Complete Table 1 by putting a tick (✓) where a cell wall component is present.

Cell walls make up much of the fibre that people eat.

Scientists investigated the relationship between the mass of fibre people ate each day and their risk of cardiovascular disease (CVD).

They gathered data from a large sample of people and used this to calculate a relative risk.

• A relative risk of 1 means there is no difference in risk between the sample and the whole population. • A relative risk of 1 means CVD is more likely to occur in the sample than in the whole population.

Their results are shown in Figure 3. A value of ± 2 standard deviations from the mean includes over 95% of the data.

A student concluded from Figure 3 that eating an extra 10 g of fibre per day would significantly lower his risk of cardiovascular disease.

Evaluate his conclusion.

The scientists estimated the mean mass of fibre eaten per day using a food frequency questionnaire (FFQ).

The FFQ asks each person how often they have eaten many types of food over the past year.

An alternative method to calculate fibre eaten is for a nurse to ask each person detailed questions about what they have eaten in the last 24 hours.

Suggest one advantage of using the FFQ method and one disadvantage of using the FFQ method compared with the alternative method.

Advantage

Disadvantage