Introduction

Respiratory Syncytial Virus (RSV) is a common pathogen responsible for respiratory infections, particularly in young children and the elderly. Strengthening immunity against RSV involves maintaining a healthy lifestyle and diet. Following dietary considerations supported by research findings can help boost immunity against RVS in adults. 

Embrace a balanced diet 

A well-balanced diet, including various fruits, vegetables, whole grains, lean proteins, and healthy fats is vital to maintain good health and boost immunity. A balanced diet enhances immunity against RSV infection by providing essential nutrients that support various immune functions. Key nutrients include:

• Fats: Omega-3 fatty acids exhibit anti-inflammatory properties that help modulate immune responses during infections, potentially reducing the severity of RSV symptoms
• Vitamins A, C, D, and E: these act as antioxidants, enhance epithelial barrier integrity, and support the growth and activity of immune cells
• Minerals: Zinc and selenium support immune cell development, reduce oxidative stress, and possess antiviral properties 

Researches underscore the importance of these nutrients in strengthening the immune system, thereby reducing the severity and frequency of infections like RSV.¹​

Increase intake of antioxidant-rich foods 

Antioxidants are crucial in neutralising harmful free radicals, which damage cells and impair immune function. 

• Sources: Many studies and research highlight the importance of antioxidants in respiratory health. Foods rich in antioxidants, such as vitamin C, vitamin E, and flavonoids, include fruits (e.g., berries, citrus fruits), green leafy vegetables (e.g., spinach, kale), nuts, seeds, green tea and colourful vegetables like bell peppers and carrots² 
• Benefits: Antioxidants help by neutralising reactive oxygen species, ROS, thus reducing oxidative stress. This can prevent the cellular damage and inflammation typically associated with RSV infections
• Quercetin has been shown to inhibit viral replication and reduce the secretion of pro-inflammatory mediators, while curcumin can block virus entry into cells and reduce viral replication and lung injury​
• Antioxidants help protect lung tissue from damage. For example, curcumin has been found to reduce lung injury in animal models infected with viruses similar to RSV by lowering the expression of vital cytokines and chemokines involved in the inflammatory response
• Antioxidants like epigallocatechin gallate (EGCG), commonly found in green tea, have immune-boosting properties. They can modulate immune responses and have been found effective against various viral infections, potentially offering protective effects against RSV³​

Optimise vitamin D levels 

Vitamin D is critical for immune health, with deficiency being associated with increased susceptibility to respiratory infections, including RSV. Research suggests that maintaining adequate vitamin D levels may help reduce the risk and severity of respiratory infections⁴ 

• Sources: This includes fatty fish (e.g., salmon, mackerel), fortified dairy products, fortified orange juice and supplementation

Immune function: Vitamin D helps maintain the integrity of epithelial barriers, the first line of defence against pathogens. These barriers reduce the likelihood of viral entry and subsequent infection​. Vitamin D induces the production of antimicrobial peptides like cathelicidin and defensins in epithelial cells and macrophages. These peptides have direct antiviral effects, helping to neutralise RSV before it can establish an infection.​ Vitamin D enhances the function of innate immune cells. It promotes the differentiation of monocytes into macrophages and boosts their phagocytic activity, superoxide production, and overall bacterial killing capacity. 

Several studies have shown an inverse relationship between vitamin D levels and the incidence of respiratory tract infections. A meta-analysis of 25 randomised controlled trials involving over 11,000 participants found that vitamin D supplementation significantly reduced the risk of acute respiratory infections, particularly in those with initially low vitamin D levels​​. Another study found that individuals with higher vitamin D levels had a lower risk of developing severe respiratory infections, supporting the notion that adequate vitamin D status is protective against RSV and other respiratory viruses.^5,6

Ensure sufficient zinc intake

Zinc is indispensable for immune function and may help protect against respiratory infections. Studies suggest that zinc supplementation can reduce the incidence and duration of respiratory infections.⁷ Dietary sources of zinc include meat, poultry, seafood, especially shellfish, legumes, nuts, seeds, and whole grains.

Consume probiotic-rich foods

Probiotics, beneficial bacteria that support gut health, have been shown to enhance immune function. Many studies have suggested that probiotics can reduce the risk and severity of respiratory tract infections by modulating the immune response. Probiotic-rich foods, including yoghurt, kefir, kimchi, sauerkraut, and other fermented foods, may help to support gut health and strengthen the immune system.⁸

Garlic supplementation

Garlic contains compounds with antimicrobial and immunomodulatory properties. Garlic supplementation may help prevent respiratory infections by enhancing immune function and reducing inflammation. Incorporating fresh garlic into meals or taking garlic supplements may offer immune-boosting benefits.⁹ 

Adequate hydration

Adequate hydration is vital to maintain mucosal integrity in the respiratory tract and is essential for trapping and clearing pathogens, including RSV. Hydrated mucous membranes are more effective at serving as a barrier against infections since the moisture supports the optimal function of immune cells. Immune responses, including lymphocyte activity and antibody production, are highly dependent on fluid balance within the body. Hydration aids in the elimination of toxins and metabolic waste products, reducing the overall burden on the immune system and allowing it to focus more effectively on fighting infections. 

While specific research on hydration and RSV immunity is limited, staying well-hydrated supports overall immune function and respiratory health. Herbal teas and broth along with water can also be incorporated to maintain good hydration. Research highlights that while direct studies on hydration and RSV specifically are limited, the general principles of immune function support the role of hydration. For instance, maintaining fluid balance is known to help symptoms and improve outcomes in various respiratory infections. Proper hydration supports the body's overall homeostasis and is critical during immune responses to infections like RSV.¹⁰

Limiting sugar and processed food

Excessive consumption of sugar and processed foods can suppress immune function. Try to minimise intake of sugary snacks, sodas, and processed foods.

Restricting alcohol consumption 

It has been researched that alcohol consumption weakens the immune system by making one susceptible to infections, increasing recovery times and causing organ damage. Alcohol consumption can also lead to the development of certain cancers which makes the immune system compromised.¹¹

Summary

Dietary changes, supported by scientific evidence, can help strengthen immunity against RSV infection in adults. While specific research directly linking these dietary interventions to RSV immunity in adults is limited, the cumulative evidence underscores their importance in bolstering overall immune function and reducing the risk of respiratory infections. 

Adopting a comprehensive approach to immune health, includes regular exercise, sufficient sleep, stress management by practising stress-reducing activities like meditation, deep breathing exercises, yoga, or spending time in nature, and good hygiene practices.