Ditch the processed food and focus on high fibre for a healthier microbiome: this is advice from scientific researchers who have just launched a book that includes a meal plan and recipes for those interested in embarking on a new eating system.
The kicker is that this is not a new way of eating. It’s based on research into traditional eating patterns in non-industrialised societies like rural Papua New Guinea.
Cork-based Dr Jens Walter, professor of ecology, food, and the microbiome at UCC and the APC Microbiome Ireland, along with dietitian Dr Anissa Armet, a postdoctoral researcher at the University of Alberta, collaborated on the research that led to their writing a book on this newly devised diet. The NiMe Diet: Scientific Principles and Recipes was inspired by Walter’s research into what Papua New Guineans eat, with Armet coming on board to devise recipes and test the findings on human volunteers.
German-born Walter took up his UCC post in 2020 after 20 years of microbiome research experience at universities in New Zealand, America, and Canada. His interest in ] Papua New Guinea dates back to when he was a young child, watching a documentary on the country that, he says, “really stuck with me”.
As a researcher specialising in the gut microbiome — the community of microbes living in our intestines — he realised that Papua New Guinea was one of the few places in the world where it was possible to study microbiomes unaffected by the kind of industrialised food we consume in our Western-style diets.
Jens Walter pictured in Papua New Guinea.
This modern dietary pattern, dominant in many high-income countries, is characterised by its reliance on industrially produced foods: high in saturated fats and carbohydrates and low in fibre.
Papua New Guinea has a predominantly rural population that relies heavily on subsistence farming and eats mainly fibre-rich, unprocessed plant-based foods. “So I sent them an email asking for poop samples,” says Walter, matter-of-factly.
By studying faecal samples from rural Papua New Guinea’s indigenous communities, he discovered their gut microbiomes were much more diverse than those of industrialised countries. This diversity is linked to many health benefits, such as as strong immune system and gut health.
There was also a commonality between research that Walter drew on from non-industrialised populations in Malawi, Venezuela and even the Tanzanian Hadza hunter-gatherers. Walter says: “They eat different plant and animal sources but their diets are mostly plant-based and their food has not been industrialised.”
Processing — like freezing, pasturisation, and canning — “has made food more secure and safe and stable,” says Walter, but when it becomes industrialised, that comes with a cost: a reduction in the nutritional value of food. The food we eat shapes our gut microbiome, and unless it is nourished, it can’t do its job and keep us healthy.
“Our main motivation is actually the prevention of chronic diseases,” says Walter, who notes that the disquieting increase in diseases like colon cancer, heart disease and type-2 diabetes has been linked to “industrialisation and urbanisation, and to the western diet in general”.
Dietitian Dr Anissa Armet, a postdoctoral researcher at the University of Alberta, collaborated on the research that led to the writing of a book with Cork-based Dr Jens Walter, professor of ecology, food, and the microbiome at UCC and the APC Microbiome Ireland, on the newly devised ‘NiMe’ diet.
This is where the NiMe — non-industrialised microbiome restore diet comes in. Walter had the hypothesis; Armet put it into practice. Using scientific principles established from the research, she devised recipes focused on whole-plant foods, vegetables, legumes and fruit and included a single small serving of animal-based protein — salmon, chicken or pork — per day.
Highly processed foods were avoided, as were dairy, beef, and wheat, as they would not be available in a traditional Papua New Guinean diet.
Armet conducted a strictly controlled nutritional trial with 30 participants, rotating dishes that included rice pudding, yellow pea soup, and baked chicken breast. The participants consumed around 45g of fibre daily.
The Irish Heart Foundation recommends consuming between 24 and 35g of fibre a day; the most recent National Adult Nutrition Survey found that Irish adults only consume about 19g.
Although the sample was small, the results were significant. LDL, or “bad” cholesterol, dropped by 17%, blood sugars reduced by 6%, and C-reactive protein decreased by 14%, indicating inflammation and heart disease. Participants also lost weight despite not changing calorie intake.
With the recipes and a meal plan in the free-to-download book, this scientifically trialled, verifiably healthy diet can be followed by anyone.
“That was very important for us,” says Walter.
“All the research was funded through foundations and public sources, so we thought this information should be available to as many people as possible [and] it should be free.”
Most ingredients can be easily found in supermarkets, and none are especially costly. “We weren’t trying to radically push certain ingredients,” Walter notes.
“These are not the only healthy recipes in the world, but they are the ones that have been tested in a human trial. It’s more important to follow the overall principles: eat more whole foods, a diversity of vegetables, and more fibre.”