Written by Annie Lennon — Fact checked by Alexandra Sanfins, Ph.D.
The HND (healthy Nordic diet) consists of berries, fish, root vegetables, and rapeseed oil. It is known to benefit various aspects of health, including weight loss, blood pressure, inflammation, and blood lipid profiles.
Nutritional research often faces challenges due to a lack of objective measures, as studies typically rely on subjective tools, such as food consumption questionnaires. Using biomarkers instead can allow researchers to measure dietary health effects more accurately.
In the present study, researchers from Scandinavia assessed the metabolic effects of HND on glucose metabolism, blood lipid profiles, and inflammatory markers using data from a randomized control trial from 2013.
When examining metabolites in the blood and urine of the participants, they found a link between closer adherence to the diet and more benefit on low grade inflammation and lipid profiles, as well as indicators of glucose metabolism.
“The original analysis compared participants in the intervention arm [with] those in the control arm,” said Christina C. Dahm, Ph.D., associate professor in the Department of Public Health at Aarhus University in Denmark, in an interview with Medical News Today. Dr. Dahm was not involved in the study.
“This reanalysis uses metabolites in blood plasma and urine to group people with high levels of metabolites sourced from either the intervention diet or the control diet,” she added.
The study appears in Clinical Nutrition.
After an initial 4-week period, during which the participants consumed their typical diets, the researchers randomly assigned them to follow either HND or a control diet, defined as the average nutrient intake across Nordic countries.
The researchers then instructed the participants in the HND group to increase their consumption of whole grain products, such as rye and barley, alongside berries, fruit, and vegetables.
Those in the control group received instructions to eat low fiber wheat products, including refined white bread and pasta, and not to moderate their consumption of vegetables and fruit.
Both diets contained similar amounts of calories to keep the participants’ weight stable throughout the study. The researchers followed the participants for either 18 or 24 weeks and had them provide blood and urine samples at the beginning and end of the intervention, as well as at week 12.
For the present metabolic profiling study, the researchers analyzed data from 98 participants in the HND group and 71 in the control group.
They found that those who adhered to HND most had different fat-soluble metabolites in their blood than others. The researchers link these metabolites to better glucose regulation, improved cholesterol profile, and reduced cardiometabolic risk.
These findings build upon the initial results from 2013, stating that although HND has a positive effect on lipid profiles and inflammation, it does not affect blood glucose metabolism.
“Participants with higher levels of the metabolites sourced from the Nordic diet had lower triglyceride levels than those with lower levels of the metabolites, even though none of the participants lost weight during the study,” said Dr. Dahm.
“Assuming that greater intake of the Nordic diet leads to higher levels of blood metabolites, this means that a better quality diet can improve some health parameters, even in the absence of weight loss.”
– Dr. Christina C. Dahm
Dr. Dahm noted, however, that she is unsure how clinically significant the results may be.
“We can only speculate as to why a change in fat composition benefits our health so greatly,“ says Lars Ove Dragsted, one of the study authors. “However, we can confirm that the absence of highly processed food and less saturated fats from animals have a very positive effect on us.”
“The fat composition in the Nordic diet, which is higher in omega-3 and omega-6 unsaturated fats, [probably explains many of] the health effects we find from the Nordic diet, even when the weight of participants remains constant,” he adds.
Christopher Gardner, Ph.D., Rehnborg Farquhar Professor at Stanford University, not involved in the study, told MNT that the findings are not surprising. “The intervention was focused on healthy foods, and specifically listed berries, veggies, fish, whole grains, [low fat] dairy products, and rapeseed oil.”
“I can think of multiple mechanisms for cardiometabolic benefits, regardless of weight loss: less saturated fat, more unsaturated fat, more fiber, and lower sodium. All of these would beneficially impact lipids, glucose, blood pressure, inflammation,” he added.
The authors of the present study conclude that assessing metabolites is an effective way to evaluate the health benefits of different diets.
They say, however, that their findings have some limitations. For example, their analysis may have overlooked some metabolites that other profiling techniques may have found. They also say that their sample size was relatively small.
Dr. Gardner added that these results may have been due to a generally healthier diet rather than due to anything particular to HND: “[The results could have arisen from the] Nordic, Mediterranean, vegetarian, DASH,
whole food plant-based diet, or half a dozen others. Many of the components of [HND] are similar to these [other diets].”