A Healthy Nordic Diet to Reduce the Progression of Atherosclerosis in Individuals with Coronary Heart Disease: a Secondary Prevention Trial

Atherosclerosis of coronary arteries is the main cause of coronary heart disease (CHD). In atherosclerosis, atherogenic lipids are deposited in the arteries to form plaques, and the larger the plaque volume, the more narrowing of the vessel. It is now feasible to directly visualize clinically relevant changes in plaque volume and composition (e.g. calcification, lipid content) by modern computed tomography (CT) angiography. Diet is a cornerstone in both primary and secondary prevention, but it is still not clear if dietary intervention can reduce coronary plaque progression as assessed by modern imaging technique.

In the Nordic countries, a promising alternative to Mediterranean diets is the Healthy Nordic diet. Controlled trials conducted in various Nordic populations have shown that healthy Nordic diets cause reduction of several key CVD risk factors such as elevated blood lipids and blood pressure, hyperglycemia, and inflammation. The Healthy Nordic diet is mainly, but not exclusively, a plant-based diet that accord with the Nordic Nutrition Recommendations (NNR 2023), e.g. is rich in vegetable fats from oils, spreads, nuts and seeds, whole-grains from rye, barley and oats, legumes, vegetables, Nordic fruits and berries but with moderate portions (2-3 times per week) of fatty fish (e.g. Salmon). The effects of a Healthy Nordic diet in a secondary preventive setting and in particular the potential impact on atherosclerosis is yet unknown. The investigators hypothesize that a Healthy Nordic Diet has anti-atherosclerotic properties that can reduce the progress of atherosclerosis and reduce key CVD risk markers and inflammation in patients with a recent MI or chronic coronary syndrome (CCS). Further, the investigators hypothesize this diet will have favorable changes on the gut microbiota, which in turn can contribute to reduced coronary plaque progression.

The overall aim is to compare the ability of a Healthy Nordic Diet versus usual care dietary advice to influence coronary plaque volume and CVD risk after 18 months in patients with MI or with CCS.

The primary aim is to investigate if a Healthy Nordic Diet can reduce plaque volume after 18 months as compared with usual care and routine dietary and lifestyle advice, and secondary aims are to investigate dietary effects on plaque composition, coronary artery calcium (CAC) and coronary inflammation (perivascular fat, fat attenuation index), as well as on ectopic fat content (e.g. liver). Exploratory aims are to investigate the dietary effects on gut microbiota, as well as on metabolomic- lipidomic- and proteomic plasma profiles. In addition, the investigators will monitor blood glucose control using wearable continous glucose monitors (CGMs) as well as Actiheart monitors to record heart ECG and activity with multiple data endpoints.

This study, named NORDHEART, is a randomized, single-blinded, parallel study including a dietary intervention group and a control group, in individuals with diagnosed MI or CCS. The investigators aim to include n=150 individuals in this trial. The majority of participants will be recruited at the Uppsala University hospital but further Swedish recruitment center in mid Sweden might be added if the recruitment rate in Uppsala is slower than expected.