Foods to Fight the Flu

With cold and flu season upon us, here are four tips to help you keep fighting fit throughout the winter.

1. Vegetables are vital
If you normally tuck into an orange at the first hint of a sore throat, it could be time to think again. Adding a red pepper to your salad will give you twice as much vitamin C, and broccoli or Brussels sprouts contain nearly 50% more vitamin C than an orange. Including a variety of different coloured vegetables in your diet exposes you to a range of protective antioxidants that will support your immune function. As well as antioxidant vitamins and minerals, vegetables contain plant compounds such as carotenoids and flavonoids which studies have shown to support an effective immune function. Flavonoids contain the pigment that gives the bright colours to different vegetables; as well as having an antioxidant effect on the body they are believed to enhance the action of vitamin C. For a super-healthy winter, make sure that at least 4 of your 5 a day are vegetables and beware of over-cooking, as you can lose 30-40% of the nutrients through excessive boiling or frying, so including some raw vegetables by having a mixed salad or snacking on veg sticks and houmous would be a good move.
2. Don’t forget the D
Vitamin D is so crucial to our health that Mother Nature has left nothing to chance and it’s produced by the body through exposure to sunlight and stored in our fat cells. Our understanding of vitamin D has grown significantly in recent years and it is now recognised that, as well as ensuring healthy bones, it plays a key part in our immune function by promoting anti-microbial activity which protects the body from infection. Recent studies suggest that optimal levels of vitamin D can reduce the risk of developing respiratory infections such as colds, flu or pneumonia. Small amounts of vitamin D can be found in certain foods such as offal, dairy products or oily fish, but recent advice from Public Health England suggests that adults and children over the age of 1 should take vitamin D supplements over the winter to avoid a deficiency. Vitamin D3 supplements are easily available in the shops and you should seek advice from your GP if you have concerns about your vitamin D status.
3. Build your Bacteria
Over 60% of our immune cells are found in the gastrointestinal tract which means that it makes a lot of sense to look after our digestive system if we want to stay fit and well, because a happy gut = a happy immune function. Optimal levels of ‘friendly’ bacteria in the gut play a crucial role in feeding and supporting the activity of our immune cells. Eating a diet rich in fibrous foods such as wholegrains and vegetables will help to support optimal digestion. Prebiotic foods such as garlic, onions or pulses can help to feed the beneficial bacteria in the gut, encouraging them to multiply. Eating fermented foods such as live natural yoghurt, sauerkraut, kimchi or natto is a great move, because the fermentation process produces large amounts of culture which will top up levels of ‘friendly’ bacteria in the gut, keeping your immune system very happy indeed. Keeping sugar to a minimum will also make a big difference, as a high sugar diet can disrupt the balance of gut flora by encouraging the development of ‘unfriendly’ bacteria and yeasts.
4. Stop the Stress
It will probably come as no surprise to hear that you’re more likely to pick up colds and infections if you’re constantly stressed. Our adrenal glands release the steroid hormone cortisol as part of the stress response and high levels of cortisol over an extended period suppress the immune function making you more vulnerable to coughs and colds. Relaxation, sleep, exercise and deep breathing can all help to relieve stress, but what you eat also plays a huge part in regulating cortisol levels. Every time your blood sugar crashes, your body will release cortisol as an emergency response to activate mechanisms to redress the balance. There are two main reasons for a dramatic drop in blood sugar – firstly this will happen if you have been consuming too much of the type of food or drink that triggers the insulin response. Sugar, refined (white) carbohydrate and stimulants such as caffeine or alcohol are all common culprits and it’s insulin’s job to remove it all from the blood which leads to a blood sugar crash. Secondly, if you leave very long gaps between meals (5+ hours), the body will gradually burn through all the energy until the blood sugar drops and you’re running on empty. Maintaining steady blood sugar levels throughout the day will prevent the body having to resort to these emergency measures and ensure your cortisol levels don’t start to creep up. The best way to balance blood sugar is to have a combination of protein (e.g. meat, fish, lentils or nuts) and fibre (e.g. vegetables or wholegrains) with every meal and snack, to limit your intake of sugary foods and stimulants and to avoid long gaps between meals.

For more advice on smart food choices, take a look at my new book:
The Right Bite, Nourish Books, £6.99.