There’s no need to fear carbohydrates. In fact, alongside protein and fat, carbohydrates are an essential macronutrient that, ideally, should meet between 45 and 65 percent of a healthy adult’s daily energy needs. Not only do they provide essential fuel for cellular metabolism throughout the body, but carbohydrates are also integral to a healthy gut microbiome, and healthy gut function overall. Read on to find out about the benefits of carbohydrates for gut health.
Before we begin, it’s important to know that not all carbohydrates are created equal. While simple carbohydrates (sugars such as glucose, sucrose and fructose) most definitely have their place in a healthy diet, especially when found within minimally-processed wholefoods, complex carbs, including dietary fibre (found in all plant-derived foods, including vegetables, fruits, wholegrains and legumes) and resistant starch (commonly found in legumes and unripe bananas) are much more nutrient-dense and deliver a multitude of health benefits. Once consumed, the influence of carbohydrates upon the gut microbiome depends on whether they are ‘digestible’ or ‘non-digestible’ in the small intestine.
How to feed the gut microbiome with carbs
A diverse ecosystem of up to 100 trillion microorganisms – primarily bacteria – within the gastrointestinal tract, the gut microbiome is not only critically important for digestive health, but also directly affects liver detoxification, mental health and immune function. Moreover, a state of gut dysbiosis – an imbalance between certain bacterial species – is associated with various disease states, including irritable bowel syndrome and certain autoimmune conditions.
Within the gut, bacterial growth is primarily supported by energy obtained from the diet. Microbial composition and activity shift dramatically in response to both short- and long-term dietary change, particularly with regards to carbohydrates. Non-digestible carbohydrates, including dietary fibre and resistant starch, resist digestion in the small intestine, passing through to the large intestine where they undergo fermentation. The resulting by-products, known as short-chain fatty acids, selectively support the growth of beneficial bacteria and help maintain a healthy intestinal barrier.
Microbial diversity, which refers to a balance between multiple beneficial bacterial strains within the gut microbiome, is another indicator of overall gut health. Given the direct influence of diet on microbial composition, an intake of 30+ unique plant foods is recommended over the course of each week to achieve optimal gut microbial diversity. Thus, including diverse carbohydrate sources. Think wheat, oats, rye, barley, buckwheat, rice, sweet potato, and more to achieve this goal.
How carbohydrates fuel gut function
Dietary fibre also supports healthy bowel function, slows nutrient digestion and absorption for improved glycaemic (blood glucose) control, and promotes greater feelings of fullness after eating. Soluble fibre, found in oats, barley, legumes and citrus fruits, supports cholesterol excretion and anti-inflammatory activity. Insoluble fibre, mostly from vegetables and whole grains, facilitates elimination, easing constipation and protecting the bowel lining. To support gut health and function, a minimum of 25-30 g of dietary fibre is recommended for healthy Australian adults, with more research showing that aiming for 30-50 g daily may be even more beneficial.
Choosing quality carbs for optimal gut health
In addition to consuming appropriate amounts of carbohydrate-rich foods every day, choosing quality sources is paramount. Quality carbohydrates are formed from large molecules that release energy slowly for sustained energy throughout the day. By undergoing less processing, they also commonly contain beneficial micronutrients – such as B vitamins and essential minerals including magnesium, zinc and copper, which are commonly found within wholegrains – along with dietary fibre.
My favourite quality carbohydrate sources include:
- Legumes like lentils, chickpeas, peas and beans
- Wholegrain breads, pasta and crackers
- Brown rice
- Sweet potato
For individualised dietary advice and gut health support, book your appointment with one of the accredited practising dietitians at my Telehealth clinic, Verde Nutrition Co.