© Niki Clark
September 20, 2026
Marianne Waldenfels
Pumpkin is good for your gut — and apparently not just because of its fiber. New studies show how gut bacteria break down certain pumpkin compounds and what they produce in the process
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Pumpkin is now at peak season. It has long been known to be a good source of fiber. More recent studies now show that certain components can also be used directly by our gut bacteria. This produces short-chain fatty acids, which are important for a healthy gut: among other things, they supply the cells of the intestinal mucosa with energy and help maintain the gut barrier.
The focus is on what are known as polysaccharides. These complex carbohydrates are resistant to breakdown by our digestive enzymes and can therefore reach the gut bacteria intact. Several research groups have taken a closer look at what happens to them there over the past two years.
A 2025 study published in Food Chemistry first simulated human digestion. The researchers found that the pumpkin polysaccharides studied remained largely stable in the stomach and were only slightly broken down in the small intestine.
They were then fermented with gut bacteria from stool samples of healthy individuals. This produced elevated amounts of short-chain fatty acids, particularly acetate. The composition of the bacterial community also shifted: Lactobacillus increased, while Escherichia-Shigella decreased.
The results suggest that certain pumpkin polysaccharides have prebiotic potential: they reach the gut bacteria, are fermented there, and in the process influence the bacteria's metabolism.
When gut bacteria break down certain carbohydrates, they produce short-chain fatty acids such as acetate, propionate, and butyrate. These are among the most important metabolic products of the gut microbiome and carry out a range of functions in the gut.
Butyrate is especially significant. This fatty acid supplies the cells of the intestinal mucosa with energy and supports the gut barrier — the protective layer that separates the interior of the intestine from the rest of the body. Short-chain fatty acids also play a role in immune system processes and the regulation of inflammation.
That pumpkin polysaccharides can promote the production of these fatty acids was also demonstrated by a second study from 2025. The polysaccharides studied largely survived simulated digestion and were subsequently fermented by human gut bacteria. After 48 hours, the total amount of short-chain fatty acids was around 24 percent higher than in the control group.
The researchers also examined the substances produced during fermentation in cell cultures. The pro-inflammatory signaling molecules TNF-α and IL-6 decreased, while the inflammation-regulating IL-10 increased. This does not yet prove an anti-inflammatory effect of pumpkin in humans, but it does show that the substances gut bacteria produce from pumpkin components can be biologically active.
A 2026 study published in Food Research International examined pumpkin polysaccharides under different conditions: this time, the gut bacteria came from stool samples of people with constipation.
These gut bacteria were also able to make use of the pumpkin polysaccharides. In doing so, the proportion of certain butyrate-producing bacteria increased, while Escherichia-Shigella decreased. At the same time, more short-chain fatty acids were produced. Also notable was that comparatively little gas was generated during fermentation.
A similar pattern emerges across several recent studies: certain pumpkin polysaccharides reach the gut bacteria, are broken down by them, and promote the formation of substances important for gut health. The most recent study suggests that this may also work in a gut flora already altered by constipation.
This question cannot be answered on the basis of the new study. Although the gut bacteria examined came from people with constipation, the individuals themselves were not given pumpkin to eat. The study looked exclusively at what happened outside the body when their gut bacteria came into contact with isolated pumpkin polysaccharides.
Even so, the fact that butyrate-producing bacteria increased and more short-chain fatty acids were produced is noteworthy.
Hokkaido, butternut, or muscat pumpkin — so far, no study has shown that any one of these varieties is particularly beneficial for the gut. The new studies focused on isolated polysaccharides and do not allow for a direct comparison of the pumpkin varieties commonly eaten here.
Nor can a specific quantity be derived from the studies. At present, there is neither a "best" pumpkin for the gut nor a serving size from which a particular effect on the microbiome could be expected.
Pumpkin is usually boiled, steamed, or roasted. Does cooking cause it to lose the very components that are of interest for gut health? There is no evidence of this so far. However, a study published in 2026 shows that preparation can alter the composition of individual components, and that there are differences between boiling, steaming, and baking.
Whether and to what extent cooking specifically alters the polysaccharides examined in the new microbiome studies cannot be determined from this. There is therefore currently no preparation method that could be particularly recommended for gut health. That said, based on the current state of research, those who enjoy pumpkin as soup or roasted vegetables need not assume that its gut-relevant properties are lost through cooking.
The new studies show that pumpkin can support gut health in several ways. Beyond its fiber content, certain polysaccharides play a key role: they reach the gut bacteria, are broken down there, and promote the formation of short-chain fatty acids, which are important for the intestinal mucosa and gut barrier, among other things.
How pronounced this effect is after a normal serving of pumpkin still needs to be established through human studies. Nevertheless, the findings so far already offer a compelling explanation for why pumpkin can be valuable for the gut.
