Sunday, April 17, 2022

How prebiotic polysaccharides strengthen mucosal immunity


It is known that strenuous exercise and sport reduces innate mucosal immunity, which is the first line of defense against catching viruses and bacteria that play a role in most respiratory diseases.

A small but interesting study of 41 male marathon runners who completed the 42,195 km Barcelona Marathon in 2016 showed that those who did not receive the test supplement (made of polysaccharides from arabinogalactants, aloe vera, gums and algae) had significantly lower salivary sIgA after the race. Lower levels of sIgA indicate decreased mucosal immunity, which is the first and most important defense mechanism to stop pathogens, such as viruses, to enter our body through the mucous membranes of the airways.

Polysaccharides are known to play a role in immune activation and inflammatory processes. Many are better known as prebiotics. Currently, there are three major types of prebiotics that are well documented: inulin, oligosaccharides and arabinogalactans. Other well known polysaccharides are beta-glucans from mushrooms, seaweeds or oats. 

Food for friendly bacteria

These types of polysaccharides are not digested by human enzymes of digestive tract but they have an important role to play as a food source for our microbiota. 

Many studies suggest that the combination of different types of these indigestible polysaccharides provides nutritional benefits by prolonging microbial fermentation in the intestines. This is known to increase uptake of micronutrients such as vitamins and minerals. The presence of prebiotic polysaccharides keeps the intestinal mucous layer healthy, which promotes the process of absorption of nutrients. If the mucous layer becomes unhealthy and inflamed, the absorption of nutrients is compromised (such as happens in coeliac disease).

Training immune cells

It is easy to understand why prebiotic polysaccharides are useful for the intestinal mucosa. However, it is somehow more difficult to imagine their mechanism of action on other mucous membranes, such as in the respiratory tract. Here comes the second action of polysaccharides. When parts of their molecules cross the intestinal wall, they get scrutinised by the immune cells in the same way as any large and undigested structures would be. Immunity becomes vigilant, but not over-reactive. It becomes activated sufficiently to function properly and ready for a real threat.

The runners took the supplement at dose of 8 g/day for 15 days before the marathon. The supplement was made of arabinolactans, Aloe Vera, rice starch, ghatti gum, gum Tragacanth, Glucosamine HCl and Wakame algae extract. These 15 days were probably enough to ensure more optimal and less-inflammatory state in the intestinal mucosa, which would help better nutrients absorption. However, it is believed that the main effect is happening on the other side of the intestinal layer, called lamina propria, where most of the body's immune cells are trained and developed. This training of immunity would cause a systemic effect (that is, in the rest of the body), thereby promoting a healthier condition of all mucous layers, not only the intestinal ones.

Arabinogalactans are class of long, densely branched polysaccharides belonging to hemicelluloses. In most plants, arabinogalactans occur bonded to protein, either as proteoglycans or as glycoproteins. Many edible and inedible plants are rich sources of arabinogalactans including leeks, radishes, carrots, tomatoes, coconut etc. However the structure in the Western larch tree is slightly different and water-soluble, which makes it more suitable to make concentrated prebiotic supplement.

Aloe Vera, gums and algae extracts (containing fucose, fucoidan, mannose, mannitol...) in the tested supplement would enhance the fermentation in the intestines and therefore help to create stronger and faster immune effect. 

Are supplemental prebiotics polysaccharides suitable for me? 

How much fruit and vegetables do I need to consume to have the same effect? 

What about SIBO??

Find out!