Effect of homocysteine-lowering nutrients on blood lipids: results from four randomised, placebo-controlled studies in healthy humans

Olthof MR, van Vliet T, Verhoef P, Zock PL, Katan MB · PLoS Medicine

The precise size of the lipid signal: 6 g/day of betaine raised LDL cholesterol by 0.36 mmol/L (95% CI 0.25-0.46) and triacylglycerol by 0.14 mmol/L (0.04-0.23) versus placebo, with the total-to-HDL ratio up 0.23; the LDL rise was already present at 2 weeks, and lower doses moved LDL in the same direction without reaching significance.

Population

Healthy adults pooled across three placebo-controlled betaine trials (plus folic acid and phosphatidylcholine arms)

Intervention

Betaine 6 g/day for 6 weeks

Comparator

Placebo

Limitations

Every study was designed for homocysteine, not lipids: in two of the four the lipid measurements were made post hoc, and in the other two they were planned but the power calculation rested on a different endpoint. Healthy volunteers; doses below 6 g/day were not individually powered.