CClinicalTrials.gg
Sign In
CompletedNCT00962195Updated Apr 14, 2010

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

An interventional study of purple sweet potato (PSP)-juice in Health, Blood Pressure and Liver Function, sponsored by TNO. Completed at 1 site in Netherlands. Open to participants aged 40 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2010-04-14.

Sponsored by TNO · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
40
Allocation
Randomized
Ages
40 Years to 70 Years
Sex
All
01

Study summary

Purple Sweet Potato juice (PSP-juice) is a juice based on purple-fleshed sweet potato concentrate, containing a high level of anthocyanins. Purple-fleshed sweet potatoes have attracted attention to industry and scientists due to multiple physiological functions such as radical-scavenging, ACE-inhibitory and α-glucosidase inhibitory activities in vitro, and also hepato-protective, antihypertensive and antihyperglycemic effects in vivo. Previous studies in Japanese subjects showed potential beneficial effects of PSP beverages on liver function and blood pressure in volunteers with impaired hepatic function and/or hypertension.

The main objective of this study is to examine the effect of PSP-juice on liver enzymes and blood pressure. The secondary objective is to examine the effects of PSP-juice juice on insulin resistance.

Read the detailed description

Study design: The study is designed as a randomized, parallel, placebo-controlled, double-blind study.

Study population: 40 healthy adult female and/or male subjects, 40-70 yr old with a BMI 25-35 kg/m2, mildly elevated serum liver enzymes, and high normal blood pressure or mild hypertension.

Intervention: Daily oral intake of 3x 125 ml of PSP-juice or control juice for a period of 8 weeks.

Main study parameters/endpoints: Liver enzymes (GGT, ALAT, ASAT), blood pressure, glucose, insulin, haematology and serum clinical chemical profile

02

Conditions studied

  • Health
  • Blood Pressure
  • Liver Function
  • Insulin Resistance

Browse trials for

Keywords

  • health
  • blood pressure
  • liver enzymes
  • insulin resistance
03

In context

Insulin Resistance

1,960 studies on the registry are indexed under Insulin Resistance; 306 are open to participants now.

This study's enrollment of 40 is close to the median of 40 across 1,536 interventional studies indexed under Insulin Resistance.

Browse Insulin Resistance studies →

Lead sponsor

TNO is the lead sponsor of 31 studies on the registry; 1 is open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
40 Years to 70 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

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

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.
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
40 participants (actual)

Study arms

  • Experimental
    purple sweet potato juice

    Daily oral intake of 3x 125 ml of PSP-juice for a period of 8 weeks

    Dietary Supplement: purple sweet potato (PSP)-juice

  • Placebo comparator
    Control juice

    Daily oral intake of 3x 125 ml of control juice for a period of 8 weeks

    Dietary Supplement: purple sweet potato (PSP)-juice

Interventions

  • Dietary supplementpurple sweet potato (PSP)-juice

    Daily oral intake of 3x 125 ml of PSP-juice or control juice

06

What researchers measure

Primary outcomes

  1. liver enzymes

    Time frame: every 2 weeks during 8-weeks intervention

Secondary outcomes

  1. blood pressure

    Time frame: every 2 weeks during 8-weeks intervention

  2. insulin resistance

    Time frame: every 2 weeks during 8-weeks intervention

07

Study locations

1 site
  • TNO Quality of Life
    Zeist, Utrecht, Netherlands
08

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Apr 14, 2010, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT00962195
Lead sponsor
TNO
Collaborators
Yakult Honsha Co., LTD
First posted
Aug 19, 2009
Start date
Jun 2009
Primary completion
Dec 2009
Completion
Dec 2009
Last update
Apr 14, 2010

Study contacts

Esther Boelsma, PhD
principal investigator · TNO
Ineke Klopping-Ketelaars, PhD
study director · TNO

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Apr 2010. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Other studies in this condition

Insulin Resistance→

Other studies from this sponsor

TNO

Start the discussion