Prebiotics & probiotics

Summary

The human gastrointestinal tract is home to trillions of microbes, collectively known as the gut microbiome. Diet plays a crucial role in shaping the microbiome, with fiber-rich and protein-heavy foods affecting its composition. Probiotics and prebiotics are two key elements that influence gut health. Probiotics, found in fermented foods, introduce beneficial microorganisms, while prebiotics, found in high-fiber foods, serve as food for gut microbes. This balance of microbes is linked to various health benefits, including improved digestion and immune function. Research on the gut microbiome continues to reveal its significant impact on human health.

Takeaways

• 😀 The human gastrointestinal tract hosts trillions of microbes, known as the gut microbiome.
• 😀 Microbial cells in the human body may outnumber human cells, with a close to one-to-one ratio, possibly making us slightly more microbe than human.
• 😀 The gut microbiome consists primarily of two groups of bacteria: Bacteroidetes and Firmicutes, with smaller populations of other bacteria.
• 😀 The microbiome composition varies greatly from person to person, and there's no universally agreed-upon definition of a 'healthy' microbiome.
• 😀 Diet significantly affects the gut microbiome, with high-fiber diets promoting Prevotella and high-protein or high-fat diets promoting Bacteroides.
• 😀 Even a single day of a strict animal-based or plant-based diet can alter the microbiome, but it usually returns to normal once regular diets resume.
• 😀 Probiotics are live microorganisms beneficial to gut health, commonly found in fermented foods like yogurt, kefir, kimchi, and sauerkraut.
• 😀 For a food to be considered a probiotic, it must contain live bacteria that survive processing and have proven health benefits.
• 😀 Prebiotics are components in food that support gut microbes by providing them with fiber to ferment, especially from vegetables, fruits, and legumes.
• 😀 Short-chain fatty acids produced by gut microbes fermenting prebiotics offer health benefits, such as reducing cancer risks, improving calcium absorption, and aiding digestion.
• 😀 Research on probiotics and prebiotics is ongoing, but despite promising results, probiotic supplements aren't widely used in hospitals due to unresolved health benefit questions.

Q & A

What is the gut microbiome and why is it important?

The gut microbiome refers to the trillions of microbes living in the gastrointestinal tract. It plays a crucial role in digestion, immune function, and overall health by influencing various biological processes.

How many microbial cells are estimated to be in the human body compared to human cells?

It was once thought that there were about ten times as many microbial cells as human cells, but more recent estimates suggest that the ratio is closer to one-to-one, with microbes slightly outnumbering human cells.

What are the two main groups of bacteria that dominate the gut microbiome?

The two main groups of bacteria that dominate the gut microbiome are Bacteroidetes and Firmicutes.

How does diet affect the composition of the gut microbiome?

Diet can significantly alter the composition of the gut microbiome. For instance, a high-fiber diet tends to increase the levels of Prevotella bacteria, while a diet higher in protein and fat increases the abundance of Bacteroides.

What are probiotics, and how do they benefit our health?

Probiotics are live microorganisms that offer health benefits, primarily by supporting or restoring the gut microbiome. They are commonly found in fermented foods like yogurt, kefir, kimchi, and sauerkraut, and are believed to improve gut health.

What are prebiotics and how do they affect the gut microbiome?

Prebiotics are food components that microbes use for energy. They typically consist of high-fiber foods that reach the large intestine undigested, where they are fermented by gut bacteria, resulting in beneficial compounds like short-chain fatty acids.

How do short-chain fatty acids benefit the body?

Short-chain fatty acids, produced when gut bacteria ferment prebiotics, nourish the cells lining the gut, enhance calcium absorption, relieve constipation and diarrhea, and may reduce the risk of colorectal cancer. They also communicate with the brain and help regulate immune function and inflammation.

What are the best sources of prebiotics in the diet?

The best sources of prebiotics are high-fiber foods such as vegetables, fruits, whole grains, and legumes like peas and beans. Additionally, some packaged foods contain prebiotic ingredients like inulin and oligosaccharides.

Why do many people not consume enough fiber?

Many people don’t consume enough fiber because the average American diet typically provides about 16 grams of fiber per day, while the recommended daily intake is between 25 and 38 grams.

Why are probiotics and prebiotics not commonly used in hospital settings?

Despite promising research, probiotics and prebiotics are not widely used in hospital settings because their health benefits haven’t been conclusively proven for all populations. Additionally, some probiotic supplements have been linked to infections in immunocompromised patients.