Amy: I have been diagnosed with severe leaky gut and was told by my functional dietician to not consume raw fruits and vegetables. Why is this and are there other dietary recommendations you can offer to heal my leaky gut?

Dr. Chutkan: For those who don’t know, I’ll begin with a quick description of leaky gut and why it can pose such a threat. Leaky gut, also known as increased intestinal permeability, refers to a condition where the tiny holes in the intestinal lining get larger and allow things to pass through that ordinarily couldn’t. The inner lining of the intestines is a porous membrane, like a fishing net constructed of very fine mesh. Under normal circumstances, fat, protein, and carbohydrates are broken down, absorbed through the tiny holes in the membrane into the bloodstream, and transported to cells. The gut membrane also keeps toxins and threats to the body from being absorbed through the net.

With leaky gut, the net develops large holes. Substances that are normally kept in the gut and excreted in the stool instead pass through the membrane into the bloodstream. The immune system, sensing invaders, is roused, increasing the potential for autoimmune disease as the body starts to mount reactions to these foreign substances. Large, incompletely digested food particles can find their way into the bloodstream, resulting in multiple food sensitivities and allergies, as the body doesn’t fully recognize these unfamiliar substances and treats them as enemies. On constant alert, the immune system can become very reactive, responding to stimuli it would normally ignore, and more serious disease can ensue.

The most likely reason your functional dietician recommended avoiding raw fruits and vegetables is because digesting raw plant foods is hard work for your digestive tract and requires lots of digestive enzymes. Because some people with gut issues have a decrease in digestive enzyme production, it can result in a lot of bloating, gas, and abdominal cramping. So, some experts recommend avoiding raw fruits and vegetables during the healing process, and a slow reintroduction once your intestinal permeability is repaired and your symptoms subside. 

While this thought process makes sense, if you take a good look at the research, there is no direct link between leaky gut and decreased digestive enzyme production. Decreased digestive enzyme production is most often seen in pancreatic diseases, so just because someone has leaky gut, doesn’t necessarily mean they have digestive enzyme production impairment. However, it is true that consuming raw fruits and vegetables can cause more gas, bloating, and stomach cramping than their cooked counterparts, and if you’re susceptible to GI-related symptoms, consuming raw plant foods could be problematic for you, increasing uncomfortable gut symptoms.

As a rule of thumb, consuming a mix of cooked and raw vegetables daily is an important component of a healthy diet and a healthy gut, as they each offer differing beneficial nutrient components. If you feel an increase in GI-related symptoms when you consume raw fruits and veggies, it’s fine to eliminate them from your diet for a limited amount of time, then gradually reintroduce them, assessing how you feel as you do so. You can also consider consuming very small portions of raw fruits and vegetables (for example, 1 cup of raw leafy greens) daily to gain their benefits without completely eliminating them.

Other dietary recommendations for treating leaky gut include those that will reduce inflammation, increase the health and balance of the gut microbiome, and in turn restore the integrity of your gut lining: