A.1.1 Define nutrient.
·
Nutrient:
a chemical substance found in foods
that is used in the human body.
A.1.2 List the type
of nutrients that are essential in the human diet, including amino acids, fatty
acids, minerals, vitamins and water.
·
Essential nutrients are those that cannot be
synthesized by the body.
·
Carbohydrates are not included because in
certain traditional human diets energy is obtained from other sources without
ill effect.
A.1.3 State that
non-essential amino acids can be synthesized in the body from other nutrients.
A.1.4 Outline the
consequences of protein deficiency malnutrition.
·
Protein deficiency is shortage of one or more
essential amino acids.
·
The consequences are lack of blood plasma
proteins and subsequent tissue fluid retention, with swelling of the abdomen.
·
Development of children is likely to be both
mentally and physically retarded.
A.1.5 Explain the
causes and consequences of phenylketonuria (PKU) and how early diagnosis and a
special diet can reduce the consequences.
- Limit the causes to:
- A mutation of a gene for an enzyme that converts the essential amino acid phenylalanine to tyrosine.
- The name of the gene and enzyme concerned are not required.
A.1.6 Outline the
variation in the molecular structure of fatty acids, including saturated fatty
acids, cis and trans unsaturated fatty acids, monounsaturated and polyunsaturated
fatty acids.
- Include omega-3 fatty acids as an example.
A.1.7 Evaluate the
health consequences of diets rich in the different types of fatty acid.
- The Maasai, are an example
of people with a low rate of heart disease.
- The link between
consumption of saturated fatty acids and coronary heart disease is not a
sample correlation.
A.1.8 Distinguish
between minerals and vitamins in terms of their chemical nature.
- Limit this to:
- Minerals are elements in
ionic form whereas vitamins are organic compounds.
A.1.9 Outline two of
the methods that have been used to determine the recommended daily intake of
vitamin C.
Include brief details
of one method involving human subjects and another involving small mammals.
A.1.10 Discuss the
amount of vitamin C that an adult should consume per day, including the level
needed to prevent scurvy, claims that higher intakes give protection against
upper respiratory tract infections, and the danger of rebound malnutrition.
·
Rebound malnutrition can occur when a normally
adequate intake of a vitamin follows a period of excessive intake and
excretion.
A.1.11 List the
sources of vitamin D in human diets.
A.1.12 Discuss how
the risk of vitamin D deficiency from insufficient exposure to sunlight can be
balanced against the risk of contracting malignant melanoma.
A.1.13 Explain the
benefits of artificial dietary supplementation as a means of preventing
malnutrition, using iodine as an example.
A.1.14 Outline the
importance of fibre as a component of a balanced diet.
A.2.1 Compare the
energy content per 100g of carbohydrate, fat and protein.
- · Carbohydrates contain approximately 1760kJ of energy per 100g
- · Protein contains 1720kJ of energy per 100g
- · Fats contain 4000kJ of energy per 100g
A.2.2 Compare the
main dietary sources of energy in different ethnic groups.
Include ethnic groups
using rice, wheat, cassava, maize, fish and meat as their staple energy source.
A.2.3 Explain the
possible health consequences of diets rich in carbohydrates, fats and proteins.
A.2.4 Outline the function of the appetite control centre in the brain.
Only a simple account is expected.
- Hormones are produced by the pancreas and small intestine after eating and by adipose tissue in response to fat storage.
- These pass to an appetite control centre in the brain, which makes the person feel that they have eaten enough.
A.2.5 Calculate body mass index (BMI) from the body mass and height of a person.
BMI = (mass in kg) ÷ [(height in m)(height in m)]
BMI = (mass in kg) ÷ [(height in m)(height in m)]
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