Does eating whole grains cause gastrointestinal issues like bloating and gas?

Fact

Whole grains are very beneficial for your digestive system and overall health. They’re rich in fibre, which is crucial for our gut microbiome—the trillions of beneficial bacteria living in your intestines. These fibres act as food for these good bacteria, helping them thrive and produce beneficial compounds like short-chain fatty acids (SCFAs). They protect our health by improving insulin sensitivity and ensuring lower levels of glucose and lipids in our bloodstream. Over the long term this might improve energy balance which indirectly protects against cardiovascular diseases, obesity and type 2 diabetes.^1-3

Whole grains are more complex than refined grains and are promoted as part of a healthy and sustainable diet, largely due to their high content of indigestible carbohydrates (dietary fibres) and higher levels of vitamins, minerals, and other nutrients.⁴

Myth

This idea that whole grains are a common culprit for bloating and gas often stems from the fact that whole grains contain fibres and certain carbohydrates that are not fully digested in the small intestine. When these reach the large intestine, gut bacteria ferment them, which can produce gas. However, this natural process is usually a sign that your gut bacteria are hard at work, not that whole grains are inherently problematic.

Fallacy

The fallacy here is a misattribution. The natural fermentation process that occurs when gut bacteria break down fibres in whole grains is mistakenly perceived as a negative side effect, rather than a beneficial one. While some individuals might experience temporary discomfort when first increasing their fibre intake, this often subsides as their gut adapts. For those with specific sensitivities, like Irritable Bowel Syndrome (IBS), certain components in grains, such as fructans, might trigger adverse symptoms.⁵ However, for the general population, whole grains are an important part of a balanced diet. If you experience persistent or severe digestive issue, consult a healthcare professional (e.g., GP or registered dietitian/nutritionist) for personalised advice.

Before cutting out whole grains from your diet there are a few tips & tricks you can do to retrain your gut to embrace these fibre-rich foods and ease the bloat:

1. Gradually introduce fibre-rich foods into your diet and spread your intake throughout the day. This means training your gut to have a few extra grams of fibre over time to let it gently transition to a higher-fibre diet.
2. Avoid swallowing extra air by taking your time when eating. Slow down, savour each bite, and chew your food thoroughly.
3. Keep your body moving and hydrated! Regular exercise helps keep things moving in your digestive system, reducing the likelihood of discomfort. And don’t forget to stay hydrated with plenty of water.