Mother's milk is always the best for babies. It contains all the basic nutrients and antibodies against diseases. It's God given. With the turmoil in many parts of Africa, mother's milk is getting not enough. Pity the babies that will grow up malnourished.
The supply of mother's milk was quite abundant not many years ago though life was barely scraping by for many of the tribes then (perhaps worse now due to fighting and population increase) as these pictures show. The signs of malnutrition were already there.