Ulcerative Colitis (UC) is a type of inflammatory bowel disease in which inflammation
and structural damage occurs in the innermost layer of the large bowel. Currently, there isn’t enough evidence to suggest which diet is the best diet for the management of UC. This can bring some confusion and challenges when trying to determine the best way to manage your UC. One thing we DO know, however, is that overall dietary patterns have always shown to be more impactful in the long-run versus focusing on only one single nutrient or food group.
So what’s the deal with sulfur and why do some suggest it may be harmful to those with UC? Let’s take a look at the science!
What is Sulfur?
First off, sulfur is a naturally occurring element found in our soil, plants, food and water¹. In our bodies, sulfur has many essential roles, such as supporting skin health, connective tissues, metabolism, reducing oxidative stress, and is a key player in gene expression². Sulfur is found in a lot of nutritious foods and is most-commonly in the form of amino acids – the building blocks of protein. Sulfur can also be found in fruits and vegetables, as it makes up certain vitamins and antioxidants².
Then why is sulfur getting a bad rep?
There’s something called the hydrogen sulfide toxin hypothesis. Inflammation seen with UC is typically greatest in the rectum and extends towards the colon. The idea with this hypothesis is that high concentrations of a “toxin” near the rectum could be involved in the pathogenesis of UC. The identity of this toxin is not known, however emerging research points to hydrogen sulfide (H₂S) as a possible candidate³.
This hypothesis states that H₂S becomes toxic in high concentrations in our colon and can potentially disrupt the intestinal barrier and mucous layer; this can include reducing short-chain fatty acid (SCFA) production which could lead to cell death, oxidative stress, and bowel inflammation. Dietary sulfur is involved in the production of H₂S when it is reduced by sulfur reducing bacteria³. This hypothesis also suggests that increases in dietary sulfur can lead to increases of H₂S in our colon, leading to inflammation and UC exacerbation³.
Where does this hypothesis fall short?
Studies to support the H₂S toxin hypothesis mainly come from preclinical animal models and therefore do not fully reflect true for humans. In addition, the hypothesis is challenged by the fact that H₂S at low levels has an anti-inflammatory effect, and is better viewed in a concentration dependent manner, which can vary from person to person.
Lastly, the H₂S toxin hypothesis focuses primarily on the intake of sulfur-containing foods and neglects all other dietary components in the pathogenesis of UC. There are many moving parts to consider when looking at how food can ultimately impact both the symptoms and the underlying inflammation of UC. Bottom line, we need to consider the complexity of our gut microbiota and it’s metabolic environment, rather than focus on a single compound.
A Low Sulfur Diet
If we step back from the science to see what a low sulfur diet ACTUALLY might look like, there are some pros and cons to this way of eating. And although the science isn’t quite where we’d like it to be yet, there are some definite wins that can come from a diet lower in sulfur.
A high sulfur diet would include high levels of animal protein and fat (such as red meat, cheese, & eggs) and inherently low amounts of fibre. Generally, studies that look to reduce sulfur intake for UC suggest shifting from the traditional Western diet to a more plant-based diet³. Patients that modify their diets to fit a more plant-based or vegetarian diet tend to better achieve remission and alleviate symptoms³. Keep in mind, these studies were based on small sample sizes and case reports, and more research still needs to be done.
Additionally, plant-based diets are diverse and varied and simply being “plant-based” doesn’t always mean a person’s diet consists of high quality foods! Working with a dietitian when implementing any diet for UC is highly recommended, especially when considering a new diet pattern like going more plant-based.
Although research looking at low sulfur diets as a diet intervention for UC is still limited, there is strong research that suggests plant-based dietary patterns to be beneficial for patients with inflammatory bowel disease (IBD), including UC.
Components of the Western diet, such as meat, fat, processed foods, alcohol, preservatives and emulsifiers have shown to have detrimental effects on the gut microbiome and have been indicated in the pathogenesis of IBD⁴ ⁵. A recent Dutch study that followed 724 IBD patients for 2 years found a dietary pattern similar to the Western diet (higher in red meats and processed foods) was associated with higher flare occurrence⁶.
We also know that the Mediterranean diet pattern, which promotes increased plant intake, whole grains, fibre, fish and chicken, with reduced red meat consumption, has been shown to decrease inflammatory markers in humans and therefore may support patients with IBD⁷.
Is a Low Sulfur Diet worth following?
As mentioned before, overall dietary patterns are KEY for long-term positive outcomes and also for our overall quality of life. In the context of IBD, dietary patterns that include more fruits, vegetables and plant-based foods, and lower amounts of red meats have shown to be beneficial for disease management, and would be easier to incorporate into your day-to-day eating regimen.
Caution should be taken when deciding to pursue a diet low in sulfur products. This can become quite restrictive and deprive our bodies from essential nutrition, not to mention eradicate the beneficial functions of sulfur. Restrictive diets can easily start to villainize foods that are still SO important for overall health, so we should always weigh the benefits and risks carefully.
It is also good to note that following any restrictive diet, such as one low in sulfur can have a negative impact on your general mental health as well as your social and family life.
Keep in mind that having UC can already put you at risk of nutritional deficiencies, therefore, following a restrictive diet would not be supportive of this. Studies show that the majority of patients with IBD will restrict their diet in some way to relieve their symptoms⁷ ⁸. If this is you, it is highly recommended you work with a registered dietitian to assess any nutritional gaps in your diet.