The Effect of Purple Sweet Potato (PSP)-Juice on Liver Enzymes and Blood Pressure

Inclusion Criteria: * Healthy as assessed by the: Health and Lifestyle Questionnaire, results of the pre study laboratory tests in blood * Males/Females aged 40-70 years (boundaries included) at Day 01 of the study * Body Mass Index (BMI) 25-35 (boundaries included) kg/m2 * Liver enzymes above reference values GGT ≥ 45 IU/L (for males) and ≥ 35 IU/L (for females), and/or ASAT ≥ 45 IU/L (for males and females), and/or ALAT ≥ 50 IU/L (for males) and ≥ 40 IU/L (for females) * Blood pressure (automated measurements at site): systolic blood pressure 130-159 mm Hg (boundaries included) and/or diastolic blood pressure 85-99 mm Hg (boundaries included) * Voluntary participation * Having given written informed consent * Willing to comply with the study procedures * Willing to give up blood/plasma donation during the study * Willing to accept use of all nameless data, including publication, and the confidential use and storage of all data for at least 15 years * Willing to accept the disclosure of the financial benefit of participation in the study to the authorities concerned. Exclusion Criteria: * Participation in any clinical trial including blood sampling and/or administration of substances up to 90 days before Day 01 of this study * Participation in any non-invasive clinical trial up to 30 days before Day 01 of this study, including no blood sampling and/or oral, intravenous, inhalatory administration of substances * Having a history of medical or surgical events that may significantly affect the study outcome * Any concomitant medication, with the exception of occasional use of a paracetamol tablet, that may influence the outcome of the study (to be judged by the medical investigator) * Food allergy/intolerance * Alcohol consumption \> 28 units/week for males and \> 21 units/week for females * Smoking \> 10 cigarettes per day * Reported unexplained weight loss or gain of \> 2 kg in the month prior to the pre study screening * Reported slimming or medically prescribed diet * Participation in night shift work * Pregnant or lactating or wishing to become pregnant in the period of the study * Personnel of TNO Quality of Life, their partner and their first and second degree relatives * Not having a general practitioner * Not willing to accept information-transfer concerning participation in the study, or information regarding his/her health, like laboratory results, findings at anamnesis or physical examination and eventual adverse events to and from his general practitioner.