This study will examine what contribution of 'markers' of fruit and vegetable (FV) intake in blood and urine is most closely related to FV intake. 30 healthy volunteers will be fed either 2, 5 or 8 portions of FV per day for 4 weeks (ten participants per group, randomly assigned). Volunteers will have all their food provided during the study, and will consume two meals each weekday at the University. Volunteers will complete diet and lifestyle questionnaires at the start and end of the study and will have blood and urine samples collected at 0, 2 and 4 weeks.

Single biomarkers of FV consumption, such as Vitamin C and certain carotenoids and flavonoids, have been proposed, but associations between these compounds and FV intake are relatively weak. The investigators propose that, given the complexity of FV, production of an algorithm based on a wide variety of bioactive compounds found in FV might better predict FV consumption. A controlled feeding study (30 volunteers randomised to 2, 5 or 8 portions of FV day for 4 weeks) will allow development of such an algorithm. Volunteers will be recruited by advertisement from QUB and the general public, and will have all their food provided for the 4 week period (two meals per day during the week to be consumed under supervision at the University).

Inclusion Criteria:

• 18-65 years
• Usual consumption of fruit and vegetables <= 2 portions/day

Exclusion Criteria:

• Use of any high dose vitamin, mineral or dietary supplements
• Current smoker
• BMI > 35 kg/m2
• Inability to provide informed consent
• Excessive alcohol consumption (>28 Units/week men or >21 Units/week women)
• Food sensitivities or allergies that would interfere with a tolerance of a fruit and vegetable rich diet
• Medical conditions or dietary restrictions that would substantially limit inability to complete the study requirements