Nordic diet to help tackle type 2 diabetes and non-alcoholic fatty liver disease

A healthy diet emulating the Nordic eating habits — which is high in dietary fiber from whole grains, fruits, and vegetables but with a small percentage of saturated fat — could aid therapies for both type 2 diabetes and non-alcoholic fatty liver disease. 

In a new clinical study supporting these effects, researchers compared three different types of the diet: an anti-lipogenic diet aimed to reduce fat production in the body; a “healthy Nordic diet,” which is a variant of the Mediterranean diet; or one following the current Nordic Nutrition Recommendations.

Researchers at Sweden’s Uppsala University working on this year-long study note that the “healthy Nordic diet” is better than both the Nordic Nutrition Recommendations and an anti-lipogenic diet when it comes to tackling these conditions. 

“The healthy Nordic diet gave the best results in the study participants with diabetes; just over 20% of their liver fat was reduced, and blood sugar (glucose) control improved over one year,” says lead researcher Ulf Risérus, professor of Clinical Nutrition and Metabolism.

“More than half of the participants also saw a remission of their fatty liver disease. This makes these results equally important for people with non-alcoholic fatty liver disease as those with type 2 diabetes.”

Three different diets

The randomized controlled trial published in Nature Communications enrolled 150 people with either type 2 diabetes or prediabetes and randomly assigned each to follow one of three diets for one year.

The first was an anti-lipogenic diet, which is low in carbohydrates and animal-derived foods but high in polyunsaturated fats from plants-based foods. Participants in this group ate more high-fat foods such as sunflower oil, walnuts, pumpkin and sunflower seeds; low-carbohydrate vegetables; protein-rich beans and lentils; and some lean dairy products. 

Next, participants in the “healthy Nordic diet” group were prescribed a Nordic variant of the Mediterranean diet. This was low in saturated fat, but high in dietary fiber from whole grains, fruits, and vegetables, with importance placed on foods such as oat and rye flakes, oat bran, rye bread, crispbread, rapeseed oil, almonds, apples, pears, blueberries, raspberries, cabbage, and peas. Participants also regularly consumed mackerel and salmon, low-fat natural yogurt, cultured milk products, and plant-based cooking fat.

Meanwhile, the control group received usual care based on dietary advice according to the current Nordic Nutrition Recommendations, which is a diet rich in different types of fruits, vegetables, legumes, olive oil, and lean dairy products.

Across all three groups, participants limited their consumption of red and processed meats, sweetened drinks, candy, and snacks with added sugar.

Surprising results

The researchers set out to investigate which diet was the most effective in reducing both liver fat and blood glucose levels. 

The benefits of the Nordic diet surprised the researchers, who initially assumed that the anti-lipogenic diet would yield the best results. All three were expected to have beneficial effects, however, the Nordic diet turned out to be most effective.

“The study shows that both the anti-lipogenic diet and the Nordic diet were relatively similar in reducing liver fat as well as ‘bad’ LDL cholesterol. But the healthy Nordic diet was more effective in reducing blood glucose over the long term and also had more beneficial effects on body weight, inflammation, and lipid profile, as well as reducing signs of liver damage,” Risérus elaborates.

The study results revealed that the diets were “surprisingly easy to follow.”

Michael Fridén, lead author of the study, adds: “Even though the participants were allowed to eat as much as they wanted from the foods recommended, they still lost weight. In many previous studies of different diets, calorie intake has been restricted, which is effective in the short term, but increases hunger and can be difficult to follow in the longer term.” 

Diabetes treatment

While some of the benefits of the healthy Nordic diet could be explained by the participants’ weight loss, the researchers attribute weight loss to 56% of the positive liver fat reductions.

“This is very interesting, as it suggests that the diet itself has contributed to reducing fat deposits in the liver, but probably also to improved blood glucose levels and lipid values, as well as reducing inflammation,” details Risérus.

“There has been a great need to find new, evidence-based diets for long-term diabetes care. Our results are important for future dietary recommendations and are particularly important for overweight people with type 2 diabetes or prediabetes.”

In other recently published metabolic research, scientists identified specific metabolites that impact liver metabolism and insulin sensitivity. Leading to this discovery, they pinpointed differences in the gut microbiomes of humans and rodents with and without obesity, type 2 diabetes, glucose intolerance, and insulin resistance.