Carbohydrate intake has long been known to affect blood sugar levels, resulting in insulin release by pancreatic cells more than other nutrients. Novel laboratory research now suggests that individuals might actually exhibit unique insulin responses to different nutrients, with some showing larger reactions to proteins or fats. While it’s unclear if the findings translate to living humans, experts are optimistic that further clinical research will enhance personalized nutrition strategies for managing blood sugar. A groundbreaking study published in Cell Metabolism has shed new light on how different macronutrients—carbohydrates, proteins, and fats—might affect insulin secretion. The study examined insulin responses in pancreatic islets from deceased human donors with and without type 2 diabetes, as well as stem cell-derived pancreatic islets.
Pancreatic islets are small clusters of pancreatic cells, including beta cells, crucial in regulating blood sugar levels by producing hormones like insulin and glucagon in response to nutrient intake. It has long been understood that carbohydrates significantly contribute to blood sugar levels, prompting insulin release, while proteins have a moderate effect, and fats have minimal immediate impact. However, this study suggests that insulin secretion in response to nutrients may actually be more complex and individualized than previously believed. For the first time, researchers identified subsets of human pancreatic islets exhibiting larger insulin responses to proteins or fats than carbohydrates.
Researchers at the University of British Columbia studied how human pancreatic islets secrete insulin in response to different nutrients, examining pancreatic islets from deceased donors of various ages, including those with and without type 2 diabetes. They exposed the islets to glucose (carbohydrates), amino acids (proteins), and fatty acids (fats) while monitoring insulin secretion. The researchers also analyzed gene expression changes in pancreas cells from donors with and without type 2 diabetes to understand their impact on insulin production. The study found that most donors’ islets showed the strongest insulin response to glucose, a moderate response to amino acids, and little response to fatty acids. Islets from donors with type 2 diabetes had fewer insulin-producing beta cells and a delay in their peak insulin time in response to high glucose, with a lower insulin response overall. Surprisingly, about 9% of donors’ pancreatic islets responded more strongly to proteins than carbohydrates, while 8% responded more strongly to fats.
The study also found that islets that reacted more to proteins often came from donors with type 2 diabetes but had similar blood sugar levels as others, while those reacting more to fats were usually from donors with worse HbA1c levels. The researchers noted sex differences in insulin responses, with female donor islets secreting less insulin in response to moderate glucose exposure compared to males. While there is uncertainty if the variability in responses is due to natural differences in pancreatic islet cell responses or lab conditions, the findings suggest that insulin responses to different nutrients may vary among individuals. However, it’s important to consider the limitations in translating these findings directly to living humans due to factors like blood flow, hormone levels, and lifestyle.
The authors hope their research will inspire clinical studies involving larger and more diverse groups to enhance the applicability of their results to real-world settings. The findings from this research could lead to more customized dietary care plans for diabetes treatment. While traditional diabetes diets focus on controlling carbs, this study suggests the need for personalized approaches based on individual insulin responses to different macronutrients. There may be genetic tests in the future to determine the best macronutrient ratio for an individual’s insulin response. In the meantime, individuals are advised to work closely with healthcare professionals to identify dietary patterns and lifestyle changes that best support their unique needs for maintaining healthy blood sugar levels and optimal health.
