Boosting Winter Immunity by Rebecca Weller

As the cold days of winter approach and the first sniffs and sneezes are heard, many of our start thinking about improving our immunity. For some of us the flu jab is the solution, but this is generally only available to those over 65, or for people with a serious medical condition affecting their heart or respiratory system. However there are lots of other ways we can boost our natural immunity and this is where diet and lifestyle choices are so important.

Before we start looking at specific foods, what actually is the immune system? The immune system is a collection of different systems designed to protect the body. We are born with our innate immune system, the cells and mechanisms that defend us from infection in a non-specific manner. There are the physical barriers to prevent infection, such as the skin, tears, eyes, respiratory system and the stomach and digestive system; there are also the different types of white cells or leukocytes in our blood which fight infection.

We also have an acquired immunity which is made up of antibodies produced when the body first comes into contact with a toxin or infection, the next time it meets that infection it has the antibodies to prevent the disease becoming established. We build up most of our acquired immunity in our childhood – this is why we don’t get chicken pox time and time again.

As a nutritional therapist I am interested in harnessing the power of food to naturally boost our immune system. Eating a diet rich in fruit and vegetables will ensure you get plenty of the key immune boosting vitamins and minerals such as vitamins A, C, E and the minerals zinc and selenium. However there are some “super-foods” worthy of a special mention - here are some of my personal choices.

• Oriental Mushrooms such as Reishi, Shiitake and Maitake are not only fantastic sources of selenium and vitamin C, but they contain a compound called beta-glucan which acts like a key to turn on some of our most important immune cells, such as the impressive sounding ‘natural killer cells’ which kill off viruses by secreting powerful chemicals to cause the death of viral cells. Oriental mushrooms have a meaty texture, and can be added to soups or casseroles.
• Natural Bio Yoghurt – did you know that a large part of your immune system is in your gut? Beneficial bacteria such as bifidobacter are known to help increase the proliferation of immune cells and heighten the immune response. Eating natural bio yoghurt is a great way to introduce gut friendly bacteria. A perfect start to the day would be some muesli, a handful of seasonal berries and some natural yoghurt. Although the heavily advertised little bottles of yoghurt drink do contain good bacteria, they are often heavily sweetened and are relatively expensive.
• Oregano – you maybe familiar with this commonly grown garden herb with its distinctive smell and pale pink flowers, but you may not be aware that in a recent analysis conducted by the US Department of Agriculture, oregano scored the highest in antioxidant activity out of all the foods and herbs tested. Anti-oxidants fight off the health damaging free radicals. Oregano has a natural affinity with Italian foods, especially tomatoes, so try growing some on the window sill and add it liberally every time you have a tomato based pasta sauce.
• Red and Purple berries – berries such as blackcurrants, blackberries, blueberries, cherries, and elderberries are worthy of a special mention. The pigments in the skin contain powerful substances called anthocyanins which increase the production of chemical messengers called cytokines, which act like an army general marshalling the troops for an attack. There have been some studies to show that these fruits may have an anti-viral effect, so at the first sign of a cold try a traditional remedy of a hot toddy made with elderberry syrup, hot water and lemon. For our grandmothers home-made elderberry syrup was an established part of their medicine chest; however the habit of making the syrup seems to have disappeared. Next time the family is all together – Thanksgiving would be ideal, why not see if anyone still has a traditional recipe for elderberry syrup they could share. Thanksgiving Dinner is a great time for reliving memories and reviving traditions.
• Garlic is thought to have an especially important effect on the production of macrophages. Do you remember the 1980’s arcade game Pac-man? This involved a yellow Pac-man racing around the screen gobbling up Pac-dots – well I like to think of macrophages in a similar way, large cells which zoom around the body and literally gobble up invading nasties. When seen under the microscope you can actual watch a macrophage approach, engulf and destroy a virus particle. So garlic with everything is the order of the day.
• Green Tea – has become very popular in the last few years, and deservedly so. The high concentrations of an amino acid called L-theanine found in green tea may help strengthen the body’s immune system response when fighting off infection. One of the keys to enjoying green tea is not to brew it for too long, as this can impart a bitter flavour. It is also worth remembering that green tea does contain caffeine (although a lesser amount than coffee) so I wouldn’t drink too much in the evening if you have difficulty sleeping.

On a final note, there is an interesting relationship between happiness and the immune system. Research carried out by Professor David Warburton of Reading University has shown that physical and emotional enjoyment, even in small doses, can enhance immune function for hours afterwards - which I guess does prove the old adage “A little of what you fancy does you good”.

Copyright 2008 Rebecca Weller. Rebecca is a practicing Nutritional Therapist in the south of England, and a member of The British Association for Applied Nutrition and Nutritional Therapy.
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