Kwashiorkor is a severe form of malnutrition, caused by a deficiency in dietary protein. The extreme lack of protein causes an osmotic imbalance in the gastro-intestinal system causing swelling of the gut diagnosed as an edema or retention of water.
In wet beriberi, a more acute form, there is edema(overabundance of fluid in the tissues) resulting largely from cardiac failure and poor circulation. In infants breast-fed by mothers who are deficient in thiamin, beriberi may lead to rapidly progressive heart failure
So,edema is seen in both