Healthy plant-based diets could help lower IBD risk, new evidence suggests.
- Inflammatory bowel disease (IBD) is an umbrella-term that covers
several conditions affecting the intestines, including Crohn’s disease and
ulcerative colitis.
- It occurs when the immune system mistakenly attacks cells in the
bowel, causing inflammation and symptoms such as pain, changes in bowel
movements and weight loss.
- People with IBD can often relieve their symptoms by modifying their
diet, excluding certain foods and including others.
- Now, a study has found that a plant-based diet made up of mainly
nutrient-dense plant foods may help reduce the risk of developing IBD and
reduce the need for surgery in those who have the condition.
Inflammatory
bowel disease (IBD) describes many long-term conditions that
affect the intestines and lead to a range of digestive symptoms.
Around the world, in 2019, there were around 5 million
people living with the condition, which is more common in women
and is usually diagnosed before the age of 30.
The two main types of IBD are:
- ulcerative
colitis, which causes inflammation in the large intestine,
usually the colon
- Crohn’s
disease, linked to inflammation in any part of the digestive
tract but most frequently in the end of the small intestine and the large
intestine.
Both types cause a number of symptoms, which may include
pain, diarrhea, fatigue, nausea, weight loss, lack of appetite, intestinal
bleeding and anemia.
The symptoms tend to flare up for short periods of time then go into remission.
Although there is currently no cure for IBD, several
treatments, such as anti-inflammatories (aminosalicylatesTrusted Source and corticosteroids)
and immune suppressants can alleviate the symptoms.
Sometimes surgery is
required to remove severely affected parts of the intestine.
Can a plant-based diet keep IBD at bay?
Modifying diet can help control symptoms for some
people. Dietary
changes that may help include:
- keeping a food
diary to track whether certain foods lead to symptoms
- limiting intake of dairy
products
- restricting intake of unhealthy
fats and increasing omega-3 fats
- avoiding or limiting spicy
foods, caffeine, and alcohol
- limiting high fiber foods,
particularly if the bowel has narrowed
- frequent small meals instead of
fewer large ones
- drinking plenty of water
- taking vitamin and mineral
supplements to prevent deficiencies.
Now, a study has found that eating a healthy plant-based diet
may both reduce the risk of developing IBD, and reduce the need for surgery in
those already diagnosed with the condition.
The study, published in The Lancet Regional Health EuropeTrusted
Source, analyzed data from more than half a million
people enrolled in the UK Biobank (UKB, 2009–2022) and the European Prospective Investigation into Cancer and Nutrition (EPIC,
1991–2010)
Researchers found
that those who adhered to a healthy plant-based diet had a lower risk of IBD,
whereas those eating an unhealthy plant-based diet (high in processed plant
foods) showed an increased risk of the conditions.
Kelsey Costa,
MS, RDN, a registered dietitian nutritionist and owner of Impactful Nutrition,
not involved in the study, explained for Medical News Today that
“this observational study analyzed data from two large cohorts, strengthening
the validity of findings through its size and methodologies.”
“However,” Costa pointed out, “the participants were
predominantly European and white adults, limiting the applicability of results
to other populations.”
“The study explored important IBD
outcomes like surgery, comorbidities, and death. But, it overlooked key aspects
like disease activity, relapse rates, and quality of life — these are critical
factors that future research should address.”– Kelsey Costa, MS, RDSN
Not all plant-based diets are beneficial
Plant-based diets may be healthful, including lots of fresh
fruit and vegetables, and little processed food or additives.
However, the
researchers emphasize that many plant-based products are highly processed, such
as meat substitutes and refined plant oils, which may dilute the
health-benefits of traditional plant-based diets if they are not properly
accounted for.
For this study, they identified three types of plant-based
diets:
1. overall plant-based, which included
all healthy and unhealthy plant foods
2. healthy plant-based, in which
nutrient-dense plant foods — whole grains, fruits, vegetables, nuts, legumes
and vegetarian protein alternatives, as well as tea and coffee — were
positively scored, while refined grains, potatoes/fries, sugary drinks, fruit
juices and desserts gained negative scores
3. unhealthy plant-based, with positive
scores for less nutritious plant foods, and negative scores for healthier
plant-based options.
In all cases, highest intake scored 5 points and lowest
scored 1.
The researchers also scored a healthy omnivorous diet, with
positive scores given to healthy animal products such as dairy, eggs, fish and
seafood, for sensitivity analysis.
Ashkan
Farhadi, MD, a board-certified gastroenterologist at MemorialCare
Orange Coast Medical Center in Fountain Valley, CA, who was not involved in the
study, pointed out some of the difficulties of investigating the health effects
of diet.
“There’s a limitation in all nutritional studies,
particularly longitudinal,” Farhadi told us.
He also noted: “It’s really hard to define diets. When people
say what they are eating, they may also be eating other things. Things may
change during the course of a longitudinal study. They may eat cookies for 6
years, then change to the Mediterranean diet and report that!”
However, he added that “the good thing about this study is that
they pulled a huge amount of data.”
Healthy plant-based and omnivorous diets reduced IBD risk
The researchers concluded:
“In two large cohorts covering more
than 500,000 participants across [eight] nations, we found that a healthy
[plant-based diet] was inversely associated with IBD incidence and IBD-related
surgery, whereas an unhealthy [plant-based diet] was positively associated with
the same outcomes.”
The healthy omnivorous diet reduced IBD risk at least as much
as the healthy plant-based diet.
Costa commented on
this finding, saying that “the results indicate that a ‘healthy omnivorous
diet,’ which includes plants, dairy, eggs, and fish or seafood, may have a
slightly stronger association with IBD prevention after accounting for dietary
fiber intake.”
“This implies that the protective effects of a healthy
plant-based diet against IBD might not only come from fiber but potentially
other factors as well. But, it doesn’t necessarily mean one diet is better than
the other; both may offer benefits through different mechanisms,” she
explained.
“More research is needed to fully understand the impact of
different diets on IBD risk and disease course, but we can say without doubt
that a healthy diet rich in nutrient-dense, plant-based foods is essential,”
Costa added.
In addition, in people already diagnosed with IBD, the
healthy plant-based diet reduced the likelihood of the condition becoming more
severe and requiring surgery.
“It is very encouraging to see that
it [a healthy plant-based diet] not only helps prevent the disease, but slows
it down or halts progression to severe cases. That’s a very interesting
finding.”– Ashkan Farhadi, MD
Why might these diets
reduce IBD risk?
Previous studies have suggested that a vegan, but not a
vegetarian diet may be linked to lower levels of inflammatory markers, and in
this study the researchers suggest that the beneficial effects of a healthy
plant-based diet may be partially, but not entirely, mediated by inflammation.
The researchers also observed that benefits may be greater
for participants with a moderate or high genetic risk of developing IBD.
Farhadi told Medical News Today that the
gut microbiome could be the mediator between diet and inflammation.
“One theory is that when you are eating refined plant-based
foods, you are feeding particular microbes and changing the gut flora. When
there is dysbiosis — a disturbed ratio in the microbiome — we see
illness,” he said.
“Unrefined foods
encourage another group in the microbiome. By using nonprocessed plant-based
foods we may be improving the beneficial microbiome population,” Farhadi
explained.
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