In the pursuit of optimal health and as continuous glucose monitoring gains popularity among non-diabetics, attention to post-meal insulin spikes has intensified, often associated with concerns about weight gain and insulin resistance.
Offering a nuanced perspective on the relationship between insulin dynamics and long-term metabolic health, researchers at Sinai Health's Lunenfeld-Tanenbaum Research Institute, led by Dr Ravi Retnakaran, conducted longitudinal research on 306 women, recruited during pregnancy – a time known for increased insulin resistance. The study observed these women over four years, evaluating the longitudinal implications of post-prandial (post-meal) insulin responses.
Cardiometabolic tests were conducted over four years, including glucose challenge tests measuring glucose and insulin levels at various time points after consuming a sugary drink containing 75 g of glucose, following a period of fasting. This provided a detailed picture of participants' metabolic dynamics.
In a news release, Retnakaran emphasised the importance of an extended time frame of observation, advocating for understanding the evolution of insulin responses beyond immediate post-meal periods.
He said: “It’s not just about insulin levels; it’s about understanding them in relation to glucose.”
High insulin response might not be an indicator of diabetes
Vitafoods Insights interviewed Retnakaran for this publication, where he discussed the nuances of the research. Retnakaran highlighted that most studies on this topic can be misleading, making assumptions based on either insulin measured in isolation or observed over a short period.
The study accounted for these intricacies by implementing an extended period of observation, in which three key findings emerged, revealing associations with both positive and negative cardiometabolic features.
Initially, higher corrected insulin response (CIR) – a metric that accounts for individuals' baseline blood glucose levels – was associated with both positive and negative cardiometabolic features, such as larger waist size and better beta-cell function.
However, when considering longitudinal data, the second finding emerged: individuals with the highest CIR tertile at baseline exhibited better beta-cell compensation and lower blood sugar levels at both three and five years post-partum, with no significant associations with body mass index (BMI), waist size, lipids, or insulin resistance.
The final finding came from logistic regression analyses, which indicated that the highest CIR tertile at baseline independently predicted a lower future risk of pre-diabetes or diabetes at both three and five years. In other words, those with the highest insulin responses were significantly less likely to develop pre-diabetes or diabetes down the road.
The rise of glucose monitoring
This research comes at a time when monitoring one's post-meal insulin levels has been gaining traction, propelled, in part, by the popularity of continuous glucose monitors (CGMs), initially designed for diabetes management but now embraced by non-diabetic individuals refining their dietary choices.
Retnakaran said: “Sometimes I see patients in the clinic who have adopted this notion, maybe from the internet or what they're reading, that they can't have their insulin level go too high.”
In this landscape, figures like French biochemist Jessie Inchauspé, known as Glucose Goddess on Instagram, have amassed substantial followings by sharing blood sugar charts and offering hacks to mitigate spikes.
Retnakaran discussed the motivation behind his team's research with Vitafoods Insights. He said: "Our interest in the future cardiometabolic implications of the postprandial insulin response relates to the fact that there are many misconceptions about the meaning of serum insulin concentrations."
Dietitian Sophie Medlin, speaking at Fi Europe 2023 in Frankfurt, discussed the burgeoning glucose stabilisation market.
She said: “The glucose stabilisation market is massive now. We've got the ZOE project in the UK and US, and I'm sure it's coming out to Europe. They are encouraging people to do continuous blood glucose monitoring – I have some fairly strong opinions about the benefits of that, if there are any.”
Medlin challenged the overreliance on this technology, particularly as a guide for dietary choices.
She highlighted the potential for CGM equipment to deliver misleading messages, exemplifying this with: “Of course, the CGM equipment will tell you that eating a stick of butter is better than eating an apple because you'll have less of a change in your blood glucose. Hopefully, all of us know that's not the right message for people to be receiving.”
