Beta-Glucan and Cholesterol: What the Evidence Actually Shows

This fiber from oats and barley has some of the strongest data of any supplement for lowering LDL cholesterol.

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By the Ration Editorial Team · Reviewed against primary research · Updated July 13, 2026

Beta-glucan is a type of soluble fiber found in the cell walls of oats, barley, and certain mushrooms and yeasts like Saccharomyces cerevisiae.

Unlike insoluble fibers, beta-glucan dissolves in water and forms a thick, gel-like substance in the gut.

That gel is the key to most of its effects, including how it interacts with cholesterol and bile acids during digestion.

When beta-glucan forms a gel in the small intestine, it traps bile acids, which are made from cholesterol in the liver.

Trapped bile acids get excreted instead of being reabsorbed, so the liver has to pull more cholesterol out of the blood to make new bile acids.

The gel may also slow the absorption of dietary cholesterol and fats, and fermentation of beta-glucan by gut bacteria produces short-chain fatty acids that may further influence liver cholesterol production.

This is one of the better-studied fibers for heart health, with several independent meta-analyses of randomized controlled trials pointing the same direction.

A 2022 meta-analysis of RCTs in adults with high cholesterol found that oat beta-glucan meaningfully reduced total cholesterol and LDL cholesterol, with effects tending to grow at higher doses^[1].

A 2016 systematic review focused specifically on LDL cholesterol, non-HDL cholesterol, and apoB, all markers tied to cardiovascular risk, and found consistent reductions across trials^[3].

An earlier 2014 meta-analysis reached a similar conclusion, estimating that each additional gram of beta-glucan per day was associated with further LDL lowering, up to a point^[4].

A randomized trial testing a specific oat beta-glucan product found LDL reductions in both Caucasian and non-Caucasian participants, suggesting the effect is not limited to one population^[6].

Another human trial reported similar cholesterol-lowering effects with oat beta-glucan^[5], and animal research on beta-glucan extracted from yeast found reductions in cholesterol in rats, hinting the effect may extend beyond oat-derived beta-glucan^[2].

• ↓LDL CholesterolAHuman trials

  Research may lower LDL Cholesterol · strong agreement · 6 studies

  View 5 studies on PubMed

  • Effects of Oat Beta-Glucan Intake on Lipid Profiles in Hypercholesterolemic Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials (2022)
  • The effect of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for CVD risk reduction: a systematic review and meta-analysis of randomised-controlled trials (2016)
  • Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials (2014)
  • Bioactive oat β-glucan reduces LDL cholesterol in Caucasians and non-Caucasians (2011)
  • Cholesterol-lowering effects of oat β-glucan (2011)

Taken together, this body of evidence is why beta-glucan's effect on LDL cholesterol is graded consistently across the literature, with six or more studies pointing in the same direction.

• Oats and oat bran, among the most studied sources
• Barley and barley bran
• Mushrooms, including shiitake and maitake, in smaller amounts
• Baker's or brewer's yeast (Saccharomyces cerevisiae)
• Concentrated oat or barley beta-glucan extracts sold as supplements

Whole grain foods deliver beta-glucan alongside other fibers, vitamins, and minerals, while supplements offer a more concentrated, standardized dose.

Most of the trials showing LDL benefits used around 3 grams of beta-glucan per day, which lines up with dietary guidance from regulatory bodies in the US and EU for cholesterol-related claims^{[1] [4]}.

That amount is roughly what you would get from 1 to 1.5 cups of cooked oatmeal, or a smaller amount of a concentrated oat bran or beta-glucan supplement.

Some research suggests higher doses may produce slightly larger reductions in LDL, though the relationship is not perfectly linear and benefits seem to plateau^[4].

Beta-glucan from food sources like oats and barley has a long history of safe consumption and is generally well tolerated.

• Bloating or gas, especially when intake increases quickly
• Mild stomach discomfort in sensitive individuals
• Possible interference with absorption of some medications or nutrients if taken at the exact same time

Starting with smaller amounts and increasing gradually, along with drinking enough water, may help minimize digestive side effects.

• People with elevated LDL cholesterol looking for a diet-based approach
• Those already eating oats or barley who want to understand the cholesterol angle
• People interested in fiber sources that also support blood sugar and gut health
• Anyone working with a healthcare provider on a broader cholesterol-lowering plan

Beta-glucan has some of the most consistent human trial evidence of any dietary fiber for lowering LDL cholesterol^{[1] [3] [4] [6]}.

The effect is real but modest, and it works best as part of an overall diet pattern rather than a stand-alone fix.

Getting it from whole foods like oats and barley offers the added benefit of other nutrients that support heart health.