Following a meal, glucose levels increase according to the type of foods that are ingested, and currently meal carbohydrate or derived glycemic index are used to estimate the postprandial (post-meal) glycemic responses (PPGR). These factors assume that PPGRs are solely dependent on the intrinsic properties of the ingested food, and this assumption is the basis of universal dietary recommendations.
In order to better understand these relationships, the Elinav and Segal teams sought to quantify individual PPGRs for a sample population, characterize the variability within their sample, and then identify factors associated with that variability. Though this could be achieved with a small set of a dozen, or perhaps a few dozen participants, this is not the approach that the teams took.
In the work they report today, Elinav and Segal report on their observations of a cohort of 800 healthy and pre-diabetic individuals, a sample population representative of the larger Western non-diabetic population.
When the researchers analyzed their collected results their findings varied from those that were expected, to those that were truly startling. As expected, the researchers were able to validate known associations of PPGRs with risk factors such as BMI, glycated hemoglobinn, morning glucose levels, and age. Within these associations the scientists did make some surprising observations, noting that these associations were not limited to extreme values; associations between these known risk factors occurred over the entire phenotypic spectrum indicating that incremental differences in the glucose response may be clinically relevant for some risk factors.
The collected observations further revealed both that an individual’s responses to the same food were reproducible, and that there exists a high levels of variability in the responses of different individuals to the same foods. The researchers found that the food associated with an individual’s highest glucose response varied greatly between individuals. Foods that induced a “healthy” response in one individual might induce an “unhealthy” response in another. In a particularly compelling figure, the researchers showed an example where two participants had opposite responses to cookies and bananas.