Guava is very high in roughage and rich in vitamins, proteins and minerals, but it has no cholesterol and a low number of digestible carbohydrates. guava also has far less sugar as compared to apples, oranges, grapes, and other fruit. Another of the tremendous positive benefits of guavas is the presence of B3 and B6 vitamins.B3 (also known as niacin) can increase blood flow and stimulate cognitive function. b6 is a great nutrient for brain and nerve function.