A higher level of diversity in gut bacteria may be associated with improved general mental and physical health. You may notice a few symptoms if you have reduced gut health. Here are seven of the most common signs:.

A balanced gut will have less difficulty processing food and eliminating waste, likely leading to fewer symptoms. Research suggests that eating too much sugar may lead to increased inflammation throughout the body.

Inflammation can be the precursor to several diseases, including cancer. Gaining or losing weight without changing your diet or exercise habits may be a sign of an unhealthy gut.

Weight loss may be caused by malabsorption because of small intestinal bacterial overgrowth SIBO. On the other hand, weight gain may be caused by insulin resistance or increased inflammation. Research indicates that an imbalance in gut bacteria may be linked to fragmented sleep and short sleep duration, which may lead to chronic fatigue.

While the cause remains unclear , it appears to be connected to inflammation, metabolic function, and mental health. Skin conditions like psoriasis may be related to the types of bacteria present in the gut. Many studies have found connections between the gut and the immune system. An unhealthy gut may increase systemic inflammation and alter the proper functioning of the immune system.

This may lead to autoimmune diseases , where the body attacks itself mistaking its cells and organs for harmful invaders. Food intolerances are the result of difficulty digesting certain foods.

This is different than a food allergy , which is caused by an immune system reaction to certain foods. Research indicates that food intolerances, like lactose intolerance, may be caused by poor quality of bacteria in the gut.

This can lead to trouble digesting the trigger foods and symptoms like:. There is also some research indicating that food allergies may be related to gut health. You may be able to improve and reset your gut health through lifestyle and diet changes.

Consider trying one or more of the following to improve your gut health naturally:. Chronic high levels of stress are hard on your whole body, including your gut. This is because your body releases certain hormones when it experiences stress. High levels of these hormones affect your body and may compromise gut health.

A few ways to lower stress may include:. Not getting enough or sufficient quality of sleep may have serious impacts on your gut health, which can in turn contribute to more sleep issues. Try to prioritize getting at least 7—8 hours of uninterrupted sleep per night.

Your doctor may be able to help if you have trouble sleeping. Chewing your food thoroughly and eating your meals more slowly may lower your chances of developing obesity and diabetes while also helping you make better food choices. Drinking plenty of water may be linked to increased diversity of bacteria in the gut, though the source of the water also matters.

One study also found that people who drank more water had less of a type of bacteria that can cause gastrointestinal infections. Staying hydrated benefits your health overall and can help prevent constipation.

It may also be a simple way to promote a healthy gut. While research is ongoing, adding a prebiotic or probiotic supplement to your diet may help improve your gut health. People who have a severe illness or a weakened immune system should not take probiotics.

Also, not all probiotic supplements are high quality or beneficial for your health. You can try eliminating common trigger foods to see if your symptoms improve. Reducing the amount of processed, sugary, and high fat foods that you eat may lead to better gut health. Eating a diet high in fiber likely contributes to a healthy gut microbiome as well.

You may also positively impact your gut by eating foods high in micronutrients called polyphenols present in:. Diet and gut health appear to be very closely linked. Avoiding processed foods, high fat foods, and foods high in refined sugars is likely important for maintaining a healthy microbiome, as these foods may promote the growth of damaging bacteria.

Chewing food thoroughly breaks it down so that it can be digested more easily. The act also produces saliva, which is needed for proper mixing of food in your stomach. Regular exercise is one of the best ways to improve your digestion. Exercise and gravity help food travel through your digestive system.

Therefore, taking a walk after a meal may assist your body in moving things along. Research suggests that short periods of low to moderate exercise may speed up your digestion, while longer and more intense exercise may slow things down In one review, gentle exercises such as Qigong, walking and physical movement significantly improved constipation symptoms Additionally, studies suggest that exercise may reduce symptoms of inflammatory bowel diseases due to anti-inflammatory effects, such as decreasing inflammatory compounds in your body 35 , Exercise may improve your digestion and reduce symptoms of constipation.

It can also help reduce inflammation, which may be beneficial in preventing inflammatory bowel conditions. Additionally, eating at a moderate-to-fast pace is associated with higher levels of indigestion, which can cause symptoms such as pain, bloating, nausea, and gas Not paying attention to your hunger and fullness cues can negatively impact digestion.

Certain habits such as smoking, alcohol consumption, and eating late at night are associated with negative effects for your overall health. Smoking is a risk factor for the development of gastroesophageal reflux disease, or GERD Furthermore, studies have shown that quitting smoking improves acid reflux symptoms Smoking has also been associated with stomach ulcers, increased surgeries in people with ulcerative colitis and gastrointestinal cancers 41 , Alcohol can increase acid production in your stomach and may lead to heartburn, acid reflux and stomach ulcers.

Excessive alcohol consumption has been linked to bleeding in the gastrointestinal tract Alcohol has also been associated with inflammatory bowel diseases, increased gut permeability, and harmful changes in gut bacteria Eating late at night and then lying down to sleep can lead to heartburn and indigestion.

Your body needs time to digest, and gravity helps keep the food you eat moving in the right direction. Additionally, when you lie down, the contents of your stomach may rise up and cause heartburn. Lying down after eating is strongly associated with an increase in reflux symptoms If you experience digestive issues at bedtime, try waiting three to four hours after eating before going to bed, to give the food time to move from your stomach to your small intestine.

Habits such as smoking, drinking alcohol, and eating late at night can contribute to digestive issues. To improve digestion, consider changing these lifestyle factors.

These healthy bacteria assist in digestion by breaking down indigestible fibers that can otherwise cause gas and bloating. Studies have shown that probiotics may improve symptoms of bloating, gas and pain in people with IBS Probiotics are found in fermented foods such as sauerkraut, kimchi and miso, as well as yogurts that have live and active cultures.

While research is ongoing, studies suggest that certain types of probiotic supplements may improve IBS symptoms. For example, one meta-analysis found that three types of beneficial bacteria found in supplements — Bifidobacterium breve, Bifidobacterium longum, and Lactobacillus acidophilus — were associated with reduced IBS pain Glutamine is an amino acid that supports gut health.

Some studies suggest that glutamine supplementation may reduce intestinal permeability and inflammation, though more research is needed You can increase your glutamine levels by eating foods such as beef, eggs and tofu Zinc is a mineral that is critical for a healthy gut, and a deficiency can lead to various gastrointestinal disorders Supplementing with zinc has been shown to be beneficial in treating diarrhea, colitis, increased gut permeability, and other digestive issues Foods high in zinc include meat, fish, seafood, fortified cereals, and pumpkin seeds Certain nutrients are necessary for a healthy digestive tract.

Ensuring that your body gets enough probiotics, glutamine and zinc may improve your digestion. Simple diet and lifestyle changes may help improve your digestion if you experience occasional, frequent or long-term digestive symptoms. Eating a whole-foods diet high in fiber, healthy fat and nutrients is the first step toward good digestion.

Finally, changing habits that may affect your digestion — such as smoking, drinking alcohol, and late-night eating — may help relieve symptoms as well.

Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.

VIEW ALL HISTORY. Laxatives can help relieve constipation and promote regular bowel movements. Learn more about natural laxatives.

Fermented foods and drinks contain beneficial probiotics that can help improve digestion, immunity, and even weight loss.

Here are 8 tasty, nutritious…. Gaining optimal health is not supposed to be complicated. Follow these 5 simple rules if you want to be healthy, lose weight and feel awesome every…. Mindful eating is a powerful tool to support managing your eating habits. It can help with weight loss, reducing binge eating, and making you feel….

Eating more slowly can help you feel full and lose weight, while enjoying your meals more. muciniphila , Faecalibacterium play an immune adjuvant role in the immunotherapy of PD There may be more bacteria that play important roles in promoting or inhibiting the efficacy of checkpoint inhibitors, but these hypotheses need to be further examined.

Overall, we can conclude that a healthy and diverse microbiota and the presence of some bacterial species contribute to the antitumor immune response. The efficacy of ICB was reduced when patients received antibiotic treatment before or soon after immune therapy.

This finding provides new insight and ideas for the use of antibiotics in clinical treatment. In addition, it is obvious that not only single species but also the ecology and metabolism of the gut microbiota affect the response to immune therapy.

It is possible that a new therapy targeting the microbiota could be developed to improve cancer treatment. Figure 1. Intestinal microbiota influence the therapeutic effect of drugs on tumors by regulating the immune system. The gut microbiota enhance anti-PD-L1 efficacy by reactivating dendritic cells.

Also the gut microbiota can trigger dendritic cell maturation and modulate IL—dependent TH 1 responses to restore the therapeutic response to anti-CTLA4. The microbiota are associated with side effects of immunotherapy Supplementary Table S1. When germ-free mice receiving anti-CTLA-4 mAb were monopolized with B.

fragilis , plasmacytoid DCs accumulated and matured in mesenteric lymph nodes. The gut microbiota help CpG-ODNs to promote myeloid cells to secrete proinflammatory cytokines such as TNF and IL TNF and IL induce macrophage and dendritic cell infiltration to promote a proinflammatory state Supplementary Table S1.

The body develops an antigen-specific adaptive T cell antitumor immunity to clear tumors in this proinflammatory microenvironment. Some of the intestinal microbiota affect the antitumor efficacy of CP. And, the gram-negative Barnesiella intestinihominis was found to improve interferon-c—producing T cell infiltration in cancer lesions to enhance the antitumor effects of CP Supplementary Table S1.

In terms of CTLA4, Vétizou et al. Germ-free mice had a minor response to anti-CTLA-4 immunotherapy, but oral feeding of either Bacteroides thetaiotaomicron or Bacteroides fragilis to germ-free mice restored the therapeutic response to anti-CTLA4.

Studies revealed that B. thetaiotaomicron and B. fragilis can trigger dendritic cell maturation and modulate IL—dependent TH 1 responses in the tumor-draining lymph nodes Cramer and Bresalier, While the monoclonal antibody against CTLA-4 is effective, ipilimumab can cause subclinical colitis.

Many factors contribute to such side effects, such as host homeostasis, immune response, and microbiota. The abundance of Bacteroidetes in new-onset, immune-mediated colitis patients who were administered anti-CTLA-4 therapy was significantly lower than in colitis-free individuals receiving ipilimumab Dubin et al.

The oral feeding of B. fragilis and B. cepacian to mice can restore the response to anti-CTLA4 and significantly decrease the extent of immune-mediated colitis.

However, a single administration of either B. fragilis or B. thetaiotaomicron failed to produce the same effect. Moreover, Dubin et al. This may be a possible mechanism for the protective role of B. fragilis against ipilimumab-associated colitis.

Individual antibiotics play an important role in the immunotherapy of tumors and even affect the curative effects of immune agents by changing the composition of the gut microbiota.

For example, when mice were administered vancomycin, the efficacy of CTLA-4 blockade was enhanced because vancomycin preserved the gram-negative Burkholderiales and Bacteroidales and decreased gram-positive bacteria in the gut Vétizou et al. Pitt et al. Ipilimumab could alter the composition of microbiota at the genus level in both patients and mice and the dominance of distinct Bacteroides spp.

fragilis , was necessary for successful treatment of cancer Pitt et al. The feces from patients who had received ipilimumab treatment led to the recovery of anti-CTLA-4 therapeutic efficacy in germ-free mice.

The researchers found that B. fragilis did not induce the side effects of ipilimumab Pitt et al. As a result of these observations, we can conclude that B.

fragilis may be used to modulate the efficacy of anti-CTLA-4 therapy. Synthetic CpG oligonucleotides CpG-ON are ligands for TLR9 on immune cells, which enhance the immune response to cancer cells and induce an antitumor effect.

When patients were administered IL receptor antibodies to prevent the immunosuppressive effects of tumor-infiltrating Treg cells, the effect of CpG-ON was potentiated Guiducci et al.

CpG-ONs promote myeloid cells to secrete proinflammatory cytokines such as TNF and IL TNF and IL induce macrophage and dendritic cell infiltration to promote a proinflammatory state and cause rapid hemorrhagic necrosis. The body develops an antigen-specific adaptive T cell antitumor immunity to clear tumors in this proinflammatory microenvironment Guiducci et al.

In microbiota-depleted mice, CpG-ODNs and anti-ILR therapy for subcutaneous tumors are largely inefficient, and tumor-infiltrating myeloid cells cannot produce proinflammatory cytokines. Microbiota-depleted mice also have no efficient antitumor adaptive immunity and experience strong TNF-dependent hemorrhagic necrosis.

However, the expression of genes encoding inflammatory factors and markers such as TNF and IL was a major difference between conventionally raised mice and microbiota-depleted mice when CpG-ODNs were administered in tumor-infiltrating myeloid cell subsets.

The frequencies of the gram-positive Ruminococcus and the gram-negative Alistipes genera favor TNF production. The frequencies of Lactobacillus sp. After mice were exposed to antibiotics, the recolonization of Alistipes shahii induced myeloid cells to produce TNF again in microbiota-depleted mice, but L.

fermentum transplantation often impaired the TNF production of conventionally raised mice Iida et al. Thus, probiotics could help modulate the response to immunotherapies by changing the frequencies of individual species.

According to previous studies, the efficacy of various conventional chemotherapeutics can be influenced by some specific microbiota. Currently, the goals of the pharmaceutical and biotechnology industries are to improve the efficiency, and reduce the toxicity, of chemotherapy and immunotherapy in clinical practice.

In the near future, microbial drug targets have the potential to ease the adverse effects of chemotherapy drugs on the GI tract. The tumor-retardation effects of oxaliplatin platinum chemotherapeutic depend on microbiota.

Oxaliplatin efficacy was attenuated due to reduced intratumoral ROS generation in germ-free mice Iida et al.

Moreover, when people were treated with antibiotics, the recruitment of immune cells that are important for mediating tumor regression was decreased, and their proinflammatory potential also decreased.

This finding suggests that the microbiota mediated immunomodulatory effects in response to chemotherapeutic compounds. Cyclophosphamide CP is an alkylating agent commonly used for chemotherapy.

CP induces commensals to translocate into secondary lymphoid organs due to the disruption of the intestinal barrier and the decrease of small intestinal villus height.

Viaud et al. The antibiotics selectively working on gram-positive bacteria significantly reduced CP efficacy compared with antibiotics targeting gram-negative bacteria.

Thus, specific gram-positive bacteria E. hirae , Lactobacillus johnsonii , L. murinus , and segmented filamentous bacteria were identified as essential to regulate the antitumor efficacy of CP in a non-metastasizing sarcoma mouse model.

At the same time, the gram-negative Barnesiella intestinihominis was found to improve interferon-c—producing T cell infiltration in cancer lesions to enhance the antitumor effects of CP Daillère et al. Interestingly, when patients with advanced ovarian and lung cancer have a specific TH 1 cell memory response to B.

intestinihominis and E. hirae , they are predicted to have longer progression-free survival. Importantly, more studies should be conducted to find an optimized microbiota cocktail including Enterococcus and Barnesiella coadministered with CP and other alkylating agents.

Some side effects resulting from chemotherapeutic compounds are so serious that patients cannot receive a sufficient dose of compounds or a sufficient duration of treatment. Irinotecan topoisomerase I inhibitor hinders DNA replication, particularly in rapidly dividing cells, and is administered to treat pancreatic cancer and CRC.

The metabolic process of irinotecan in vivo is as follows: 1 irinotecan is metabolized from a prodrug into the active working chemotherapeutic agent SN38; 2 the liver glucuronidates SN38 into the inactive form SNG and excretes it into the GI tract.

In the human gut, microbiota can reactivate SN38 by secreting b-glucuronidase enzymes that hydrolyze the glucuronic acid moiety in the GI lumen.

Increased SN38 levels cause serious diarrhea, and patients often need to de-escalate and frequently adjust doses. Clostridium species decrease from the initial time of irinotecan therapy to recovery on day 7, but the abundance of Bifidobacterium and Lactobacillus species is persistently reduced Lin et al.

Interestingly, germ-free mice can receive more doses of irinotecan and exhibit less GI damage than conventional mice with intact microbiota Brandi et al.

Small-molecule inhibitors, which are innocuous to either human cells or bacteria, inhibit bacterial b-glucuronidases and do not cross-react with human b-glucuronidases Wallace et al. Preclinical studies revealed that mice concurrently administered irinotecan and b-glucuronidase inhibitors were free from irinotecan-induced diarrhea Wallace et al.

These findings indicate that the side effects of multiple chemotherapeutics may diminish with gut microbiota. The relationship between intestinal dysbiosis and specific chemotherapeutic agents has been explored in animal models, and 5-fluorouracil 5-FU is one of the best studied agents in colorectal cancer therapies.

Studies have shown that mice receiving 5-FU chemotherapy exhibit dysbiosis. Specifically, the abundance of Staphylococcus and Clostridium species increased and that of Bacteroides and Lactobacillus decreased after administration with 5-FU Stringer et al.

Multiple animal studies showed that the abundance of Enterobacteriaceae facultative gram-negative bacteria increased after either irinotecan or 5-FU therapy Stringer et al. However, these studies relied on targeted PCR or culture methods and cannot evaluate the influence of chemotherapy on the extensive gut microbiota.

It is still a challenge to manipulate probiotics to treat intestinal dysbiosis in 5-FU therapy. Severe side effects induced by doxorubicin, such as intestinal mucositis and cardiomyopathy, are related to significant changes in the microbiota of the oral cavity and the intestinal tract Napeñas et al.

Studies have revealed that bacterial muramyl dipeptide prevented doxorubicin-induced mucosal damage by stimulating NOD2 Nigro et al. Clinical practice shows that adipose tissue and fat metabolism are influenced in many tumor patients, resulting in cachexia Das et al.

Pancreatic beta-cell mass, uptake of lipids, and adipose tissue inflammation are regulated by the gut microbiota. Cancer therapy can exacerbate the serious effects of cancer-induced cachexia Antoun et al.

We do not completely understand the cachexia mechanism underlying these conditions, but this observation raises the possibility that the close relationship between energy metabolism and gut microbiota could be a therapeutic target, as the microbiota composition could affect the pathogenesis of this condition Bindels and Delzenne, ; Klein et al.

Probiotics can improve body weight in mice and patients with cancer-associated cachexia Yeh et al. Recent studies in mice have found that colonization by the E.

Modulation between gut microbiota and homeostasis could be an effective clinical means to treat cancer-associated diseases, such as cachexia and anorexia, and adverse cancer treatment effects.

Additional mechanism studies and rigorous clinical trials are necessary. Ionizing radiation therapy RTX is an effective way to treat tumors based on its genotoxic effect on tumor cells.

Immunogenic tumor cell death can be induced by local irradiation, and systemic immunity and inflammation are also promoted Demaria and Formenti, ; Kroemer et al. Unfortunately, ionizing radiation also induces some side effects, including genomic instability, bystander effects on nearby cells, and systemic radio-associated immune and inflammatory reactivity Azzam and Little, Although there has been considerable progress in the development of ionizing radiation therapy, the main limitations are the safety and effectiveness of RTX and heterogeneity in the therapeutic sensitivity of diverse cancer types and kinds of side effects with RTX Deng et al.

Healthy tissues are also damaged by RTX, which is more obvious in actively proliferating tissues Barker et al. RTX alters the microbiota composition, breaks the intestinal barrier, and causes apoptosis in intestinal crypts Barker et al. The pathogenesis of oral mucositis, enteritis, colitis, diarrhea, and bone marrow failure in patients and mice receiving RTX is associated with alterations in the epithelial surface microbiota composition Touchefeu et al.

The serious oral mucositis and enteropathy induced by RTX may limit therapy completion. Some studies have shown that irradiation-mediated intestinal toxicity is regulated by TLR3 in dsRNA. TLR3 mice receiving ionizing radiation survived longer and suffered less severe intestinal toxicity compared with wild type mice, suggesting that suppression of TLR3 signaling may decrease the gastrointestinal damage induced by radiation Adams, ; Takemura et al.

In contrast, TLR2-activating microorganisms in mice, such as the probiotic Lactobacillus rhamnosus GG Ciorba et al. In some clinical studies, probiotics have been shown to help prevent radiation-related enteropathy.

Preparations containing B. bifidum , L. acidophilus , Lactobacillus casei , and the VSL 3 formulation containing Streptococcus , Lactobacillus , and Bifidobacterium spp. have been proven to reduce radiation-induced gut toxicity, such as diarrhea Delia et al.

Head and neck cancer patients who were administered radiation and chemotherapy treatment and received Lactobacillus brevis oral-treatments with CD2 lozenges had a lower incidence of mucositis and greater treatment completion.

All of these findings raise the possibility that probiotics could become an adjuvant therapy for cancer treatment. Studies have shown that intestinal microbiota have a significant effect on total body irradiation Crawford and Gordon, Irradiation drives fewer endothelial cells of the intestinal mucosa into apoptosis and induces less lymphocyte infiltration in germ-free mice than in conventional mice Crawford and Gordon, This finding indicates that gut commensals can play a negative role in resistance to the enteric toxicity of TBI in germ-free mice.

However, the production of angiopoietin-like 4 ANGPTL4 , a protein inhibitor of lipoprotein lipase, is one of the major mechanisms resulting in the resistance of germ-free mice to TBI.

The expression of ANGPTL4 is restrained by the gut microbiota in conventional mice Crawford and Gordon, The transcription of Angptl4 is administered by the PPAR family in response to small chain fatty acid-producing bacteria Grootaert et al.

Further exploration revealed that probiotic bacteria that induce Angptl4 expression include Streptococcus , Lactobacillus , and Bifidobacterium spp. and these render both germ-free mice and conventional mice resistant to radiotherapy toxicity.

We can conclude that gut microbiota regulates the response and repair of irradiation-induced damage. Future research will be invaluable to inform the alleviation of radiotherapy-collateral toxicity, the increase of therapeutic effectiveness to better understand the regulation mechanisms, and the therapeutic manipulation of commensal microbiota.

Several clinical trials are ongoing. gov, The goal of this research was to study whether normal gut bacteria help the body fight cancer. Febrile neutropenia FN is a major treatment-related complication and a life-threatening condition for cancer patients receiving intensive chemotherapy.

One of the main sources of infection during neutropenia is the endogenous flora. According to existing human and animal studies, probiotics probably not only decrease the degree of enrichment of the pathogenic bacteria colonizing the gut but may also reduce the duration of neutropenia.

Although a significant number of studies have shown that probiotic treatment is effective, evidence of the safety of probiotics is still insufficient, especially in immunocompromised patients. This new study will explore the safety and practicability of probiotics in cancer treatment ClinicalTrials.