In this article
- What beta-glucan fiber is
- Two kinds of beta-glucan: grains vs mushrooms
- Beta glucan foods ranked by dry weight
- The fresh weight reality check
- How to read dry weight numbers
- Oats and barley: the cereal leaders
- Can mushroom beta-glucan help with cholesterol?
- Beta-glucan, blood sugar and your gut
- What about yeast?
- A day with both kinds of beta-glucan
- How to choose your beta-glucan foods
- Beta-glucan foods: what people ask
- Sources
Ask most people to name beta glucan foods and they’ll say oats. Oats and barley do lead the grains, but gram for gram of dry weight, some everyday mushrooms carry far more: in a 2024 lab study, dried oyster mushrooms held about 37 grams of beta-glucan per 100 grams, while oats tested in the same lab held about 7.6 grams.
There’s a catch that keeps oats and barley on top for most people. Mushroom beta-glucan is built differently from the grain kind, fresh mushrooms are mostly water, and the cholesterol research is strongest for oats and barley.
What beta-glucan fiber is
Beta-glucan is a fiber made of glucose units linked in a way your digestive enzymes can’t break. Harvard’s Nutrition Source describes the grain form as a soluble, highly fermentable fiber found in oats and barley.
Harvard says it acts as a prebiotic, feeding gut bacteria, and may help normalize blood glucose and cholesterol levels. Harvard Health adds that barley and other whole grains help lower heart disease risk mainly through the soluble fiber they deliver.
Two kinds of beta-glucan: grains vs mushrooms
Not all beta-glucan is the same molecule. The authors of the 2024 mushroom study, Belobrajdic and colleagues, explain the difference in their paper:
| Source | How the glucose is linked | Where you find it |
|---|---|---|
| Cereal beta-glucan | Mixed beta 1,3 and beta 1,4 links, no 1,6 branches | Oats, barley |
| Fungal and yeast beta-glucan | Beta 1,3 backbone with short beta 1,6 side branches | Mushrooms, yeast |
That structural difference may explain why cooking affected oats and mushrooms in opposite ways in their tests. Whether it changes the health effects is still an open question.
Beta glucan foods ranked by dry weight
Two recent studies measured beta-glucan in freeze dried mushrooms, and one grain study measured barley and wheat. All values below are grams per 100 grams of dry weight:
| Food | Beta-glucan per 100 g dry | Study |
|---|---|---|
| Oyster mushroom | 37.4 g | Belobrajdic 2024 |
| Shimeji mushroom | 32.5 g | Belobrajdic 2024 |
| Oyster mushroom | 29.8 g | See Toh 2023 |
| Shiitake mushroom | 22.4 g | See Toh 2023 |
| Enoki mushroom | 17.1 g | See Toh 2023 |
| White button mushroom | 8.1 to 9.8 g | Both studies |
| Waxy barley | 9.5 g | Messia 2017 |
| Mini portobello mushroom | 9.2 g | See Toh 2023 |
| Oats | 7.6 g | Belobrajdic 2024 |
| Barley, average of 5 varieties | 5.3 g | Messia 2017 |
| Wheat, average of 5 varieties | 0.6 g | Messia 2017 |
Oyster, shimeji and shiitake mushrooms sit well above any grain on a dry basis. Button and portobello mushrooms land close to oats and barley.
Wheat barely registers, at well under 1 gram. So bread and pasta made from wheat aren’t meaningful beta-glucan foods.
The fresh weight reality check
Dry weight numbers flatter mushrooms, because fresh mushrooms are mostly water. Belobrajdic and colleagues also reported raw, fresh weight values:
| Mushroom, raw | Beta-glucan per 100 g fresh |
|---|---|
| Shimeji | 3.7 g |
| Oyster | 3.2 g |
| Button | 0.7 g |
| Brown (cremini) | 0.7 g |
| Cup | 0.5 g |
| Flat | 0.3 g |
So 100 grams of fresh oyster or shimeji mushrooms gives you roughly 3 to 4 grams of beta-glucan. Common button mushrooms give well under a gram.
Oats are sold dry, so their 7.6 gram figure already reflects what’s in the bag. That’s a big reason grains stay the most practical beta-glucan source for most people.
Want more ways to cook oyster mushrooms, shiitake and barley? Our recipe eBooks are full of easy, high fiber dishes.
How to read dry weight numbers
Lab tables often report beta-glucan per 100 grams of dry weight, meaning the food after its water has been removed. That’s useful for comparing foods, but it isn’t what lands on your plate.
Compare the two oyster mushroom figures from the Belobrajdic study. Dried, they held 37.4 grams per 100 grams. Fresh, the same mushrooms held 3.2 grams, so water accounts for most of the weight of a raw oyster mushroom.
Grains work the other way. Oats and barley flakes are already dry when you buy them, so their table values are close to what you actually eat before you add water or milk.
| Portion | Beta-glucan, approx. | Based on |
|---|---|---|
| 100 g fresh oyster mushrooms | 3.2 g | Belobrajdic 2024, fresh weight |
| 100 g fresh shimeji mushrooms | 3.7 g | Belobrajdic 2024, fresh weight |
| 100 g fresh button mushrooms | 0.7 g | Belobrajdic 2024, fresh weight |
| 100 g dry oats | 7.6 g | Belobrajdic 2024, dry weight |
| 1 serving oat flakes | 1.39 g | Dodevska 2013 |
| 1 serving barley flakes | 1.30 g | Dodevska 2013 |
Read this way, a generous plate of fresh oyster or shimeji mushrooms is in the same range as two servings of oat or barley flakes. A plate of button mushrooms is not.
Oats and barley: the cereal leaders
Among grains, oats and barley are the beta-glucan foods that matter. A 2013 study by Dodevska and colleagues found about 1.39 grams of beta-glucan per serving of oat flakes and 1.30 grams per serving of barley flakes.
Barley varies a lot by variety. In the Messia study, five barleys ranged from about 3.9 to 9.5 grams per 100 grams of dry weight, with a waxy type at the top.
Harvard Health puts a bowl of oatmeal at 1 to 2 grams of soluble fiber. Pairing oats with barley in the same day is the simplest way to build a solid cereal beta-glucan intake.
The gap between barley and wheat is worth a second look. In the Messia study, the five barleys averaged about 5.3 grams of beta-glucan per 100 grams of dry weight, while the five wheats averaged about 0.6 grams.
That’s close to a ninefold difference between two grains that often sit side by side on the shelf. If you want a grain swap that actually moves your beta-glucan intake, trading some wheat for barley does more than switching between wheat products.
Serving size matters too. The Dodevska figures are per serving of flakes, so a single bowl gives you a little over a gram, and a second grain meal later in the day roughly doubles it.
Can mushroom beta-glucan help with cholesterol?
Cereal beta-glucan is thought to help lower cholesterol partly by binding bile acids in the gut. Belobrajdic and colleagues tested whether mushrooms could do the same in a lab model of digestion.
Raw button type mushrooms bound 29 to 36% of bile acids, similar to raw oats at 36%. Oyster mushrooms bound about 22%, and needed roughly three times more beta-glucan to match oats.
Cooking changed the picture. Boiling and frying generally increased bile acid binding in the mushrooms but reduced it in oats.
The authors are clear that this is a test tube result. Clinical trials are needed to show whether mushrooms lower cholesterol in people, and whether the amount needed is realistic.
Beta-glucan, blood sugar and your gut
Harvard’s Nutrition Source says cereal beta-glucan may help normalize blood glucose. Because it’s highly fermentable, it also feeds gut bacteria, which turn fiber into short chain fatty acids that help nourish the colon.
For mushroom beta-glucan, See Toh and colleagues describe broad potential benefits, including effects on blood sugar and cholesterol, but much of that evidence comes from lab and animal studies. Treat mushrooms as a promising extra rather than a proven replacement for oats.
Not sure how much total fiber you need each day? Our fiber calculator gives you a personal target in seconds.
What about yeast?
Yeast cell walls contain beta-glucan too, of the fungal type with 1,6 branches, according to the Belobrajdic team. That’s the form often sold as a supplement ingredient.
None of the studies used here measured yeast foods, so there are no gram figures to compare. For everyday eating, oats, barley and mushrooms are the reliable whole food sources.
The same goes for mushroom varieties outside these two studies. If a mushroom isn’t in the tables above, there’s no solid number to give you, and it’s better to lean on the tested ones.
A day with both kinds of beta-glucan
Picture a day that mixes the two families. Breakfast is a bowl of oatmeal, good for about 1 to 2 grams of soluble fiber by Harvard Health’s estimate.
Lunch is a barley and vegetable soup. Dinner is a stir fry with 100 grams of fresh oyster mushrooms, adding roughly 3 grams of fungal beta-glucan by the fresh weight figures.
That’s three meals and two very different kinds of beta-glucan, without a supplement in sight. It also brings plenty of other fiber along with it.
If your gut isn’t used to this much fermentable fiber, our guides walk you through building up gradually.
How to choose your beta-glucan foods
- If cholesterol is your main goal: make oats and barley your daily base, since the evidence is strongest for cereal beta-glucan.
- If you want the most beta-glucan per bite of a fresh food: choose oyster or shimeji mushrooms over button mushrooms.
- If you already eat lots of button mushrooms: enjoy them, but don’t count on them for much beta-glucan.
- If you’re choosing a grain: pick oats or barley over wheat, which carries very little.
- If you cook mushrooms: boiling or frying didn’t hurt their bile acid binding in lab tests.
Beta-glucan foods: what people ask
Which food has the most beta-glucan?
By dry weight, oyster and shimeji mushrooms tested highest, at about 32 to 37 grams per 100 grams. Among grains, oats and barley lead, with oats at about 7.6 grams per 100 grams in the same lab.
Do mushrooms have beta-glucan?
Yes. Mushrooms carry a fungal type of beta-glucan, with oyster, shimeji and shiitake highest. Fresh button mushrooms have well under 1 gram per 100 grams.
Is mushroom beta-glucan the same as oat beta-glucan?
No. Cereal beta-glucan has mixed 1,3 and 1,4 links, while mushroom and yeast beta-glucan has a 1,3 backbone with 1,6 branches. The health effects may not be the same.
Does barley have more beta-glucan than oats?
It can. Barley varied from about 3.9 to 9.5 grams per 100 grams of dry weight in one study, and some types beat oats, which tested at 7.6 grams in another lab.
Does wheat contain beta-glucan?
Very little. Wheat averaged about 0.6 grams of beta-glucan per 100 grams of dry weight in one study, roughly a tenth of barley.
Can mushrooms lower cholesterol like oats?
Possibly, but it isn’t proven. In a lab model, button type mushrooms bound bile acids about as well as oats, but clinical trials are still needed.
Does cooking destroy beta-glucan in mushrooms?
Not in lab tests of bile acid binding. Boiling and frying generally increased mushrooms’ bile acid binding, while the same cooking reduced it in oats.
Sources
- Belobrajdic DP, Brook H, James-Martin G, Stonehouse W. “Ξ²-Glucan content and in vitro bile-acid binding capacity of Agaricus bisporus and Pleurotus spp.” Food & Function, 2024. pubs.rsc.org
- See Toh CJY, Bi X, Lee HW, Yeo MTY, Henry CJ. “Is mushroom polysaccharide extract a better fat replacer than dried mushroom powder for food applications?” Frontiers in Nutrition, 2023. frontiersin.org
- Messia MC, Candigliota T, De Arcangelis E, Marconi E. “Arabinoxylans and Ξ²-glucans assessment in cereals.” Italian Journal of Food Science, 2017. distantreader.org
- Dodevska MS, Djordjevic BI, Sobajic SS, et al. “Characterisation of dietary fibre components in cereals and legumes used in Serbian diet.” Food Chemistry, 2013. agris.fao.org
- Harvard T.H. Chan School of Public Health. “Fiber.” The Nutrition Source, 2022. nutritionsource.hsph.harvard.edu
- LeWine HE. “11 foods that lower cholesterol.” Harvard Health Publishing, 2024. health.harvard.edu
