The concept of prebiotics can be traced back to 1995, when the international "father of prebiotics" - G. R. Gibson first proposed the concept of prebiotics: "indigestible food components that can have beneficial effects on the host by selectively stimulating the growth or activity of one or a few bacteria in the colon, thereby enhancing host health. This activated bacteria should be naturally beneficial, such as bifidobacteria and lactobacilli.

In 2017, the International Scientific Association for Probiotics and Prebiotics (ISAPP) proposed the broad concept of prebiotics: "substrates that can be selectively utilized by host microorganisms and have health benefits.

In 2021, the "Consensus on Probiotics and Health Experts" of the Chinese Nutrition Society (hereinafter referred to as the "Consensus") was released, stating that prebiotics are "food ingredients that are generally not digested and absorbed by the human body but can be selectively utilized by the human microbiota, which can improve the composition and/or activity of intestinal microbiota and benefit human health".

The consensus also clearly states that prebiotics have health benefits such as improving microbiota balance, regulating intestinal function, immune regulation, weight regulation, and glucose and lipid regulation.

At present, there are three main recognized standards for prebiotics:

1. Not digested and absorbed before entering the intestine

Probiotics must be able to resist the digestion and breakdown of saliva, stomach acid, pancreatic juice, and bile before entering the intestine. Only when they enter the intestine smoothly can prebiotics work better.

2. Can be selectively fermented by gut microbiota

Fermentation is the process by which gut microbiota breaks down and utilizes prebiotics. Although some food ingredients cannot be fermented by gut microbiota and can also have health benefits by regulating stool volume and moisture, the current definition emphasizes that prebiotics must be able to be fermented by gut microbiota.

3. Has the function of regulating intestinal microbiota

It can regulate the composition and/or activity of gut microbiota, and this effect is beneficial to the health of the body, which has been fully demonstrated by human experiments.

The strict standards for prebiotics greatly limit the types and quantities of prebiotics. But with the continuous deepening of research related to prebiotics, especially human trials and clinical studies, more and more ingredients are recognized as belonging to prebiotics or possessing functional characteristics of prebiotics.

A study by King's College London suggests that omega-3 fatty acids can effectively improve the composition of the gut microbiota and increase the production of short chain fatty acids.

Researchers in London registered 69 individuals from the TwinsUK registry and randomly assigned them to receive omega-3 supplements (500 milligrams per day) or inulin (a prebiotic) supplements (20 grams per day) for six weeks. The results showed that after adding omega-3 for 6 weeks, there was a significant change in the levels of bacterial fermentation products, and the overall effect was comparable to supplementing with inulin fiber. This indicates that omega-3 has the potential to act as a prebiotic and can have a positive impact on human health by improving the microbiota.

Similar results were observed in the levels of short chain fatty acids (SFCA) and branched chain fatty acids (BCFA) such as butyrate, isovalerate, and isobutyrate in the omega-3 and inulin groups.

The researchers also pointed out that the current research results indicate that the cardiovascular benefits of supplementing omega-3 may be mediated by the gut microbiome. ”

Based on current research findings, researchers believe that omega-3 fatty acids have prebiotic functional properties, not only improving the composition of gut microbiota, but also increasing the levels of certain gut derived metabolites such as BCFAS and SCFAS, which have a positive impact on metabolic health.

Therefore, it can be said that omega-3 is a new high-quality member of the prebiotic family,

An article published in the International Journal of Molecular Science further reviews the role of Omega-3 in restoring the ecological balance of gut microbiota and suggests that Omega-3 can be considered a prebiotic.

More than 90% of the gastrointestinal bacteria in healthy individuals belong to the phyla Bacteroidetes and Firmicutes. Imbalance between these two bacterial species is associated with weight gain, insulin resistance, high-fat diet, intestinal mucosal permeability, inflammatory bowel disease, and depression. A decrease in bifidobacteria and an increase in Escherichia coli may lead to endotoxemia, which can trigger chronic inflammation associated with insulin resistance, intestinal mucosal permeability, and depression.

Omega-3 can restore the ratio of two dominant bacterial species, Bacteroidetes and Firmicutes, improve dysbiosis, increase the production of short chain fatty acids (butlates) by the family Molluscaceae, and increase the production of bifidobacteria while reducing the production of Escherichia coli to inhibit endotoxins.