My gut feeling (no pun intended) is that malnutrition stemming from poverty and inability  to get relatively balanced meals cannot be fixed by any amounts of probiotics. They are useful for tweaks and reestablishing a normal balanced that may have been offset by careless usage of antibiotics and poor food habits.

Of course, education goes a long away - one doesn't need to eat expensive food to get a balanced meal but a good understanding is necessary to combine a variety of seasonal items that are available locally and relatively inexpensively. If a small piece of land is accessible, one can grow a number of vegetables, keep a few chickens to get fresh eggs and meat etc to stretch their limited food budget.

Probiotics cannot overcome Malnutrition, it can only render its health benifits to the host. Malnutrition is a deficiency disorder due in availability of nutrient rich food. 

Probiotics can only maintain your health, keep you healthy. They are not solution for malnutrition. To combat malnutrition balanced diet is essential. Availability of cheap nutrient sources, particularly for poor people, is more important to combat malnutrition.