Definitions

• Prebiotic: The food that probiotics need to sustain themselves (e.g., fructooligosaccharides)
• Probiotic: A living organism that benefits the health of the host (e.g., bacteria and yeast)
• Synbiotic: A supplement that contains both a prebiotic and a probiotic
• Postbiotic: A metabolic byproduct of probiotics (e.g., n-butyrate from fermentation of fiber and bacteria)

Nutrition: The Ultimate Prebiotic

Although a person’s population of bacteria originates at the time of birth, most of the microbiome is established in the human gut with the introduction of food. Breast milk includes milk oligosaccharides (MOS) that provide bacteria with nutrients to grow, particularly Bifidobacteria. Diets that contain the most fiber, fruit, and vegetables are known to engender the most diversity and richness of bacteria growth in the gut. Healthy bacteria produce short-chain fatty acids, such as n-butyrate, that support the health of the intestinal lining.¹

Foods rich in choline and carnitine (e.g., red meat and eggs) are metabolized by the intestinal microbiota to form the gas trimethylamine (TMA). TMA is converted by the liver to trimethylamine oxide (TMAO). This substance (an unhealthy postbiotic) has been strongly linked to the development of atherosclerosis and coronary artery disease.²

Eating a diet low in red meat and animal fat and rich in fibrous plants has been found to support bacteria in the gut that can reduce how much energy the body stores; our gut’s microbiome can influence one’s risk of obesity.³ When humans were hunters and gatherers, it was harder to kill wild game, so eating meat and animal fat was less common. It may have been advantageous in the past to have a gut that contained bacteria able to maximize energy storage when such foods were available. Unfortunately, in modern times, when animal-based foods are easy to obtain, it may be that our gut bacteria increase our risk of obesity.