List of foods that don't ferment in the intestine

Intestinal fermentation: a natural phenomenon

The first thing to remember is that fermentation is a perfectly normal physiological process.

It results from the breakdown of dietary fibre and other non-digestible carbohydrates by the bacteria of the microbiota when they reach the large intestine.

It then leads to the production of gases (nitrogen, hydrogen, methane, carbon dioxide, etc.) as well as beneficial metabolites such as short-chain fatty acids (SCFAs), which nourish the colonocytes, the cells in the colon (1).

In this sense, fermentation is not a problem in itself. But when it becomes excessive, it can cause digestive discomfort that can seriously affect quality of life.

Excessive fermentation: what are the symptoms?

Excessive fermentation causes a massive build-up of gas in the intestine, leading to:

• abdominal distension and bloating (2);
• flatulence, often foul-smelling;
• painful intestinal spasms;
• transit disorders (diarrhoea, constipation, or alternation of the two).

These symptoms are particularly marked in people with irritable bowel syndrome (IBS) and/or sensitivity to FODMAPs, fermentable sugars that are poorly absorbed by the small intestine (3-4).

Common causes of excessive fermentation

Several factors encourage excessive fermentation in the intestine:

• a diet too rich in fibre and fermentable carbohydrates (FODMAPs);
• an imbalance in the microbiota (intestinal dysbiosis);
• chronic stress that affects intestinal motricity (5);
• visceral hypersensitivity, frequently associated with IBS (6);
• inadequate mastication (7);
• certain specific food intolerances, notably lactose or gluten (8–9).

One of the most effective ways of countering this phenomenon is to review your diet, giving priority to foods that ferment little or not at all in the intestine.

The list of foods that do not ferment in the intestine

The following foods are low in fermentable compounds, making them generally well tolerated by sensitive intestines (10):

• eggs;
• lean meat (chicken, turkey, veal, rabbit, etc.);
• white fish (cod, hake, sole, pollack, etc.);
• refined starches (white rice, white pasta, white bread, etc.);
• naturally gluten-free cereals (quinoa, buckwheat, millet, polenta, etc.), potatoes, sweet potatoes;
• clarified butter (ghee), olive oil, coconut oil;
• fruit low in FODMAPs: citrus fruit, bananas, strawberries, raspberries, passion fruit, papaya, kiwi fruit, melons, mandarins, rhubarb, coconuts;
• vegetables low in FODMAPs: spinach, carrot, chicory, olives, celery, courgette, cucumber, salad;
• lactose-free dairy products such as mature hard cheeses (comté, emmental, beaufort, parmesan, etc.), plant-based drinks and yoghurts (coconut, soya, almond, rice);
• maple syrup;
• coffee, tea and herbal teas.

Note that cooking methods also affect the digestibility of food. Wherever possible, gentle methods, such as poaching, steaming or stewing should be used.

Swollen belly: which foods to avoid?

Conversely, certain foods are known to ferment excessively in the gut (11):

• cabbage and alliaceous vegetables (onions, garlic, leeks, etc.);
• sources of fructose (honey, certain fruits such as apples and pears);
• high-fat meats and cold meats;
• legumes;
• wholegrain products, especially those made from wheat;
• lactose-rich dairy products such as milk and fromage frais;
• fizzy drinks;
• sweeteners (polyols) contained in chewing gum, low-fat products, etc.

It's not necessarily a question of eliminating them completely, but rather of moderating their consumption (in terms of frequency and/or quantity) in order to assess individual tolerance.

What supplements can help relieve fermentation-related problems?

In addition to these dietary measures, certain targeted food supplements help to reduce excessive fermentation, regulate transit and provide more general support for the intestinal mucosa.

Often considered a 'natural intestinal dressing', activated vegetable charcoal helps to reduce excess flatulence after meals (12).

With its spongy structure, it has adsorbent properties that enable it to bind intestinal gases and prevent their accumulation in the colon (extracted naturally from a resinous wood, Charcoal is activated to form a network of ultra-fine pores, guaranteeing superior effectiveness).

Several studies have observed disturbances in the microbiotic composition of IBS sufferers, who are particularly prone to bloating and transit problems (13).

In this context, a probiotic combining strains active in the lower tract (such as Colon Friendly, which combines Saccharomyces cerevisiae, Bifidobacterium longum infantis, Bifidobacterium longum longum and Lactobacillus acidophilus) may help to restore a healthy intestinal balance (14).

Butyrate is one of the valuable short-chain fatty acids mentioned above.

Derived mainly from the fermentation of dietary fibres, it is thought to help strengthen the intestinal barrier by fusing the tight junctions that line the walls (15).

Studies also suggest that it plays a key role in modulating intestinal inflammation (16). The problem is that its synthesis varies greatly from one individual to another, and is thought to be considerably reduced in the case of irritable bowel, hence the importance of external supplementation (Butyrate Colon Formula is based on tributyrin, an optimised, highly assimilable form of butyrate) (17).

Since the discovery of the gut–brain communication axis, researchers have suspected a close link between functional digestive disorders, such as IBS, and stress (18).

Because it contributes to the normal functioning of the nervous system and muscles, magnesium is an interesting option in the case of intestinal spasms linked to nervous 'hyperactivity' (the magnesium orotate at the heart of Magnesium Orotate is a highly bioavailable form that is very well accepted at digestive level) (19).

Finally, soft, non-fermentable soluble fibres such as those found in blond psyllium (featured in Psyllium Husk) help to harmonise transit gently, i.e. without inducing overproduction of gas, and to restore intestinal comfort (20-21).