After they have passed screening tests, participants will be allocated by chance to receive either the tomato extract product (Ateronon), or a matching placebo (a dummy capsule with no active ingredients), which they will take once a day for 8 weeks. At the beginning and end of the treatment period, the investigators will test blood vessel stiffness using an ECG machine and external probe. The investigators will also measure forearm blood flow, which involves infusing 3 separate agents that affect how the lining of the blood vessel wall works, and helps to assess whether this is affected by the study treatment. Blood tests will also be used to look at how the food supplement is working and its effects on cholesterol and markers of inflammation. Including the screening period, and a follow-up telephone call two weeks after the end of treatment, participants will be in the study for 14 weeks.