Are Post-Meal Insulin Surges Beneficial?

Rapid surges in insulin following a meal are associated with favorable long-term cardiometabolic benefits, including improvements in beta cell function and a lower risk for the development of prediabetes or diabetes, contrary to some concerns of the surges being indicative of more negative effects.

“There are practitioners who subscribe to this notion of higher insulin levels being a bad thing, and sometimes are making recommendations to patients to limit their insulin fluctuations after the meal,” said first author Ravi Retnakaran, MD, an endocrinologist and Boehringer Ingelheim Chair in Beta-cell Preservation, Function and Regeneration at the Leadership Sinai Centre for Diabetes at Mount Sinai Hospital, Toronto, Ontario, in a press statement.

“But it’s not that simple,” he said. “We observed that a robust post-challenge insulin secretory response, once adjusted for glucose levels, is only associated with beneficial metabolic effects.”

The findings were published on December 13, 2023, in eClinicalMedicine, part of The Lancet Discovery Science.

Insulin levels increase after food consumption in the normal management of blood glucose; however, some research has suggested that more rapid spikes in insulin, especially after a high-carbohydrate meal, are linked to an anabolic state contributing to weight gain and insulin resistance.

As public awareness of those reports has grown, “patients are coming in concerned about the possibility of their insulin levels being high, and there is confusion about the physiology of these effects,” Dr. Retnakaran told this news organization. 

However, other studies have shown that the effects of insulin surges are important relative to baseline factors, including ambient glycemia and, specifically, baseline glucose levels prior to a meal.

Therefore, a more appropriate assessment is to use a corrected insulin response, measuring insulin secretion at 30 minutes after an oral glucose challenge, in relation to baseline glucose levels, research has suggested.

To investigate the issue in a longitudinal context, Dr. Retnakaran and colleagues conducted a prospective cohort study of 306 pregnant women representing a full range of glucose tolerance, who were enrolled at a hospital in Toronto between October 2003 and March 2014.

The women received comprehensive cardiometabolic testing, including oral glucose tolerance tests at 1-year, 3-year, and 5-year postpartum, and their baseline post-challenge insulinemia was established using corrected insulin response at 1 year.

Over 4 years of follow-up, a progressive worsening of cardiometabolic factors was associated with higher tertiles of corrected insulin responses at baseline, including waist circumference (P = .016), high-density lipoprotein (P = .018), C-reactive protein (CRP; P = .006), and insulin sensitivity (P < .001).

However, those trends were also associated with progressively improved beta cell function (P < .001).

After adjustment in the longitudinal analysis for the clinical risk factors for diabetes, including age, ethnicity, family history of diabetes, and body mass index (BMI) at 1 year, a higher corrected insulin response tertile at baseline was independently associated with improved Insulin Secretion-Sensitivity Index-2 and insulinogenic index/insulin resistance index (IGI/HOMA-IR), as well as lower glycemia, as observed on fasting and 2-hour glucose at 3 years and 5 years (all P < .001).

The insulin response was meanwhile not associated with BMI, waist, lipids, CRP, or insulin sensitivity or resistance.

Importantly, the highest corrected insulin response tertile at 1-year postpartum was also significantly associated with a lower risk for prediabetes or diabetes than the lowest tertile at 3 years (adjusted OR [aOR], 0.19) as well as 5 years (aOR, 0.18).

“The real question in my mind was whether we had the statistical power to be able to demonstrate a longitudinal beneficial effect on glucose regulation, but we did,” Dr. Retnakaran told this news organization. “The results show lower prediabetes and diabetes among people who had the most robust postprandial insulin excursion at 1-year postpartum.”

While the unadjusted analyses at baseline showed adverse as well as favorable outcomes, “adjusted longitudinal analyses revealed consistent independent associations of higher complete insulin response with better beta cell function, lower glycemia, and lower risk of prediabetes or diabetes in the years thereafter,” the authors reported.

“This evidence should help push back concern around the postprandial insulin spike,” Dr. Retnakaran said.

Commenting on the study, James D. Johnson, PhD, a professor of cellular and physiological sciences and director of the Life Sciences Institute at the University of British Columbia, Canada, noted that “it is already well-known that the loss of postprandial first phase insulin secretion can be a key and early defect in the transition to prediabetes and type 2 diabetes. That is not new, but the confirmatory data are welcome,” he told this news organization.

However, with other data linking high insulin with adiposity and insulin resistance, “the nuance and subtleties are critical for us to understand the directions of the causality,” he said.

“It is quite possible that both of these models are true at different life stages and/or in different people. There may be more than one pathway to diabetes. This is the nature of science and progress.”

A key caveat is that with a specific cohort of pregnant women, the question remains of the generalizability to men and to those younger or older than childbearing age.

Nevertheless, “I think this is an interesting and important study,” Dr. Johnson said. “More data on this topic is always welcome, but I am not sure this will be the final say in this debate.”

The authors and Dr. Johnson had no disclosures to report.

A version of this article appeared on Medscape.com.

Rapid surges in insulin following a meal are associated with favorable long-term cardiometabolic benefits, including improvements in beta cell function and a lower risk for the development of prediabetes or diabetes, contrary to some concerns of the surges being indicative of more negative effects.

“There are practitioners who subscribe to this notion of higher insulin levels being a bad thing, and sometimes are making recommendations to patients to limit their insulin fluctuations after the meal,” said first author Ravi Retnakaran, MD, an endocrinologist and Boehringer Ingelheim Chair in Beta-cell Preservation, Function and Regeneration at the Leadership Sinai Centre for Diabetes at Mount Sinai Hospital, Toronto, Ontario, in a press statement.

“But it’s not that simple,” he said. “We observed that a robust post-challenge insulin secretory response, once adjusted for glucose levels, is only associated with beneficial metabolic effects.”

The findings were published on December 13, 2023, in eClinicalMedicine, part of The Lancet Discovery Science.

Insulin levels increase after food consumption in the normal management of blood glucose; however, some research has suggested that more rapid spikes in insulin, especially after a high-carbohydrate meal, are linked to an anabolic state contributing to weight gain and insulin resistance.

As public awareness of those reports has grown, “patients are coming in concerned about the possibility of their insulin levels being high, and there is confusion about the physiology of these effects,” Dr. Retnakaran told this news organization. 

However, other studies have shown that the effects of insulin surges are important relative to baseline factors, including ambient glycemia and, specifically, baseline glucose levels prior to a meal.

Therefore, a more appropriate assessment is to use a corrected insulin response, measuring insulin secretion at 30 minutes after an oral glucose challenge, in relation to baseline glucose levels, research has suggested.

To investigate the issue in a longitudinal context, Dr. Retnakaran and colleagues conducted a prospective cohort study of 306 pregnant women representing a full range of glucose tolerance, who were enrolled at a hospital in Toronto between October 2003 and March 2014.

The women received comprehensive cardiometabolic testing, including oral glucose tolerance tests at 1-year, 3-year, and 5-year postpartum, and their baseline post-challenge insulinemia was established using corrected insulin response at 1 year.

Over 4 years of follow-up, a progressive worsening of cardiometabolic factors was associated with higher tertiles of corrected insulin responses at baseline, including waist circumference (P = .016), high-density lipoprotein (P = .018), C-reactive protein (CRP; P = .006), and insulin sensitivity (P < .001).

However, those trends were also associated with progressively improved beta cell function (P < .001).

After adjustment in the longitudinal analysis for the clinical risk factors for diabetes, including age, ethnicity, family history of diabetes, and body mass index (BMI) at 1 year, a higher corrected insulin response tertile at baseline was independently associated with improved Insulin Secretion-Sensitivity Index-2 and insulinogenic index/insulin resistance index (IGI/HOMA-IR), as well as lower glycemia, as observed on fasting and 2-hour glucose at 3 years and 5 years (all P < .001).

The insulin response was meanwhile not associated with BMI, waist, lipids, CRP, or insulin sensitivity or resistance.

Importantly, the highest corrected insulin response tertile at 1-year postpartum was also significantly associated with a lower risk for prediabetes or diabetes than the lowest tertile at 3 years (adjusted OR [aOR], 0.19) as well as 5 years (aOR, 0.18).

“The real question in my mind was whether we had the statistical power to be able to demonstrate a longitudinal beneficial effect on glucose regulation, but we did,” Dr. Retnakaran told this news organization. “The results show lower prediabetes and diabetes among people who had the most robust postprandial insulin excursion at 1-year postpartum.”

While the unadjusted analyses at baseline showed adverse as well as favorable outcomes, “adjusted longitudinal analyses revealed consistent independent associations of higher complete insulin response with better beta cell function, lower glycemia, and lower risk of prediabetes or diabetes in the years thereafter,” the authors reported.

“This evidence should help push back concern around the postprandial insulin spike,” Dr. Retnakaran said.

Commenting on the study, James D. Johnson, PhD, a professor of cellular and physiological sciences and director of the Life Sciences Institute at the University of British Columbia, Canada, noted that “it is already well-known that the loss of postprandial first phase insulin secretion can be a key and early defect in the transition to prediabetes and type 2 diabetes. That is not new, but the confirmatory data are welcome,” he told this news organization.

However, with other data linking high insulin with adiposity and insulin resistance, “the nuance and subtleties are critical for us to understand the directions of the causality,” he said.

“It is quite possible that both of these models are true at different life stages and/or in different people. There may be more than one pathway to diabetes. This is the nature of science and progress.”

A key caveat is that with a specific cohort of pregnant women, the question remains of the generalizability to men and to those younger or older than childbearing age.

Nevertheless, “I think this is an interesting and important study,” Dr. Johnson said. “More data on this topic is always welcome, but I am not sure this will be the final say in this debate.”

The authors and Dr. Johnson had no disclosures to report.

A version of this article appeared on Medscape.com.

Rapid surges in insulin following a meal are associated with favorable long-term cardiometabolic benefits, including improvements in beta cell function and a lower risk for the development of prediabetes or diabetes, contrary to some concerns of the surges being indicative of more negative effects.

“There are practitioners who subscribe to this notion of higher insulin levels being a bad thing, and sometimes are making recommendations to patients to limit their insulin fluctuations after the meal,” said first author Ravi Retnakaran, MD, an endocrinologist and Boehringer Ingelheim Chair in Beta-cell Preservation, Function and Regeneration at the Leadership Sinai Centre for Diabetes at Mount Sinai Hospital, Toronto, Ontario, in a press statement.

“But it’s not that simple,” he said. “We observed that a robust post-challenge insulin secretory response, once adjusted for glucose levels, is only associated with beneficial metabolic effects.”

The findings were published on December 13, 2023, in eClinicalMedicine, part of The Lancet Discovery Science.

Insulin levels increase after food consumption in the normal management of blood glucose; however, some research has suggested that more rapid spikes in insulin, especially after a high-carbohydrate meal, are linked to an anabolic state contributing to weight gain and insulin resistance.

As public awareness of those reports has grown, “patients are coming in concerned about the possibility of their insulin levels being high, and there is confusion about the physiology of these effects,” Dr. Retnakaran told this news organization. 

However, other studies have shown that the effects of insulin surges are important relative to baseline factors, including ambient glycemia and, specifically, baseline glucose levels prior to a meal.

Therefore, a more appropriate assessment is to use a corrected insulin response, measuring insulin secretion at 30 minutes after an oral glucose challenge, in relation to baseline glucose levels, research has suggested.

To investigate the issue in a longitudinal context, Dr. Retnakaran and colleagues conducted a prospective cohort study of 306 pregnant women representing a full range of glucose tolerance, who were enrolled at a hospital in Toronto between October 2003 and March 2014.

The women received comprehensive cardiometabolic testing, including oral glucose tolerance tests at 1-year, 3-year, and 5-year postpartum, and their baseline post-challenge insulinemia was established using corrected insulin response at 1 year.

Over 4 years of follow-up, a progressive worsening of cardiometabolic factors was associated with higher tertiles of corrected insulin responses at baseline, including waist circumference (P = .016), high-density lipoprotein (P = .018), C-reactive protein (CRP; P = .006), and insulin sensitivity (P < .001).

However, those trends were also associated with progressively improved beta cell function (P < .001).

After adjustment in the longitudinal analysis for the clinical risk factors for diabetes, including age, ethnicity, family history of diabetes, and body mass index (BMI) at 1 year, a higher corrected insulin response tertile at baseline was independently associated with improved Insulin Secretion-Sensitivity Index-2 and insulinogenic index/insulin resistance index (IGI/HOMA-IR), as well as lower glycemia, as observed on fasting and 2-hour glucose at 3 years and 5 years (all P < .001).

The insulin response was meanwhile not associated with BMI, waist, lipids, CRP, or insulin sensitivity or resistance.

Importantly, the highest corrected insulin response tertile at 1-year postpartum was also significantly associated with a lower risk for prediabetes or diabetes than the lowest tertile at 3 years (adjusted OR [aOR], 0.19) as well as 5 years (aOR, 0.18).

“The real question in my mind was whether we had the statistical power to be able to demonstrate a longitudinal beneficial effect on glucose regulation, but we did,” Dr. Retnakaran told this news organization. “The results show lower prediabetes and diabetes among people who had the most robust postprandial insulin excursion at 1-year postpartum.”

While the unadjusted analyses at baseline showed adverse as well as favorable outcomes, “adjusted longitudinal analyses revealed consistent independent associations of higher complete insulin response with better beta cell function, lower glycemia, and lower risk of prediabetes or diabetes in the years thereafter,” the authors reported.

“This evidence should help push back concern around the postprandial insulin spike,” Dr. Retnakaran said.

Commenting on the study, James D. Johnson, PhD, a professor of cellular and physiological sciences and director of the Life Sciences Institute at the University of British Columbia, Canada, noted that “it is already well-known that the loss of postprandial first phase insulin secretion can be a key and early defect in the transition to prediabetes and type 2 diabetes. That is not new, but the confirmatory data are welcome,” he told this news organization.

However, with other data linking high insulin with adiposity and insulin resistance, “the nuance and subtleties are critical for us to understand the directions of the causality,” he said.

“It is quite possible that both of these models are true at different life stages and/or in different people. There may be more than one pathway to diabetes. This is the nature of science and progress.”

A key caveat is that with a specific cohort of pregnant women, the question remains of the generalizability to men and to those younger or older than childbearing age.

Nevertheless, “I think this is an interesting and important study,” Dr. Johnson said. “More data on this topic is always welcome, but I am not sure this will be the final say in this debate.”

The authors and Dr. Johnson had no disclosures to report.

A version of this article appeared on Medscape.com.