An herbal remedy extracted from the leaves of the Lagerstroemia speciosa tree, banana may help fight diabetes. In animal-based research, scientists have shown that banaba extract may help keep blood sugar in check (as well as reduce cholesterol levels). Banaba is rich in both corosolic acid (a substance found to offer blood-sugar-lowering and anti-inflammatory benefits) and ellagitannins (a class of compounds with antioxidant effects). For more help in boosting your diabetes defense, try spicing up your meals with cinnamon (another natural substance known to aid in blood sugar control). There's also some evidence that drinking tea on a regular basis and maintaining ample levels of vitamin D may help with diabetes prevention.