Expert Dietitian Guidance on Managing Common Digestive Issues: From IBS to Food Intolerances

Posted January 24, 2024
Man holding stomach with waffles on tableAround 20% of Americans suffer from chronic digestive issues, and many do not seek help until it gets bad enough to disrupt daily life. Digestive issues can come and go, with seemingly no rhyme or reason, making it difficult to identify patterns independently.

According to the American Gastroenterological Association, it is common for those with digestive issues to avoid talking about their symptoms unless their provider brings it up. This is troubling when you consider that around 40% of Americans with chronic digestive distress have had to stop or reduce daily activities (such as exercise, errands, or social time) due to the extent of their discomfort.

As a dietitian and a long-term sufferer of digestive issues, I can personally relate to how difficult it can be to both endure the symptoms and to talk about it. If this is you, too, let me tell you how a dietitian can be supportive in working with you on digestive concerns:

Understanding The Basics of Digestive Distress- Possible Causes

First, while working with your dietitian, it is important to see a Gastroenterologist (GI) doctor to rule out more serious causes of digestive issues:

Irritable Bowel Disease (IBD)

Irritable Bowel Disease (IBD) is an autoimmune disease that targets the digestive tract, with two subtypes – Crohn’s Disease and Ulcerative Colitis. 

Crohn’s Disease and Ulcerative Colitis

They lead to inflammation and irritation of different parts of the digestive tract, causing diarrhea and poor absorption of nutrients. If left untreated, this can lead to permanent damage to the intestines and a higher risk of intestinal and colon cancers.

Celiac Disease (CD)

Celiac Disease (CD) is an autoimmune disease that causes damage to the intestines with the ingestion of gluten, the main protein in wheat, barley, and rye. Over time, untreated CD can lead to malnutrition and weight loss and an increased risk of other autoimmune diseases, intestinal cancers, and heart disease.

Small Intestinal Bacterial Overgrowth (SIBO)

Small Intestinal Bacterial Overgrowth (SIBO) is when the small intestine has an abnormal amount of bacteria present, leading to malabsorption of nutrients, damage to the intestinal lining, and possibly weight loss or malnutrition. It is normal for the large intestine (the colon) to have many bacteria, but not the small intestine.

Infections of the GI from SIBO

Infections of the GI tract can be bacterial, viral, or parasitic. These typically require treatment with medication and cannot be fixed through dietary changes.

Common SIBO testing

Common testing to rule out the above diagnoses includes a Hydrogen Breath Test (SIBO), stool sample (infections), upper endoscopy or small bowel endoscopy (imaging and biopsies of the esophagus, stomach, and small intestine), colonoscopy (imaging and biopsies of the lower small intestines, colon, and rectum). Your doctor will determine which are most essential based on your symptoms.

Food allergies

Although more common in children than adults (only about 4% of adults have them), they are still essential to rule out due to the potential severity. A food allergy occurs when your body perceives the proteins in a specific food as a (false) threat, therefore launching an immune response against them. It is possible to suddenly develop an allergy to a food you’ve long tolerated.

The only way to diagnose one is to work with an allergist. They can perform skin-prick and/or blood tests to indicate whether food-specific immunoglobulin E (IgE) antibodies are present in your blood.

Food intolerances

Food intolerances are different than an allergy because they do not involve the immune system. They have similar (but often less severe) symptoms to food allergies – digestive concerns (cramping, nausea, bloating) and others such as headaches or skin rashes. There is currently no valid testing for diagnosing food intolerances, despite many companies now offering “food sensitivity” testing. These blood tests target IgG, a food–specific protein; its presence in the blood is likely a normal response of the immune system to food exposure, and higher levels may be due to tolerance of foods, not the other way around.

Irritable Bowel Syndrome (IBS)

If your doctor rules out the above, they may diagnose you with Irritable Bowel Syndrome (IBS). This is a functional disorder of the digestive tract, classified by its cluster of symptoms rather than a physical abnormality of the digestive tract. It has three subtypes – IBS-C (constipation), IBS-D (diarrhea), and IBS-M (mixed subtype). While it does not cause an increased risk for cancer over time, it can lead to serious distress and affect the quality of everyday life, with symptoms such as urgent bowel movements, watery stools, blood in the stools, chronic constipation, bloating, and abdominal pain.

Evaluating Overall Health with Your Dietitian

Gut issues are complex. There are often many causes, and therefore, a multifaceted solution is needed during the process of working with a GI doctor, and after, your dietitian can support you in navigating your diet and lifestyle. A dietitian will look at all aspects of your health – nutrition of course, but also sleep, stress, physical activity, potential food intolerances and triggers, supplements/medications, etc.

For instance, if your dietitian identifies that your diet is lacking in essential nutrients (such as healthy fats, fruits, and vegetables, etc.), they can explain what is missing, where to get these nutrients, and how to grocery shop for and cook these foods in an enjoyable way.

A dietitian can also help differentiate conflicting information on the internet for treating digestive concerns because symptom management for these issues is not always the same. For example, while a high-fiber diet can improve constipation, it may worsen or trigger symptoms of diarrhea. A dietitian can help you find the right balance of fiber and other nutrients for your specific condition.

Coming Up with a Personalized Plan

Many people believe that food sensitieves or intolerances are the causes of their digestive issues, and this is true in a small percentage of cases. However, for most, their overall pattern of eating and lifestyle habits tend to matter more. For instance, a client with IBS-D may have persistent diarrhea that worsens with trigger foods when they are in a flare-up, but they may be able to tolerate some of those trigger foods when they are not in a flare-up.

When food intolerances are present, a dietitian can help you identify them over time with detailed food recalls, targeted elimination, and, more importantly, reintroduction of foods. The goal is to eliminate as little as possible from your diet over time. Why? Because food variety is one of the keys to long-term gut health!

Keys to Gut Health

A dietitian can help you target this list specifically to your needs, but here are a few essentials for building up your gut-health overtime:

Include Fiber in Your Diet

Fiber* is in plant foods, including fruits, vegetables, whole grains, and beans/legumes. It is known as a pre-biotic in the digestive health world, which acts as fuel for the abundant bacteria in your colon. When they are well-fed, the healthy bacteria in your colon can thrive. Research shows that variety in plant foods – different colors, types, and ways of eating them – is the most beneficial for gut health.

*If you have chronic diarrhea, your dietitian can help you navigate the amount and types of fiber you consume. For instance, many folks with chronic diarrhea tolerate cooking better than raw vegetables.

Manage Stress, Anxiety, Depression, and other mental health concerns:

There is a strong connection between your brain and the gut, which is mediated by the bundle of Vagus nerves. These are the main nerves of your parasympathetic nervous system. This system controls body functions such as digestion, heart rate, and your immune system. If you are chronically anxious or stressed, your brain will send these messages to your gut, which can cause disruptive symptoms. Likewise, if your gut health is poor, it can affect your mental state.

Work with your dietitian to discuss techniques for managing stress, including yoga, meditation, and work-life balance, and ask for a referral to a therapist or psychiatrist if needed.

Consider Probiotic Foods, but be Wary of Supplementation

We have no good way of knowing what specific probiotics (or healthy bacteria) are needed for overall gut health. Therefore, I do not often recommend probiotic supplements to my clients – it’s essentially a “shot in the dark” and can be more expensive than helpful. Instead, getting probiotics from various food sources may be more beneficial. They are abundant in yogurt and fermented foods such as kefir, kimchi, cabbage, and more.

Drink Enough Fluids; Reduce Alcohol

Focus on water, tea, and coffee (<400mg/day, or <4 cups) to improve your gut health. Try to reduce alcohol (1 drink a day for cis-woman, 2 drinks a day for cis-men, and avoid/reduce binge drinking – which is 4-5 drinks in one sitting) or abstain from it if needed.

Increase movement

Movement helps with stress management, and digestion (especially for constipation), and works to reduce the body’s overall inflammation.


Adrienne DinkArticle by Adrienne Dink, MS, RD, LDN
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