A recent study found that individuals' blood glucose responses to carbohydrate-rich meals may vary widely, even when eating identical foods.
These variations were strongly linked to individual differences in insulin sensitivity, beta-cell function, and microbiome composition.
Researchers monitored postmeal glucose levels in 55 adults using continuous glucose monitors (CGM). The participants consumed seven standardized carbohydrate meals, each containing 50 g of carbohydrates. The meals included jasmine rice, white bread, potatoes, pasta, beans, grapes, and mixed berries. Each meal was repeated on different days to assess consistency.
Rice caused the highest average blood glucose spike, while beans and mixed berries caused the lowest. Notably, individuals responded differently to each carbohydrate type. Some had their highest glucose spike after eating potatoes, whereas others experienced the highest spike after bread, rice, or grapes.
Based on these responses, the participants were grouped by the food that triggered their highest spike—labeled as "spikers." Potato-spikers showed greater insulin resistance and reduced beta-cell function. Grape-spikers were more insulin sensitive and had lower fasting glucose. Bread-spikers had higher blood pressure.
Rice-spikers were the largest group, making up about one-third of the participants, and were more likely to be of Asian descent. This supported earlier findings demonstrating that rice can produce higher glycemic responses in Asian individuals.
To examine whether certain foods could reduce glucose spikes, the researchers evaluated the effects of preloading meals with fiber, protein, or fat. The participants consumed pea fiber, egg whites, or cream 10 minutes prior to eating rice—the most glucose-elevating meal on average.
These “mitigators” had only mild effects overall. Benefits were more pronounced in insulin-sensitive participants and those with normal beta-cell function. Insulin-resistant individuals showed minimal response, indicating that metabolic health influences how effectively the body manages blood sugar.
The researchers also analyzed blood and stool samples to investigate the molecular basis of these differences. Individuals with higher glucose spikes from potatoes had elevated triglycerides and fatty acids. Gut microbiome profiles also varied, with some bacterial species linked to greater or reduced glucose responses and others influencing how well mitigators worked.
The findings emphasized that the same carbohydrate meal can produce different glycemic effects depending on an individual's metabolic condition. This variability may explain why some individuals are more prone to type 2 diabetes or cardiovascular disease, even with similar diets.
The study suggested that dietary recommendations may be more effective if tailored to individual physiology. Larger and more diverse studies are needed to validate and expand on these findings.
Full disclosures can be found in the study.
Source: Nature Medicine
