Properties of oat β‐glucan influence its LDL cholesterol lowering effect in humans

Consuming 3g oat β‐glucan (OBG) daily is considered sufficient to lower serum LDL cholesterol (LDL). Not all studies show this, possibly because β‐glucan bioactivity is reduced in some food products by low solubility or low molecular‐weight (MW). We tested whether daily consumption of 3g OBG (OatWell®) reduced LDL and whether LDL lowering depended on log(MW×C), where C = dose×solubility. Healthy subjects (n=367) with LDL ≥3.0 and ≤5.0mmol/L were randomly assigned to the following treatments in a double‐blind, parallel design clinical trial: 1.5g high‐MW (3H), 2g medium‐MW (4M), 1.5g medium‐MW (3M) or 2g low‐MW (4L) OBG in cereal or a control wheat fiber cereal (W) twice daily for 4wk. After 4wk on 3H LDL was less than on W by 0.21 mmol/L (95% confidence interval; 0.11, 0.30, P =0.0023). Analysis of covariance showed log(MW×C) was a significant determinant of week 4 LDL ( P =0.003). The size of treatment effects was not significantly affected by age, sex, centre or baseline LDL. We conclude that consuming 1.5g high‐MW OBG twice daily reduces LDL by 0.2mmol/L, but efficacy is reduced with OBG of lower MW and/or C. Thus, the physico‐chemical properties of β‐glucan influence oat's LDL‐lowering effect. Funded by the Swedish Governmental Agency for Innovations Systems and CreaNutrition.