How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Oat beta-glucan
Soluble oat fiber. From 3 g per day, it slightly lowers LDL cholesterol (5% to 9% in trials); added to a carbohydrate-rich meal, it slows the rise in blood sugar. Nothing on blood pressure.
Benefits
- LDL cholesterol: at least 3 g per day lowers LDL by 0.25 mmol/L and total cholesterol by 0.30 mmol/L (meta-analysis of 28 trials); EFSA considers the cause-and-effect relationship established from 3 g per day.
- High cholesterol: 2.9 g twice a day lowered total cholesterol by 9%, and LDL by 9% as well, in 19 hypercholesterolemic adults in 4 weeks; a meta-analysis of 13 trials (927 people) confirms the drop in total and LDL.
- Cardiovascular risk: a drink providing 3 g per day lowered LDL by about 6% and the Framingham risk score by about 8% in 4 weeks.
- Post-meal blood sugar: added to a carbohydrate-rich meal, oat beta-glucan reduces the rise in blood sugar and insulin (meta-analysis of 103 comparisons, 538 participants).
- Type 2 diabetes: 2.5 to 3.5 g per day for 3 to 8 weeks lowered fasting blood sugar and glycated hemoglobin (HbA1c) in 350 patients (meta-analysis of four studies).
Precautions
Digestion: temporary digestive disorders were noted with a drink providing 3 g per day. Limits: in 194 adults at risk of diabetes, an enriched bread providing 6 g per day for 16 weeks did not do better than whole wheat bread on HbA1c, fasting blood sugar, or LDL. 4 g per day for 4 weeks did not lower the blood pressure of 21 adults with mild hypertension. A ready meal at 4 g did not do better than the control meal on cholesterol or post-meal blood sugar. No effect on HDL, triglycerides, or insulin sensitivity, and no effect on appetite or the amount eaten afterwards in two trials.
Recommended dosage
3 g per day or more (up to 6 g in trials), in foods or a drink; 4 g added to a carbohydrate-rich meal for blood sugar.
How to take it
- For whom: trials on cholesterol mainly involve adults with high or borderline cholesterol; the effect is more pronounced when the starting LDL is high, or in cases of diabetes.
- Dose against cholesterol: at least 3 g per day, the threshold retained by EFSA and the meta-analysis of 28 trials. 6 g per day of concentrated beta-glucan also lowered total cholesterol and LDL in six weeks.
- Form: a high or medium molecular weight beta-glucan. Cut into smaller molecules, it lost half of its effect on LDL.
- Duration: cholesterol drops appear in 4 to 6 weeks in trials, and disappear upon stopping.
- Against blood sugar: in a carbohydrate-rich meal, like a muesli at 4 g; taken just before the meal, 4 g did not change the blood sugar peak in healthy people.
- With phytosterols: 3 g of oat beta-glucan and 2 g of phytosterols per day added their effects on cholesterol.
- What does not work: blood pressure, HDL cholesterol, and triglycerides do not budge in trials.
Did you know?
Molecule size matters: at an equal dose, 3 g per day, an oat beta-glucan cut into small molecules lost half of its effect on LDL cholesterol, in a trial involving 345 adults.
What the studies say
This meta-analysis of 13 randomized clinical trials (927 participants) focused on the effect of oat beta-glucan in hypercholesterolemic adults. Oat beta-glucan supplementation significantly reduced total cholesterol and LDL cholesterol. In contrast, no significant effect was observed on triglycerides or HDL cholesterol.
Yu J, Xia J, Yang C, Pan D, Xu D, Sun G, Xia H. — Nutrients (2022) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more