Immunity: how to increase your resilience to infection

COVID-19 and the current flu season has brought immune health to the forefront of people’s minds. Improving immune function can reduce the chance of getting an infection and potentially reduce infection severity. However, ‘immune boosting’ strategies alone are not enough to strengthen immunity. A well-balanced holistic approach is needed encompassing good nutrition, sleep, stress reduction, exercise and social connection.

What is immune resilience and why does our health depend on it?

The immune system protects us from potentially harmful substances in our external environment. When the immune system senses danger, it should activate a balanced immune response which is quick and appropriate to the stimulus.

Immune resilience is how long it takes us to bounce back i.e. how quickly we fight off an infection and return to health. Immune resilience is hindered when the immune system is overreactive in response to inflammatory conditions, such as diabetes and heart disease, or when it is suppressed by chronic stress. In such circumstances, the immune response is often inappropriate i.e. overactive or underactive.

What’s nutrition got to do with it?

Seventy percent of your immune system is found in your gut so immune function and nutrition are intricately linked.

A shift from eating a traditional Western diet towards a diet resembling the Mediterranean diet can reduce low-level chronic inflammation and improve immune function.

Plant-based foods which are nutrient dense and high in antioxidants and dietary fibre can help temper an overactive immune response. Changes you can make to your diet to lower its inflammatory burden on the body and improve your resilience to infection include:

·         Reduce or avoid added sugars and salt, high-glycaemic index foods (such as processed carbohydrates) and excessive amounts of saturated fats, all of which provoke inflammation

·         Eat plenty of fruits and vegetables – aim for 8 to 10 portions a day. Variety is key so include as many different types of brightly coloured fruits and vegetables as you can

·         Increase dietary fibre – aim for 30 to 35 grams daily, preferably from whole foods

·         Increase omega-3 fatty acids – found in oily fish, flaxseed, chia seeds and walnuts

·         Introduce small amounts of fermented foods to feed your gut bacteria, such a sauerkraut, kimchi, kefir, miso, kombucha or yogurt containing live cultures

Specific nutrients known to support immune function are:

·         Probiotics (from fermented foods or as supplements) contain ‘good bacteria’ that support gut health and influence immune function. Studies have shown that probiotics use can reduce susceptibility to respiratory tract infections

·         Vitamin D is one of the most important and powerful nutrients for supporting the immune system. Evidence suggests that it reduces the risk of cold and flu. In the UK many of us are deficient in vitamin D, and as it is not widely available from food sources, it may be worth supplementing with vitamin D3 over the winter months

·         Vitamin C may help to prevent infections caused by bacteria and viruses. Studies have shown regular ingestion of vitamin C can shorten the duration of colds. Foods rich in vitamin C include citrus fruits, berries and peppers

·         Zinc plays a significant role in boosting immunity. Zinc can reduce the frequency of infections as well as the duration and severity of the common cold. Zinc is found in oysters, red meat and poultry

·         Selenium is a key nutrient for immune function and helps boost the body’s natural defences against bacteria and viruses. Selenium is found in brazil nuts, seafood and organ meats

·         Garlic contains a variety of compounds that can influence immunity. Garlic may reduce viral infection severity and can also prevent infection by viruses that cause common colds

The restorative ability of sleep

Sleep plays a powerful role in supporting immune function. Anxiety is a leading cause of sleep disruption and a lack of sleep reduces your body’s ability to naturally fight off infection. Therefore, it is essential to have a regular sleep routine and to prepare well for sleep.

Experts recommend 7 to 9 hours of sleep every night. The following activities can help facilitate the body’s natural rhythm and improve the quality of your sleep:

·         Go to bed and wake up around the same time every day, including weekends

·         Take in more daylight and limit your exposure to artificial light 1 hour before bed

·         Have your last caffeinated drink around midday

·         Avoid large meals and alcohol 3 hours before bed

·         Take time to unwind before trying to sleep - try some light stretching or deep breathing techniques

Stress reduction techniques

Presently we are all under a great deal of stress. Susceptibility to illness is more likely when we experience high levels of stress so identifying stress reduction strategies that work for you and practicing them regularly could increase your immune resilience. These are some strategies you could try:

·         Avoid information overload - set yourself boundaries on reading the news

·         Practice gratitude – list what you are grateful for / tell people when they have had a positive impact on your day

·         Consider meditating – there are many free online videos and apps

·         Celebrate good habits – recognise the steps you are taking to make positive change

Regular exercise stimulates immune function

Physical activity helps the immune system by raising infection-fighting white blood cells and antibodies, stimulating the circulation of oxygen and nutrients in the blood and decreasing stress hormone levels. Exercise also increases feel good neurotransmitters like serotonin.

A good guideline for most individuals is 30 minutes of moderate physical activity daily. It is important not to over-exercise as prolonged periods of strenuous physical activity may suppress immune function.

Social connection

Supportive social relationships are a significant determinant of immune health. Research indicates that individuals who feel a sense of interconnection with others experience less stress, have increased antibody levels and better health outcomes.

References

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This article is intended to identify practices which may benefit immune function. It is not meant to recommend any treatments, nor have any of these techniques been proven effective against coronavirus. This advice should not be used as an alternative to seeking specialist medical advice, which should be sought before any action is taken. The author and publisher cannot be held responsible for any errors or omissions that may be found in the text, or any actions that may be taken by a reader as a result of any reliance on the information contained in the text which is entirely at the reader’s own risk.