Defining Oral Rehydration Therapy (ORT) and ORT Food
Oral Rehydration Therapy (ORT) treats dehydration, primarily caused by diarrhea, by administering a special solution orally. The solution, an Oral Rehydration Solution (ORS), contains water, glucose, and a specific balance of salts (electrolytes) like sodium and potassium. ORT works because the intestine can still absorb fluids and electrolytes when glucose is present, even during diarrhea.
The term "ORT food" refers to a food-based ORS where complex carbohydrates, often from cereals like rice, are used instead of simple glucose. This is significant in developing countries where rice is a staple and can be a cost-effective, culturally acceptable alternative. These cereal-based ORS formulations emerged from research aimed at creating more effective and widely accessible solutions.
The Dual-Action Mechanism of Food-Based ORS
The effectiveness of standard ORS relies on the sodium-glucose cotransport system in the small intestine, where glucose helps pull sodium and water into the body. Food-based ORS uses this same principle but adds a second mechanism involving the large intestine.
Here’s how it works:
- Small Intestine Absorption: Just like standard ORS, simple sugars from complex carbohydrates are absorbed in the small intestine alongside sodium and water.
- Large Intestine Absorption: Complex carbohydrates (e.g., rice powder) not fully digested in the small intestine reach the large intestine. There, they are fermented by gut bacteria to produce short-chain fatty acids (SCFAs), like butyrate. These SCFAs further stimulate the absorption of sodium and water in the colon, creating a "dual-action" effect that aids rehydration. This colonic absorption is unaffected by the cyclic AMP pathways stimulated by cholera and other enterotoxins, making it effective even in severe cases.
Comparison of Standard vs. Food-Based ORS
| Feature | Standard (Glucose-Based) ORS | Food-Based ORS (ORT Food) |
|---|---|---|
| Key Carbohydrate | Simple glucose (dextrose) | Complex carbohydrates (e.g., rice powder, maize, sorghum) |
| Primary Action | Stimulates sodium-glucose cotransport in the small intestine. | Works in both the small intestine (glucose) and large intestine (fermentation to SCFAs). |
| Effect on Stool Volume | Does not reduce stool volume compared to intravenous fluids. | Some studies have shown a reduction in stool volume and duration of diarrhea. |
| Cost & Availability | Generally inexpensive, especially in sachet form. Widely available globally. | Often more affordable and uses readily available local ingredients in many regions. |
| Use Case | Effective for all forms of dehydration from diarrhea, including severe cases. | Especially beneficial in resource-limited settings and can also help reduce stool output. |
| Nutritional Benefit | Primarily rehydration with some energy from glucose. | Provides some additional nutrients, calories, and a more pleasant taste for some patients. |
Cereal-Based Solutions and Their Preparation
The most common ORT food involves cereal grains. Research shows promising results with rice-based ORS in reducing stool output. Some guidelines have historically mentioned preparing these at home, but it is crucial to understand the risks of incorrect measurements. The proper balance of ingredients is vital for effectiveness and safety, and incorrect proportions can be harmful.
Here's a list of typical components for food-based ORS:
- Cereal Powder: Common choices include rice, maize, or sorghum, which are boiled and used as the carbohydrate source.
- Electrolytes: Specific amounts of sodium chloride (salt), potassium chloride, and trisodium citrate are added to the boiled mixture.
- Water: Clean, safe water is the base for the solution.
For most people in areas with access to commercial products, using pre-packaged ORS sachets is the safest option. These ensure the correct World Health Organization (WHO) recommended formulation, such as the reduced-osmolarity ORS introduced in 2003.
The Role of Zinc in Diarrhea Management
For children, the WHO also recommends supplementary zinc alongside oral rehydration therapy to aid recovery and reduce the duration of diarrhea. This has been shown to be effective and is often provided in co-packs with ORS sachets to increase access. Zinc supplementation helps restore intestinal function and reduces the likelihood of future diarrheal episodes in the short term.
Conclusion: A Global Health Success Story
Oral rehydration therapy, including ORT food or food-based solutions, remains one of the most significant medical breakthroughs of the 20th century. It is a simple, cost-effective, and powerful tool for preventing and treating dehydration, especially in children with diarrheal diseases. By leveraging both the small and large intestinal absorption mechanisms, food-based ORS can offer additional benefits in terms of stool reduction and nutritional value. While commercial ORS packets are the standard and safest option for most, the underlying principles of ORT food highlight a profound understanding of human physiology that continues to save lives worldwide.
For more detailed information on Oral Rehydration Solutions and treatment guidelines, consult resources from the World Health Organization (WHO) and UNICEF.
