The randomised trial investigated the combined effects of wholegrain, fish and bilberries on serum metabolic profile and lipid transfer protein activities in people with metabolic syndrome – finding that increasing the intake of fatty fish increases the number of ‘good’ cholesterol particles
Led by Maria Lankinen from the University of Eastern Finland, the team showed that people who increased their intake of fish to a minimum of three to four weekly meals have more large HDL particles in their blood than people who are less frequent fish eaters.
“Consumption of diet rich in whole grain, bilberries and especially fatty fish causes changes in HDL particles shifting their subclass distribution toward larger particles,” said the authors, writing in PLoS One.
“These changes may be related to known protective functions of HDL such as reverse cholesterol transport and could partly explain the known protective effects of fish consumption against atherosclerosis.”
Healthy fish
Lankinen and her team noted that while the intake of fish has long been known to be beneficial for health; some of the mechanisms by which fats and other useful nutrients found in fish work in the human body are not fully known.
The new data provides valuable information on how the consumption of fish affects the size and lipid concentrations of lipoproteins which transport lipids in the blood, they said.
Research highlights
The team recruited 131 participants with impaired glucose metabolism and features of metabolic syndrome to the trial. These were randomized into three groups with 12-week periods according to a parallel study design.
The groups consumed either: 1) a wholegrain and low postprandial insulin response grain products, fatty fish 3 times a week, and bilberries 3 portions per day (HealthyDiet), 2) wholegrain and low postprandial insulin response grain products (WGED), or 3) refined wheat breads as cereal products (Control).
“We found significant changes in lipid metabolites in the HealthyDiet group reflecting increased polyunsaturation of plasma fatty acids, particularly increase in omega-3 PUFAs,” wrote the team.
“Furthermore, in the within-the-group comparisons we found an increasing trend in variables related to large HDL particles in the HealthyDiet group, and when analysing this in more detail we found that the increase of fish intake correlated strongly with the increased concentration of large HDL particles, larger average diameter of HDL particles and increased concentrations of large HDL lipid components.”
The team noted that large HDL particles have been associated with reduced risk of cardiovascular diseases, whereas small HDL particles may even have opposite effects.
Positive changes in lipid metabolism were observed in persons who increased their intake of fish most, they added – noting that state-of-the-art metabolomics were used to enable a very detailed analysis of lipoprotein particles.
“The changes which we saw in large HDL particles could be related to those parameters that are functionally related to reverse cholesterol transport. Thus, our findings could partly explain the known protective effects of fish consumption against the atherosclerosis,” concluded the team.
Source: PLoS One
Published online ahead of print, doi: 10.1371/journal.pone.0090352
"Effects of Whole Grain, Fish and Bilberries on Serum Metabolic Profile and Lipid Transfer Protein Activities: A Randomized Trial (Sysdimet)"
Authors: Maria Lankinen, Marjukka Kolehmainen, et al