People with prediabetes have gut bacteria different from those of healthy individuals. Know More!

Prediabetes is a condition characterized by high glycated haemoglobin levels, ranging from 5.7% to 6.5%, and fasting blood glucose levels between 100 and 126 mg/dL. It increases the risk of mortality and puts a significant burden on the healthcare system. In general, 70% of individuals with prediabetes will develop T2DM at some point in their lives. A further reason for understanding the biological progression from prediabetes to diabetes is the estimated 642 million people who are expected to develop T2DM by 2040.

The human gut microbiota, also known as gut microbiome or gut flora, is a complex community of microorganisms that live in the gastrointestinal (GI) tract. It includes bacteria, fungi, archaea, protozoa, and viruses and is made up of over 100 trillion microbial cells. The gut microbiota is established during infancy, and diet is considered one of the main factors that shape it throughout life. The gut microbiota is a crucial factor affecting various aspects of human health. It plays a crucial role in immune function, metabolic homeostasis, protection against pathogens, nutrition, and neurobehavioral traits.

Recent research suggests that gut microbiota composition changes in people with prediabetes and that these changes may be linked to health conditions like type 2 diabetes. In this article, we will explore the latest studies that discussed changes in gut microbial composition in people living with prediabetes and how to maintain good gut health.

Gut microbiome and metabolic syndromes

The gut microbiome plays a vital role in regulating lipid and glucose metabolism. For example, changes in intestinal bacterial composition and abundance influence intestinal permeability, which induces insulin resistance and the introduction of bacterial lipopolysaccharides into the bloodstream. Dysbiosis of the microbiota may result in dysregulation of bodily functions and diseases, such as cardiovascular disease (CVD), cancer, and diabetes. Fig. 1 shows how external changes can affect the balance of microbiota communities, leading to dysregulation of bodily functions and diseases.

Increasing gut permeability promotes low-grade systemic inflammation as a result of gut microbial dysbiosis. Metabolic syndrome and other chronic diseases, such as type 2 diabetes, are associated with this condition.

Effective new strategies to prevent prediabetes from progressing to diabetes require understanding how changes in intestinal bacteria influence the development of diabetes. Gut microbiota are altered by a number of factors. Although numerous studies have identified differences in intestinal bacteria between diabetics and healthy individuals, few have examined the composition of intestinal bacteria in prediabetic patients and its effects on physiological mechanisms. To inform targeted interventions, it is imperative to explore the relationship between gut microbiota alterations and prediabetes.

Diet, prediabetes and gut microbiota composition

A 2024 study compared the gut microbial composition of prediabetic patients and healthy individuals. In order to identify nutrition-based interventions that could potentially prevent prediabetes from progressing to diabetes, the impact of diet was also assessed on the gut microbiome of prediabetic patients. Participants (n=57) were instructed to keep a three-day food diary and collect faecal samples on the third day. Nutritionist Professional 2.0 software was used to measure the nutrient composition of the participants' diets. The composition, diversity, and abundance of the gut microbiota were significantly reduced in prediabetic patients compared to healthy individuals. Prediabetic patients also exhibited a higher body mass index (BMI) than controls.

The microbial diversity of diabetes patients was lower than that of healthy individuals, with 9 genera of bacteria being less abundant and 14 genera being more abundant. Patients with prediabetes who consumed a low-carbohydrate diet had a greater diversity of gut microbiota than those who consumed a high-carbohydrate diet. A higher abundance of Coprococcus (beneficial bacteria) was observed in the prediabetic patients on a low-carb (LC) diet. The study concluded that compared to healthy individuals, the gut microbiota of prediabetic patients was significantly different, and adopting a low-carb diet with high dietary fibre consumption may positively impact the gut microbiota.

Diet determines 57% of the gut microbiota, whereas genetic variation accounts for only 12%. Diet, therefore, plays an important role in regulating gut bacterial diversity. Gut microbiota can also obtain energy from dietary fibre. Short-chain fatty acids are produced by intestinal bacteria when fermentable dietary fibres are consumed. Those with prediabetes who maintain a low carbohydrate intake and eat a lot of dietary fibre have improved intestinal barrier integrity. The low carbohydrate intake group had a higher relative abundance of Coprococcus. A previous study found that dietary fibre enriches Coprococcus. Several studies have shown that Coprococcus contributes to the production of butyrate, which helps maintain the integrity of the gut barrier. Despite the findings of this study emphasizing the role of Coprococcus and its differences between low-carb and high-carb groups, many other bacterial genera (Bifidobacterium, Lactobacillus, Faecalibacterium, Akkermansia, etc.) also play a significant role in modulating the integrity of the gut barrier, therefore it should not be considered the only marker to assess gut integrity.

A 'good gut diet' is crucial

A balanced diet rich in prebiotics and probiotics can promote the growth of beneficial bacteria in the gut, leading to improved digestion, enhanced immune function, and better overall health. Here's a comprehensive guide to crafting a good gut diet that includes prebiotics and probiotics.

Two primary components of a good gut diet are prebiotics and probiotics.

• Prebiotics: Prebiotics are non-digestible fibres that serve as food for beneficial bacteria in the gut. They promote the growth and activity of these bacteria, particularly bifidobacteria and lactobacilli, which are known for their health benefits.
• Probiotics: Probiotics are live microorganisms that confer health benefits when consumed in adequate amounts. They can help restore the balance of beneficial bacteria in the gut and support various aspects of digestive and immune health.

Components of a Good Gut Diet:

• High-Fiber Foods: Incorporate plenty of fiber-rich foods into your diet, such as fruits, vegetables, whole grains, legumes, nuts, and seeds. These foods are excellent sources of prebiotic fibres that nourish beneficial gut bacteria.
• Fermented Foods: Include fermented foods that are naturally rich in probiotics. Examples include yoghurt, kefir, sauerkraut, kimchi, tempeh, miso, and kombucha. These foods contain live cultures of beneficial bacteria that can help populate the gut with healthy microbes.
• Colourful Fruits and Vegetables: Aim to consume a variety of colourful fruits and vegetables, as they provide essential vitamins, minerals, antioxidants, and phytonutrients that support gut health. Berries, leafy greens, cruciferous vegetables, citrus fruits, and onions are particularly beneficial.
• Whole Grains: Choose whole grains such as oats, quinoa, brown rice, barley, and whole wheat, as they contain prebiotic fibres that support gut health. Avoid highly processed grains and refined carbohydrates, which can disrupt gut bacteria balance.
• Healthy Fats: Incorporate sources of healthy fats like avocados, olive oil, nuts, seeds, and fatty fish into your diet. These fats support the absorption of fat-soluble vitamins and help reduce inflammation, which can benefit gut health.
• Lean Protein: Include lean sources of protein such as poultry, fish, tofu, legumes, and beans in your diet. Protein is essential for muscle repair and growth, and incorporating plant-based protein sources can provide additional fibre and nutrients beneficial for gut health.
• Limit Processed Foods and Sugars: Minimize the consumption of processed foods, sugary snacks, and beverages, as they can negatively impact gut health by promoting the growth of harmful bacteria and inflammation.

Sample Meal Plan:

Here's a sample meal plan that incorporates prebiotic and probiotic-rich foods:

• Breakfast: Greek yoghurt topped with fresh berries, nuts, and a drizzle of honey.
• Snack: Carrot sticks with hummus.
• Lunch: Quinoa salad with mixed greens, cherry tomatoes, cucumbers, avocado, and grilled chicken.
• Snack: Kefir smoothie with banana, spinach, and almond butter.
• Dinner: Baked salmon with roasted sweet potatoes and steamed broccoli

Conclusion

The gut microbiota of prediabetic individuals differs from that of healthy individuals according to emerging research. It was evident from the significantly different physiological and metabolic responses. In order to maintain normal physiological metabolism and intestinal bacterial diversity, a balanced intake of nutrients and a high-fibre diet may be helpful.