Ultimate Guide to the Elemental Diet for SIBO, IBS & More

1. What is the elemental diet? 

Elemental diets are made up exclusively of liquid formulas designed to provide essential nutrients. What makes them "elemental" is their hydrolyzed (pre-digested) proteins, carbohydrates, and fats.1

If you're at the point of wanting to try an elemental diet, chances are your digestion is in a bad space. Elemental diets are usually the last resort option after you've tried everything else with no success. Basically, at this point, you're telling your digestive system to take a breather while letting the formula takeover to do the digestive work for you. 

More often than not, elemental diets aren't necessary. Most of the time, several real-food strategies can be tried first to get relief. 

There are also standard formulas (non-elemental ) that are usually tried before looking for a more broken down option. These are referred to as polymeric formulas. They have "intact" or non-digested nutrients. These are the formulas you see in the grocery store, like Boost or Ensure, for example.

However, sometimes a partially hydrolyzed (semi-elemental) or fully hydrolyzed (elemental) meal replacement is needed. We often see this for people who need a meal replacement supplement but can't tolerate standard polymeric formulas without symptoms. 

These formulas may also be used for people with immune system over-reactivity to foods,2 low nutrient absorption, dysfunction of the pancreas, certain gastrointestinal diseases, and those transitioning back onto foods after bowel rest or abdominal surgery.1

2. What foods & drinks can & can’t you eat? 

Following an elemental diet means replacing everything you eat or drink with a unique elemental formula. Elemental diets can be used temporarily for a matter of days or 2-3 weeks. However, on rare occasions, they can also be part of a permanent diet regimen. This most often happens for people requiring long-term tube feedings who poorly tolerate standard polymeric formulas. 

If you require an elemental diet, it should only be carried out under a medical provider's supervision, such as a registered dietitian. 

Depending on why the elemental diet is being used, it is possible other foods and beverages may be added into the mix. In fact, some studies have used a half elemental, half regular diet intervention and still found benefits in Crohn's disease treatment.3 Any diet additions to an elemental diet should be the judgment call of a qualified medical professional. 

A dietitian may make other tweaks to the diet that might include adding supplemental fats, vitamins, and minerals or adjusting the amount of fluid mixed into powdered formulas. Much of this will depend on your personal nutrition and fluid needs, blood work, and formula tolerance.

While there are recipes available for a DIY version of the diet online, we don't recommend taking this approach. Concerns we've had while looking over some DIY recipes include the risks of electrolyte imbalances or the use of certain hydrolyzed protein sources that may not provide all essential amino acids. For instance, if a recipe only uses hydrolyzed collagen protein as the protein source, this could lead to problems since collagen is naturally lacking in the essential amino acid, tryptophan. 

If you are considering going the DIY route, we strongly encourage you to hire a dietitian first. The dietitian can evaluate the recipe you plan to use for any nutritional shortcomings. Also, purchasing a standard elemental formula doesn't automatically put you in the clear for nutritional adequacy. Several elemental diets are extremely low in fat and could result in an essential fatty acid deficiency if carried out for too long without medical supervision. 

There are several types of elemental formulas. The one that's best for you will depend on your individual needs. Ideally, it should be chosen with the help of a registered dietitian.

Examples of Elemental Formulas

Adapted from:  https://www.nutritioncare.org/Guidelines_and_Clinical_Resources/EN_Formula_Guide/EN_Adult_Formulas/

3. What a typical day of meals looks like

We chose a product called Vivonex Plus to create our sample day of meals. For starters, Nestle's Vivonex is a mainstay in the world of elemental diets. Vivonex is well studied and comes in 4 separate formula options. All Vivonex formulas except for Vivonex RTF can be used as drinkable oral supplements, and all are tube-feeding friendly. 4

Elemental diets are gaining steam for the treatment of small intestinal bacterial overgrowth (SIBO). Most practitioners base their use for this purpose off of a 2004 study in IBS patients using a Vivonex product.5 Because Vivonex sparked the use of elemental diets for SIBO, we thought it made sense to highlight the product here. 

Soy and corn-based ingredients in the formula may send off alarm bells for those with a history of allergies or food intolerance. However, due to being a hydrolyzed formula, Vivonex is too broken down to be allergenic, with no reported allergies to date.4 

Keep in mind that Vivonex Plus is a low-fat formula. There is a disclaimer on the box about the low-fat content, which may not be adequate to meet essential fatty acid needs. This product, like all elemental formulas, should only be used with medical supervision. 

4. How easy is it to do? 

The elemental diet is easy to follow in terms of knowing what you can eat-- which is practically nothing outside of the formula. The tricky part is staying on the diet and following through to the end (commonly 2-3 weeks). What makes the diet hard to follow is the awful taste, cost, and lifestyle or social limitations the diet requires.

Scanning through online forums suggests that most of the products out there aren’t very appetizing, with the DIY versions and some formulas used in the hospital generally being the worst in taste. There are formulas on the market now that claim to have perfected their formula's flavor, but even then, exclusively drinking shakes for 2-3 weeks straight may still be difficult to stomach.

If you choose to go the DIY route, which we don't recommend, you'll save money but lose out on flavor and, possibly, nutritional adequacy. Formulas online start around $550 for a 2-week diet plan. It’s usually a last resort for those who try the elemental diet, and spending several hundred dollars may likely feel worth it to them. It's also helpful to keep in mind that you won't be buying other groceries or going out to eat for the diet's duration.

Generally, it’s suggested to drink the formula every 2-3 hours throughout the day. This formula-only meal pattern can throw off your social life. Going out for drinks after work, meeting friends for brunch, or family dinners are now a little more complicated and a lot less fun. However, most of the time the diet isn’t permanent, and you may get to enjoy regular foods once you've done your time.  In some cases, if the diet works, you may be enjoying foods even more than you were able to before.

5. Is the elemental diet good for you

Crohn’s Disease 

Exclusive tube feedings have been used to treat and maintain remission of Crohn’s disease. A 2019 review which looked at 30 studies with 1070 participants found that both polymeric and elemental formulas provided as exclusive tube feedings were beneficial for Crohn’s disease. Surprisingly, polymeric formulas appeared to decrease a marker of inflammation (C-reactive protein) slightly better than elemental formulas. Overall, there wasn’t much of a difference in benefits between the polymeric and elemental diets. Though elemental diets are known to be beneficial for Crohn’s disease, research to date points towards the use of polymeric formulas as the first choice. This is due to superior improvements in inflammatory markers, lower costs, and better taste.6  

IBS, SIBO

In a study of 93 patients with IBS and abnormal lactulose breath tests (LBT) (a clinical marker for SIBO) 80% had normal LBT after 15 days on the elemental diet. This increased to 85% normal LBT after 21 days.5 

Rheumatoid Arthritis 

In a pilot study, 30 patients with active rheumatoid arthritis (RA) were randomly assigned to 2 weeks of treatment with an elemental diet (n = 21) or an oral steroid called prednisolone 15 mg/day (n = 9). In this study, the elemental diet was as effective as the steroid in improving clinical parameters of  RA except the swollen joint score. An improvement of greater than 20% in early morning stiffness and pain occurred in 72% of the elemental diet group and 78% of the steroid group. However, not all RA patients benefited from the elemental diet.7

Short Bowel Syndrome

Short bowel syndrome is the result of a loss of important absorptive tissue in the gut due to a variety of causes (e.g. surgery, trauma, cancer, etc.) No matter the cause, the condition can result in poor nutrient absorption, and depending on the amount of bowel lost, may even require feedings to be given through the veins  (parenterally). If enough bowel is intact, polymeric formulas are the first choice for patients with short bowel syndrome. However if there is persistent diarrhea and poor nutrient absorption is suspected, semi-elemental or elemental formula may be appropriate.1

Poor Digestion and Absorption

An inability to properly digest and absorb nutrients is a possible indication for using an elemental diet.8 Because digestion is complex and relies on multiple parts of the GI tract and other organs, there are a number of conditions that can lead to poor digestion and absorption. Usually, the need for an elemental diet is at the discretion of healthcare providers based on the symptoms and severity of any underlying poor digestion. Below are potential causes of poor digestion and absorption that might lead to the use of an elemental diet in severe cases: 

• Loss of absorptive surface/intestinal injury 
• Autoimmune enteropathy
• Crohn’s disease
• Ulcerative colitis
• Celiac disease
• Liver disease
• Chronic pancreatitis
• Pancreatic resection (loss of tissue) 
• Cystic fibrosis
• Pancreatic cancer 
• Shwachman Syndrome 
• Zollinger-Ellison disease
• Celiac disease
• Stomach surgery 
• Lymphatic system disorders 
• Whipple disease
• Enzyme deficiencies
• Bowel surgery 
• HIV/AIDS
• Congenital causes of diarrhea
• Bacterial malabsorption 9
  

Eosinophilic Esophagitis (EoE) 

Eosinophilic esophagitis is a chronic immune system stimulated disease of the esophagus triggered by specific foods. Symptoms can include difficulty swallowing, reflux, or vomiting. There are 3 primary treatments for EoE, including an elemental diet, an empiric elimination diet, and a food allergy testing-guided elimination diet. Overall the elemental diet is the most effective approach (90%) followed by the 6-food elimination diet restricting milk, wheat, eggs, soy, nuts, and seafood (72%).2

6. Warnings about the elemental diet

Before trying an elemental diet, realize that it’s meant to be a last resort. It’s best to have exhausted all other diet options first, and of course, only undertake the diet with medical supervision.

Be mindful that DIY formulas may have significant inadequacies, opting in favor of prepared formulas if at all possible. Know that the flavor may take getting used to and expect a high food cost for the duration of the diet.

While elemental diets are used for food intolerance, components of elemental diets can still be agitating to the gut. The concentration of nutrients in the formula can increase something called the osmolality of elemental formulas.10

A high osmolality can draw water into the gut, possibly leading to diarrhea and irritation. Also, be aware that therapeutic fibers are sometimes added to elemental formulas. Some are used in an attempt to regulate the rate of stool transit, while others are added as prebiotics. Some short-chain fibers/prebiotics may be irritating for some, causing gas, diarrhea, and bloating. This is another reason why working with an expert is ideal for picking a formula that’s best suited to your individual needs.1

7. Our conclusion

• Elemental diets are made up of liquid formulas designed to provide essential nutrients. What makes them "elemental" is their hydrolyzed (pre-digested) proteins, carbohydrates, and fats. 
• Three categories of formulas include standard/polymeric, semi-elemental, and elemental. 
• Standard formulas have intact nutrients. These are formulas like Boost or Ensure. In contrast, semi-elemental formulas are partially broken down, and elemental formulas are fully broken down.
• Following an elemental diet involves exclusively eating an elemental formula for a set amount of time and foregoing all other foods. How long an elemental diet needs to be followed depends on individual circumstances. 
• Elemental diets are often used for malabsorption and poor digestion, intolerance to intact formulas, and intestinal and immune system-related diseases. Recently, elemental diets have been used for the management of SIBO. 
• Elemental diets should always be medically supervised. Be leary of DIY versions opting for products formulated by a reputable company.
• Anticipate a poor taste and a high cost. Know that most of the time, polymeric formulas may be just as effective as elemental formulas. Outside of a few medical circumstances, a trial with a standard polymeric formula before moving onto an elemental formula is often warranted. 
• Know that it's possible to have an intolerance to elemental formulas even if they are fully "pre-digested." Some formulas may have a high osmolality, which may cause diarrhea. In contrast, others may have added prebiotics, which can be irritating for some.
• Work with a registered dietitian to choose the most appropriate elemental diet formula and duration for your individual needs.