Nutritional facts: antioxidants, phytochemicals -- plant compounds an 8-ounce cup of brewed coffee offers approximately 7 milligrams of magnesium, 0.6 milligram of manganese plus 0.5 milligram of niacin and 0.2 milligram of riboflavin -- both of which are b vitamins health benefits: the arabic coffee’s intake can minimize the onset of such devastating ailments as type ii diabetes, dementia, heart diseases, and even certain types of cancer.