There are any number of books that promise you'll be able to live to 200, run marathons, and never catch a cold in your life... if you follow their rules. In reality, all you need in order to enjoy a healthy immune system is a lifestyle that recognises your body's basic requirements and some iron will for a few months, while you clear your body out and let it get back to a more 'natural' state. Then just continue to eat decent food and you'll be fine, assuming that you are otherwise in good health.
What is the Immune System?
Your immune system is, to all intents and purposes, your lymph system. Remember that liquid that comes out of cuts? Or when you had mumps when you were a kid? That lymph system, with its focused nodes under your chin and arms is the thing that keeps you together. Research suggests that those people with Lymphagioma or Cystic Hygroma (defects in the growth of the lymph system) end up with a compromised immune system as a result of abnormal growth and operations on those lymph nodes. So if you can, be gentle with them! And if you have to be rough on them, it's worth following the diet below.
If you want to know more about the medical background of the immune system, there are some great resources on the web.
Compromised Immune System
There are several things that can affect your immune system and a lot of them link in to symptoms of full blown diseases; or they can become diseases if your initial symptoms aren't checked. Two primary linkages happen here; one is with diabetes and another is with a condition known as candida, which in a frustrating way also shows signs of diabetes (just to confuse matters). Your hormones can also be affected by extreme tiredness, so you might get some odd symptoms as a result of that. There is a (C) next to symptoms more allied to candida in the list below:
'Background' tiredness all the time: you feel like you're keeping yourself going on adrenaline only.
Carbohydrate or sugar craving in the afternoons particularly (about 4pm) when you've run out of energy (C).
Sore throat all the time (C), but particularly when feeling run down.
Athletes foot, but you can't work out why (C).
Can't walk uphill or stairs without your legs feeling like you've run a marathon (C).
Feeling dog tired when you go to bed and still feeling tired when you wake up, no matter how long you slept.
Possibly a bit depressed.
Possibly putting on weight in a really weird way that you can't really justify in your diet.
Why is Candida Important?
Sometimes we forget that we are biological entities and have living things, like digestive flora and bacteria that aren't actually helping to keep us going. Candida is actually fungal and is present in just about all human beings. In a healthy person with a good balanced diet it's kept in check by bacteria, such as those associated with live yoghurts and the like. As soon as your immune system starts to become compromised, however, it can start running riot. Candida also lives for carbohydrates and it loves sugar; so it wants you to eat pastry and encourages you indulge yourself. Once you've become run down enough for it to take hold, it'll grab you and drag you down faster. Ironically, it is its own worst enemy, in that it shows itself to you quite unmistakably; but it's also hellishly difficult to get rid of. There is some advice below that will keep it in check; but you will need professional help to get things put back in order. If you have any of the symptoms above, then go and see your doctor; and be prepared for a long haul. The good news is that it's not desperately awful to have it lurking in the background, trying to catch you unawares, as long as you know it's there and can keep an eye on it.
'How could I end up compromising my immune system other than with candida?', you may ask yourself. In a word: stress. An important association with stress is adrenaline, which can have a deleterious effect on your body if you drive yourself on it all the time. Actually, there's other important stuff about eating and drinking chemicals in food that actively contributes to your body not working properly. But it's very, very important to realise that we are animals and our bodies don't seem to like working 12-hour days behind desks, getting no exercise, and eating processed food that's been sprayed with weed killer, colourant, and preservatives.
The human body's evolution has been a gradual process over many thousands of years. It is only in the last couple of hundred that we've been bombarding our bodies with so many new experiences - both mentally and physiologically - that we are finding it difficult to cope. One of the consequences of modern living is that your vital mechanisms, including your immune system, begins to deteriorate after years of being hammered with junk food and over work.
Well... it's not too bad. It can be tough at the beginning though; but you might find your evangelical zeal gets you through the first couple of weeks; and after that it's a doddle. First things first - and this is a good tip for anyone to do regularly; it will really stop candida in its tracks, as well as shock your body into feeling healthy again. You need to do a good long stretch of 'detoxing'. This doesn't mean drinking weird drinks that you can buy over the counter in the hope that they will solve your problems overnight, but at least a month (longer if you can stand it) of trying to give your body only the kind of food that it's evolved to cope with and nothing that's been introduced in the last couple of centuries. So here's a long list of things you shouldn't eat. Grit your teeth - it is possible; and it does bring back your energy and well being.
Caffeine - We all know about the problems with caffeine; so no need to go into them here. Peppermint tea is a reasonable alternative, or perhaps caffeine-free tea or coffee... but they could leave you craving for the real thing. A quick word of warning; you can get headaches for a few days when you come off caffeine, but it passes.
Alcohol - Yup. We know red wine can be good for us, but alcohol is a depressant; and you want your body to find its own natural level. Not only that, but it contains some sugar; so candida loves it, unlike your immune system, which is trying to help your blood sugar level stay even. Sad but true, but there are an awful lot of chemicals in factory-produced alcoholic drinks.
Refined sugar - If you think you've got candida, then anything sugary is right off the menu. But either way, refined sugar is something our bodies really hate. The system simply can't cope with that amount of carbohydrate pumping its way into your system all at once. As a result, you can have a huge slump in your blood sugar only hours later; and, as all dieters know, you'll be craving something energising to eat again, which just makes things worse.
Wheat - Sounds weird, but the wheat that we make bread, pastry, just about anything with is something that your body finds very irritating in large amounts. Remember seeing 'gluten-free' products in supermarkets? It's the gluten in wheat that helps it bind together, but it also acts as an irritant to the body. What can you eat instead? There's a number of wheat free breads on the market - you can even get them in supermarkets, as well as health food stores. An alternative for breakfast is good old fashioned porridge... works wonders; and, contrary to popular belief, it only takes a couple of minutes to cook. Read the ingredients on the package carefully as some porridge may contain wheat, you're looking for those brands that are made from oats.
Cows' milk products - Cows' milk isn't really liked that much by your body. While you're well and your body energy is high, you're able to cope with this sort of food without any problems; but when you're struggling, it's far, far better just to cut it out. And the shock news is that the kind of fresh, semi-skimmed goats milk that you can get from supermarkets tastes... well, to be frank, it tastes an awful lot like cow's milk. Once you look into it, there is a plethora of delicious sheep and goat's milk cheeses out there, including the king of cheese, Roquefort.
Because candida is fungal, you want to steer clear of mushrooms, yeast, and anything fermented (soy sauce is an example). Fruit juice is a no-no, because there's enough sugar in it to help your little bugs to keep going even without the cake and sugar. But try not to weep too hard - remember, it doesn't last forever. Granted, if you actually have got candida then you need to keep going for a bit longer with abstinence... but you can do it.
What Should I Eat Instead?
Try to think that you want your body to have real food. So, when you're buying any food to eat or (better still) buying ingredients to cook at home, think of those magic words 'no additives'. Everything that's in the food should be simple, 'natural', non-tampered with or chemically derived, and 'primary', as whole food is. Once you get into the home cooking aspect of this, it becomes something positively enjoyable - getting to know your body again and giving it the decent stuff it really wants to have as fuel.
The second big point to remember here is that buzzword du jour is 'organic'. There's a reason organic foods are growing in popularity. Organic foods really are very, very good for your body. When humans were evolving, they were genetically mutated to eat the only food that was available at the time - and that was organic by default, there being no crop spraying available at the time. Factory made chemicals genuinely do mess up your immune system. And that's as good a reason to eat organic as any other considerations. For that reason as well it's worth at least remaining cautious of genetically modified crops.
Quick Note for Vegetarians
You will probably have eaten less and less decent protein and more and more take away pasta and pizza over the years; and put many a load of vegetables into the oven for a fashionable roasted veg supper. In doing that you're getting virtually no protein in your diet; so you will have to really bolster up your pulse and nut eating. Don't go mad and eat 15 eggs a week; but make sure you've got protein in every meal you eat. Your body needs it to help keep the immune system boosted.
Supplements and Extras
Water is almost the most important thing in this entry. If you're rich enough, you should try to drink mineral water (still, not fizzy) from glass bottles. Try to buy a standard bottle of mineral water every day; and when it's empty, refill it from the water cooler at work or, better yet, buy another one. Again, it is worth remaining sceptical of the claims made by our water companies. Even filtered tap water contains chemical residues that can't be removed in the normal treatment process. If you're trying to give your body a clear run for a while, it's worth making the investment in buying good mineral water1.
There are many herbal supplements, such as echinacea, that are known to have a positive effect on your immune system. These should be treated with a great deal of respect, as they are often potent medicines, which may do serious harm to your body if taken improperly or in large doses. Do your homework before prescribing any medicine for yourself. Or, better yet, talk to your doctor about the possible side effects associated with herbal supplements.
Traditional practices, such as acupuncture, are gaining a wider acceptance in Western medicine. There are parallels between acupuncture energy points on the body and lymph system function. Acupuncture attempts to focus on the body's energy and balance, key areas that tap straight back in to how you are coping with stress, how tired you are, and possible candida symptoms. In Chinese medicine it is recommended that you eat, among other things, plenty of spring onions, ginger, and melon if your Chi is low, all of which have been confirmed by Western medicine to be very beneficial to the immune system.