Adherence to healthy Nordic diet may decrease risk of stroke

Adults who were born and raised in Denmark had a significantly lower risk of stroke if they adhered to a healthy Nordic diet, according to a registry analysis.

The researchers defined a healthy Nordic diet as high intakes of fish, apples and pears, cabbages, root vegetables, rye bread and oatmeal.

Lead researcher Camilla Plambeck Hansen, PhD, of Aarhus University in Denmark, and colleagues published their results Dec. 27 online in Stroke.

This trial, known as the Diet, Cancer and Health Study, included 55,338 men and women who were between 50 and 64 years old when they enrolled from December 1993 to May 1997. All of the adults were born in Denmark, lived in the greater areas of Aarhus or Copenhagen and had no previous cancer diagnosis. More than 52 percent of the participants were women.

At baseline, participants completed a 192-item semiquantitative food-frequency questionnaire (FFQ) and reported their average intake of food and beverage items during the previous 12 months. The researchers used a software program to calculate the average daily intakes of food and nutrients based on the Danish food composition tables.

The researchers used the Healthy Nordic Food Index to assess adherence to a healthy Nordic dietary pattern. The index comprised fish, apples and pears, cabbages, root vegetables, rye bread and oatmeal. The root vegetables were carrots and celeriac, while the cabbages were cauliflower, brussels sprouts, broccoli, kale, white cabbage and red cabbage.

The researchers then added the scores of each component. Participants were considered low adherers if they had 0 or 1 point, medium adherers if they had 2 or 3 points and high adherers if they had 4, 5 or 6 points.

During a median follow-up period of 13.5 years, 2,283 participants experienced a first-time stroke.

After the researchers adjusted for potential confounders, high adherers had a statistically significant 14 percent lower risk of stroke compared with low adherers. They noted that high adherers had a significantly lower risk of ischemic stroke, but there was no difference in the risk of hemorrhagic stroke. They mentioned that the association was mainly driven by a 32 percent lower risk of large-artery atherosclerosis among high adherers compared with low adherers.

For all of the individual Healthy Nordic Food Index components except for fish, the risk of stroke was reduced among high adherers compared with low adherers. High adherers also had a lower risk of intracerebral hemorrhage, but the difference was not statistically significant.

The results were similar when the researchers performed sensitivity analyses, adjusted for smoking using five categories instead of three and included body mass index and waist circumference as separate variables.

The researchers mentioned a few limitations of the study, including the small number of strokes due to cardioembolism and subarachnoid hemorrhage. They also used a self-administered FFQ, which could have contributed to misclassifications of participants’ diets. In addition, they only had information on participants’ diet at baseline, so the participants could have changed their diet during the follow-up period.

“The results suggest that a healthy Nordic diet based on traditional Nordic food items may be recommended in stroke prevention as a regional alternative to the Mediterranean diet,” the researchers wrote. “A healthy diet based on well-known regional foods could be more easily attainable for people than to make dietary changes including unfamiliar food items. Future cohort studies are warranted to confirm our results and to investigate whether regional diets from other part of the world may also be promoted in stroke prevention.”