- Vitamin C: Enough cannot be said for the benefits of vitamin C. Oxidative stress is when there are more reactive oxygen species or "free radicals" in the body than antioxidants to neutralize them. Diabetes, hypertension, cardiovascular disease, heart attack, stroke, dementia, Alzheimer's disease, arthritis, and several other conditions have been linked to oxidative stress and chronic inflammation!
- Potassium: Potassium cations are required for brain and nerve function, and is essential for allowing muscle contraction (which is why they put it in all those sports drinks). Guava is rich in magnesium too, which is also required for correct muscle function. Magnesium is essential for many important for many cellular functions; magnesium deficiency is often undiagnosed and can lead to diabetes, high blood pressure, heart disease and stroke.
- Lycopene: The same active ingredient that makes tomatoes a potent cancer-fighting food is also abundant in guava. In a group of 48,000 men participating in a Harvard University study, 45% less risk of prostrate cancer was found in the group with additional lycopene in their diets.
Sources: Wikipedia; Guava & Vitamin C & Potassium, Magnesium: Nutritional Aspects, Health Benefits of Guava, The Daily Plate