- Fiber is an essential part of a balanced diet and is beneficial for gut health, prevents constipation, and helps people manage their weight.
- However, less than 10% of Americans have enough fiber in their diet.
- A new study suggests that incorporating plenty of fiber-rich foods, such as vegetables, whole grains, fruits, and nuts, in your diet may have even more health benefits.
- The research found that two byproducts of fiber digestion by gut bacteria may alter gene expression, reducing the risk of cancer.
Dietary fiber is the part of plant foods that we cannot digest, but our gut microbiome can. Fiber is an essential part of a healthy diet, helping to prevent constipation, keep the gut healthy, and maintain a healthy weight.
However, few Americans eat enough fiber, with research suggesting that as few as 1 in 20 people meet the adequate intake of 14g of fiber per 1,000 kcal each day.
A new study has reinforced advice that you should incorporate plenty of fiber-rich foods in your diet. Researchers found that when gut bacteria break down plant fiber, they produce two compounds that act on genes to help prevent the growth of cancers.
The study is published in
Dr. Eamon Laird, Assistant Lecturer in Human Nutrition at Atlantic Technological University Sligo and Adjunct Assistant Professor Trinity College Dublin, Ireland, who was not involved in the study, commented:
“This is a well-run and comprehensive cell study with good methodologies but limited in scope — there are further questions to ask with many cell line variations and also real-life scenarios — the typical diet and lifestyle will have major effects, and it is unknown if these compounds still display these potential effects in the field, so to speak.”
The gut microbiome is made up of many millions of bacteria and other microorganisms that help us digest what we eat. Although people cannot digest plant fiber, our gut bacteria break it down into molecules that we can then use.
One type of molecule these microbes produce from fiber is short-chain fatty acids (SCFAs). SCFAs are essential for modulating immune responses and may help prevent the formation of tumors in the gut.
In this study, the researchers investigated the effects of two SCFAs,
“The research focuses on short-chain fatty acids (SCFAs) like propionate and butyrate, which are produced when gut bacteria break down dietary fiber. These SCFAs can influence the activity of both cancer-promoting (proto-oncogenes) and cancer-suppressing (tumor-suppressor) genes by modifying histones, the proteins that help package DNA. By making the DNA more accessible, SCFAs can turn certain genes on or off, depending on the cell type and conditions.”
— Şebnem Ünlüişler, Genetic Engineer and Chief Longevity Officer at the London Regenerative Institute, who was not involved in the study.
The researchers found that both propionate and butyrate altered gene expression in several isolated human cell types: healthy cells and treated colon cancer cells. Similar effects were seen in cells in the intestines of living mice.
Importantly, these
Ünlüişler told Medical News Today that one of the most interesting findings was how butyrate works in cancer cells:
“It blocks enzymes called histone deacetylases (HDACs), leading to changes in DNA packaging that can slow down cancer cell growth or even trigger their [the cancer cells’] death.”
Laird emphasized that, as a cell study, this “is on the bottom part of the evidence pyramid.”
“I would like to see this in real life — for instance large-scale observational studies measuring indicators of these markers and then risk of cancer and disease followed by the gold standard of randomized controlled trials before we start implementation of the findings. […] Is there a benefit or other effects in cells being treated for cancer?” he told Medical News Today.
“What about those with Crohn’s disease or other conditions that cannot tolerate high fiber — what is the effect of these compounds then? There is still a lot more to investigate,” he said.
On average, in the U.S., adults eat around
“Regardless of the findings from this study, we should be aiming for the [UK] recommendations of 30 grams of fiber per day every day. Unfortunately, few people actually meet these recommendations. The findings of the study add to the already known evidence base that fiber is crucial for health both in terms of human health and the gut microbiome which directly affects our colonic [gut] health.”
— Eamon Laird
To increase fiber intake, it is important to include a wide variety of plants in your diet, eating the skins of those with edible skins. Good sources of plant fiber include:
- fruits, such as avocados, apples, pears and raspberries
- nuts and seeds
- vegetables, particularly legumes, potatoes, sweet potatoes, broccoli, and squashes
- whole grain foods, such as freekeh, bulgur wheat, and brown rice.
Ünlüişler welcomed the findings, telling MNT: “Eating enough fiber increases SCFA production in the gut, which may help prevent colorectal cancer by supporting Healthy gene regulation. It’s a clear reminder of how closely diet and Health are linked. [It] opens exciting doors for using diet and gut Health to influence gene activity and prevent disease.”
