as they cause damage to the heart.
· Too much cholesterol in the blood is harmful.
· High blood cholesterol concentrations have been liked to 45-47% of deaths from coronary heart disease.…read more

Slide 6

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Discuss the possible effects of a high blood cholesterol level on the heart and circulatory system, with reference to high-
density lipoproteins (HDL) and low-density lipoprotein (LDL) ­ High-density Lipoproteins
· Cholesterol is essential to the normal functioning of the body.
· It is found in cell membranes and in the skin. It is also used to make steroid sex hormones and bile.
· Cholesterol must be transported around the body ­ it is not soluble in water ­ it must first be converted to a form that will mix
with water.
· Cholesterol is transported, in the blood, in the form of lipoproteins. These are tiny balls of fat that are combined with protein.
· There are two types of lipoproteins:
· High-density lipoproteins (HDL)
· Low-density lipoproteins (LDL).
· Both types of lipoprotein are released into the blood and are can be taken up by cells that have the correct receptor site.
High-density Lipoproteins
· A combination of unsaturated fats, cholesterol and proteins.
· Tend to carry cholesterol from the body tissues to the liver.
· The liver cells have receptor sites that allow HDLs to bind to their cell surface membranes.
· In the liver the cholesterol is used in cell metabolism to make bile or is broken down .
· Therefore, high levels of HDLs are associated with reducing blood cholesterol levels.
· They reduce deposition in the artery walls by atherosclerosis.
· Since HDLs are unsaturated fats these fats are thought to be more beneficial to health than saturated fats.…read more

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