Winter is notorious for increased incidence of the common cold and upper respiratory tract infections (URTI’s). Olivia Warnes, Accredited Sports Dietitian, brings us some expert advice on avoiding dietary deficiencies and maintaining a healthy immune function so your training isn’t derailed.

Numerous factors influence immune function including:

• Inadequate diet
• Physiological stress (i.e. prolonged intense exercise)
• Psychological stress
• Environmental stress
• Poor sleep quality
• Poor hygiene
• Crowds

Insufficient dietary protein and not supporting key training sessions with carbohydrate are potential causes of immune dysfunction. Ensuring sufficient intake of all vitamins and minerals are important to maintain a healthy immune system.

There are many nutritional supplements that claim to boost immunity. Such claims are often based on limited scientific evidence and in selective, small population groups. Prevention is always better than treatment. While there are no magic bullets to eliminate the risk of contracting an infection, there are several effective evidence-based nutrition strategies to lower your risk of succumbing to the common cold and URTI’s.

Protein and Zinc

• Lean meat and poultry provide a quality protein source, while they offer a highly absorbable form of iron to support healthy red blood cells and an excellent source of zinc.
• Zinc supplementation commenced within 24 hours of onset of common cold symptoms reduces the duration of symptoms. For those considering using zinc, the current evidence indicates a dose of 75mg a day is taken throughout the duration of cold symptoms only.

Plant Polyphenols

• Potent antioxidant compounds known for their antioxidant, anti-inflammatory, anti-pathogenic, cardio-protective and anti-carcinogenic activities.
• Ensure a nutrient-rich diet high in polyphenols – fruit, notably berries, vegetables, legumes, grain products and tea.

Vitamin D

• Recent studies in both the general population and athletes have provided evidence that sufficient vitamin D status optimises immune function and helps defend against the common cold.
• Main source is exposure to sunlight. Dietary sources include oily fish (salmon, sardines), sun-soaked mushrooms and fortified products i.e. milk, cereals.
• If you are concerned about your vitamin D status leading into winter, please see your doctor for a blood test.

Probiotics

• Probiotics are food supplements that contain live microorganisms similar to that found in the gut. They are often referred to as ‘good bacteria’.
• There is now a good body of evidence that probiotics can reduce incidence of URTI, along with gastrointestinal illness.
• Dietary sources include yoghurt, kefir and kombucha. If you are illness prone a daily probiotic during the winter months would offer further immune protection.

Nutrient-Rich Carbohydrate Foods

• High intensity exercise increases stress hormone levels. Consuming carbohydrates leading into high intensity exercise can assist in reducing the levels of these hormones and the risk of contracting colds and URTI’s. i.e. fruit, yoghurt, oats, quinoa, brown rice, grain bread.

Olivia Warnes is available for dietitian consultations at our Stepney Healthcare Hub. For all appointments and enquiries with Olivia, contact 08 8362 8111.