For the treatment of any infection, a steady stream of vitamins and nutrients is your best option. Vitamin A is a very important part of your immune system function, as this essential vitamin breaks down into beta-carotene, which is a powerful antioxidant. This can help to reduce inflammation throughout the respiratory tracts and lower oxidative stress throughout the body, which can complicate infections like Middle East Respiratory Syndrome. Some of the best vitamin A-rich foods available include carrots, sweet potatoes, apricots, spinach, liver and bell peppers.