A few weeks ago I completed a food diary of everything I ate and drank for a week. This was for the EPIC study: a long-term research project being undertaken across Europe to look at the prevelance of cancer and its relation to diet. I found that there’s nothing like writing everything down to make you acutely aware of just how much you snack during the day and for me one thing stood out: chocolate! So when my family succumbed to a bout of flu last week I decided it was time to clean up my act and try to boost my immunity. But just what changes would be necessary?
I strongly believe that prevention is better than cure, so I set about investigating what changes I could make to improve my natural defences against infection. Some factors are probably genetic - my wife generally succumbs to less colds than I do. Other widely accepted factors are stress, exercise and sleep. But I was also interested in whether there were nutritional ways I could boost my immunity.
First to be cut down was the chocolate of course! I have a very sweet tooth and it’s all too easy to nibble biscuits and sweets while working on a computer most of the day. Excess sugar is known to suppress the immune system, yet it is often tempting to eat sweet snacks when you start to feel ‘one degree under’. For others alcohol, smoking, and various drugs (both ‘recreational’ and many pharmaceutical ones such as antihistamines) will be an issue as they also suppress the immune system. However, as any dieter will tell you, just focussing on the things to cut out is no way to make a long term change. It is more important to focus on the things you are going to introduce than what you need to abstain from.
The immune system is extremely complex and one of the wonders of the human body. Because of this it requires a wide variety of nutritional sources for all the various elements to work in optimal balance. I used a number of sources to research this and in particular the book Eat for Immunity by naturopath Kirsten Hartvig. Here are the main nutritional recommendations:
- Vegetables: Practically all vegetables contain a wealth of vitamins essential to good health and immune system functioning. Most have high levels of vitamins A and C and varying B vitamins and minerals, with good dietary fibre. Members of the brassica family such as curly kale and broccoli are often singled out for their wide spectrum of vitamins as well as bioflavinoids which directly stimulate the immune system. Beetroot also has a long history of being used as a ‘vitality plant’ in many areas of the world.
- Fruit: Most fruits are excellent sources of vitamin C which is a well known immune system booster and therefore protector against disease. Citrus fruits are particularly high in vitamin C, although they should not be used to replace vegetables in a diet as they also contain high levels of simple sugars.
- Nuts and Seeds: These contain a wide range of minerals and trace elements as well as being good protein sources. Brazil nuts are particularly effective in boosting the immune system due to the combined effect of selenium and vitamin E.
- Grains and Pulses: As well as providing a good range of nutritional essentials most grains provide several B vitamins and trace elements. A mixed muesli is a good way to get a range of grains at the start of the day. Lentils and quinoa are both excellent nutritionally and incorporating them into meals can again boost immune response.
- Others: Good oils, particularly those which are sources of Omega-3 and 6 such as linseed (flaxseed) are worth adding in to any balanced diet. Shitake mushrooms are known for their immune-stimulating properties.
Of course, there is no better way to ensure that fruit, vegetables, nuts and seeds are packed with vitamins than growing them organically and picking them fresh. Much supermarket produce is picked well before ripening, to allow for transit time, and this can severely limit the vitamin content. So it is easy to see why growing your own organic produce provides the necessary ingredients for a great immune-boosting diet. When I want some Swiss chard, spinach or leeks I step out and harvest them from my front garden and can be sure that they offer me maximum goodness. Plus the exercise and fresh air of gardening are great ways of relieving stress.
Why is this so important? Well, there is a growing certainty amongst health professionals that a highly virulent strain of something like bird flu is going to strike in the next few years. Anyone who works at a hospital, surgery or school in the UK will tell you that they now have to have a pandemic flu plan in place to keep essential services running in the event of such an outbreak. So immunity is not something just for the ultra health-conscious. It is an important part of our ability as communities to thrive and survive. Take that to its logical conclusion and you get yet another great reason for us all to adopt a highly nutritious diet made up of as much home grown produce as possible!