New research emerges every day that reveals the connections between the gut and overall health. You may have already read about how your gut microbiome affects all aspects of your health. However, intestinal inflammation is also a crucial determinant of intestinal and whole body health.
Read on to learn what diet and lifestyle factors can cause intestinal inflammation, the health consequences of having a chronically inflamed intestine, and practical strategies to alleviate inflammation and restore intestinal health.
Gut health influenced by the barrier and the gut microbiota
Gut health is influenced by two related variables: the gut barrier and the gut microbiota. Disturbances in any of these factors can induce intestinal inflammation, prompting a damaging chain reaction that begins locally and can spread systemically throughout the body.
The intestinal barrier
The intestinal barrier is a multilayered system made up of intestinal epithelial cells, proteins, protective mucus, and immune cells. Enterocytes are absorbent cells that make up most of the gut's epithelial cell layer.
Goblet cells intercalate between enterocytes and secrete protective mucus that serves as a habitat for commensal bacteria (or normal gut inhabitants) and inhibits infection by pathogens.
Together, the enterocytes and goblet cells function as “gatekeepers” of the intestine, regulating the interactions that intestinal bacteria have with the host's immune system.
M cells and Paneth cells have functions in the immune system by presenting intestinal luminal contents (from within the intestinal tract) to the immune system and releasing antimicrobial molecules such as lysozyme.
Altogether, the intestinal barrier prevents the passage of non-nutritive substances and pathogens from the intestinal lumen into the systemic circulation, promotes digestion and regulates immunity.
Intestinal epithelial cells are bound together by tightly bound proteins, including zonula-occludens-1, claudin-1, and occludin, forming a semipermeable seal between the intestinal lumen and the systemic circulation.
This seal is delicate and can be easily disturbed by a variety of dietary and lifestyle factors. When the integrity of the intestinal barrier is compromised, tiny gaps open between epithelial cells, allowing molecules to escape through the intestinal lumen into the systemic circulation.
This condition is known as "leaky gut." Leaky gut, in turn, causes the body to initiate both inflammatory responses outside of itself in the gut and systemically in other distant tissues and organs.
The human intestine is home to 100 trillion microorganisms and their entire set of genes, which is at least 150 times larger than ours. Known collectively as the "gut microbiota," these microbes and their genetic material evolved in tandem with the human species and influence nearly every aspect of our health.
The gut microbiota is a crucial promoter of immune system development and balances levels of inflammation both locally in the gut and systemically in other tissues and organs.
Dysbiosis is a disturbance of the intestinal microbial community due to various stressors, such as having an unhealthy diet and the use of antibiotics.
Dysbiosis promotes intestinal inflammation and, if left unchecked, contributes to the development of chronic diseases such as inflammatory bowel disease (IBD), colon cancer, obesity, and asthma.
12 diet and lifestyle factors that can cause intestinal inflammation
Gluten proteins are the main energy storage proteins in wheat, barley and rye. Located in the endosperm of these grains, the gluten family encompasses a wide variety of proteins, including gliadins and glutenins.
Gluten causes inflammation in people with celiac disease and non-celiac gluten sensitivity. Celiac disease is an autoimmune response to gluten characterized by alteration of the healthy structure of intestinal tissue, gastrointestinal discomfort, and extra-intestinal symptoms, such as skin rashes and anemia.
Non-celiac gluten sensitivity is characterized by gluten-triggered intestinal and extra-intestinal symptoms in the absence of celiac disease and wheat allergy.
Gluten triggers intestinal inflammation in sensitive individuals when it binds to intestinal CXCR3 receptors, causing the release of zonulin.
Zonulin is a protein that facilitates the breakdown of tight junction proteins found between intestinal epithelial cells, increasing intestinal permeability and inflammation. Gluten also activates intestinal mast cells, which release pro-inflammatory molecules like histamine and tryptase.
It is important to note that gluten does not cause inflammation in everyone. People without celiac disease or non-celiac gluten sensitivity can tolerate gluten in their diet.
2. Industrial seed oils
Industrial seed oils, the highly processed oils extracted from soybeans, corn, rapeseed (the source of canola oil), cottonseed, and safflower seeds, make up a large portion of the standard Western diet.
Introduced to the human diet less than two centuries ago, these oils represent an evolutionary mismatch and promote intestinal inflammation.
The high omega-6 fatty acid content of industrial seed oils makes them susceptible to damage from heat and light. Processing and cooking with industrial seed oils create oxidized and inflammatory by-products that, when consumed, induce intestinal inflammation.
In fact, a diet rich in industrial seed oils has been found to cause intestinal inflammation and at the same time promote the growth of intestinal pathogens.
3. Acellular carbohydrates
Acellular carbohydrates are foods that contain carbohydrates that lack cell walls, such as flour and sugar, and therefore have a high carbohydrate density. Acellular carbohydrates are abundant in the standard Western diet and promote a highly inflammatory gut microbiota.
On the other hand, cellular carbohydrates, on the other hand, are carbohydrate-containing foods with intact cells, such as sweet potatoes and whole fruit. Unlike acellular carbohydrates, cellular carbohydrates promote gut health by stimulating the growth of anti-inflammatory gut bacteria.
4. Food additives
Ultra-processed foods comprise nearly 60 percent of the energy intake in the United States and are saturated with food additives. Most food additives have not undergone long-term safety studies, a concerning fact given the accumulating evidence of their harmful effects on intestinal inflammation.
Maltodextrin, a synthetic carbohydrate used as a thickener and preservative in processed foods, promotes the adhesion of harmful bacteria to intestinal cells and promotes the formation of biofilms.
The artificial sweetener "Splenda" stimulates the growth of inflammatory intestinal bacteria.
Carrageenan, a seaweed-based polysaccharide used for its thickening and emulsifying properties, can make IBD (Inflammatory Bowel Disease) worse. Carboxymethylcellulose and polysorbate-80, two most ubiquitous food emulsifiers, increase intestinal permeability.
5. Cesarean delivery and formula feeding
Cesarean delivery profoundly alters the developing infant gut, filling the microbiome with microbial species derived from the surrounding environment, rather than beneficial microbes from the mother's vaginal canal.
Babies delivered by cesarean section are also exposed, through the placental circulation, to antibiotics given to their mothers to prevent postoperative infection.
This early exposure to antibiotics further skews the development of the infant's gut microbiota, predisposing the child to intestinal inflammation and chronic inflammatory diseases, such as asthma and obesity, in the future.
Formula feeding is also a problem for the baby's small intestine. Formula feeding promotes the growth of inflammatory gut bacteria and increases intestinal permeability and total bacterial load.
In contrast, breastfeeding increases the colonization of the infant's intestine with Lactobacillus and anti-inflammatory Bifidobacteria, reducing the risk of intestinal inflammation and chronic inflammatory diseases.
6. Intestinal infections
Bacterial, viral, fungal and parasitic intestinal infections alter the composition of the intestinal microbiota, creating a pro-inflammatory intestinal environment.
For example, influenza A virus transiently increases susceptibility to the Salmonella pathogen by reducing protective commensal bacteria, while Helicobacter pylori infection increases the growth of Prevotella, a pro-inflammatory bacterium.
An acute episode of food poisoning can also trigger intestinal inflammation and irritable bowel syndrome (IBS) by stimulating the intestinal production of inflammatory autoantibodies.
The human gut is extremely sensitive to chronic stress. Chronic psychological stress increases intestinal permeability and allows lipopolysaccharide (LPS), an inflammatory bacterial byproduct, to enter the bloodstream. This elicits localized and systemic inflammatory responses.
Stress also depletes the protective layer of the gastrointestinal mucosa and increases bacterial adhesion and penetration into intestinal epithelial cells, causing intestinal inflammation.
8. Sedentary lifestyle and overtraining
Moderate exercise increases beneficial gut bacteria, including short-chain fatty acid-producing anti-inflammatory bacteria (SCFA), thereby inhibiting intestinal inflammation.
On the contrary, a sedentary lifestyle is associated with a greater infiltration of inflammatory molecules in the intestine.
In addition, excessive physical activity increases intestinal permeability and negatively alters the intestinal microbiota.
If you have a chronic inflammatory disease or are under significant psychological stress, it's best to limit strenuous exercise and focus on calmer activities like walking, yoga, or swimming.
9. Disruption of the circadian rhythm and loss of sleep
The circadian rhythm is a set of internal biochemical processes that occur in cycles of approximately 24 hours and regulate many aspects of your physiology, including gut health and inflammation.
When the circadian rhythm is disrupted by factors such as nighttime blue light exposure and irregular sleep schedules, gut health suffers.
Circadian disruption has been found to promote the growth of inflammatory gut bacteria, decrease beneficial microbes, and increase intestinal permeability and LPS transport into the systemic circulation.
Loss of sleep is closely related to circadian disruption and is equally detrimental to gut health. Just experiencing two nights of partial sleep deprivation induces changes in the gut microbiota, increasing pro-inflammatory bacterial species.
Insufficient sleep also exacerbates intestinal inflammation in IBD. To minimize intestinal inflammation, it is crucial to support your circadian rhythm and optimize your quality of sleep.
The frequency with which doctors prescribe antibiotics has instilled a false sense of security in many patients; after all, your doctor won't prescribe a medication unless you really need it, right?
Unfortunately, flexible prescribing of antibiotics is the norm in our society, and the effects they have on gut health tend to be minimized.
However, extensive research indicates that antibiotics can have long-term detrimental effects on the gut microbiota and induce intestinal inflammation.
Antibiotics reduce the diversity and abundance of commensal intestinal bacteria, allowing overgrowth of inflammatory pathogens such as Clostridium difficile and pathobionts such as Escherichia and Candida.
These microbial changes can last for months or years after antibiotics are stopped. Its adverse effects are most pronounced in infants and young children, who go through a critical time window in the development of their gut microbiota.
11. Non-antibiotic drugs
Probably very few physicians consider the impact of non-antibiotic medications on their patients' gut health before pulling out their prescription pads.
However, more and more evidence indicates that this is a significant oversight, as multiple classes of non-antibiotic drugs alter the gut microbiota and induce intestinal inflammation.
Proton pump inhibitors (PPIs), used in the treatment of gastroesophageal reflux disease (GERD) and acid reflux, decrease heartburn. When the stomach produces enough acid, the entry of bacteria from the environment into the intestine is limited.
By inhibiting stomach acid production, PPIs allow more bacteria to enter the digestive tract and proliferate in the small intestine, leading to bacterial overgrowth and intestinal inflammation.
PPIs also reduce the growth of SCFA-producing anti-inflammatory bacteria.
Selective serotonin reuptake inhibitors (SSRIs) are known to cause constipation and changes in appetite. Preclinical studies indicate that fluoxetine (Prozac) alters the structure of the gut microbial community, increasing dysbiotic gut bacteria.
Oral contraceptives also cause intestinal inflammation. In fact, its use is associated with an increased risk of Crohn's disease, a subtype of IBD.
12. Environmental toxins
Thousands of new chemicals are developed by industries each year. Many chemicals do not undergo extensive safety testing prior to release.
This fact is alarming, considering the large number of adverse health effects related to chemicals in our environment. Intestinal inflammation is one of the most common consequences of exposure to environmental toxins.
Bisphenol A (BPA), found in plastic water bottles and food containers, children's toys and cash register receipts, promotes intestinal inflammation by increasing harmful intestinal bacteria and intestinal permeability.
Alternative plasticizers, found in BPA-free products, are just as harmful, if not more.
Triclosan, a synthetic antibacterial agent used in hand sanitizers and personal care products, also increases intestinal inflammation.
Glyphosate, the main component of the herbicide Roundup, decreases Lactobacillus and facilitates the growth of antibiotic-resistant Escherichia coli, suggesting that glyphosate acts as an antibiotic in the gut microbiome.
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