Effect of Betaine and Folic Acid on Vascular Function in Healthy Humans

Inclusion Criteria:

• Apparently healthy.
• Women postmenopausal: two or more years after last menstruation. If the uterus was surgically removed, the women must be 55 years or older.
• Normal blood values for: hematology, total homocysteine, blood lipids, vitamin B6, vitamin B12, folate, liver enzymes, creatinine.
• Absence of protein and glucose in urine sample.
• Body mass index (BMI) between 18 and 30 kg/m2.
• Good ultrasound visibility of the brachial artery, judged by the sonographer.
• Willing not to use supplements containing B-vitamins, antioxidant vitamins (A, beta-carotene, C and E) or n-3 fatty acids/fish oil supplements from screening day (>2 months before start of the study) until end of study.
• Willing not to be blood or plasmapheresis donor from 4 weeks before the screening day, and 4 weeks before the start of the study until the end of study.

Exclusion Criteria:

• Any chronic or acute disease (e.g. diabetes, renal disease, inflammation).
• Current, or history of cardiovascular disease.
• Hypertension.
• Medical history or surgical events known to interfere with the study.
• Fasting plasma total homocysteine > 26 micromol/L.
• Alcohol consumption: more than 21 consumptions /week for women, and more than 28 consumptions/week for men.
• Weight loss or gain > 2 kg in the month prior to screening.
• Any special diet (prescribed, slimming, macrobiotic or total vegetarian). Sole exclusion of meat and fish from an otherwise ‘normal’ western diet is allowed.
• Lactose intolerance.
• Use of supplements containing B-vitamins more than once weekly in the period from 3 months before the screening day.
• Participation in any other trial up to 3 months before this study.
• Use of medication known to interfere with the study outcome.