Probiotics and prebiotics

• Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of longer progression-free survival among people with advanced kidney or lung cancers undergoing immune checkpoint inhibitor treatment also treated with probiotics

See How can probiotics and prebiotics help you? What the research says ›

What is your body terrain? ›

Strong, good, or modest evidence of benefit

• Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of less inflammation after surgery among people with colorectal cancer treated with probiotics or synbiotics
• Strong evidenceconsistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analyses of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results (this is the CancerChoices definition; other researchers and studies may define this differently) of one lower marker of inflammation but not other markers among people eating fermented foods
• Good evidence of lower fasting blood glucose and insulin levels and a weak trend toward lower blood sugar among people with type 1 or 2 diabetes or prediabetes treated with probiotic, prebiotic, or synbiotic supplementation
• Good evidence of lower markers of high blood sugar and insulin levels, but no evidence of an effect on peripheral and adipose tissue insulin sensitivity, among adults treated with dietary prebiotics (not specific to cancer)
• Good evidence of a better microbiome status among people with cancer treated with probiotics, including during chemotherapy and surgery
• Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of lower blood sugar and insulin resistance among adults, most of whom are diabetic or prediabetic, treated with probiotics
• Modest evidence of lower levels of ghrelin, a “hunger hormone”, among overweight or obese people treated with prebiotics or synbiotics
• Modest evidence of lower markers of inflammation among people with inflammatory conditions, including cancer, treated with probiotics

Preliminary evidence of benefit

• Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of more excess weight loss after gastric surgery for morbid obesity among people treated with a probiotic
• Preliminary evidence of lower testosterone but no evidence of an effect on luteinizing hormone or follicle stimulating hormone among women with polycystic ovarian syndrome treated with synbiotics
• Preliminary evidence of a lower marker of stress after elective orthopedic or colorectal surgery among elderly people treated with probiotics
• Preliminary evidence of lower measures of body weight among women with polycystic ovarian syndrome treated with synbiotics
• Preliminary evidence of higher immune activation after surgery among people with liver or colorectal cancer treated with a synbiotic or probiotic
• Preliminary evidence of higher immune activation among overweight or obese and insulin-resistant people treated with a probiotic
• Preliminary evidence of greater immune responses after liver removal among people with biliary cancer involving the hepatic hilus treated with synbiotics both before and after surgery compared to only after surgery
• Preliminary evidence of lower markers of inflammation during chemotherapy and radiotherapy among people with cancer treated with a synbiotic
• Preliminary evidence of lower markers of inflammation among healthy young volunteers treated with a probiotic, whether with or without prebiotics but stronger effects with prebiotics
• Preliminary evidence of less disruption to the gut microbiome among people with cancer treated with probiotics
• Preliminary evidence of higher abundance of microbial genera after surgery among people treated with probiotics
• Preliminary evidence of beneficial changes in the microbiome among healthy people treated with probiotics
• Preliminary evidence of less bacterial vaginosis among people treated with oral probiotics
• Preliminary evidence of better intestinal pH during chemotherapy among children treated with a probiotic
• Preliminary evidence of beneficial changes in the microbiomes of people treated with prebiotics
• Preliminary evidence of greater gut bacterial diversity and higher levels of the main short-chain fatty acids during chemotherapy after colorectal cancer surgical resection among people treated with probiotic tablets

No evidence of benefit

• No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on insulin levels, blood sugar, fasting plasma glucose, insulin resistance, or insulin-like growth factor-1 among postmenopausal, overweight, and obese women with hormone receptor-positive breast cancer treated with a synbiotic
• No evidence of an effect on measures of body weight among adults with metabolic syndrome treated with various strains of probiotics or synbiotics in a combined analysis of studies
• No evidence of an effect on measures of body weight or composition among overweight, obese, or prediabetic people treated with prebiotics in 2 small studies
• No evidence of an effect on leptin or pancreatic polypeptide levels among prediabetic people treated with prebiotics in a small study
• No evidence of an effect on sex hormones during a low-calorie diet among overweight and obese people with hormone-receptor positive (HR+) breast cancer treated with a synbiotic in a small trial
• No evidence of an effect on oral bacterial community composition or diversity after radiotherapy among people with head and neck cancer treated with oral probiotics in a small trial
• No evidence of an effect on trimethylamine N-oxide (TMAO)—a promoter of atherosclerosis and linked to colorectal cancer—among people with metabolic syndrome treated with Lactobacillus casei Shirota

See How can probiotics and prebiotics help you? What the research says ›

Good evidence of benefit

• Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of lower incidence of abdominal distension after surgery among people with gastrointestinal cancer treated with probiotics or synbiotics
• Good evidence of better bowel function after cancer treatment, including surgery, among people treated with probiotics
• Good evidence of lower risk and severity of treatment-induced diarrhea among people with cancer treated with probiotics, although some variations are seen across populations and treatments
• Good evidence of lower incidence and severity of oral mucositisinflammation and ulceration of the mucous membranes lining the digestive tract, usually as an adverse effect of chemotherapy and radiotherapy treatment for cancer during cancer treatment among people with cancer treated with probiotics
• Good evidence of less infection, shorter hospital stays, and other indicators of better recovery after surgery among people with gastrointestinal cancer, including colorectal cancer, treated with probiotics or synbiotics
• Good evidence of lower risk of infection after colorectal cancer surgery among people treated with probiotics
• Good evidence of higher self-reported feelings of satiety among healthy adults treated with dietary prebiotics (not specific to cancer)
• Good evidence of less depression among people with symptoms of depression treated with probiotics (not specific to cancer)
• Good evidence of shorter duration of diarrhea during antibiotic therapy among patients treated with specific probiotics (not specific to cancer)
• Good evidence of less surgical site infection, pneumonia, or sepsis, plus shorter duration of antibiotic administration and hospital stays after surgery (not specific to cancer) among people treated with synbiotic therapy

Modest evidence of benefit

• Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of less constipation among people treated with probiotics (not specific to cancer)
• Modest evidence of less perceived stress among healthy volunteers treated with probiotics (not specific to cancer)

Preliminary evidence of benefit

• Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of fewer chemotherapy-induced gastrointestinal complications during chemotherapy after colorectal cancer surgical resection among people treated with probiotic tablets
• Preliminary evidence of less functional constipation during chemotherapy among people with cancer treated with a probiotic
• Preliminary evidence of frequency of diarrhea during pelvic radiation among people treated with a prebiotic
• Preliminary evidence of lower frequency and intensity of vomiting but no evidence of an effect on nausea during chemotherapy and radiotherapy among people with cervical cancer treated with a synbiotic
• Preliminary evidence of lower depression scores after completing cancer treatment among people with colorectal cancer treated with probiotics
• Preliminary evidence of lower fatigue scores after completing cancer treatment among people with colorectal cancer treated with probiotics
• Preliminary evidence of less oral infection after completing head and neck radiotherapy among people with cancer treated with probiotic sachets
• Preliminary evidence of better quality of life scores among people with colorectal cancer treated with probiotics
• Preliminary evidence of less stress (no elevation in markers of stress) among people with laryngeal cancer awaiting laryngectomy treated with probiotics
• Preliminary evidence of fewer infectious complications after liver removal among people with biliary cancer treated with synbiotics both before and after surgery compared to only after surgery
• Preliminary evidence of fewer infectious complications after Whipple procedure (pancreaticoduodenectomy) among people treated with probiotics
• Preliminary evidence of less cognitive impairment after elective orthopedic or colorectal surgery among elderly people treated with probiotics (not specific to cancer)
• Preliminary evidence of fewer stress-induced gastrointestinal symptoms among people with symptoms of stress treated with a probiotic (not specific to cancer)
• Preliminary evidence of improved frequency of defecation among healthy adults treated with a probiotic
• Preliminary evidence of lower markers of enzymes indicating liver dysfunction among overweight or obese and insulin-resistant people treated with a probiotic (not specific to cancer)
• Preliminary evidence of maintained quality of life scores among home-living adults receiving tube feedings enriched with prebiotics (not specific to cancer)
• Preliminary evidence of a lower marker of stress 5 to 7 days after elective orthopedic or colorectal surgery among elderly people treated with probiotics (not specific to cancer)
• Preliminary evidence of lower incidence of multiorgan failure, septic complications, and mortality among people with severe acute pancreatitis treated with synbiotics (not specific to cancer)

No evidence of benefit

• No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on periodontal screening and plaque index scores after radiotherapy among people with head and neck cancer treated with oral probiotic lozenges in a small trial
• No evidence of an effect on gastrointestinal function after elective orthopedic or colorectal surgery (not specific to cancer) among elderly people treated with probiotics in a small trial
• No evidence of an effect on pain intensity after elective orthopedic or colorectal surgery among elderly people treated with probiotics in a small trial (not specific to cancer)
• No evidence of an effect on sleep quality among people treated with probiotics in small trials (not specific to cancer)
• No evidence of an effect on stress among people with symptoms of stress treated with probiotics in a combined analysis of studies (not specific to cancer)

See How can probiotics and prebiotics help you? What the research says ›

• Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of bladder, colorectal, or esophageal cancer among people eating fermented dairy foods as a whole
• Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of recurrence among people with superficial transitional cell carcinoma of the bladder treated with an oral probiotic
• Preliminary evidence of lower risk of breast cancer among women drinking beverages containing Lactobacillus casei Shirota 4 or more times a week
• Preliminary evidence of better epithelial barrier function and a weak trend toward lower colorectal proliferation after colorectal polypectomy among people treated with a synbiotic
• Preliminary evidence of lower atypia grade of tumors and fewer tumors or aberrant crypt foci among people with prior colorectal tumor removal treated with a probiotic dairy product
• No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on the number or size of recurring tumors among people with prior colorectal tumor removal, resected colon, or more than 5 aberrant crypt foci treated with a probiotic or prebiotic in small trials

See How can probiotics and prebiotics help you? What the research says ›

• A clinical practice guideline found that evidence supports the use of probiotics for prevention of chemoradiotherapy and radiotherapy-induced diarrhea in patients with pelvic cancer
• Widely used by integrative practitioners

See How do experts use probiotics and prebiotics? ›

• Probiotics are regarded as safe to use for bowel symptoms, with few adverse effects.
• Case reports indicate occasional problems among immunocompromised people.

See Safety and precautions ›

• Probiotics and prebiotics are widely available in foods and as supplements without a prescription.
• Probiotics and prebiotics are generally inexpensive (under $500/year)

See Affordability and access ›