In the last blog I questioned the wisdom of focusing on single nutrients and their involvement with the immune system. Whilst it may be useful to encourage awareness of the fundamental role of nutrition, it is possible to lose sight of the complex interplay that exists between nutrients.
An example of this is vitamin C and its often heralded role in combatting the common cold. When I was growing up it was a commonly held belief that vitamin C could stop a cold in its tracks, despite evidence suggesting that this wasn’t the case. There is a wealth of research that demonstrates that taking vitamin C at the start of a cold does little to reduce its severity or duration. There is also evidence that regular vitamin C intake can reduce both when consumed regularly, a result that was especially pronounced in people who were under physical stress, which included athletes. In other words, it became the norm to take vitamin C here and there, rather than eating foods that contain vitamin C.
But the potential of vitamin C for the immune system goes significantly further than what it may or may not do for you if you feel a sniffle. Vitamin C has been shown to assist phagocytic action in which cells change shape to surround and contain a pathogen. It can also help increase numbers of lymphocytes, as well as clearing away depleted immune cells. There is far more, but from this alone we can see its relevance, but vitamin C is not the only nutrient that supports the same activity, nor does vitamin C work is isolation as many other nutrients work in the same way, yet vitamin C gets top billing.
I touched on some of the nutrients in the previous post, but to that list (vitamins A, B6, C and the minerals iodine, selenium and zinc etc) we can add folic acid as well as vitamins D and E. In truth, every nutrient plays a role in the human immune response. You may remember that I compare the cohesive functioning of the immune system to that of an orchestra, and whilst you may not be able to identify every instrument being played, it’s all about the totality of what happens when they are played together in harmony.
"In truth, every nutrient plays a role in the human immune response."
As well as the more familiar nutrients mentioned above, there are others that are increasingly widely studied to investigate their potential role in supporting immune function. For example, polysaccharides, such as alpha and beta-glucans, may stimulate an array of immune responses ranging from modulating inflammation to enhancing the activity of T cells (lymphocytes that act against cells infected by pathogens). Polysaccharides are especially concentrated in medicinal mushrooms, of which there are several varieties each with slightly different properties. Some mushrooms also contain terpenes, which are plant chemicals that provide aroma and flavour, which may stimulate white blood cell activity and modulate inflammatory agents such as cytokines (I wrote about cytokines, their activity and vitamin D in an earlier post).
Olive Leaf extract may also offer a wide range of benefits for the immune system, in the form of oleuropein, a phenolic compound that gives olive oil it's pungency and distinctive flavour.
So, what does all this add up to? If I had to encapsulate how to support the immune system into one sentence it would be something along the lines of "eat lots of different foods, including plenty of vegetables and fruit, lean protein and wholegrains". This may not feel like cutting edge advice but here’s a sample day that includes most every nutrient that contributes to the maintenance of the immune system;
Breakfast -Greek yoghurt, berries and pumpkin seeds
Lunch -Salad with radish, asparagus, peppers, soft boiled egg with a dressing of olive oil, garlic and lemon juice. Sprinkle crushed walnuts on top as well.
Dinner -Tofu or prawns, served with broccoli, broad beans and brown rice.
Snacks -Plums with Brazil nuts or oat cake with nut butter.
If you are vegan or vegetarian, then swap out animal products for something that suits you, and if you do, it's highly probable that your preferred option will also offer relevant nutrients.
Ian Marber’s interest in food and nutrition was piqued when diagnosed with coeliac disease in his late twenties. He soon after gave up a successful career in investment to study nutrition at the Institute for Optimum Nutrition, graduating in 1999 and founding the now-globally recognised nutritional consultancy, The Food Doctor.
Departing the Food Doctor in 2012, Ian now advises individuals and industry alike. He has since worked with over 8,000 clients, leads seminars, workshops and lectures and works closely with brands such as Innocent Drinks to formulate new ranges. His expertise has lead him to be recognised as go-to contributor within the press, writing regularly in The Times, The Spectator and The Telegraph, as well as making regular appearances on both TV and radio.
For references, click here.