How to enhance your immunity through plant-based nutrition

As the temperatures drop and flu and cold season approaches, we need to start thinking about looking after our immune health. This means enjoying a plant-rich diet based around fruit, vegetables, legumes (beans, lentils, peas, soya), whole grains, nuts and seeds, herbs and spices. As well as providing us with protein, fat and carbohydrates, these foods are rich in micronutrients such as Vitamin C and zinc, which support healthy immune function.

In the winter, we might crave high-fat foods which are energy dense due to biological changes that happen at this time of year. Craving these types of foods may also be a sign of Seasonal Affective Disorder (SAD) when coupled with depression, fatigue and withdrawal from society. In general, many people feel a drop in mood as the level of light wanes and temperatures drop. The stress resulting from this can lead us to seek “comfort foods”, usually in the form of simple carbohydrates (white bread, cakes, pastries, pies) and sugar that seem to decrease the emotional stress responses. Eating “comfort foods” often relaxes us due to the release of dopamine, serotonin, and endorphins, and temporarily takes away feelings of anxiety and stress.

However, this behaviour can become a cycle that leads to increased patterns of unhealthy food consumption and weight gain as we tend to choose hyper palatable foods rich in salt, oil, sugar and fat. Ultra-processed foods such as processed meats and fried foods promote inflammation and oxidative stress. These products deliver combinations of fat, refined oils, sugar, salt and artificial flavours and emulsifiers. These hyper-palatable food-like substances (think biscuits, crisps, pastries) are easy to over-consume. They hijack the brain’s reward system and result in powerful cravings.

Swap ultra-processed snacks and animal foods for fibre-rich whole plant foods. Opt for fresh fruit with walnuts, rich in healthy omega-3 fats which are anti-inflammatory and heart and brain-healthy. This will help you sustain energy levels rather than crashing a few hours later after a processed sugary snack bar. As well as these foods, consuming a lot of caffeine (especially if you are sensitive) may interfere with your sleep patterns and thus negatively affect the amount of sleep you get, leaving you tired, groggy and irritable. Choose warming, fibre rich foods instead—soup can help you hydrate and is a great way to eat more pulses and vegetables while a jacket potato with baked beans is a fantastic fibre rich meal. 

Eat a varied, whole food, plant-based diet that includes an array of colourful fruits and vegetables. These are packed full of antioxidants, phytonutrients and anti-inflammatory compounds which all act to support the function of our immune system. An adequate intake of VItamin C is needed to support the immune system with top sources including bell peppers, citrus fruits, kiwi fruit and broccoli.

Choose fibre-rich foods including whole grains (such as oats, brown rice), legumes (beans, lentils, peas, soya) and herbs and spices. Flavonoids, found in dark chocolate, green tea and berries, have been found to significantly reduce the risk of upper respiratory tract infections.

Ginger may have a role in immune support and reducing inflammation in the gut. Ginger can be incorporated in a variety of ways as a seasoning, in hot drinks, smoothies, stews, marinades, salad dressings, curries and soups. Pickled ginger is also great. While the fresh root has a unique flavour, ginger powder is nutritious, convenient and budget-friendly. 

Findings from the American Gut Project found that those with the best gut microbiome health ate at least 30 different types of whole plant foods per week. Consume more frozen fruit and vegetables as well as tinned pulses to keep within your food budget without compromising on nutrition. Stay hydrated with herbal teas and soups. 

If you are following a plant-based diet, ensure you have a reliable source of B12. Given the importance of vitamin D in the functioning of the immune system, it is strongly advised that everyone in the UK considers a supplement especially during the winter months from September to early April. Some groups such as people with darker skin may require higher doses throughout the year, but it is important to seek the advice of your GP.

Chronic elevated levels of stress promotes inflammation and reduces your defence against infection. Meditation, a gratitude practice, yoga or breathwork can all help lower levels of cortisol, the primary stress hormone.

Relationships also play a crucial role in our wellbeing, whether it is volunteering in the community, picking up the shopping for an elderly neighbour, nurturing your friendships or making quality time for your friends and family. 

Regular exercise improves cardiovascular health, lowers blood pressure, insulin resistance, helps maintain healthy body weight, and protects against a variety of diseases including viral and bacterial infections.

Aim to be physically active every day for 30-60 minutes per day. Adults need at least 150 minutes (30 minutes daily) to 300 minutes of moderate intensity aerobic activity each week (or the equivalent of 1 hour daily) plus muscle strengthening activities on two days each week to attain the most health benefits from physical activity. 

There is strong evidence that sleep enhances immune defence. Try to aim for between seven and nine hours of good quality, restorative sleep every night.

Improving sleep often starts by focusing on your daily habits, routines and bedroom environment. Develop a relaxing bedtime routine and avoid screen time around 90 minutes before you sleep. You might find having a cup of chamomile tea helpful or a warm bath to unwind, reading a book, meditating and using an eye mask and/or ear plugs. 

The relationship between smoking and/or excessive alcohol consumption and adverse immune-related health effects such as susceptibility to pneumonia is well documented.

Avoid inhaling any substance that might be toxic to the lungs, including vaping. Try to eliminate or reduce risky substances such as alcohol as these have a negative impact on immune health.