A multinational study has shown that high consumption of high glycaemic index foods increases the risk of cardiovascular disease (CVD) events such as stroke or heart disease, regardless of pre-existing CVD.
The study examined low-, middle- and high-income countries, beginning in 2006, with a median follow-up of 9.5 years. Data was used from nearly 120 000 participants.
The glycaemic index was first introduced in the 1970s to compare the rise of blood glucose from a given carbohydrate food in a patient in comparison to their blood glucose curve from the same patient ingesting glucose. This ranges from 20 for fructose to 100 for barley. In comparison to individuals eating low glycaemic index foods, those eating high glycaemic index foods had a greater risk of CVD events (51%) if there was pre-existing CVD, and even without CVD (21%).
The highest glycaemic index foods were eaten in China, followed by Africa and Southeast Asia. The highest glycaemic loads were seen in Southeast Asia, followed by Africa and China. Glycaemic load is a better measure of a food’s effect on blood sugar taking into account how quickly it enters the bloodstream and how much glucose can be delivered.
There was less of an effect seen with glycaemic load only those with preexisting CVD showed an association between high glycaemic load diets and patient outcomes.
The participants were given a questionnaire, breaking foods down into seven categories based on glycaemic load and frequency, with a number of options each.
The broad geographic and economic scope of this study enabled the investigation of glycaemic index and load across a wide range of diets that would not be possible if it were restricted to sampling only Western-style diets.
“As expected, a higher glycaemic index was associated with an increased risk of adverse effects among the participants with a higher BMI, as reported previously,” the researchers wrote. “Although the glycaemic index of foods is independent of glucose-tolerance status, the overall postprandial glycaemic response to diet increases as the BMI increases.”
The authors acknowledge that economic development may have altered the mix of diets sampled over time, leading to an overestimation of glycaemic foods in China, for example. The findings nonetheless have important implications for primary and secondary prevention of CVD.
Source: MedPage Today
Journal information: Jenkins DJA, et al “Glycemic index, glycemic load, and cardiovascular disease and mortality” N Engl J Med 2021; DOI: 10.1056/NEJMoa2007123.
