4.3 Strengths and limitations
The Graandioos study is a noteworthy contribution to existing literature on whole grains, because a double-blind randomized controlled trial provides a lot of definitive evidence. The comprehensive phenotyping approach with multiple assessed variables gave a complete picture of the impact of WGW on health. The use of a nutritional challenge in combination with a dietary intervention is a key strength of present study, as this metabolic challenge magnified the difficult measurable effects of whole grains [29, 70]. Other key strengths of this study are the long duration and the four weeks run-in period prior to intervention. Blinding of the participants succeeded as they were unaware of the particular products tested, …show more content…
Furthermore, weekly meetings resulted in high rate of adherence regarding to the intake of the intervention products as compliance was higher than 95%, based on counts of empty product packages. The study is subject to only a few limitations. First, it would have been better to use a cross-over intervention study where participants function as their own control. Especially with respect to the variance in gene response between participants, cross-over interventions or larger intervention groups when using parallel designs are highly relevant, though a cross-over study was not feasible due to the long intervention period. As the intervention period was relatively long, participants might have changed their diet and physical activity due to seasonal differences. Perhaps changes may have counterbalanced any health benefits of the whole grain components. It is unfortunate that the study did not provide participants with food frequency- and physical activity questionnaires during the study period to check whether dietary patterns have changed in order to accommodate the difference in whole grain intake. Another limitation lies in the fact that the outcome of plasma biomarker alkylresorcinol was not yet available, since this is a better method to measure …show more content…
Other outcomes in this study, the fasting plasma metabolic markers, also do not indicate a preventive action of whole grains against atherosclerosis. However, cholesterol metabolism is a candidate pathway for further investigations with a whole genomic transcriptomic approach, as differences in expression pattern were observed between whole grain wheat and refined wheat intervention. In addition, current study supports the importance of including nutritional metabolic challenge tests in human intervention studies as this enabled the detection of slight alterations in resilience capacity of PBMCs between the WGW and RW intervention
The Graandioos study is a noteworthy contribution to existing literature on whole grains, because a double-blind randomized controlled trial provides a lot of definitive evidence. The comprehensive phenotyping approach with multiple assessed variables gave a complete picture of the impact of WGW on health. The use of a nutritional challenge in combination with a dietary intervention is a key strength of present study, as this metabolic challenge magnified the difficult measurable effects of whole grains [29, 70]. Other key strengths of this study are the long duration and the four weeks run-in period prior to intervention. Blinding of the participants succeeded as they were unaware of the particular products tested, …show more content…
Furthermore, weekly meetings resulted in high rate of adherence regarding to the intake of the intervention products as compliance was higher than 95%, based on counts of empty product packages. The study is subject to only a few limitations. First, it would have been better to use a cross-over intervention study where participants function as their own control. Especially with respect to the variance in gene response between participants, cross-over interventions or larger intervention groups when using parallel designs are highly relevant, though a cross-over study was not feasible due to the long intervention period. As the intervention period was relatively long, participants might have changed their diet and physical activity due to seasonal differences. Perhaps changes may have counterbalanced any health benefits of the whole grain components. It is unfortunate that the study did not provide participants with food frequency- and physical activity questionnaires during the study period to check whether dietary patterns have changed in order to accommodate the difference in whole grain intake. Another limitation lies in the fact that the outcome of plasma biomarker alkylresorcinol was not yet available, since this is a better method to measure …show more content…
Other outcomes in this study, the fasting plasma metabolic markers, also do not indicate a preventive action of whole grains against atherosclerosis. However, cholesterol metabolism is a candidate pathway for further investigations with a whole genomic transcriptomic approach, as differences in expression pattern were observed between whole grain wheat and refined wheat intervention. In addition, current study supports the importance of including nutritional metabolic challenge tests in human intervention studies as this enabled the detection of slight alterations in resilience capacity of PBMCs between the WGW and RW intervention