Hazel CourteneyIMMUNE FUNCTION© Copyright Hazel Courteney Oct 2013  Adapted from 500 of the Most Important Health Tips You’ll Ever Need by Hazel Courteney. Cico Books

With new strains of bacteria and viruses mutating with alarming speed, the challenge for our immune systems has never been greater. Our immune system is made up of a network of cells, organs and fluids that help defend us against the millions of bacteria, viruses and fungi that bombard us in our daily lives. And one of the most important things you can do to stay healthy, throughout your life, is to keep your immune system in good shape. For example, when I was younger and did not realise how diet and lifestyle affected my ability to fight off illnesses, if  I was under pressure, not getting sufficient sleep, and eating the wrong foods, I was always ill. At times when I felt ghastly, I would turn to a sugary snack to keep me going and I could literally feel my immune system going ‘over the edge’. Stress alone can suppress immune function by up to 60%

These days I recognise my limits, I know when to stop and get more sleep. I eat a cleaner diet and try as much as possible to keep my stress levels within limits. You need to listen to your body and take notice! Often the first signs of an immune system under threat are a chronic sore throat, regular colds or niggling infections. If this is the case with you, it’s time to take action.

Meanwhile, most people don’t think of their skin as being part of the immune system, but it forms a physical barrier against attack, and the immune system is in charge of cell regeneration within your skin. The more efficient your immune system, the fresher your skin will look.

And within a child’s bone marrow are ‘stem cells’ which, as we grow, develop into various types of immune cells some of which mature in the thymus gland, where they become known as T cells. The spleen also contains immune cells that manufacture antibodies; and the lymphatic system, often called the master drain, is also a major player in immune function. The lymph system removes toxins and microbes from the body’s tissue and along with bone marrow manufactures lymphocytes (a specific kind of white blood cell that comes in 3 types – B cells, T cells and natural killer cells – which keep your immune system in good shape). Lymph nodes are found all over the body, but the ones most people are aware of are situated in the neck, groin and arm pits. During an infection the lymph glands can swell as they produce more white blood cells, this is very common in throat conditions for example. If the lymphatic system becomes congested, the fluid thickens and becomes more gel like, which inhibits proper drainage and detoxification and puts more pressure on the liver and kidneys. This is why a fully functioning lymph system helps you to fight off invading bacteria and viruses. The liver and thymus gland also play a huge role in immune function .

Unfortunately, as we age our immune system becomes less effective at protecting us and more viruses and bacteria get through our defences. Conversely our immune system can also overreact, which produces chronic inflammation when we eat certain foods, or are exposed to pollen, pollutants and so on. The immune system may even begin attacking the body’s own tissue, called an ‘autoimmune response’, in conditions such as lupus and rheumatoid arthritis.

High cholesterol levels are also linked to a lowered immune response, because cells containing high levels of cholesterol can disrupt our cells’ ability to communicate with each other, which is vital for proper immune responses .

Lowered immune function is also linked to chronic fatigue, allergies, parasite infections, and some forms of heart disease. Many women also have low iron levels which can reduce immune function – have a blood test to check iron levels if you think this may be a problem.

Prostaglandins, which are hormone-like substances, become more out of balance as we age. This has the effect of suppressing the immune system and affecting important processes such as body temperature and metabolism. Essential fatty acids, such as EPA (from fish oil) and GLA (from evening primrose, blackcurrant, and borage oils) help to restore the proper prostaglandin ratios, thereby supporting the immune system (see Fats You Need To Eat).

Foods to Avoid

  • Refined sugar greatly compromises your immune system. If you are run-down and then you eat one, say, mass produced sugary breakfast bar, it can literally send your immune system into free-fall – and the next thing you know, you have a cold, or develop cold sores or whatever. So if you know that you are under stress, stay away from products high in refined sugars and allow your immune system time to regroup. Use a little organic Maple Syrup or Xylitol as healthier alternatives to refined sugar , but generally cut down on pies, biscuits, sweets and shop-bought sugary snacks and drinks.
  • Reduce your intake of caffeine and alcohol, which place an extra burden on the immune system.
  • Avoid any foods containing lots of preservatives, additives and especially the artificial sweetener aspartame, which adds an extra burden on your liver.
  • Avoid all smoked foods and cheeses.
  • Reduce your intake of saturated fats found in red meat and full-fat dairy produce including milks, cheese, Greek yoghurts, and chocolates, as well as hydrogenated and trans fats (see Fats You Need To Eat).


Friendly Foods

  • When the body is under attack it requires more protein, so eat fresh fish, organic tofu (cooked), fresh chicken, turkey and lean organic meats . Lentils, beans and pulses are also excellent sources of low fat, healthy protein.
  • Eat organic as much as possible. Make sure your diet is high in all fresh fruits and vegetables, which are packed with nutrients.
  • Eat more fresh fish, broccoli, cabbage, cauliflower, parsley, green beans, apples, green salads, pumpkin, buckwheat,  watercress, papaya, mango,  quinoa, soya beans and millet.
  • Eat sprouts such as alfalfa and brown rice, and algae, such as spirulina and chlorella. Otherwise use  Green Magic Powder – containing Hawaiian Spirulina, Chlorella, Lecithin, Barley and Wheat Grass, Kamut, Pectin Apple fibre, kelp and Wheat Sprouts, CoQ10, Royal Jelly, Artichoke Powder and Lactobacillus Acidophilus is a great all round way to ingest good nutrients, healthy bacteria, keep the body more alkaline and  help keep you regular. Details on www.itsgreenmagic.com .   Add a teaspoon of this powder to a breakfast smoothie to boost immune function – Watch my Video Blog showing me making this Smoothie.
  • Eat more purple, red and orange foods: blueberries, bilberries and blackberries are high in immune-boosting nutrients, as are sweet potatoes, apricots, pumpkin, papaya and red peppers.
  • Nuts and seeds are packed with essential fats, and minerals such as zinc and selenium (see Fats You Need To Eat).


  • Eat more freshly made soups – many supermarkets and take-away shops now sell freshly made organic soups. They are easy on the digestive system and full of nutrients. Add barley, brown rice, lentils and more cabbage to soups.
  • Alternatives to refined sugars are Blackstrap Molasses, Raw organic unrefined Honey or  Xylitol (a plant derived sugar) which has a low glycemic index and thus a minimal impact on blood sugar levels. Higher Nature make Zylo Sweet.
  • Useful Remedies
  • Take a good-quality, high-strength multi-vitamin and mineral, and an antioxidant formula daily.
  • Organic source Hemp Seed Protein Powder (a/v from all good health shops), or Vianesse Protein Powder which is free from lactose, but contains plenty of easy to absorb protein – To order call The Wholistic Medical Centre Tel: 020 7580 7537.
  • Add organic-source green food powders to your breakfast cereals, smoothies, or vegetable juices, and drink daily. They are packed with nutrition that helps to keep your immune system in good shape.  See details of Green Magic above, or try  Viridian’s 100% Organic Green Food Blend Powder. Watch my VT under my Video Blog page of me making a healthy Breakfast blend.
  • Echinacea and astragalus in a combination formula can be taken in capsules or fluid extract to really help boost immune function, if taken daily for 3 months. Astragalus has been shown to increase white blood cell counts. Try Ultimate Echinacea Complex by Holos Health, which is available from www.holoshealth.com or the Nutri Centre. NC
  • Colostrum is the pre-milk fluid produced by all mothers after giving birth. It arrives before breast milk and contains 37 natural immune-boosting factors and 8 growth factors, which support the immune system and regeneration of all types of cells. Recent studies have shown it to be extremely beneficial, not only for the newborn, but for people of all ages. Dose: 2000–4000mg per day.  Try Kirkman’s Colostrum. Take for one month NC   This supplement is great for young children as it boosts immune function and reduces the likelihood of suffering food intolerances.
  • Astragalus is a traditional Chinese herb used to strengthen the immune system. At least one clinical trial in the US has shown astragalus to boost T-cell levels close to normal in some cancer patients, suggesting the possibility of a synergistic effect of astragalus with chemotherapy. Dose: 250mg twice a day.
  • Sunlight and vitamin D are absolutely  crucial to good immune health. Take sensible amounts of sunshine and take 1000iu of vitamin D3 daily.

Helpful Hints

  • One of the simplest ways to boost immune function is to get more sleep – take a day off to call your own; book a holiday; walk out in the countryside breathing the fresher air – and see how that alone lifts your spirits.
  • Laugh a lot: watch films that make you laugh; make friends with people who make you laugh. Laughter and having some fun strengthen immune function.
  • Stress alone can suppress immune function by up to 60%. Stress triggers the release of the hormone cortisol, which is thought to shrink the thymus gland (which is where T cells mature and is situated in your upper chest area, just below the hollow in your neck). Therefore, keep your stress levels in check. (see also Adrenal Exhaustion and Stress).
  • Learn to say no and not feel guilty.
  • Greatly reduce your exposure to external pollutants, such as cigarette smoke, car fumes, chemical-based sprays and heavy metals.
  • If possible take regular holidays in the sunshine, which helps to boost your immune system.
  • Think positively – people who are cheerful and who look on the bright side have stronger immune systems.
  • Take regular exercise but not to excess. Don’t over exercise if you are truly exhausted.
  • To help decongest your lymphatic system, apply therapeutic grade essential oils along the spine, under the arm, and in the neck, breast and groin areas – anywhere that is congested.  Try a blend of 3 drops of cypress, 1 of orange and 2 of grapefrui