Your respiratory system consists of your trachea, throat, lungs and nose. Its main function is to expel old air and inhale fresh oxygen into your lungs. Harmful substances such as tobacco smoke and germs can reduce oxygen content in your lungs and damage your airways. Adjusting your diet to include lung-friendly foods can promote optimal respiratory health.

GREEN TEA

Injury to your lungs due to smoking or pollution exposure can increase lung inflammation. Chronic lung inflammation can impair healing and lung functions. According to a 2005 clinical study conducted by Policlinico Universitario, green tea contains properties that can reduce lung inflammation. The study found that giving green tea to laboratory rats with damaged lungs drastically decreased inflammation and promoted healing. Green tea contain catechins, a class of powerful antioxidants.

CARROTS

Consuming vitamin A enables your body to defend itself against bacteria, toxins and other infection-causing pathogens, according to "Prescription for Nutritional Healing." If left untreated, these harmful agents can lead to dangerous infections, pneumonia and other respiratory problems. Carrots contain substantial amounts of vitamin A.

OMEGA-3 FATTY ACIDS

Eating omega-3-rich fish reduces asthma severity and incidence in children and adults, according to the Agency for Healthcare Research and Quality. Also known as polyunsaturated fatty acids, these nutrients help reduce inflammation in your body. Sources of omega-3 acids include tuna, mackerel, lake trout, salmon, herring, sardines, flaxseed oil, Brazil nuts, macadamia nuts, almonds and peanuts.

VITAMIN C

According to the "Prescription for Nutritional Healing," consuming a diet rich in vitamin C nutrients can significantly increase lung functions. Vitamin C is an ascorbic acid that acts an antioxidant to protect your lungs and body from free radicals that cause infection and chronic disease. Sources of vitamin C include blueberries, tomatoes, mangoes, limes, fortified cereals and baked potatoes.