Kwashiorkor is a form of malnutrition that is caused by a deficiency of proteins. Proteins are essential nutrients for the body as they are responsible for building and repairing tissues, producing enzymes and hormones, and supporting the immune system. When there is a lack of protein intake in the diet, it can lead to a condition like Kwashiorkor.

Minerals, vitamins, and fats are also important nutrients for the body, but they are not directly related to the development of Kwashiorkor. Minerals such as iron, calcium, and zinc, and vitamins like vitamin A, vitamin C, and vitamin D are necessary for various bodily functions and maintaining overall health. Fats are a concentrated source of energy and also play a role in storing vitamins and providing insulation to the body.

Therefore, the correct answer is option 4: Proteins. Alert - correct answer should be option 4: Proteins.