High blood pressure is another risk factor for cardiovascular disease.
In one study, the effect of food supplements on blood pressure was investigated.
A group of 25 male volunteers with systolic blood pressures above 17 kPa were
selected for this study.
For the first week, the volunteers consumed their normal diet but with the
addition of beetroot. At the end of the week their blood pressure was measured.
For the second week, the volunteers consumed their normal diet but with the
addition of garlic. At the end of the second week, their blood pressure was
measured again.
The results of this study are shown in the graph below.
Using the information in the graph, describe the effect of eating beetroot and
garlic on blood pressure.