How Probiotics Help Support Your Immune System

Probiotics are microorganisms, including bacteria and yeast, that promote good health. Probiotic literally means ‘for life’. With as many as 10,000 different microorganisms making up our human ecosystem, though, how can we tell which ones are friends and which are foes? Thankfully, researchers have been hard at work for decades, and some of these scientists have looked specifically at how probiotics help support your immune system.

Probiotics and immune function

The International Scientific Association for Probiotics and Prebiotics note that microorganisms can have widespread effects on health that are specific to the genus and species of probiotic. These effects can include those that help reduce your risk of infection, such as:

• Supporting resistance to colonisation by pathogens (disease-causing microbes)
• The normalisation of a disturbed microbiome (dysbiosis)
• Regulation of digestive transit (reducing the risk of putrefaction)
• Increased turnover of enterocytes (cells in the digestive tract that form an important part of the immune system)
• Direct competition with pathogens.

The immune system also relies on good communication between the gut and the brain, which happens via the vagus nerve and spinal nerves as well as through hormones in the blood. In a way, the immune system integrates the microbiome, gut, and brain, playing a key role in keeping the body coordinated and healthy. The microbiome also helps to promote immune cell maturation, synthesises vitamins, and produces short-chain fatty acids that support gut health and have anti-inflammatory and immunoregulatory effects. Some research even suggests that probiotics may help support a positive response to flu vaccines.[i]

Which probiotics are the most helpful for immune function?

Probiotics, in general, can help maintain a healthy microbiome, which itself reduces the likelihood of a pathogen getting out of control in the gut or elsewhere in the body. Beneficial bacteria can both outcompete pathogenic microbes for food and nutrients and can create undesirable conditions for pathogens to grow and thrive. Several species of Lactobacillus and Bifidobacterium have been shown to support innate immunity by increasing the ability of natural killer cells and macrophages (two types of immune system cells) to kill pathogens. These species can also support adaptive immunity, which is the part of the immune system where certain cells remember encountering pathogens before and can be quick to mount a counterattack if invaded again.[ii]   In one randomized, double-blind, placebo-controlled trial, 28 critically ill adults were given high potency probiotics for a week and were seen to have enhanced immune system function and reduced intestinal permeability.[iii] While maintaining a healthy microbiome supports immune health in general, there are a few specific probiotics that seem especially beneficial for immune response. These include:

• Lactobacillus acidophilus 
• Bifidobacterium bifidum 
• Lactobacillus bulgaricus
• Lactobacillus brevis
• Saccharomyces thermophilus.

Several of these can help reduce oxidative stress, for example, which helps keep the immune system healthy and responsive.[iv] Naturally, the potency of any given probiotic supplement makes all the difference when it comes to the realisation of these potential health benefits. If there are few, or no, active cultures in a supplement by the time you take it, you’re throwing your money away and doing nothing to support immune health. Happily, the potency and number of colony forming units (CFUs) in all Natren probiotics is guaranteed through third party verification, so you know that what is on the label is what you're getting. Natren Healthy Trinity is a three-in-one probiotic supplement providing meaningful amounts of:

• Lactobacillus acidophilus, NAS super strain, 5 billion cfu
• Bifidobacterium bifidum, Malyoth super strain, 20 billion cfu
• Lactobacillus bulgaricus, LB-51 super strain, 5 billion cfu.

These are some of the most thoroughly researched probiotics around, all of which can help you support your immune system.   [i] Lei, W. T., Shih, P. C., Liu, S. J., et al. (2017). Effect of Probiotics and Prebiotics on Immune Response to Influenza Vaccination in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients, 9(11), 1175. [ii] Azad, M., Sarker, M., & Wan, D. (2018). Immunomodulatory Effects of Probiotics on Cytokine Profiles. BioMed research international, 2018, 8063647. [iii] Alberda C, Gramlich L, Meddings J, et al. (2007). Effects of probiotic therapy in critically ill patients: a randomized, double-blind, placebo-controlled trial. Am J Clin Nutr, Mar;85(3), 816-23. [iv] Asemi Z, Zare Z, Shakeri H., et al. (2013). Effect of multispecies probiotic supplements on metabolic profiles, hs-CRP, and oxidative stress in patients with type 2 diabetes. Ann Nutr Metab, 63(1-2), 1-9.