An analysis led by University of Copenhagen researchers found that the so-called Nordic diet concept reduces the risk of cardiovascular disease, type 2 diabetes, high blood pressure and high cholesterol, even without weight loss.
The main ingredients of the diet are berries, vegetables, fish, whole grains and rapeseed oil.
“It’s surprising, because most people believe that positive effects on blood sugar and cholesterol are solely due to weight loss. Here, we have found this not to be the case. Other mechanisms are also at play,” said Lars Ove Dragsted, a researcher and head of section at the University of Copenhagen’s Department of Nutrition, Exercise and Sports.
With researchers from Finland, Norway, Sweden and Iceland, Dragsted examined blood and urine samples from 200 people over 50, all with elevated BMI and increased risk of diabetes and cardiovascular disease. The participants were divided into two groups, one provided with foods according to Nordic dietary recommendations, and a control group on their habitual diet. After six months of monitoring, the result was clear.
“The group that had been on the Nordic diet for six months became significantly healthier, with lower cholesterol levels, lower overall levels of both saturated and unsaturated fat in the blood, and better regulation of glucose, compared with the control group. We kept the group on the Nordic diet weight stable, meaning that we asked them to eat more if they lost weight. Even without weight loss, we could see an improvement in their health,” said Dragsted.
The fat makes us healthy
Instead of weight loss alone, the researchers point to the unique composition of fats in a Nordic diet as a possible explanation for the significant health benefits.
“By analysing the blood of participants, we could see that those who benefited most from the dietary change had different fat-soluble substances than the control group. These are substances that appear to be linked to unsaturated fatty acids from oils in the Nordic diet. This is a sign that Nordic dietary fats probably play the most significant role for the health effects seen here, which I hadn’t expected,” said Dragsted.
Fats in the Nordic diet come from fish, flaxseeds, sunflower and rapeseed (Canola), among other things. As a whole, they constitute a very beneficial mix for the body, although the researchers have yet to accurately explain why these fats seem to lower both blood sugar and cholesterol levels.
“We can only speculate as to why a change in fat composition benefits our health so greatly. However, we can confirm that the absence of highly processed food and less saturated fats from animals have a very positive effect on us. So, the fat composition in the Nordic diet, which is higher in omega-3 and omega-6 unsaturated fats, is probably a considerable part of the explanation for the health effects we find from the Nordic diet, even when the weight of participants remains constant,” said Dragsted.
Nordic Nutrition Recommendations
The Nordic Nutrition Recommendations were adopted by dietary experts in 2012 and will be updated this year.
The diet is adapted to the Nordic countries: Denmark, Sweden, Norway, Finland, Greenland, the Faroe Islands, and Iceland, and based on ingredients produced locally and thereby sustainable.
Recommended foods include vegetables like peas, beans, cabbage, onions and root vegetables, as well as fruits, including apples, pears, plums and berries. Also recommended are nuts, seeds, whole grains, fish, and shellfish, as well as vegetable oils made from rapeseed, sunflower or flaxseed.
Finally, low-fat dairy products are also recommended, as well as a significantly smaller proportion of meat than currently consumed.
The diet contributes to important fatty acids, minerals, vitamins, and plant materials that have a positive effect on our health and, among other things, reduce the risk of blood clots, type 2 diabetes, high blood pressure and cholesterol levels, as well as cardiovascular disease in general.
Weight loss in relation to a Nordic diet
The researchers stress that weight loss, which frequently results from a Nordic dietary pattern, remains very important for the diet’s overall health benefits.
“This study simply shows that it is not only weight loss that leads to the benefits of this diet. The unique composition of fats plays an important role as well,” said Dragsted.
Study details
Analysis of the SYSDIET Healthy Nordic Diet randomised trial based on metabolic profiling reveal beneficial effects on glucose metabolism and blood lipids.
Gözde Gürdeniz, Matti Uusitupa, Kjeld Hermansen, Markku J. Savolainen, Ursula Schwab, Marjukka Kolehmainen, Lea Brader, Lieselotte Cloetens, Karl-Heinz Herzig, Janne Hukkanen, Fredrik Rosqvist, Stine Marie Ulven, Ingibjörg Gunnarsdóttir, Inga Thorsdottir, Matej Oresic, Kaisa S. Poutanen, Ulf Risérus, Björn Åkesson, Lars Ove Dragsted.
Published in Clinical Nutrition on 24 December 2021
Summary
Background & aims
Intake assessment in multicentre trials is challenging, yet important for accurate outcome evaluation. The present study aimed to characterise a multicentre randomised controlled trial with a healthy Nordic diet (HND) compared to a Control diet (CD) by plasma and urine metabolic profiles and to associate them with cardiometabolic markers.
Methods
During 18–24 weeks of intervention, 200 participants with metabolic syndrome were advised at six centres to eat either HND (e.g. whole-grain products, berries, rapeseed oil, fish and low-fat dairy) or CD while being weight stable. Of these 166/159 completers delivered blood/urine samples. Metabolic profiles of fasting plasma and 24 h pooled urine were analysed to identify characteristic diet-related patterns. Principal components analysis (PCA) scores (i.e. PC1 and PC2 scores) were used to test their combined effect on blood glucose response (primary endpoint), serum lipoproteins, triglycerides, and inflammatory markers.
Results
The profiles distinguished HND and CD with AUC of 0.96 ± 0.03 and 0.93 ± 0.02 for plasma and urine, respectively, with limited heterogeneity between centres, reflecting markers of key foods. Markers of fish, whole grain and polyunsaturated lipids characterised HND, while CD was reflected by lipids containing palmitoleic acid. The PC1 scores of plasma metabolites characterising the intervention is associated with HDL (β = 0.05; 95% CI: 0.02, 0.08; P = 0.001) and triglycerides (β = −0.06; 95% CI: −0.09, −0.03; P < 0.001). PC2 scores were related with glucose metabolism (2 h Glucose, β = 0.1; 95% CI: 0.05, 0.15; P < 0.001), LDL (β = 0.06; 95% CI: 0.01, 0.1; P = 0.02) and triglycerides (β = 0.11; 95% CI: 0.06, 0.15; P < 0.001). For urine, the scores were related with LDL cholesterol.
Conclusions
Plasma and urine metabolite profiles from SYSDIET reflected good compliance with dietary recommendations across the region. The scores of metabolites characterising the diets associated with outcomes related with cardio-metabolic risk. Our analysis therefore offers a novel way to approach a per protocol analysis with a balanced compliance assessment in larger multicentre dietary trials.
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