Chestnut Mushroom Nutrition
Chestnut Mushroom Nutrition: What's Actually Inside the UK's Favourite Cooking Mushroom
A straightforward look at the calories, protein, B vitamins and antioxidants in chestnut mushrooms, from a six-generation Sussex grower.
Chestnut mushrooms are low in calories, low in carbs and genuinely useful in the kitchen. A 100g serving provides around 22 kcal, 2.5g of protein, 3.3g of carbohydrates and a solid hit of B vitamins, selenium and antioxidants, all for less than a handful of crisps in calorie terms.
Chestnut mushrooms are a cultivated form of Agaricus bisporus, the same species as the common white button mushroom, picked a little later for a firmer texture and nuttier flavour. They are one of the most widely sold fresh mushrooms in the UK, and a strong everyday choice for anyone who cares about what they eat without wanting to overthink it.
This guide breaks down the nutrition in plain English, explains which health benefits are genuinely supported by research, and shows how home-grown chestnut mushrooms can fit into a healthy weekly shop.
Quick Takeaways
- Around 22 kcal and 3.3g of carbs per 100g, making them low-calorie and keto-friendly.
- A useful source of B vitamins, especially riboflavin, niacin and pantothenic acid.
- Provide selenium and copper, two minerals that support immune function.
- Contain ergothioneine and glutathione, two antioxidants studied for cell protection.
- Home-grown chestnut mushrooms are at their nutritional peak when cooked fresh.
- Firmer and nuttier than white button mushrooms, so they hold their shape in stir-fries and stews.
Chestnut mushroom nutrition per 100g
Nutrition figures for any fresh mushroom vary slightly with growing conditions, maturity at harvest and variety strain, but the numbers below are a reliable average for raw chestnut mushrooms sold in the UK.
Averages drawn from USDA and UK food composition data for Agaricus bisporus (chestnut and cremini).
Why chestnut mushrooms are low-calorie and keto-friendly
Chestnut mushrooms are around ninety percent water, which is the main reason the calorie count sits so low. The rest is made up of a small amount of protein, a small amount of carbohydrates, and a tiny amount of fat and fibre. That combination makes them a genuinely useful ingredient for anyone eating lighter without wanting to feel underfed.
The keto angle works because most of the carbohydrate in mushrooms is not easily available sugar. At just over three grams of total carbs per 100g, chestnut mushrooms slot into a ketogenic day without using up much of the daily allowance. They also bring savoury umami depth, which matters more on a low-carb diet where bread, pasta and rice are off the menu. If you want the broader picture, our guide to keto-friendly mushrooms covers where each variety fits.
Home-grown chestnut mushrooms deliver the same nutrition profile, with fresher flavour.
Health benefits of chestnut mushrooms
The health story on chestnut mushrooms is less about dramatic single claims and more about a combination of small, useful contributions. Here is what the research genuinely supports.
B vitamins for energy metabolism
Chestnut mushrooms are a meaningful source of riboflavin, niacin and pantothenic acid. All three are involved in converting food into usable energy, and all three are essential nutrients your body cannot store in large amounts. A 100g portion provides a useful share of the daily recommended intake for niacin and riboflavin in particular.
Selenium and copper for immune function
Selenium supports the body's antioxidant defence system and is involved in normal immune cell function. Copper contributes to iron transport, red blood cell formation and healthy connective tissue. Chestnut mushrooms are not the richest source of either mineral, but they are a steady, accessible one that fits into weekly meals without any effort.
Ergothioneine and glutathione
These are two antioxidants that mushrooms produce in unusually high amounts compared with most other foods. Ergothioneine is sometimes called the longevity vitamin because human cells have a specific transporter for it, and levels in the body tend to drop with age. Research into both compounds is ongoing, but the direction of travel suggests they play a protective role against cellular oxidative stress.
Fibre for gut health
The fibre content is modest at 0.6g per 100g, but it includes small amounts of beta-glucan, a type of soluble fibre linked to healthy gut bacteria and cholesterol balance. Regular mushroom eaters tend to get these small benefits cumulatively across the week rather than in one serving.
Vitamin D, if you let them see the light
Chestnut mushrooms are one of the few natural plant-side sources of vitamin D. If you leave fresh mushrooms, gill-side up, in direct sunlight for fifteen to thirty minutes before cooking, the ergosterol in the flesh converts to vitamin D2. A good winter habit, especially in the UK where sunlight exposure is limited for much of the year.
How cooking affects chestnut mushroom nutrition
Cooking slightly reduces the B vitamin content, because those vitamins are water-soluble and can leach into cooking liquid. On the other hand, cooking improves the availability of ergothioneine and makes the protein and minerals easier for the body to absorb. The overall balance is a net positive.
Dry-heat cooking methods, such as roasting, grilling and sautéing, preserve nutrients best. Long boiling is the least nutritionally efficient method, though the liquid itself makes an excellent stock base. If you are making a soup or stew, there is no real loss because the liquid is part of the dish.
Chestnut versus white button mushrooms
Chestnut and white button mushrooms come from the same species. The chestnut is simply the more mature form, with a darker cap, a firmer texture and a more developed flavour. Nutritionally they are very close, but the chestnut has a very slight edge in antioxidant content thanks to its longer growing period and darker pigment.
For cooking, chestnut mushrooms hold their shape better than white buttons, which is why they work so well in stir-fries, stews, roasts and pasta bakes. The flavour also stands up better to strong seasoning and longer cooking times.
Getting the most nutrition from home-grown chestnut mushrooms
Freshness matters for both flavour and nutrition. Mushrooms begin losing moisture, flavour compounds and some vitamins from the moment they are picked. Shop-bought chestnut mushrooms can easily be several days old before they reach the fridge, whereas home-grown ones can go from kit to pan in under an hour.
Our Chestnut Mushroom Growing Kit arrives already colonised, so you can harvest a first flush within days of setting it up. A single kit typically produces two to three harvests, giving you a steady supply of mushrooms at their nutritional peak without relying on the shop.
Frequently asked questions
Are chestnut mushrooms good for weight loss?
Yes. At around 22 kcal per 100g, chestnut mushrooms are one of the lowest-calorie savoury ingredients you can use. They add volume, umami flavour and a satisfying bite without adding much energy, which is why they work well in meat-reduced or calorie-conscious meals.
How much protein is in chestnut mushrooms?
Around 2.5g per 100g. It is not a protein powerhouse compared with beans or meat, but it is a useful contribution for vegetarians and vegans, especially since mushroom protein is reasonably well balanced across the essential amino acids.
Are chestnut mushrooms safe to eat raw?
Technically yes, but cooking is recommended. Heat breaks down the tough chitin in the cell walls, making nutrients more available and improving digestibility. Most of the flavour benefits also come out during cooking.
Do chestnut mushrooms have vitamin D?
A small amount naturally, but you can boost levels significantly by placing fresh mushrooms in sunlight for fifteen to thirty minutes before cooking. The ergosterol in the flesh converts to vitamin D2 under UV light.
Are chestnut mushrooms the same as cremini?
Yes. Chestnut is the UK name, cremini and baby bella are the common names in the United States. All three are the same mushroom at the same stage, Agaricus bisporus, harvested before it matures into a portobello.
Grow the freshest chestnut mushrooms at home
Our ready-growing kits arrive already colonised, so you get your first harvest within days. Fresher mushrooms means better flavour, better texture and better nutrition in every dish.
Shop Mushroom Growing KitsRelevant reading
If you are using chestnut mushrooms as part of a broader interest in healthy eating or home growing, these guides go deeper.
Keto-friendly mushrooms: a variety-by-variety guide
Which mushroom varieties fit best into a low-carb or ketogenic diet, with honest carb counts for each.
Chestnut mushroom recipe ideas
Easy, everyday ways to make the most of a fresh chestnut harvest, from stir-fries to stews.
Chestnut Mushroom Growing Kit
Our ready-growing chestnut kit, colonised and ready to fruit within days of arriving.
Mushroom growing glossary and information
Plain-English definitions for flushes, pins, mycelium and the other terms used across our growing guides.
Final thoughts
Chestnut mushrooms are a quietly impressive ingredient. Low in calories, low in carbs, useful in the kitchen and genuinely nutrient-dense for something so light. Home-grown adds freshness, control over timing, and the satisfaction of pulling dinner straight from a kit on the kitchen side.
Have a question about growing chestnut mushrooms at home, or about other varieties in our range? Contact our team, follow us on Instagram, or explore our blog for more growing and cooking tips.
Published by Merryhill Mushrooms, a six-generation family grower based in Storrington, West Sussex.