The Immune Link – LGG and Your Defenses
Your immune system and your gut are deeply connected, around 70% of your body’s immune cells live in or around the intestinal wall. That means a calm, balanced gut and digestive environment can play a key role in supporting overall immune stability. We all know the importance of having a strong immune system as it’s our body’s primary defence against any invading force, whether it’s viral, bacterial, or something else.
Sometimes the immune system can overreact though, causing it to attack things that aren’t really a threat, or in some extreme cases, to attack the body itself! Taking all of this into account, having a healthy and well functioning immune system is important to say the least.
Lactobacillus rhamnosus GG (LGG) has been one of the most intensively studied bacterial strains in this area, with numerous studies conducted to find out if LGG can interact with, and even help, the immune system. With landmark studies involving large groups of people and powerful findings, this is a very promising area of research into this remarkable bacterium, and since the bulk of these studies are randomised control trials, we know that the results were based on a fair test for science we can trust.
So what did these studies unearth?
Over the past three decades, scientists have explored how LGG interacts with the gut lining and the immune system in both children and adults, and the findings have been consistently encouraging. We’ve split this section up into a few areas since the immune system is a complicated mechanism, so there’s a lot to be studied here! Here are just a few of the studies undertaken and the interesting results they found.
Fewer infections and fewer missed days
In a landmark study involving 571 children attending day-care centres, those who drank milk containing LGG every day for seven months had 15% fewer sick days than children who received ordinary milk. They also needed fewer antibiotics overall, 44% in the LGG group compared to 54% in the placebo group.
Another large trial of 742 children turned up similar results: the trial found that giving LGG to hospitalised children reduced their chance of picking up hospital-acquired GI (gastro-intestinal) and respiratory infections, and when infections did occur, they were less frequent and less prolonged.
In both studies, children taking LGG were not only ill less often, but when they did get sick, their symptoms were milder and their recoveries faster, so we can see that in these two studies, LGG appeared to help the immune system work more effectively, but how? Read on.
Immune balance, not overstimulation
In adults, researchers have focused on how LGG might help keep the immune system in balance, not by pushing it harder, but by helping it respond more calmly and efficiently. They did this by measuring different immune markers and how they responded to LGG supplementation.
In one controlled trial, adults taking LGG for just three weeks had significantly higher activity in their natural killer (NK) cells; the immune cells that patrol and respond to early threats; compared with those taking a placebo.
Another RCT found that LGG increased levels of interleukin-10 (IL-10), a molecule that helps regulate inflammation and maintain tolerance to everyday triggers.
These studies consistently found that LGG helped to boost immune markers in those taking it. Coupled with the studies that found a reduction in sick days and faster recovery, this makes a strong case for LGG’s effects on the immune system! So how does this magnificent microbe meet our immune system? Let’s find out.
The Wall of the Gut
The interaction between LGG and the immune system seems to start right where they meet: in the gut lining.
In one double-blind study, healthy adults taking LGG showed a measurable increase in IgA (Immunoglobulin A), a natural antibody found in the mucous membranes that line the intestines, nose, and mouth. IgA acts like a first line of defence, it has an ability to bind itself to viruses, bacteria and toxins, preventing them from passing through the gut barrier and causing trouble. For this reason it is often associated with a healthy gut barrier, and has also shown an ability to keep the immune system calm around non-harmful particles such as food proteins, helping to prevent any overreactions.
This subtle but powerful response suggests that LGG can help reinforce the gut’s natural barrier by boosting the levels of one of its most important agents.
So how can it benefit me?
We all want a strong immune system, because none of us want to get ill, it’s that simple. The studies taken together paint a very promising picture. Studies showed that LGG helped to reduce the rate of illness in children, leading to fewer antibiotics and fewer sick days. It did this by keeping the immune system balanced. It’s demonstrated an ability in studies to boost the levels of IL-10, a molecule known to suppress a variety of inflammatory cytokines, such as IL-6 and TNF Alpha, helping to keep the immune system on track.
Not only this, but it’s shown an ability to boost the levels of one of the immune system’s most important agents, IgA, helping to up the body’s defences and maintain a strong gut barrier. IgA is also found in the nose and throat, so it would be interesting to see if LGG has boosted levels here too! It might explain how one study found a drop in respiratory infections in children taking LGG.
The cherry on the cake is that these studies are randomised control trials, gold standard science that you can trust was impartial and fair. So if you’re looking for something to help keep your immunity on track, LGG could be an option well worth considering!
References (the science) – Don’t just take our word for it:
6. Kumpu, M., Kekkonen, R.A., Korpela, R., et al. (2012) Effect of Lactobacillus rhamnosus GG on respiratory tract infections in children: a randomized trial. European Journal of Clinical Nutrition, 66(9), 1021–1026. https://pubmed.ncbi.nlm.nih.gov/22824830
7. Hatakka, K., Savilahti, E., Pönkä, A., Meurman, J.H., Poussa, T., Näse, L., Saxelin, M. and Korpela, R. (2001) ‘Effect of long term consumption of probiotic milk on infections in children attending day care centres: double blind, randomised trial’, BMJ, 322(7298), p. 1327. Available at: https://pubmed.ncbi.nlm.nih.gov/11387176/
- Hojsak, I., Abdović, S., Szajewska, H., et al. (2010) Lactobacillus GG in the prevention of nosocomial gastrointestinal and respiratory tract infections. Clinical Nutrition, 29(4), 483–488. https://pubmed.ncbi.nlm.nih.gov/20074854
- Kumpu, M., Kekkonen, R.A., Järvenpää, S., et al. (2013) Lactobacillus rhamnosus GG modulates immune responses in healthy adults: a randomized, placebo-controlled trial.* British Journal of Nutrition, 110(5), 858–866. https://pubmed.ncbi.nlm.nih.gov/23388074
10. Segers ME, Lebeer S. Towards a better understanding of Lactobacillus rhamnosus GG--host interactions. Microb Cell Fact. 2014 Aug 29;13 Suppl 1(Suppl 1):S7. doi: 10.1186/1475-2859-13-S1-S7. Epub 2014 Aug 29. PMID: 25186587; PMCID: PMC4155824. https://pmc.ncbi.nlm.nih.gov/articles/PMC4155824/
