No Gluten. Sprue is also called celiac disease. When you eat foods with gluten (ex wheat), your body attacks your small intestine's absorptive cells and you cannot absorb important nutrients. This leads to diarrhea, weight loss & nutrient deficiency. Avoid all foods, vitamins, etc that contain gluten and see your doctor.
Sprue. Sprue (celiac disease) and tropical sprue both tend to be a chronic condition typically characterized with diarrhea and malabsorption. I am not sure how you mean by you often get sprue. But if you got celiac, avoid gluten, and if you got tropical sprue, then take antibiotics (doxycycline or bactrim) with vitamin b12/folic acid for >6 months.