Nordic diet lowers cholesterol – even without weight loss
A healthy Nordic diet lowers the bad cholesterol even for those who do not lose weight.
When eating a healthy Nordic diet, blood pressure and the bad cholesterol are reduced in relation to the good cholesterol, compared to an average Nordic diet, two new studies show. This also applied to participants who did not lose weight during the process.
”We wanted to make sure that the results came directly from the diet. It would have been difficult to tell if the patients lost weight during the experiment, because we wouldn’t know whether it was the weight loss or the diet that caused the positive results,” says Professor Kjeld Hermansen, of the Department of Clinical Medicine at Aarhus University, Denmark.
Separating weight loss from the diet in a study like this is a good idea, according to Marit Eika Jørgensen, the head of Clinical Epidemiology at the Steno Diabetes Center, which carries out research into the prevention and treatment of diabetes:
“In the real world, diet and weight loss are not separated, but if the objective is to study the effect of the diet alone, I would say that this method strengthens the findings,” she says.
The healthy Nordic diet had a positive short-term effect, but it is difficult to say anything about the long-term effect.
In the study, subjects were randomised to either a healthy Nordic diet or a control diet. A healthy Nordic diet embraced whole grains, rapeseed oil, berries, fruits, vegetables, fish, nuts and low-fat dairy products of Nordic origin.
The mean nutrient intake in the Nordic countries formed the control diet, embracing wheat products, dairy fat-based spread and a lower intake of fruits, vegetables and fish. Ambulatory blood pressure was monitored and urine samples were taken throughout the experiment.
It turned out that the ‘bad’ cholesterol (also known as low-density lipoprotein, or LDL), which is associated with atherosclerosis, decreased in the group that ate a healthy Nordic diet. At the same time, a sub-study showed that the blood pressure also decreased in this group.
Good news for those at risk of type 2 diabetes
It appears that overweight people who are at risk of developing cardiovascular disease or type 2 diabetes would benefit greatly from eating a healthy Nordic diet:
We know that lowering LDL cholesterol levels through medical treatment can decrease the risk of cardiovascular disease by up to 20 percent, so why should that not also apply through diet?
Marit Eika Jørgensen
“What is most important for these people is to improve their cholesterol levels and lower their blood pressure. Fifty percent of those who develop type 2 diabetes suffer from low blood pressure,” says Hermansen.
Even though the total amount of cholesterol did not decrease significantly in the healthy diet group, the ratio between the ‘good’ and the ‘bad’ cholesterol dropped considerably in this group, while in the control group it did not.
“We can therefore conclude that the healthy Nordic diet had a positive short-term effect, but it is difficult to say anything about the long-term effect,” says Hermansen.
According to Jørgensen, who did not take part in the study herself, a lowering of the LDL levels can also have a positive effect on cardiovascular disease – at least when it is lowered through medication:
“We know that lowering LDL cholesterol levels through medical treatment can decrease the risk of cardiovascular disease by up to 20 percent, so why should that not also apply through diet?” she says.
Hermansen does not believe that anything can yet be said with certainty about whether the LDL levels would have dropped with some other healthy diet.
Dropouts in ‘unhealthy’ group
Conducting a similar study over a prolonged period can be difficult, he says:
”It is expensive and difficult to carry out diet studies over extended periods when you want the participants to stick to a specific diet.”
This problem manifested itself in that several members of the control group dropped out. The study started out with 104 people who at a healthy Nordic diet and 96 people in the control group. Over the 24-week course of the experiment, eight dropped out of the intervention group and no less than 26 from the control group.
Hermansen does not, however, believe that this has affected the results, as the remaining number of participants was sufficient to complete the study.
- "Effects of an isocaloric healthy Nordic diet on insulin sensitivity, lipid profile and inflammation markers in metabolic syndrome -- a randomized study (SYSDIET)", Epub (2013), DOI: 10.1111/joim.12044.
- "Effects of an isocaloric healthy Nordic diet on ambulatory blood pressure in metabolic syndrome: a randomized SYSDIET sub-study", Nature (2014), DOI: 10.1038/ejcn.2013.192