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Pasta consumption induces better postprandial glucose response vs. potatoes, white bread
Pasta consumption is associated with a lower postprandial glucose response vs. carbohydrate-rich foods like white bread or potatoes, but evidence on pasta’s long-term influence on cardiometabolic risk factors is lacking, according to a recent meta-analysis.
“Pasta is overlooked as an important low-[glycemic index] component of the Mediterranean diet, which has been proven to have beneficial effect on [type 2 diabetes] and cardiovascular risk factors in randomized clinical trials, possibly because the Mediterranean diet usually includes large amounts of fruits, vegetables and unsaturated fatty acids that may also exert cardiometabolic benefits,” Mengna Huang, MPH, a PhD student in the department of epidemiology and the Center for Global Cardiometabolic Health at Brown University, and colleagues wrote. “Nevertheless, the role of pasta deserves more extensive investigation. To our knowledge, no study has summarized the available evidence in its totality regarding the potential benefit of pasta on cardiometabolic diseases and related risk factors.”
In a meta-analysis, Huang and colleagues analyzed data from seven studies assessing the postprandial glucose response to pasta consumption vs. white bread consumption and six studies assessing postprandial glucose area under the curve of pasta consumption vs. potato consumption, using the standardized mean difference method with random-effects models.
Among studies evaluating the postprandial glucose response to mixed meals in patients with diabetes, researchers observed a lower glucose response to pasta meals compared with bread meals and/or potato meals; lower peak glucose responses were also observed for pasta meals. The postprandial glucose response difference between pasta and bread rose to statistical significance (standardized mean difference, –0.96; 95% CI, –1.52 to –0.4), as did the difference between pasta and potato consumption (standardized mean difference, –0.87; 95% CI, –1.3 to –0.43).
In seven randomized controlled trials evaluating pasta as part of a low-glycemic index intervention, a pasta-containing, low-glycemic load diet lowered HbA1c in participants with type 2 diabetes in two studies and reduced plasma triglycerides in another study, according to researchers. However, other included studies showed no differences between pasta-containing low-glycemic index diet and high-glycemic index diet groups.
“Overall, [randomized controlled trials] comparing pasta to other high-[glycemic index] starchy foods are lacking,” the researchers wrote. “Since it is difficult to disentangle the effects of pasta in a mixed diet, there was not sufficient evidence for us to draw any conclusions regarding the effect of pasta on cardiometabolic biomarkers.”
Researchers observed mixed results in three crossover-design studies comparing whole grain vs. refined grain interventions, which included pasta as a substantial component of diets. In one study, participants consuming a whole grain diet including pasta saw reduced fasting insulin, improved insulin resistance and improved insulin sensitivity vs. those consuming a refined grain diet, without a change in body weight. Results were not confirmed in a similar study that included overweight adults, whereas the third study, which included whole-grain foods rich in lignans, led to a modest cholesterol-lowering effect, according to researchers.
Researchers observed conflicting results for studies evaluating fiber-enriched vs. regular pasta on postprandial glucose and insulin responses. In two randomized controlled trials comparing soy germ pasta to conventional pasta, researchers observed a reduction in LDL cholesterol and increase in flow-mediated vasodilation in adults with hypercholesterolemia consuming soy germ pasta. Separate analyses comparing Khorasan wheat vs. durum or soft wheat suggested a reduction in total and LDL cholesterol in populations consuming Khorasan wheat, and reductions in fasting insulin and insulin resistance were also associated with Khorasan wheat consumption in participants with type 2 diabetes, the researchers noted.
“Overall the evidence is convincing that pasta meals induce lower postprandial glucose responses as compared to other carbohydrate-abundant foods, for example white bread and potato, which are frequently consumed in Western diets,” the researchers wrote. “In other words, we confirmed that pasta is a type of low-[glycemic index] carbohydrate, especially compared with other starch-dense foods. It is also probable that pasta consumption can result in a blunter postprandial insulinemic response, which fewer studies examined, probably because it is more variable and dependent on disease progression in diabetic patients.” – by Regina Schaffer
Disclosure: The American Heart Association, NIH and the Barilla Foundation funded this study.