A tailored approach to treating severe malnutrition
For children suffering from severe acute malnutrition (SAM), a standardized and medically supervised feeding protocol is vital for recovery. The World Health Organization (WHO) has established a two-stage approach using specific therapeutic milks: F-75 and F-100. These are not general-purpose nutritional supplements but medical foods designed for specific physiological needs during different phases of treatment.
F-75 diet: Stabilization phase
The F-75 diet is the starting point for inpatient treatment of children with SAM, particularly those with serious medical complications such as infections or electrolyte imbalances. Its primary goal is not weight gain but metabolic stabilization. The '75' in its name signifies its energy density: 75 kilocalories (kcal) per 100 millilitres (mL).
Key characteristics of the F-75 formula include:
- Low Protein and Sodium: Severely malnourished children have a fragile metabolism, and a high protein or sodium load can be dangerous. The F-75 formula is designed to be gentle on their weakened systems.
- High Carbohydrate Content: It provides a moderate level of sugar, primarily to prevent life-threatening hypoglycemia (low blood sugar).
- Fortified with Micronutrients: Despite its lower energy and protein content, F-75 is fortified with essential vitamins and minerals needed for recovery.
- Used for a Short Duration: This phase typically lasts for 2 to 7 days, depending on the child's progress. Healthcare workers monitor the child's appetite, general condition, and vital signs closely during this period.
F-100 diet: Rehabilitation phase
Once a child has stabilized on the F-75 diet, their appetite returns, and any severe medical complications are under control, they are ready to transition to the F-100 diet. This is known as the rehabilitation or 'catch-up' growth phase. The '100' indicates its higher energy density: 100 kcal per 100 mL.
Key characteristics of the F-100 formula include:
- High Energy and Protein: F-100 is rich in protein and fat, providing the dense nutritional support necessary for a child to gain weight rapidly and rebuild wasted tissues.
- Increased Micronutrients: It contains the same essential vitamin and mineral mix as F-75 but in a higher concentration to support rapid growth.
- Longer-Term Use: This formula is used for a longer period, sometimes for several weeks, to ensure the child reaches a healthy weight.
- Supports Muscle and Tissue Growth: The higher protein and energy content directly fuel the body's growth processes, allowing for rapid recovery.
Comparison table
| Feature | F-75 Diet | F-100 Diet |
|---|---|---|
| Primary Purpose | Metabolic stabilization and treatment of complications | Rapid weight gain and nutritional rehabilitation |
| Treatment Phase | Phase 1 (Initial / Stabilization Phase) | Phase 2 (Rehabilitation / Catch-up Phase) |
| Energy Density | 75 kcal per 100 mL | 100 kcal per 100 mL |
| Protein Content | Low (approx. 0.9 g / 100 mL) | High (approx. 2.9 g / 100 mL) |
| Fat Content | Low | High |
| Sodium Content | Low | High |
| Duration of Use | Short (typically 2–7 days) | Longer (several weeks) |
| Targeted Conditions | Children with SAM and medical complications | Children with SAM who have regained appetite |
| Weight Gain Focus | No, prevents further deterioration | Yes, promotes rapid catch-up growth |
Transitioning between F-75 and F-100
The transition from F-75 to F-100 is a carefully managed process. According to WHO guidelines, the shift occurs over 2–3 days once the child's appetite returns and any oedema (swelling) has subsided. Healthcare staff monitor the child's tolerance to the increased nutrient intake. In many outpatient settings, a ready-to-use therapeutic food (RUTF), such as Plumpy'Nut®, is used in place of liquid F-100 for the rehabilitation phase, offering similar nutrient levels in a paste form. This allows children to complete their recovery at home under supervision.
Why separate formulas are necessary
The physiological state of a severely malnourished child is extremely fragile. Their metabolism is suppressed, and their ability to handle large nutrient loads, especially protein and fat, is compromised. Starting treatment with a high-energy, high-protein formula like F-100 could overwhelm the child's system, leading to refeeding syndrome, a potentially fatal metabolic complication. The staged approach, starting with the lower-nutrient F-75, allows the body to re-stabilize and regain its metabolic functions safely before embarking on the rapid growth and recovery of the rehabilitation phase.
Conclusion: The critical purpose behind the distinction
The core distinction between the F-75 and F-100 diets lies in their specific roles within a structured medical treatment plan for severe acute malnutrition. The F-75 diet is a low-energy, low-protein formula used in the initial stabilization phase to address life-threatening complications. In contrast, the F-100 diet is a high-energy, high-protein formula for the subsequent rehabilitation phase, designed to promote rapid and safe weight gain. Both are critical components of the WHO protocol for saving the lives of severely malnourished children, illustrating a phased and medically precise approach to nutritional recovery.
For more comprehensive details on the management of severe malnutrition, the WHO provides extensive guidelines: Management of severe malnutrition: a manual for physicians and other senior health workers.
