Last updated on Jun 22nd, 2020 at 06:26 pm

Eating walnuts is good for your heart health and could even protect you from colorectal cancer

The way walnuts impact the gut microbiome – the collection of trillions of microbes or bacteria in the gastrointestinal tract – may be behind some of those health benefits, according to a new study from the University of Illinois,

Dietary fibre is food for gut microbiota

Walnuts and all unprocessed plant foods contain dietary fibre. Dietary fibre acts as a food source for gut microbiota, helping the bacteria to do their jobs – breaking down complex foods, providing us nutrients, or helping us feel full, for example.

Fruits, vegetables, whole grains, nuts and legumes are important plant sources of dietary fibre. Eating a variety of these foods helps promote a diverse gut microbiota, which in turn helps to support health.

Related: Why the amount of fibre you eat matters

Subscribe to our Free Daily All4Women Newsletter to enter

Walnuts reduce cholesterol

According to the study, eating walnuts also reduced LDL-cholesterol levels in the adults participating in the study; good news for cardio, metabolic and gastrointestinal health.

“We found that when you consume walnuts it increases microbes that produce butyrate, a beneficial metabolite for colonic health. So the interaction of walnuts with the microbiome is helping to produce some of those health effects,” says Hannah Holscher, assistant professor of food science and human nutrition at the University of Illinois, and lead author of the study.

“It is about getting to the ‘black box’ that is all the microbes in our GI tract, to see how they are interfacing with the food we eat and having downstream health effects.”

How walnuts protect against colorectal cancer

The findings also show that eating walnuts reduces secondary bile acids.

“Secondary bile acids have been shown to be higher in individuals with higher rates of colorectal cancer,” Holscher explains. “Secondary bile acids can be damaging to cells within the GI tract, and microbes make those secondary bile acids. If we can reduce secondary bile acids in the gut, it may also help with human health.”

Source: University of Illinois College of Agricultural, Consumer and Environmental Sciences via

While All4Women endeavours to ensure health articles are based on scientific research, health articles should not be considered as a replacement for professional medical advice. Should you have concerns related to this content, it is advised that you discuss them with your personal healthcare provider.