Immunosuppression may be a long word, but it really is very simple: The immune system has been overburdened and compromised. This is the result of a myriad of combined effects. The chart below itemizes a few of the causes of immunosuppression:

For each of these toxins, the liver and immune system must launch a variety of macrophages, T-cells and B-cells to break them apart and escort them out of the body. This means that each toxin represents an additional load the immune system must carry.

We might compare this to moving dirt. A small handful of dirt can be carried around easily, and dispersed without much effort. However, a truckful of dirt is another matter completely. What do we do with a truckful of dirt? If we dumped it on our lawn, we’d have a hill of dirt blowing around and blocking us from getting in and out of the house.

This is a useful comparison because while our bodies can handle a small amount of toxins quite easily, modern society is increasingly dumping toxic ‘dirt’ into our atmosphere, water and foods, effectively inundating our bodies by the ‘truckload.’

The modern world’s toxin soup burdens an immune system trying to adapt and clean up each toxin and its damaging effects. Many of today’s diseases, including arthritis, cancer, heart disease, Alzheimer’s Disease and many others, are connected to immunosuppression due to the overload of toxins. Even a person’s response to viruses or even the common cold may be related to the level of immunosuppression. An immunosuppressed person will likely get much sicker and can even die from an infection that a healthy body would throw off in a few days.

What does this have to do with probiotics? Lots. Probiotics are miniature workers that help carry our immune loads. They block many toxins and pathogens from getting into our bodies in the first place. Then they break down many toxins if they do get in. They will bind to and escort toxins out of the body by latching onto them like little bulldogs. More importantly, probiotics will stimulate the immune system. Let’s look at the evidence:

Researchers from the Osaka University Graduate School of Medicine (Morimoto et al. 2005) studied 99 addicted smokers for three weeks. They were given either a fermented milk containing Lactobacillus casei or a placebo. NK cell activity among peripheral blood mononuclear cells was measured before and after taking probiotics, and before and after smoking. NK cell activity reduced with the number of cigarettes smoked. However, NK cell activity was significantly higher after taking probiotics.

Ten healthy volunteers and nine volunteers with ileostomy underwent gastroscopy or ileoscopy along with Lactobacillus reuteri ATCC 55730 supplementation for 28 days (Valeur et al. 2004). After probiotic supplementation, gastric mucosal histiocyte numbers had reduced, and duodenal B-lymphocyte numbers had increased. L. reuteri supplementation also induced a significantly higher level of CD4-positive T-lymphocytes within the ileal epithelium. The scientists concluded that L. reuteri “is associated with significant alterations of the immune response in the gastrointestinal mucosa.”

Researchers from Canada’s Memorial University of Newfoundland (Arunachalam et al. 2000) gave Bifidobacterium lactis HN019 to 25 healthy elderly volunteers for 6 weeks. Interferon-alpha levels and polymorphonuclear cell phagocytic capacity increased substantially. The probiotic group also experienced enhanced phagocyte-mediated bactericidal activity. The researchers said that, “The results demonstrate that dietary consumption of B. lactis HN019 can enhance natural immunity in healthy elderly subjects, and that a relatively short-term dietary regime is sufficient to impart measurable improvements in immunity that may offer significant health benefits to consumers.”

Researchers from the Teikyo University School of Medicine in Japan (Araki et al. 1999) gave Bifidobacterium breve YIT4064 or placebo to 19 infants for 28 days. After the treatment period, the probiotic group experienced significantly modulated levels of immunoglobulin IgA.

Scientists from The Netherlands (van Baarlen et al. 2009) gave living or heat-killed Lactobacillus plantarum to healthy adults. Biopsies were taken from the mucosa of their intestinal duodenums before and after the treatment period. These examinations indicated significantly different NF-kappaB-dependent pathways after the consumption of living L. plantarum bacteria in different growth phases. These mucosal gene expression patterns and cellular-immunity pathways correlated with increased immune tolerance among the subjects.

Pediatric medical researchers from the University of Bari (Indrio et al. 2007) gave a placebo or a combination of Bifidobacterium breve C50 and Streptococcus thermophilus 065 to 60 newborns. In addition, a control group of thirty newborns who were exclusively breastfed was included. Fecal pH of the breast-fed group and the probiotic formula group were similar—and significantly lower than the placebo group during the first few days of treatment. Meanwhile, thymus size was significantly larger in the probiotic group compared to the standard formula-placebo group. The probiotic group thymus sizes were similar to those of the breast-fed newborns.

Researchers from the Department of Immunology at Juntendo University’s School of Medicine in Tokyo (Takeda and Okumura 2007) determined in a three-week study on 19 elderly volunteers that Lactobacillus casei strain Shirota significantly increased natural killer cell activity. This effect was particularly significant among those patients who began the study with low NK-activity levels.

Researchers at Belgium’s University Hospital Leuven (De Preter et al. 2004) determined in a in a study of 19 healthy volunteers that Lactobacillus casei suppressed the production of toxic metabolites within the body.

Russian scientists (Bliakher et al. 2005) gave sickly children a Lactobacillus supplement, and assessed immune responses. They found the probiotics stimulated the immune system by modulating the activities of interferon, phagocytes, and cytokines among the children.

Researchers from the Department of Clinical Sciences at Spain’s University of Las Palmas de Gran Canaria (Ortiz-Andrellucchi et al. 2008) studied the ability of Lactobacillus casei DN114001 to modulate immunity factors among lactating mothers and their babies. L. casei or a placebo was given to expecting mothers for six weeks. T helper-1 and T helper-2 (Th1/ Th2) levels were tested from breast-fed colostrum, early milk (10 days) and mature milk (45 days). Allergic episodes among the newborns were also observed throughout their first six months of life. Among the probiotic group, T and B lymphocyte levels were increased, and natural killer cells were significantly increased. Levels of the pro-inflammatory cytokine TNF-alpha was decreased in maternal milk. Significantly fewer gastrointestinal upsets occurred among the breast-fed children of the probiotic mother group as well.

Immune system suppression has been observed in students stressed during examinations. Spanish scientists (Marcos et al. 2004) gave 136 university students either a placebo or milk fermented with Lactobacillus casei for three weeks before examinations and during the three-week examination period. The probiotic group showed a significant increase in lymphocytes during the six weeks—which decreased among the placebo group. CD56+ cells decreased in the placebo group but stayed consistent in the probiotic group. The researchers concluded that Lactobacillus casei was “able to modulate the number of lymphocytes and CD56+ cells in subjects under academic examination stress.”

Researchers from New Zealand’s Massey University (Gill et al. 2001) investigated using probiotics to enhance risk of infectious and noninfectious disease and age-related lymphocyte activity. Twenty-seven elderly volunteers consumed low-fat and low-lactose milk supplemented with Lactobacillus rhamnosus HN001 or Bifidobacterium lactis HN019 for 3 weeks. The proportion of CD56+ lymphocytes among peripheral circulation was higher after probiotic supplementation. CD4+ and CD25+ activity increased among the probiotic group. PBMC tumor killing activity also increased. Subjects more than 70 years of age and those who were immune-suppressed experienced significantly greater improvements in immune system parameters than did the other subjects.

Researchers from the College of Medicine at National Taiwan University (Chiang et al. 2000) gave Bifidobacterium lactis HN019 to 50 persons aged from 41 to 81 years old. The probiotic group had significantly enhanced PMN cell phagocytosis and NK-cell tumor killing activity. The increases leveled off after B. lactis supplementation was discontinued, but still remained above the values at the beginning of the study.

Researchers from the Russia State Medical University in Moscow (Korschunov et al. 1996) studied five men who received accidental, uneven and high-dose, whole-body gamma-irradiation from exposure to an unshielded radiation source. Feces examinations 9-12 days after irradiation showed low numbers of anaerobes and high counts of enterobacteria and staphylococci in four of the five patients. All five were treated with ampicillin and gentamicin with oral nystatin starting 4-7 days after irradiation. Three were also given an antibiotic-resistant strain of Bifidobacterium longum for 30 days starting 10-12 days following irradiation while the other two received a placebo. After three weeks after irradiation, B. longum was observed in their feces, and this continued in the following weeks. In comparison, the two placebo patients’ fecal flora was dominated by enterobacteria, including Klebsiella, Staphylococcus and Serratia spp. These showed resistance to multiple antibiotics. These pathogens were not found in the B. longum-treated group. One of the patients in the placebo group died. The other one continued to show high fecal counts of enterobacteria and staphylococci. The researchers concluded that, “Probiotic treatment with this antibiotic-resistant strain of B. longum may be of benefit in the treatment of radiation sickness, aiding normalization of the fecal flora and inhibiting colonization and overgrowth with opportunist pathogens.”

Scientists from Bulgaria’s National Oncological Centre (Krusteva et al. 1997) gave Lactobacillus bulgaricus to 78 patients who underwent combined chemotherapy and had subsequent moderate leukopenia (lack of white blood cells—a classic sign of immunosuppression). A recovery of WBC count (values above 3000) took place in all probiotic patients within three to five days. No infectious or febrile complications resulted from subsequent chemotherapy and probiotic treatment.

German scientists (Rayes et al. 2002) tested 172 patients who just had major abdominal surgery or liver transplantation with either conventional nutrition, Lactobacillus plantarum 299, or heat inactivated lactobacilli. Following treatment, bacterial infections after liver, gastric or pancreas resection was 31% in the conventional nutrition group, 13% in the heat-inactivated probiotic group and 4% in the probiotic group. Among the 95 liver transplant patients, 48% of the conventional nutrition group patients developed infections; while 34% of the inactive probiotic group and 13% of the live probiotic group developed infections (cholangitis and pneumonia were the most frequent). The use and duration of antibiotic therapy among the patients was also significantly shorter in the live probiotics group.

References and more information are available from Probiotics – Protection Against Infection: Using Nature’s Tiny Warriors to Stem Infection and Fight Disease.