Elemental diet
An elemental diet is a diet of liquid nutrients which is easy to digest and provides complete nutritional requirements. Elemental diet formulas are usually composed of amino acids, fats, sugars, vitamins, and minerals. The diet does not contain whole or partial proteins, food additives, or other common allergens. The diet can be administered orally, via a gastric feeding tube, or via intravenous feeding.
Description
Elemental diet formulas are variable, but usually consist of a liquid mixture of:- Free amino acids: both essential amino acids and non-essential amino acids.
- Lipids: medium-chain triglycerides, sometimes with long-chain triglycerides.
- Carbohydrates: simple sugars or polysaccharides that are easy to digest.
- Water-soluble vitamins and fat-soluble vitamins.
- Electrolytes.
- Hypoallergenic: low potential for allergic reaction since there are no whole proteins, food additives, or other common allergens. However, allergic reaction is rarely possible.
- Easy to digest: the liquid diet contains ingredients which require minimal processing by digestive enzymes and may be absorbed efficiently without active digestion. This causes less stimulation of the pancreas and the gall bladder.
- Anti-inflammatory.
- Generates less feces compared to regular diets. The liquid is mostly absorbed in the first part of the small intestine.
- Low fat content.
- Provides complete requirements for micronutrients and macronutrients.
- Modulates microbiome: since the elemental diet contains no complex carbohydrates which survive digestion in the small intestine, there is no fermentable food source for bacteria in the large intestine.
- Promotes healing of the mucosa by allowing the gut to rest.
Uses
An elemental diet is sometimes used for a range of gastrointestinal and systemic diseases, especially those involving atopy, inflammation, indigestion, and malabsorption. The diet is sometimes used in the following medical situations :- Severe diarrhea
- High output ostomy
- Gastrointestinal fistula
- Eosinophilic esophagitis
- Eosinophilic gastroenteritis
- Inflammatory bowel disease
- Celiac disease
- Dermatitis herpetiformis
- Food intolerance
- Food allergy
- Pancreatitis
- Oral mucositis caused by chemotherapy or radiotherapy
- Short gut syndrome
- Small intestinal bacterial overgrowth and intestinal methanogen overgrowth
- Irritable bowel syndrome
- Severe asthma
- Severe eczema
- Rheumatoid arthritis
- Intestinal lymphangiectasia
- Cronkhite–Canada syndrome
- Orofacial granulomatosis
- Chylothorax
- Chylous ascites
- To reduce gastrointestinal bleeding in burn injury
- After certain surgical procedures; e.g., gastrectomy, colectomy, pancreatectomy, and duodenectomy
Adverse effects
Possible nausea and diarrhea can result from the high sugar content which can also complicate hyperglycaemia in people with pre-existing diabetes. The elemental diet is sometimes gradually started over a period of three days, successively increasing in strength on each day to reduce the likelihood of diarrhea and abdominal colic.
The elemental diet reduces gut motility and secretions from the stomach, pancreas, and gall bladder. These functions normally prevent significant bacterial colonization of the small intestine. Furthermore, long term absence of fermentable food source arriving for bacteria in the large intestine may also promote SIBO.
Experiments have shown that elemental formulas are a perfect growth medium for Clostridioides difficile.
It can be given orally or through a nasogastric tube if the person is not able to tolerate the liquid.