• For more on this topic see our article Q&A: Natural help for healing stomach ulcers

For many decades, scientists have known that low caloric intake is linked with greater longevity in humans and other organisms. The researchers were interested in exploring how fasting worked at the molecular level, specifically in the stem cells in the intestine.

Intestinal stem cells are responsible for maintaining the lining of the intestine, which typically renews itself every five days. When an injury or infection occurs, stem cells are key to repairing any damage. As people age, the regenerative abilities of these intestinal stem cells decline, making it more difficult to recover from gastrointestinal infections or other conditions that affect the intestine.

Zinc oxide (ZnO) nanoparticles are present in the lining of certain canned goods for their antimicrobial properties and to prevent staining of sulphur-producing foods.

But according to Gretchen Mahler, associate professor of bioengineering at Binghamton University, State University at New York, “We found that zinc oxide nanoparticles at doses that are relevant to what you might normally eat in a meal or a day can change the way that your intestine absorbs nutrients or your intestinal cell gene and protein expression,”

In the study, which was published in the journal Food & Function, canned corn, tuna, asparagus and chicken were studied using mass spectrometry to estimate how many particles might be transferred to the food. It was found that the food contained 100 times the daily dietary allowance of zinc. Mahler then looked at the effect the particles had on the digestive tract.

“People have looked at the effects of nanoparticles on intestinal cells before, but they tend to work with really high doses and look for obvious toxicity, like cell death,” said Mahler. “We are looking at cell function, which is a much more subtle effect, and looking at nanoparticle doses that are closer to what you might really be exposed to.”

Inflammation and reduced nutrient absorption

“They tend to settle onto the cells representing the gastrointestinal tract and cause remodelling or loss of the microvilli, which are tiny projections on the surface of the intestinal absorptive cells that help to increase the surface area available for absorption,” said Mahler. “This loss of surface area tends to result in a decrease in nutrient absorption. Some of the nanoparticles also cause pro-inflammatory signalling at high doses, and this can increase the permeability of the intestinal model. An increase in intestinal permeability is not a good thing – it means that compounds that are not supposed to pass through into the bloodstream might be able to.”

Although Mahler studied these effects in the lab, she said she is unsure what the long-term health implications might be.

“It is difficult to say what the long-term effects of nanoparticle ingestion are on human health, especially based on results from a cell culture model,” said Mahler. “What I can say is that our model shows that the nanoparticles do have effects on our in vitro model, and that understanding how they affect gut function is an important area of study for consumer safety.”

This is the first research that analyses how ZnO nanoparticles affect the human body. The researchers are looking at how an animal model responds to nanoparticle ingestion.

“We have seen that our cell culture results are similar to results found in animals and that the gut microbial populations are affected. Future work will focus on these food additive-gut microbiome interactions,” said Mahler.

Gallstones are hardened deposits of digestive fluid that form in the gallbladder. The most common type is composed mainly of undissolved cholesterol. Although they can range in size from a grain of sand to a golf ball, people may live with gallstones for years without experiencing any symptoms.

The most common symptoms are intensifying pain in the upper right portion of your abdomen or in the centre of your abdomen, just below your breastbone, pain between your shoulder blades or in your right shoulder and nausea and vomiting.

In this study, led by researchers from the University of Kiel, in Germany, 582 people (average age 62) had lower blood levels of alpha-tocopherol than those who did not have gallstones.

Double checking the measurements

The scientists took blood samples from the subjects, from which total and low-density lipoprotein (LDL) cholesterol and two different forms of vitamin E (alpha- and gamma-tocopherol) were measured.

Vitamin E isn’t just a single nutrient but in fact is a family or complex of 10 fat-soluble compounds (in much the same way as the B-complex family). The ten forms of vitamin E are divided into two groups; five are tocopherols and five are tocotrienols. Both types are usually differentiated with prefixes like include alpha-, beta-, gamma- and delta-.

Writing in the journal Nutrients, they note that that those with the highest blood level of alpha tocopherol had around 70% less risk of developing gallstones.  A similar association was found with gamma-tocopherol levels. However, with the gamma form, the results were not as powerful.

In individuals with impaired flow of bile from the liver to the duodenum vitamin E status may be more accurately established by measuring the ratio of alpha-tocopherol to cholesterol in the blood. Here too, those with gallstone disease also had a lower ratio of alpha-tocopherol to cholesterol in the blood – but again the effect was less pronounced with gamma-tocopherol.

Lowering oxidative stress

According to the scientists, oxidative stress and free radicals are thought to play a role in gall bladder disease development. Thus, higher vitamin E might help protect against oxidative stress, reducing the risk of gallstones, hypothesised the scientists.

Previous research has also found reduced vitamin E absorption in people with gallstones, and that the disturbance of bile secretion in gallbladder disease is associated with fat-soluble vitamin deficiencies.

Many of us do not get enough vitamin E in our daily diets. There are not many large studies looking at vitamin E supplementation as a preventative for gallstones and according to  senior researcher Professor Wolfgang Lieb, it still needs to be established “if, and to what, extent dietary vitamin E supplementation may prevent gallstone formation​.”

• For more on this topic see our article Vitamin E – why you may need more

Both trials were conducted by researchers from the University of Illinois at Urbana-Champaign, Urbana.

The first trial, published in the journal Gut Microbes,​used an animal model to test the hypothesis that exercise could modify the gut bacteria profile, even when dietary intake remained unchanged.

Healthy mice given faecal transplants from other mice that had been put on an exercise regimen, showed significant differences in gut bacteria composition, metabolic parameters, colon inflammation and weight compared with a group of sedentary mice that acted as controls.

“That proved to us that the transplant worked,”​said co-lead researcher Professor Jeffrey Woods.

Additionally, exercise-trained mice showed reduced symptoms when the researchers tried to induce colitis.  The animals that had been exercising showed a reduction in inflammation and an increase in the regenerative molecules that promote a faster recovery.

Applicable in humans too​

The researchers then went on to see if the same effect could be seen in humans.

After six weeks of progressively more intense cardiovascular exercise, participants showed an increase in diversity of gut bacteria, and faecal concentrations of short-chain fatty acids (SCFAs), particularly butyrate.

This is likely due to an increase in the numbers of beneficial species capable of SCFA production. Short chain fatty acids produced when the ‘good’ bacteria in the gut ferment fibre in the colon, and are the main source of energy for the cells lining the colon.

However, these increases were only statistically significant in lean participants. Those who were overweight showed much less dramatic changes.

Participants’ gut microbiota composition gradually reverted to baseline levels after six weeks of sedentary behaviour following the end of the exercise regime.

The team observed differences in the gut microbial response of lean and obese subjects throughout the study, during which time the trial participants maintained their usual dietary patterns.

“The bottom line is that there are clear differences in how the microbiome of somebody who is obese versus somebody who is lean responds to exercise,” Woods said of the study in the journal in Medicine & Science in Sports & Exercise.​

“These are the first studies to show that exercise can have an effect on your gut independent of diet or other factors,”​he added.  ​

The team concludes that the findings increase our understanding of how the body responds to exercise.

The açaí palm is a species of palm tree cultivated for its fruit and hearts of palm. There’s growing interest in the health benefits of açai, which is sometimes called an Amazonian ‘superfruit.’ Scientists from the University of Reading and University of Roehampton suggest that its rich anthocyanin content means the fruit could help reduce the risk of age related diseases.

“We hypothesize that both fibre and plant polyphenols present in açai​ (Euterpe oleracea​) provide prebiotic and anti-genotoxic benefits in the colon,”​ they wrote in their report, published​​ in the journal Food Chemistry​.

This means that açai may have a prebiotic effect — which means it acts as food for beneficial bacteria living in the digestive system. Fermentation that comes from the bacteria’s digestion of prebiotics in turn provide health benefits to its hosts, such as anti-inflammatory activities, as well as influencing metabolism and satiety.

Genotoxicity, on the other hand, describes a substance that damages the genetic information within a cell causing mutations.

It is widely believed that antioxidants, such as polyphenols, can help protect against genotoxic stress, which has a role to play in aging and age-related diseases such as diabetes, Parkinson’s and Alzheimer’s disease.

Antioxidants are also prebiotics​

In this laboratory study the scientists traced the journey of polyphenols through the digestive process, to see if and how well they survived to reach the colon intact.

The researchers used açai pulp that had been freeze-dried and ground to a powder. Then, they simulated intestinal digestion using a standardised method that mimics the human digestive system. This was done to “look at the potential bioavailability and bioactivity of açai polyphenols,” they wrote.

From the process, they found that 49.8% of the total initial polyphenols were available post digestion. “Our work demonstrates that polyphenols present in açai may be degraded during the digestion process, but importantly, that they are not fully destroyed and a significant percentage of these compounds may therefore reach the colon,”​ according to the report.

Reaching the colon intact means they become a useful food source for good bacteria there.

Multiple studies have emerged in recent years to study how anthocyanin-rich fruits interact with bacteria in the gut, and whether or not this interaction offers health benefits.

For instance, a systematic review​​ by Brazilian researchers recently shed more light on the prebiotic properties of anthocyanins. It also found that this type of antioxidant does actually feed beneficial bacteria in the gut, offering potential health benefits to the host.

This is the conclusion of a study published in JAMA Otolaryngology Head Neck Surgery by researchers from Northwell Health’s The Feinstein Institute for Medical Research and New York Medical College.

When compared to patients who took the traditional reflux medication, proton pump inhibitors (PPI), those patients who consumed a 90-95% whole food, plant-based, Mediterranean-style diet paired with alkaline water provided a greater reduction in reflux symptoms.

In all, 63% percent of patients treated with a plant-based diet and alkaline water combination saw a six point reduction in their Reflux Symptom Index (RSI – a measurement for the severity of reflux symptoms), compared to 54% reduction in patients taking PPI’s. Though this research only focused on those with laryngopharyngeal reflux, this same diet regimen has implications to help patients with gastro-esophageal acid reflux (also known as GERD).

Looking for alternatives

Lead author of the study, Craig H. Zalvan, MD, FACS, chief of Otolaryngology and medical director of The Institute for Voice and Swallowing Disorders at Northwell Health’s Phelps Hospital and researcher at the Feinstein Institute, said he was formerly one of the largest prescribers of PPI’s in the region. Feeling that there had to be a better approach to treating reflux conditions like laryngopharyngeal reflux, he started to research alternatives.

“Although effective in some patients, I felt medication couldn’t be the only method to treat reflux and recent studies reporting increased rates of stroke and heart attack, dementia and kidney damage from prolonged PPI use made me more certain,” said Dr. Zalvan.

“I did research and saw a lot of studies using plant-based diets to treat patients for many other chronic diseases, so I decided to develop a diet regimen to treat my laryngopharyngeal reflux patients. The results we found show we are heading in the right direction to treating reflux without medication.”

Try diet first

The diet suggested by Dr. Zalvan consists of mostly fruits, vegetables, grains and nuts with near complete cessation of dairy and meats including beef, chicken, fish, eggs and pork.

This is in addition to standard reflux diet precautions like avoiding coffee, tea, chocolate, soda, greasy and fried food, spicy foods, fatty foods and alcohol.

Along with relieving reflux symptoms, Dr. Zalvan noted that many of his patients who were treated with a plant-based diet also experienced some weight loss and a reduction of symptoms and medication use from other medical conditions like high blood pressure and high cholesterol.

Her now recommends that this dietary approach, plus standard reflux precautions should either be attempted prior to the use of medication or with the short-term use of medication for more severe needs.

New research shows that broccoli contains compounds which promote a healthy gut.

“There are a lot of reasons we want to explore helping with gastrointestinal health and one reason is if you have problems, like a leaky gut, and start to suffer inflammation, that may then lead to other conditions, like arthritis and heart disease,” said lead author Gary Perdew, John T. and Paige S. Smith Professor in Agricultural Sciences, Penn State.

“Keeping your gut healthy and making sure you have good barrier functions so you’re not getting this leaky effect would be really big.”

Good intestinal barrier function means that the gastrointestinal tract is helping protect the intestines from toxins and harmful microorganisms, while allowing nutrients to pass into the system, he said.

According to Perdew, the key to the process may be a receptor in the gut called Aryl hydrocarbon receptor, or AHR. The receptor helps the body regulate its reaction to certain environmental contaminants, as well as triggers other responses to toxin exposure.

Protective effect of cruciferous veggies

The researchers, whose study was published in the Journal of Functional Foods, suggest that cruciferous vegetables – such as broccoli but also brussels sprouts and cabbage – contain an organic chemical compound called indole glucosinolates, which breaks down into other compounds, including indolocarbazole (ICZ) in the stomach.

When ICZ binds to and activates the Aryl hydrocarbon receptor (AHR) in the intestinal lining, it aids in maintaining a healthy balance in the gut flora and immune surveillance, and enhances host barrier function. This may help prevent diseases, such as various cancers and Crohn’s Disease, caused by inflammation in the lining of the gut.

According to Perdew, hyper-activating the AHR can cause toxicity, but using broccoli to activate the receptor locally – in the gut – rather than systemically with drugs or environmental toxins might help avoid some of these problems.

“Dioxin, for example, activates this receptor, and if you hyper-activate it with dioxin, it will cause toxicity,” said Perdew. “What we were interested in is: Could you locally activate the receptor naturally at a level that would cause only modest AHR activation in the gut, but not cause systemic activation, which could possibly lead to negative effects?”

The researchers used an animal model to try and answer this question. They added 15% broccoli to the diets of half of a group of mice. Then the animals were all given a chemical to induce digestive problems. The mice getting the broccoli were protected but the mice that didn’t get the broccoli were not.

Getting what you need

For humans, the amount in the experiment would be equivalent to eating about 3.5 cups of broccoli each day, according to Perdew. “Now, three and a half cups is a lot, but it’s not a huge amount, really,” said Perdew. “We used a cultivar – or variety – with about half the amount of this chemical [indole glucosinolates] in it, and there are cultivars with twice as much. Also, brussels sprouts have three times as much, which would mean a cup of brussels sprouts could get us to the same level.”

Because people with certain digestive conditions, such as colitis, are often warned to avoid too much roughage in their diets, future research may include determining the best ways for people to consume the broccoli – or other vegetables with similar effects – to receive the same health benefits, without causing any other associated digestive problems from the fibrous vegetables.

We would add that broccoli sprouts are an exceptionally rich source of these compounds and that a daily shot of broccoli sprout juice is a good way to get what you need.

The scientists at the University of Nottingham and King’s College London examined the gut microbiome of a large group of middle-aged and elderly women. They tested the diversity and abundance of ‘good’ bacteria against their intake of omega-3 fatty acids – found in fish oil – and their blood serum levels of omega-3 fatty acids. The diets of the 876 women who participated were assessed using food questionnaires

The study, published in Scientific Reports, found that the women who had a higher dietary intake of omega-3 and higher serum levels had a more diverse gut microbiome. A more diverse microbiome is associated with a number of health benefits, including lower risk of diabetes, obesity and inflammatory gut diseases like colitis or Crohn’s.

Leading the study, Associate Professor and Reader, Dr Ana Valdes, who is affiliated to the NIHR Nottingham Biomedical Research Centre, said: “The human gut is receiving a lot of attention in medical research as it is increasingly linked to a wide variety of health issues.  Our digestive systems are home to trillions of microbes, most of which are beneficial in that they play a vital role in our digestion, immune system and even regulate our weight.”

Reducing inflammation and oxidative stress

The study is thought to be the largest to date to examine the relationship between omega-3 fatty acids and the composition of the gut microbiome.

According to co-author Dr Cristina Menni, from King’s College London: “We also found that specific bacteria that have been linked to lower inflammation and lower risk of obesity are increased in people who have a higher intake of omega-3 fatty acids.”

The researchers also found that high levels of omega-3 in blood are correlated with high levels of a compound called N-carbamylglutamate (NCG) in the gut. This compound has been shown in animals to reduce oxidative stress in the gut. “We believe that some of the good effects of omega-3 in the gut may be due to the fact that omega 3 induces bacteria to produce this substance.” she says.

Previous wider research has found positive effects on health from omega-3 fatty acids on insulin resistance in diabetes, hypertension (high blood pressure), arthritis, thrombosis (blood clots), some cancers and cognitive decline. This new study has added weight to the growing global body of evidence to suggest that omega-3 also appears to improve the gut microbiome both in its diversity and composition.

The researchers from Washington State University note that there is increasing evidence showing that Western dietary and lifestyle habits contribute to an increased prevalence of inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn’s disease, by inducing intestinal inflammation.

It also contributes to rising rates of obesity – a risk factor for the development of inflammatory bowel disease.

Although peas contain a variety of beneficial nutrients including beneficial fibre, known to decrease the risk of IBD there is a widespread low awareness of the beneficial effects of green pea in many countries, say those behind a new study.

With this in mind the scientists investigated the preventive effects of green pea supplementation on colitis in mice fed a Western-style diet.

The animals were randomly divided into two groups and over a period of 9 weeks received either a high fat diet on its own or a high fat diet with added green pea.

Colitis was induced in the mice after seven weeks of dietary supplementation. Immediately after this both groups showed similar adverse reactions, but fairly quickly the mice fed green peas proved to be more resilient.

Protection – and better recovery

The results, published in the journal Nutrients, showed they also recovered also faster than mice that didn’t eat green peas, their body weight was more stable and there was a significant reduction in faecal blood leading. This led the researchers to conclude that green peas in the diet reduced inflammation and mucosal loss and improved what is known as, ‘endoplasmic reticulum signalling’ – a process necessary for, amongst other things, helping the body to utilise calcium and fats better.

The study was not able to pinpoint whether there was a specific component of green peas that was helpful. The researchers speculate that green peas – but also other legumes such as chickpeas, kidney beans – likely contain multiple factors including dietary fibre, resistant starches, protein, and antioxidants that work together to reduce inflammation and encourage healthy bacteria in the gut, thus supporting intestinal health.

There is no single diet which has been proved to work ‘best’ for IBD. But other research does suggest that in humans, diets rich in legumes – as well as cereals, fruits, vegetables, nuts, seeds and healthy fats –  such as the Mediterranean diet, may be protective against IBD.

“I think it is very significant. People who are having problems with intestinal health can use peas in their diet,” said Dr Shima Bibi, lead researcher behind the study.

• See our recipe for Creamy pea and cashew soup