Vitamin E or Lipoic Acid on Serum Oxyphytosterol Concentrations


Background of the study:

We now know that plant sterols can oxidize, which results in the formation of oxyphytosterols. Animal studies have suggested that oxyphytosterols are atherogenic components, however this relation has not yet been studied in humans. In our previous study (METC 09-3-088) we have shown in healthy volunteers that serum oxyphytosterol concentrations are linked to oxidative stress status (i.e. we were able to identify high and low sterol oxidizers). From the literature is known that especially type II diabetics and IGT subjects are characterized by increased oxidative stress markers and reduced antioxidant capacity. For this reason we also want to evaluate the oxyphytosterol concentrations in this population. Moreover, we know propose to evaluate the effect of antioxidant supplementation, i.e. vitamin E or lipoic acid, on serum oxyphytosterol concentrations in type II diabetic patients. If possible to lower oxyphytosterol concentrations in these populations this is obviously beneficial in case oxyphytosterols turn out to be atherogenic. The major objective of the present study is to examine the effect of consuming vitamin E (804 mg) or lipoic acid (600 mg) for 4 weeks on fasting oxyphytosterol concentrations in subjects with impaired glucose tolerance or type 2 diabetes.

Full Title of Study: “The Effects of Consumption of Vitamin E or Lipoic Acid on Serum Oxyphytosterol Concentrations in Subjects With Impaired Glucose Tolerance or Type II Diabetes”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Prevention
    • Masking: Triple (Participant, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: January 2014


  • Dietary Supplement: Vitamin E
    • Daily consumption of vitamin E capsules, 3 capsules of 268 mg daily, in total daily consumption of 804 mg
  • Dietary Supplement: Lipoic acid
    • Daily consumption of lipoic acid capsules, 3 capsules of 200 mg daily, in total daily consumption of 600 mg
  • Dietary Supplement: Control
    • Daily consumption of 3 placebo capsules

Arms, Groups and Cohorts

  • Experimental: Vitamin E
  • Experimental: Lipoic acid
  • Placebo Comparator: Control

Clinical Trial Outcome Measures

Primary Measures

  • Plasma oxyphytosterol concentrations
    • Time Frame: Measured after 4 weeks intervention

Secondary Measures

  • Serum lipoprotein concentrations
    • Time Frame: Measured after 4 weeks intervention
  • Markers reflecting oxidative stress
    • Time Frame: Measured after 4 weeks intervention
  • Markers reflecting antioxidant capacity
    • Time Frame: Measured after 4 weeks intervention

Participating in This Clinical Trial

Inclusion Criteria

  • Aged between 18 and 75 years
  • Body Mass Index (BMI) between 20-35 kg/m2
  • Mean serum total cholesterol <8.0 mmol/L
  • Mean serum triacylglycerol <3.0 mmol/L
  • Diagnosed with diabetes mellitus type 2 on a clinical basis or impaired glucose tolerance (defined as blood glucose >7.8 mmol/l and <11.0 mmol/L, two hours after ingesting 75 gram glucose in 150 ml water)

Exclusion Criteria

  • Unstable body weight (weight gain or loss > 3 kg in the past two months)
  • Active cardiovascular diseases like congestive heart failure or recent (<6 months) event (acute myocardial infarction, cerebral vascular incident)
  • Severe medical conditions that might interfere with the study such as epilepsy, asthma, chronic obstructive pulmonary disease, inflammatory bowel disease and rheumatoid arthritis
  • Use of medication such as corticosteroids, diuretics or lipid lowering therapy
  • Use of insulin therapy
  • Abuse of drugs or alcohol (>21 units per week)
  • Not willing to stop the consumption of vitamin supplements, containing lipoic acid and/or vitamin E, 1 month before the start of the study (wash-in period)
  • Use of an investigational product within another biomedical study within the previous month
  • Pregnant or breast-feeding women
  • Current smoker

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 75 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Maastricht University Medical Center
  • Collaborator
    • ZonMw: The Netherlands Organisation for Health Research and Development
  • Provider of Information About this Clinical Study
    • Principal Investigator: Jogchem Plat, Professor – Maastricht University Medical Center
  • Overall Official(s)
    • Jogchum Plat, Prof., Principal Investigator, Maastricht University Medical Centre

Clinical trials entries are delivered from the US National Institutes of Health and are not reviewed separately by this site. Please see the identifier information above for retrieving further details from the government database.

At, we keep tabs on over 200,000 clinical trials in the US and abroad, using medical data supplied directly by the US National Institutes of Health. Please see the About and Contact page for details.