Nutritionist Tran Pham Thuy Hoa from the Nutrition Department of Tam Anh General Hospital in Hanoi says many non-smokers without underlying health conditions still experience frequent colds, persistent coughs, and recurring sore throats. The primary cause is often a weakened immune system. Immunity is largely built on factors like sufficient sleep, regular exercise, and a balanced diet.

The respiratory tract is the first line of defense against air pollution, viruses, and bacteria. Nutrient deficiencies weaken the body's immune response to these pathogens, leading to respiratory illnesses with symptoms like coughing, phlegm production, and runny nose.

Vitamin C

Vitamin C is a powerful antioxidant, protecting the body from damage caused by free radicals and pollutants that harm the respiratory system. It strengthens white blood cell activity, enhancing the body's ability to fight off viruses and bacteria that cause respiratory illnesses. Vitamin C also reduces inflammation, maintains the integrity of the respiratory mucosa, and promotes recovery, preventing and treating respiratory infections.

Since the body cannot produce vitamin C, it must be obtained through diet. Rich natural sources include oranges, lemons, guava, pineapple, grapefruit, broccoli, and bell peppers. These should be eaten fresh or quickly cooked (boiled or steamed) to avoid destroying the vitamin through heat.

Vitamin D

Vitamin D aids calcium absorption, protects bones, boosts immunity, and reduces the risk of acute respiratory illnesses like bronchitis, pneumonia, and asthma. It also regulates inflammatory responses in the lungs, protecting lung tissue from environmental damage. Vitamin D further reduces the risk of chronic respiratory conditions like COPD (chronic obstructive pulmonary disease) and asthma.

Vitamin D is primarily synthesized through sun exposure. Working indoors, consistently using sunscreen, and limited outdoor time can lead to deficiencies. Incorporating fatty fish (salmon, tuna), eggs, liver, mushrooms, and milk into the diet can boost vitamin D levels. Spending 15-20 minutes each morning in the sun allows the skin to naturally and effectively synthesize vitamin D.

Vitamin A

Vitamin A maintains respiratory health by protecting and regenerating the respiratory mucosa. Adequate vitamin A ensures this lining functions effectively, preventing the entry of bacteria, viruses, and dust. Vitamin A deficiency can dry and damage the mucosa, increasing susceptibility to infections like bronchitis or pneumonia. Vitamin A also supports immune function, helping the body fight environmental pathogens. Individuals with lung issues should consume vitamin A-rich foods.

Vitamin E

Vitamin E protects the lungs from free radicals and environmental toxins by neutralizing their effects upon inhalation. Adequate vitamin E intake can reduce inflammation, promote lung tissue repair, rebuild lung capacity, and improve respiratory function, especially in individuals with chronic lung disease. Foods rich in vitamin E include soybeans, wheat, sprouts, and spinach.

Vitamin B12

Vitamin B12 enhances respiratory function by supporting red blood cell production and protecting the nervous system. B12 deficiency can lead to megaloblastic anemia, which reduces oxygen transport capacity, causing shortness of breath and fatigue, particularly during physical activity. Vitamin B12 also maintains the function of nerves controlling respiratory muscles like the diaphragm. Prolonged B12 deficiency can damage nerves, affecting breathing patterns and increasing the risk of respiratory infections.

Zinc

Although present in small amounts, zinc plays a vital role in immune function. It aids in the production and activation of immune cells, promotes tissue repair, and reduces inflammation. In the lungs, zinc has anti-inflammatory, antioxidant, and antiviral properties, inhibiting cancer cell migration and regulating lipid and immune cell metabolism. Zinc supplementation improves immune function and reduces the risk of respiratory illnesses.

Zinc deficiency increases susceptibility to infections, prolongs recovery from colds, and delays wound healing. Children with zinc deficiencies are prone to respiratory illnesses, while adults are more susceptible to lung diseases and complications from the flu. Sources of zinc include oysters, shellfish, beef, pumpkin seeds, mung beans, and whole grains.

Khue Lam