Incretins are gut hormones that play a vital role in blood glucose regulation and appetite control, with glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) being the most important. These hormones are released when we eat and help stimulate insulin secretion in a glucose-dependent manner, reducing the risk of hypoglycaemia. Whilst incretin-based medications have transformed diabetes management, emerging evidence suggests that certain dietary choices may naturally support incretin production. Understanding which foods stimulate incretin hormones offers a practical, physiologically sound approach to optimising metabolic health through nutrition, complementing broader healthy eating guidance from the NHS and NICE.

What Are Incretins and Why Do They Matter?

Incretins are a group of metabolic hormones released from the gastrointestinal tract in response to food intake, playing a crucial role in regulating blood glucose levels. The two principal incretin hormones are glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). These hormones are secreted by specialised enteroendocrine cells—L-cells, which produce GLP-1 and are concentrated in the distal ileum and colon, and K-cells, which secrete GIP and are found predominantly in the proximal small intestine.

The primary function of incretins is to enhance insulin secretion from pancreatic beta cells in a glucose-dependent manner, meaning they stimulate insulin release only when blood glucose levels are elevated. This glucose-dependent mechanism is associated with a lower risk of hypoglycaemia compared to some other glucose-lowering treatments, such as sulfonylureas or insulin. GLP-1 also suppresses glucagon secretion, slows gastric emptying, and promotes satiety, contributing to improved glycaemic control and potential weight management benefits.

The incretin effect accounts for a substantial proportion of total insulin secretion following oral glucose intake in healthy individuals. However, this effect is markedly diminished in people with type 2 diabetes, contributing to postprandial hyperglycaemia. Understanding how dietary choices may influence incretin secretion has become increasingly relevant, particularly as incretin-based therapies (such as GLP-1 receptor agonists like semaglutide and liraglutide) have demonstrated significant benefits in diabetes management. Certain GLP-1 receptor agonists have also shown cardiovascular benefits in specific populations with type 2 diabetes and established cardiovascular disease, as detailed in NICE guidance (NG28) and individual product summaries of product characteristics (SmPCs) available via the electronic medicines compendium (emc).

For individuals seeking to optimise metabolic health through dietary means, selecting foods that may support natural incretin production represents a physiologically sound approach. This nutritional strategy aligns with general healthy eating guidance, including the NHS Eatwell Guide and NICE recommendations on lifestyle interventions for diabetes prevention and management.

Foods That May Naturally Stimulate Incretin Hormones

Certain macronutrients and specific foods have been shown in research studies to stimulate incretin secretion, though responses vary by individual, meal composition, and metabolic health status. Protein-rich foods are particularly effective incretin stimulators in acute feeding studies, with whey protein, fish, eggs, and lean meats triggering GLP-1 and GIP release. The amino acids released during protein digestion interact with nutrient-sensing receptors on enteroendocrine cells, initiating hormone secretion. Whey protein appears especially effective in short-term studies, possibly due to its rapid digestion and high leucine content, though responses vary by dose and food matrix.

Dietary fibre, particularly soluble and fermentable types, may enhance incretin production through indirect mechanisms. Foods rich in soluble fibre include oats, barley, legumes (lentils, chickpeas, beans), flaxseeds, and vegetables such as Brussels sprouts and broccoli. When gut bacteria ferment these fibres in the colon, they produce short-chain fatty acids (SCFAs)—primarily acetate, propionate, and butyrate. Preclinical and early human studies suggest that SCFAs may stimulate L-cells to secrete GLP-1, though further research is needed to confirm the magnitude and consistency of this effect in diverse populations. The UK Scientific Advisory Committee on Nutrition (SACN) recommends 30 g of fibre daily for general health, including support for gut microbiota and metabolic function.

Dietary fats, including both monounsaturated and polyunsaturated fatty acids, promote incretin release. Foods such as olive oil, avocados, nuts (almonds, walnuts), and fatty fish (salmon, mackerel, sardines) have demonstrated incretin-stimulating properties in research. The mechanism involves fat-sensing receptors (such as GPR120) on enteroendocrine cells that respond to long-chain fatty acids. It is worth noting that whilst unsaturated fats are recommended over saturated fats for cardiovascular health, various types of dietary fat can stimulate incretin hormones, particularly GIP. The NHS recommends eating at least two portions of fish per week, one of which should be oily fish.

Polyphenol-rich foods may support incretin function, though evidence remains early and limited. Green tea, berries, dark chocolate (70% cocoa or higher), and extra virgin olive oil contain bioactive compounds that appear in some studies to support GLP-1 secretion. Fermented foods like natural yoghurt, kefir, and kimchi provide both probiotics and bioactive peptides that may influence gut health and incretin production, though robust human data are still emerging in this area.

How Diet May Affect GLP-1 and GIP Production

The relationship between dietary composition and incretin secretion is complex and influenced by multiple factors, including macronutrient ratios, meal timing, food processing, gut microbiota composition, and individual metabolic status. Macronutrient composition affects both the magnitude and duration of incretin response, though effects vary by meal composition and individual. Carbohydrates can stimulate both GIP and GLP-1 secretion, whilst protein and fat tend to produce more sustained hormone release in some studies, which may contribute to prolonged satiety and improved glycaemic control.

The glycaemic index (GI) and glycaemic load of carbohydrate-containing foods influence postprandial glucose and insulin responses. Low-GI foods—such as whole grains, legumes, and non-starchy vegetables—produce more gradual rises in blood glucose compared to high-GI refined carbohydrates, which supports better overall glycaemic control. Whilst some studies suggest differences in incretin secretion patterns between low- and high-GI foods, findings are not entirely consistent, and the primary benefit of low-GI choices relates to improved glucose homeostasis and satiety. The British Dietetic Association (BDA) provides patient-friendly guidance on the appropriate use of the glycaemic index.

Gut microbiota composition may play a role in incretin regulation, particularly through SCFA production. A diverse, fibre-rich diet promotes beneficial bacterial species that efficiently ferment dietary fibre, generating SCFAs. Evidence from preclinical models and early human studies suggests these SCFAs may stimulate GLP-1 secretion, though the magnitude and clinical relevance in diverse populations require further investigation. Conversely, diets high in processed foods, refined sugars, and saturated fats may negatively impact gut microbiota diversity.

The physical form and processing of foods also appears relevant. Whole foods generally produce more favourable metabolic responses than highly processed alternatives. For example, intact grains and whole fruits retain fibre and other components that slow nutrient absorption and provide substrate for microbial fermentation, compared to refined flour products or fruit juices.

Meal frequency and timing have been studied in relation to glucose control and satiety, but evidence linking specific eating schedules to optimal incretin function is limited and inconclusive. Individual responses vary considerably based on metabolic health status, and there is no single meal pattern proven to maximise incretin secretion for all individuals.

Practical Dietary Strategies to Support Incretin Response

Implementing dietary changes to support natural incretin production requires a structured, evidence-based approach that aligns with broader healthy eating principles recommended by NICE and the NHS Eatwell Guide. The following strategies can be incorporated into daily eating patterns:

Prioritise protein at each meal: Include a palm-sized portion of high-quality protein such as fish, poultry, eggs, Greek yoghurt, or legumes. Some research on meal sequencing suggests that consuming protein early in a meal may support satiety and glycaemic control, though findings are mixed and further evidence is needed. For vegetarians and vegans, combining plant proteins (beans with whole grains) ensures adequate amino acid profiles for overall nutritional adequacy.

Increase dietary fibre intake gradually: Aim for the NHS-recommended 30 g of fibre daily through a variety of sources. Incorporate oats or bran cereal at breakfast, include legumes in main meals at least three times weekly, and consume at least five portions of vegetables and fruits daily. Increase fibre intake slowly to minimise gastrointestinal discomfort, and ensure adequate hydration.

Choose healthy fats wisely: Replace saturated fats with unsaturated alternatives for cardiovascular health. Use extra virgin olive oil for cooking and dressings, include a small handful of nuts daily, consume fatty fish twice weekly (as per NHS guidance), and incorporate avocado or nut butters in moderation. These fats support overall metabolic and cardiovascular health.

Select wholegrain and low-GI carbohydrates: Replace refined grains with wholegrain alternatives—choose brown rice over white, wholemeal bread over white bread, and steel-cut oats over instant varieties. Include sweet potatoes, quinoa, and barley as nutrient-dense carbohydrate sources. These choices support better glycaemic control and provide fibre for gut health.

Incorporate fermented foods: Add natural yoghurt, kefir, sauerkraut, or kimchi to your diet several times weekly to support gut microbiota diversity, though evidence for direct effects on incretin function remains early.

Practical meal example: A breakfast of Greek yoghurt with berries, ground flaxseed, and walnuts provides protein, fibre, healthy fats, and polyphenols—components that may support incretin secretion and overall metabolic health.

Important safety considerations: Individuals with diabetes taking glucose-lowering medications—particularly insulin or sulfonylureas—should consult their GP or diabetes specialist nurse before making significant dietary changes, as improved dietary habits and glycaemic control may necessitate medication adjustments to prevent hypoglycaemia. Recognise symptoms of hypoglycaemia (sweating, shaking, confusion, rapid heartbeat) and seek urgent medical help if severe or persistent. Those with existing gastrointestinal conditions should seek personalised dietary advice from a registered dietitian. If you experience persistent digestive symptoms, unexplained weight changes, or difficulty managing blood glucose levels, contact your GP for appropriate investigation and management.

If you are taking any medicines and suspect you are experiencing a side effect, you can report it via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or through the Yellow Card app.

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