An elemental diet is a liquid diet designed to provide essential nutrients in an easily digestible form. It has been employed for the management of various diseases for over 50 years, with several mechanisms mediating their beneficial effects. The basic premise of an elemental diet is providing nutrition in an easily absorbable form, including all macronutrients: carbohydrates, fats, and protein. Because these macronutrients are broken down into their end components, further breakdown is not necessary for digestion, allowing the gut to rest. Formulated to give your digestive tract a rest, an elemental diet can help with a range of health problems. Elemental diets come in powder form that requires you to just add water.
What is an Elemental Diet?
An elemental diet is a type of liquid diet sometimes recommended by medical professionals for managing certain digestive conditions like SIBO (small intestinal bacterial overgrowth). It contains easy-to-digest nutrients your body needs to function. When you eat whole foods, most of the nutrients are broken down in your digestive tract and are absorbed and used by your body. For example, proteins must be broken down into amino acids, starches into sugars, and fats into fatty acids. Elemental diet formulas contain macronutrients in their most basic form, which decreases demand on the digestive system and allows it to heal and reduce inflammation.
Fully elemental formulas are deconstructed into their most basic, absorbable components. For example, you’ll find individual amino acids like L-arginine and L-glutamine, and simple sugars like dextrose. Modern semi-elemental diets, especially those with whey protein hydrolysate as the protein source, can taste pretty great too.
Forms of Elemental Diets
A full elemental diet is the evidence-based protocol intended to provide dietary management under medical supervision for adult patients with moderate to severe gastrointestinal dysfunction. During a full protocol, the elemental diet is the only nutrition the patient is receiving or consuming for a period of 2-4 weeks in duration; no other foods are consumed during these weeks. Duration and intake can be easily customized to fit individual patients' needs.
A half elemental diet is one in which half of the patient's caloric needs are met with an elemental diet while the remaining are met with tolerated whole foods. This is often used for patients who are unable to, or unwilling to, tolerate a full elemental diet. Half-elemental diets can be used to initiate a full elemental diet or to transition out of a full elemental diet. When doing either a full or half elemental diet, daily caloric needs should be calculated prior to starting. Once calculated, a total number of daily servings should be targeted. Insufficient calories during an all-liquid diet yields insufficient nutritional support for the patient.
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Elemental diet formulas can be purchased over the counter or as a prescription. These products are typically in a powder form that is mixed with water to prepare. While elemental diet formulas can be made at home, this is not typically recommended due to a lack of research and low palatability.
How Elemental Diets Work
One of the advantages of an elemental diet is that carbohydrates, proteins, and fats are in their assimilated form: partially hydrolyzed carbohydrates, free-form amino acids, and medium chain triglycerides. This takes strain off the processes that are normally required to provide this function. When evaluating the type of carbohydrates used in formulas, dextrose is a common carbohydrate source within an elemental diet. Dextrose is absorbed in the proximal small intestine prior to it reaching the distal small intestine, where commensal bacterial overgrowth is common. For the dietary management of patients with small intestinal bacterial overgrowth (SIBO), this is ideal, as it minimizes overgrowth.
Conditions Treated with Elemental Diets
Elemental diets have been employed for the management of various diseases for over 50 years, with several mechanisms mediating their beneficial effects. Yet, they are underutilized due to poor palatability, access, cost, and lack of awareness regarding their clinical efficacy. While large prospective trials are lacking, elemental diets appear to exhibit objective and subjective clinical benefit in several diseases.
| Gut Condition | Key Research Findings | Strength of Evidence |
|---|---|---|
| Crohn’s disease | The elemental diet led to remission in people with Crohn’s disease who were unable or unwilling to use conventional steroid medications. | Reasonably good-meta-analysis data |
| Eosinophilic esophagitis | Elemental diets led to remission in 9 out of 10 patients with eosinophilic esophagitis. | Reasonably good-meta-analysis data |
| Eosinophilic gastroenteritis | Preliminary observational research showed elemental diets were associated with improved clinical outcomes in children with eosinophilic gastroenteritis. | Weak-randomized controlled trials are needed |
| SIBO | A 2-week elemental diet may have normalized abnormal breath tests more often than antibiotics did (80% of cases versus 51% of cases). | - |
Eosinophilic Esophagitis (EoE) and Gastroenteritis (EGID)
EDs have been used in the management of EoE in pediatric patients since the description of the disease, with the first report on efficacy being published in 1995 by Kelly et al. In this study 10 proton pump inhibitor (PPI)-refractory children with EoE (6 also failed fundoplication) underwent a minimum of 6 weeks of exclusive ED. All subjects showed symptomatic response (80% resolution and 20% improvement of symptoms) along with endoscopic and histologic improvement. Subsequent studies in pediatric cohorts assessing exclusive ED therapy reproduced high rates of response ranging from 75 to 95%.
Two prospective studies have investigated the efficacy of exclusive ED in adult EoE. Peterson et al. assessed the efficacy of 4 weeks of ED (2 weeks if their response was complete at week 2 endoscopy) on 29 adult patients with EoE. All patients underwent at least 8 weeks of PPI therapy prior to baseline endoscopy. Compliance was poor as 11 subjects (38%) could not tolerate the elemental diet (Elecare). Of the remaining 18 subjects, one had complete response (< 2 eos/hpf) at 2 weeks and the rest completed 4 weeks of ED. Overall, there was a fivefold decrease in tissue eosinophil count (54 to 10 eos/hpf, p < 0.01). Of 18 subjects, 9 (50%) had complete histologic response (< 5 eos/hpf), 2 (12%) had near complete response (< 6-10 eos/hpf), 4 had partial histologic response (> 10 eos/hpf but > 50% drop in eosinophil count), and 1 (6%) failed (only 18% drop in eosinophil count at 4 weeks).
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Gonsalves et al. assessed the efficacy of ED in 15 cases of eosinophilic gastritis and gastroenteritis in a prospective, single-arm trial. Of 15 subjects, 14 had failed at least one standard of care treatment, including PPIs, steroids, immunosuppressive therapy, or elimination diets. All 15 subjects had complete histologic remission (< 30 eos/hpf) in both the stomach and duodenum after 6 weeks of ED.
Inflammatory Bowel Disease (IBD)
Nutrition and dietary interventions are critical steps in the management of IBD patients with and without undernutrition. Exclusive enteral nutrition (EEN) with intake of liquid elemental, semi-elemental, or polymeric formulas for 6-8 weeks has been shown to be effective in Crohn’s disease (CD). In children and adolescents, EEN is recommended as first-line therapy for induction of remission. A 3 to 6 weeks of ED appear to be effective in inducing clinical, endoscopic, and histologic remission in CD. The role of ED in management of UC remains to be elucidated.
Small Intestinal Bacterial Overgrowth (SIBO) and Intestinal Methanogen Overgrowth (IMO)
While antibiotics are the mainstay of treatment for small intestinal bacterial overgrowth (SIBO) and intestinal methanogen overgrowth (IMO), their overall efficacy is limited at 50% or less. Elemental diet provides an alternative option to treat patients who are refractory, cannot tolerate antibiotics, or prefer a non-antibiotic treatment approach.
Pimentel et al. conducted a retrospective study on patients with irritable bowel syndrome (IBS) and hydrogen-predominant SIBO (based on abnormal lactulose hydrogen breath testing). Subjects took 14 days of ED (Vivonex Plus, Nestle) and if breath test remained abnormal, they were encouraged to take the diet for an additional 7 days. Of 124 included subjects, 93 had complete records or could tolerate the diet for analysis. Normalization of breath test was observed in 80% after 14 days and another 5% normalized with an extension to 21 days.
Rezaie et al. evaluated an oral palatable ED (Mbiota Elemental) in a prospective clinical trial on 30 subjects with IMO and/or SIBO. All patients were able to tolerate 14 days of exclusive ED and a significant drop in maximum methane levels (41 ± 35 to 12 ± 15 ppm, p < 0.001) and peak hydrogen rise (43 ± 42 to 12 ± 11 ppm, p < 0.001) were observed. Complete normalization of breath test was seen in 100%, 58%, and 75% in SIBO (n = 6), IMO (n = 12), and IMO/SIBO (n = 12), respectively.
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Dermatitis Herpetiformis and Celiac Disease
We identified three studies describing the efficacy of the ED in dermatitis herpetiformis and celiac disease, 1 in celiac disease, and 3 in refractory celiac disease. Kadunce et al. conducted a trial on 8 adult patients with dermatitis herpetiformis on dapsone, 6 of whom were given an exclusive ED (Vivonex TEN) plus 30 g of gluten for 2 weeks followed by the ED alone for 2 weeks, while 2 subjects were given the dietary intervention in reverse order. Following the 2-week ED plus gluten phase, 100% of patients (7/7) demonstrated histologic worsening of their celiac disease and after only 2 weeks on the exclusive ED period, 100% (6/6) demonstrated histologic improvement. Interestingly, 6 out of 8 subjects experienced improvement of their rash during the ED with gluten exposure phase, with all 8 experiencing improvement by the end of the study.
What to do Before Starting an Elemental Diet
Ideally, you should consult with a qualified healthcare provider regarding your symptoms and what you might hope to gain from the diet. Based on your condition, your healthcare provider might recommend the diet for three to five days to manage acute symptoms, or for several weeks to give your digestive system a restorative rest and reboot. They'll also let you know how much of the formula to take to meet your body’s caloric needs. Healthcare providers often lean toward higher-calorie recommendations to make sure you won’t feel too hungry or depleted during the diet.
Before starting an elemental diet for SIBO, it’s important to talk with your gastroenterologist about the pros and cons of pursuing this treatment option. Elemental diets should always be done under medical supervision. Because all of your nutrition will come from an elemental formula during this diet, a registered dietitian can help calculate your calorie needs and the formula needed each day. They can also guide you in transitioning back to solid foods once you’ve completed the elimination diet.
Contact your insurance company to see if the product is eligible under your insurance plan. Start by proactively having your healthcare practitioner provide a letter of medical necessity regarding your use of Physicians’ Elemental Diet. Because Physicians’ Elemental Diet is a medical food product, we cannot accept exchanges or returns.
What to Expect During the Elemental Diet
On the full elemental diet, you don’t eat any other foods. The point of the diet is to replace food and minimize digestive activity. Following the diet exactly allows your gut the rest it needs to heal. You may be allowed to drink tea without anything added. Sometimes healthcare providers recommend a “half-elemental diet” for people who need a secondary source of nutrition or who are transitioning into or out of the full diet. In this case, the elemental formulas provide half of your calories, and the other half come from food. There are some formulas specifically marketed for a half-elemental diet, which may not be completely elemental - for example, they may contain MCT oil or whey. These are not completely broken-down sources of protein or fat, but they are generally easy to digest and make the half-diet easier to follow.
You can expect an elemental diet to consist of approximately three “meals” per day of liquid elemental formula, which will replace all solid food. Sipping on the formula throughout the day is not recommended because it’s important to let your digestive tract rest between meals when you have SIBO. Flavor options for elemental formulas vary based on the brand, with some being unflavored and others having a mild vanilla or chocolate taste.
Mix each scoop thoroughly with 7-8 oz. water (cold or room temperature, depending on preference). Drink slowly over the course of an hour. At first, try consuming your first meal during a one-hour TV show with commercials. Take a sip or single gulp at the beginning of the show and continue to sip or gulp during each commercial break. After opening, store remaining powder in a dry place at room temperature.
How to Survive the Elemental Diet
This diet is very restrictive, and it can be challenging. To stick to the diet successfully, healthcare providers recommend that you:
- Keep it cold. Blending the formula with ice, smoothie-style, makes it more palatable.
- Sip it slowly to prevent nausea and drink plenty of water between “meals."
- Make it portable. Have a temperature-controlled thermos to keep your formula in so you don’t get hungry when you’re out and about.
- Stay busy. Distract yourself with fun, non-food-related activities and good company.
Encourage patients to maintain an active and healthy social life while exploring activities that don't involve food (think mini-golf, pottery, and more).
Duration of the Elemental Diet
An elemental diet for SIBO is not meant to be a long-term nutrition plan. Most elemental diets last two to three weeks. The diet may be repeated in the future if the SIBO returns.
Potential Side Effects
During the diet, you may experience symptoms that make you wonder if it’s actually helping your condition or making it worse. Medical guidance can help you sort through this. Symptoms may include:
- Abdominal cramping. The first few days on a liquid diet may loosen poop that has been stuck in your colon, causing gas and discomfort as the residual poop is pushed out. This is a symptom that feels bad temporarily but indicates that something good is happening.
- Detox symptoms. During bowel rest, your liver may take the opportunity to offload extra toxins. This can lead to temporary detox symptoms, including headaches, lightheadedness, nausea and fatigue. Detox feels bad for a few days, but most people feel much better afterward.
- Bacteria die-off symptoms. If you have small intestinal bacterial overgrowth or small intestinal fungal overgrowth, the elemental diet can effectively starve them of food in your lower digestive tract, causing them to die off in great numbers. This can give you detox symptoms. These symptoms usually begin several days into the diet and recede after several days more.
- Reduced motility. It’s common to have less frequent bowel movements on the elemental diet. This may lead some people to believe they’re constipated, especially if they have residual poop in their colon that hasn’t come out yet. The diet doesn’t cause constipation, but it can slow down your bowel function. This is natural and generally no cause for concern.
What to do After the Elemental Diet
It’s important to reintroduce foods gradually as your digestive system is ramping back up again. Healthcare providers typically recommend following a half-elemental diet or a low-FODMAP diet during the transition. They may also recommend probiotics to re-populate your gut with beneficial flora and prokinetic agents to stimulate your bowels to begin moving more regularly again. As you return to your more regular diet, pay attention to the way different foods affect your digestive system.
Following the elemental diet, you’ll be instructed to slowly transition back to solid food as your primary source of nutrition. Sometimes, a low FODMAP diet is advised during this time. To help with food reintroduction, our clinic has adapted a protocol from a 2021 literature review that you might find helpful. This protocol starts with you reintroducing foods least likely to trigger sensitivities. Over several days, you’ll begin to identify what your body tolerates. This gradual approach prevents an abrupt stop and helps you transition smoothly from the elemental diet, maximizing its benefits. In week 4, you’d try the most common allergens, such as fish, dairy, peanuts, or wheat.
Considerations and Precautions
While an elemental diet may be useful to address bacteria growth and digestive symptoms in the short term, long-term solutions should focus on treating the underlying cause of the SIBO. The root cause can vary from person to person, ranging from irritable bowel disease (IBD) to diabetes.
Another major downside of an elemental diet is palatability. Drinking a medical formula for weeks with no solid food can be incredibly challenging. The highly restrictive nature of the diet can also impact social interactions and feel isolating. In addition, high-quality elemental diet formulas can be costly and may not be covered by insurance.
Some populations should exercise caution when considering an elemental diet, such as those with:
- Low body weight.
- Eating disorder history.
- Diabetes.
Unintentional weight loss can occur during an elemental diet due to inaccuracies in calorie estimation or the inability to finish the prescribed amount of formula each day. Individuals with an eating disorder history may find the restrictive nature of the diet to be a trigger for disordered thoughts and behaviors to resurface. An elemental diet is high in simple sugars, which may make it challenging for people with diabetes to maintain appropriate blood sugar control during the diet.
Tips For Successfully Completing the Elemental Diet for SIBO Symptoms
Following an elemental diet for SIBO while eliminating solid food can be very challenging. Set yourself up for success by gathering a team of healthcare professionals to supervise your progress and address your questions and concerns while following the plan. This should include a gastroenterologist and a registered dietitian. Next, choose a time to commit to the diet. It’s best to identify a few weeks when you won’t be traveling and have few social obligations. Starting an elemental diet right before a big trip or around a holiday would not be ideal. Talk to your family and friends about your plans in advance, and ask for their support. This may include not eating around you or inviting you to eat out.