Top natural immune boosters

Some 85% of your immune response is dictated by the bacteria in your gut, and even small changes in your diet can make a big difference to how well your body reacts to threats to your health.

Young woman who eats yogurt, Good Bacteria and Bad Bacteria, enteric bacteria, Intestinal flora, Gut flora, probiotics, image illustration

Just how big a difference is indicated by work by researchers at the Department of Medicine at the University of Chicago. They are researching immunotherapy – a promising new approach to the treatment of certain cancers, including melanoma. Immunotherapy encourages the body’s own immune system to attack cancer cells.

They found that immunotherapy requires the presence of particular gut bacteria – like Bifidobacteria – to work properly. Yet immunotherapy itself harms gut bacteria, which is one reason why, hitherto, it seemed to work in only about 20% of cases.

So the Chicago researchers added certain bacteria to the anti-cancer regime and found that they boosted the patients’ immune response. Indeed, when the bacteria were combined with immunotherapy, the cancers largely disappeared.

This was a major finding and many researchers now predict that the microbial composition of a patient’s gut could be the key to making all drugs work better.

But it’s not just the possibility of making drugs work better that should guide you to actively eat for a stronger immune system. A strong immune system is central to preventative healthcare and longevity.

Here are 11 ways to boost your immune system through food and nutrition. Some act directly on the gut – others act on the complex interconnected system of defensive cells which fight infection.

1. Eat foods high in probiotics

Your gut is a host to trillions of microbes – mostly beneficial bacteria collectively called your microbiome. It is now well established that a healthy microbiome is the foundation of a strong immune system. A healthy microbiome is one that contains a wide range of ‘friendly’ bacteria called probiotics. The range is important because different probiotics are made up of different strains and concentrations of bacteria that in turn have different properties.


“I Can’t Believe it’s not Trifle” from the Health Defence Cookbook

The best sources of probiotics include yogurt made with live culture ie. milk fermented mainly with lactic acid bacteria and bifidobacteria.

Kefir is fermented probiotic milk drink, made by adding kefir grains to cow’s or goat’s milk.

Other probiotic-rich foods include sauerkraut, tempeh (fermented soya bean often used as a meat substitute), kimchi, miso (a Japanese fermented soy food), buttermilk, and some cheeses including mozzarella, gouda and aged cheddar.

It’s important to note that not all strains of bacteria in yogurts make it through the acidity of the stomach to the gut, but researchers at the University of Chicago are on record as saying that Activia does.

2. Eat foods high in prebiotics


Jerusalem Artichoke Soup from the Health Defence Cookbook

The beneficial bacteria in your gut that drive a healthy immune system need something to eat themselves. That’s where prebiotics come in.

Prebiotics are a type of non-digestible fibre called oligosaccharides that pass through the stomach and are fermented in the colon by your probiotic bacteria. Best sources include high fibre foods like garlic, onions, chicory, Jerusalem artichokes, leeks, banana, wheat bran, beans and – raw dandelion leaves added to a salad!

As you can see probiotics and prebiotics work together. In addition to their vital role in immune boosting, high levels of these natural dietary compounds are associated with better digestion, lower cholesterol levels and heart disease risk, less risk of weight gain, and lower internal inflammation.

3. Ensure optimum levels of carotenoids

Carotenoids are a class of pigments found naturally in a number of plants. Beta carotene is found in carrots, sweet potatoes, mango, spinach, broccoli and apricots and is converted into vitamin A which helps regulate the immune system.

Lycopene is the pigment in tomatoes and, with the carotenoid lutein, helps cells signal their boundaries to each other. Errors in cell signalling are strongly associated with diseases such as cancer, autoimmunity and diabetes. Lutein is also important for eye health.


Simply Red Soup from the Health Defence Cookbook

The lycopene in tomatoes is made more bio-available when they are cooked – ideally sautéed with olive oil. Make sure that cooked tomatoes are frequently on your dinner table for prostate health.

Since most people do not reach an optimum level of carotenoids, especially lutein and lycopene, you may want to consider a supplement. An effective daily supplement level would be 7mg of beta carotene, 6 mg of lutein and 5mg of lycopene.

4. Ensure optimum levels of zinc

Zinc is an essential mineral in the production of immune cells. Even mildly reduced levels of zinc can reduce your immune response. In addition zinc helps lower inflammation which is a key driver of almost all age related diseases.

Some main food sources of zinc are seafood, whole grains and wheat germ, beans, sesame seeds and chick peas. An optimum daily zinc supplement level is 10 mg.

5. Eat foods high in Omega-3 fatty acids


Wild Salmon Sushi from the Health Defence Cookbook

Omega-3 fatty acids are essential nutrients – ie. the body cannot make them. We know that Omega-3 helps reduce inflammation, but new evidence from Michigan University shows that Omega-3 enhances the activity of B cells – white blood cells that produce antibodies that fight infection. Sources of Omega 3 are mainly oily fish – salmon, mackerel, tuna, sardines, herring, trout – but also flaxseeds and walnuts.

Most people do not reach an optimum daily level of Omega-3 and an Omega-3 fish oil supplement can be beneficial – at a level of 1,000 mg (1g) a day.

6. Eat foods high in Vitamins C and E

Vitamins C and E work synergistically. They are both powerful antioxidants and maintaining good levels of vitamins C and E is critical for maintaining a healthy immune system, especially among older people or people under stress.


Crimson Compote from the Health Defence Cookbook

Vitamin E rich foods include: sunflower seeds, wheat germ, almonds, spinach, avocado, peanuts.

Vitamin C rich foods include: citrus fruits, papaya, peppers, strawberries, broccoli, blackcurrants.

If you take a supplement, the research indicates that the RDA for vitamin C of 60mg a day – which is standard in a “one-a-day” supplement – is sub-optimum. Because that’s only the level to prevent scurvy! A far more effective level would be 500mg of Vitamin C and at least 100IU of vitamin E.

7. Chicken soup for a cold is not an old wives’ tale

A University of Nebraska study found that chicken soup helps to prevent the migration of inflammatory white cells into the lungs. That’s significant because cold symptoms are a response to these cells’ accumulation in the bronchial tubes.

The amino acid cysteine, released from chicken during cooking, is chemically similar to the bronchitis drug acetylcysteine, which also inhibits an inflammatory response.

For extra immune boosting oomph add some garlic and onions to the soup recipe.

8. Eat mushrooms often

Getrocknete Shiitake-Pilze

Shiitake mushrooms

Researchers at the Institute of Herbal Medicine in Washington, DC, have confirmed that mushrooms “increase the production and activity of white blood cells, making them more aggressive. This is a good thing when you have an infection.”

All mushrooms have a positive effect, but shiitake, reishi and maitake deliver the biggest effect.

9. Exercise regularly

Although we don’t really know how, exercise does boost the immune system. It improves the circulation of white blood cells, it appears to flush out harmful bacteria from the lungs and airways, and it certainly slows down the release of stress hormones. The benefits come with as little as a 30 minute walk every day. Gardening and dancing are equally effective.

10. Reduce stress levels

Although this is easier said than done, stress weakens the immune response.

One interesting, simple and cheap stress buster technique was developed by the US Airforce for their jet fighter pilots some years ago. The technique was simply to get them to squeeze hand grips, hold the grip for 5 seconds, then release. Do this for a couple of minutes with one hand, then rest for two minutes. Then switch hands. Repeat this sequence for up to 8 times.

The technique was originally developed because the jet fighter pilots were experiencing high G forces, which increased their blood pressure and stress levels – and this exercise was proven to reduce the levels effectively without drugs.

So this simple technique not only reduces stress, but blood pressure too. [Also see article on this site for 6-step Instant Relaxation guide.]

11. Take 1,3 1,6 beta glucans

Some people use Echinacea as an immune booster, and it does seem to shorten cold symptoms slightly, but the research on overall effectiveness is mixed.

A much better researched product (with over 8,000 papers published) is a natural compound refined from the walls of baker’s yeast, called 1-3, 1-6 beta glucans. This modulates the immune system increasing the number and activity of both neutrophils and macrophages. These are your immune system’s front-line killer cells which hunt down external pathogens and internal rogue cells like cancer cells.

The gold standard for clinical trials is a double-blind, randomized, placebo-controlled study. The European Journal of Nutrition reported on such a study in healthy subjects, which proved that beta-glucan 1-3, 1-6 helps prevent colds, improves symptoms and increases the body’s potential to defend against invading pathogens.

This compound is available in ImmunoShield – at

Immunoshield as button

Finally we have mentioned that specific nutritional supplements are helpful in ensuring your immune system is working well all the time. A one-a-day pill doesn’t do that.

An effective supplement for long term immune health would include carotenoids, Omega 3, zinc, vitamin E and C, plus curcumin and green tea extract.


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Dr Paul Clayton designed NutriShield as a comprehensive healthbutton-2 supplement with OPTIMUM levels of essential nutrients. See more detail elsewhere on this site or click on the button.

Health Defence bookDr Paul Clayton’s best-selling book Health Defence is available from most good bookstores. See the website for excerpts and links to buy direct from the publisher.

See online here for delicious recipes from the Health Defence Cookbook  incorporating healthy foods featuring in a Mediterranean Diet. Combined 3 courses strip


Chew BP, Park JS. “Carotenoid action on the immune response.” J Nutr. 2004 Jan;134(1):257S-261S.

Gill H, Prasad J. “Probiotics, immunomodulation, and health benefits.” Adv Exp Med Biol. 2008;606:423-54.

Hughes DA. “Effects of dietary antioxidants on the immune function of middle-aged adults.” Proc Nutr Soc. 1999 Feb;58(1):79-84.

Hunter KW, Gault RA, Berner MD. Preparation of microparticulate beta-glucan from Saccharomyces cerevisiae for use in immune potentiation. Lett Appl Microbiol. 35(4):267-71, 2002.

Kyo E, Uda N, Kasuga S, Itakura Y. “Immunomodulatory effects of aged garlic extract.” J Nutr. 2001 Mar;131(3s):1075S-9S.

Patchen ML. Radioprotective effect of oral administration of beta-1,3-glucan. Armed Forces Radiobiology Research Institute, Bethesda , MD Research Report, 1989.

Slavin, Joanne. Fiber and Prebiotics: Mechanisms and Health Benefits: Nutrients. 2013 Apr; 5(4): 1417–1435.

Simopoulos AP. “Omega-3 fatty acids in inflammation and autoimmune diseases.” J Am Coll Nutr. 2002 Dec;21(6):495-505.

Wintergerst ES, Maggini S, Hornig DH. “Immune-enhancing role of vitamin C and zinc and effect on clinical conditions.” Ann Nutr Metab. 2006;50(2):85-94.

Antibiotic crisis top 10 natural immune boosters

Different pathogen bacteria on the surfaceWe’ve just had yet another warning – this time unexpectedly from the IMF (International Monetary Fund) – that the rise of ‘super-strains’ of deadly bacteria, which resist all known antibiotics, is threatening our medical system, our economies and our families.

The Sunday Times on 15th May highlighted the fact that a simple scraped knee or urinary tract infection (UTI) could lead to complications ending in death – because the antibiotics failed to deal with the progressive breakdowns involved.

Antibiotic drugs in crisis due to over-use

Because antibiotics have been so over-used, Margaret Chan, Director General of the World Health Organisation (WHO) predicts

the end of modern medicine.

The US Food and Drug Administration (FDA) has just gone so far as to advise doctors not to use a commonly prescribed class of antibiotics called fluoroquinolone.

The UK’s Chief Medical Officer, Dame Sally Davies recently warned:

“… the rise in antibiotic-resistant diseases could trigger a national emergency comparable to a catastrophic terrorist attack, pandemic flu or major coastal flooding.”

She is on record as saying we could routinely see deaths from minor surgery if new antibiotics are not discovered – highlighting the immediate threats that antimicrobial resistance poses.

Lord O’Neill, who is heading a government review on anti-microbial resistance, forecasts that 10 million people will die each year by 2050 if nothing is done. And Big Pharma is way behind on developing new antibiotics because it has not been profitable enough. In fact O’Neill calculates that the pay-out period for an effective new antibiotic could be as much as 23 years.

Natural ways to boost immunity

So how do we best protect ourselves and our families? What natural ways to boost our immunity levels are proven to work?

The basic problem is that the bugs breed thousands of times faster than we do – so they mutate and develop resistance faster than we can modify antibiotics. The frightening implication is that routine operations could become dangerous to carry out, and minor cuts and grazes become potentially life-threatening.

In these circumstances we need to look at the most powerful natural ways to boost our immune system so it is strong enough to overcome external threats before antibiotics become necessary.

First Line of Defence – the Innate Immune System

Your first line of defence against the threat of bugs, viruses, bacteria is what is called your Innate Immune System. This is your ‘front line’ immune system. Its cells continuously patrol the body looking for foreign invaders – virus, bacteria or even abnormal cells. It includes Natural Killer cells, macrophages and neutrophils.

Second Line of Defence – the Acquired Immune System

You have another, second, line of defence which is the Acquired Immune System. This is the one that ‘remembers’ a previously encountered pathogen or illness and reacts by producing antibodies.

But that assumes you have encountered the threat before. So supporting the Innate immune system is a logical priority.


1. Eat 9 portions of fruit and vegetables a day

autumn cornucopiaNine!!??? Yes, the American Cancer Society and others are now saying that you need this number and variety of fruits and vegetables, because they contain polyphenols (flavonoids), vitamins and minerals like vitamin A, C and D, zinc and carotenoids that strongly support the immune system.

2. Take comprehensive nutritional supplements

Nine portions is a challenge, but unlike simple one-a-day A-Z vitamin supplements there are nutritional supplements that include other vital nutrients extracted from fruits and vegetables that the immune system needs – like green tea, vitamin D3, lycopene, lutein, zinc and flavonoids. See NutriShield also includes vitamin C at 500mg a day, which research indicates may be the threshold for immune-building.

3. Get 8 hours of sleep

Sleep deprivation suppresses immune function by decreasing T-cell production and increasing inflammatory cytokines – which are messenger proteins that can trigger inflammation.

4. Increase activity levels

But that doesn’t have to mean a gym membership – see

5. Take more Omega 3 in oily fish or supplements

Rollmop-caper-bruschettaNew research shows that Omega 3 fatty acids found in oily fish like salmon, tuna, herring and sardines enhance the function of immune B cells.



6. Cook with garlic

Garlic contains sulphuric compounds, like allicin, which create immune-boosting effects. When UK researchers gave 146 people either a placebo or a garlic extract for 12 weeks, they found the garlic takers were 60% less likely to catch a cold.

7. Supplement with yeast-derived 1-3, 1-6 beta glucans

There is evidence that our innate immune systems are now less active and effective than they were in the past, partly because there used to be more bacteria in the environment to react to – especially yeast bacteria in mould. So our innate immune system developed specific receptors for yeast particles and became ‘primed’ to respond to yeast.

But we have cleaned up our environment so much with anti-bacterial sprays and over-processed food produced in sterile environments, that our immune systems now get less challenge and are working at a lower level of efficiency. This is the so-called ‘hygiene hypothesis’.

Immune SystemThis is not an excuse for an unhygienic home (!) but the answer is a natural supplement called 1-3, 1-6 beta glucans. Because these beta glucans are derived from yeast cell walls, the special receptors in your immune system recognise them as a potential threat (as mould would be) and increases the number and activity of defensive neutrophils and Natural Killer cells in the bloodstream.

The beta glucan extract with the most extensive clinical trial data is called Wellmune. Clinical research shows that Wellmune beta glucans do indeed enhance the immune system. In tests by the Department of Defence of a major NATO country, Wellmune was rated the number 1 ‘immuno-modulator’ ie. immune booster. Wellmune beta glucans are the main ingredient in ImmunoShield – see

8. Feed your microbiome – your body’s friendly bacteria

The microbes in your gut are called your microbiome. These ‘friendly’ microbes are an integral part of your immune system. Indeed, according to some nutritional scientists, nearly 60 per cent of your immune system activity may be in your gut.

Microbiome Word CloudIf the numbers and range of these ‘friendly’ microbes are reduced – which happens for example if you are on antibiotics or have a sub-optimal diet – you become much more vulnerable to pathogens and infections like C difficile and Salmonella.

If the microbiome is not properly nourished, the gut becomes more permeable, which can allow toxins to leak into the bloodstream, triggering inflammation.

Different gut microbes need different types of ‘food’ to feed on and thrive. These include prebiotic fibres found in peas, beans, lentils, oats, in fibrous fruits like figs, apples, dates, prunes and in vegetables like asparagus, leeks, garlic, onions, broccoli, cabbage and root vegetables.

pre-and-pro-biotic-foodsYour microbiome also benefits from fermented probiotic foods like live active cultured yogurt, sauerkraut, tempeh, buttermilk, sourdough bread and miso soup.


9. Eat more mushrooms

Getrocknete Shiitake-PilzeThe reason many modern medicines (including penicillin) are derived from fungi is because fungi have evolved many antibiotic properties of their own. Mushrooms contain zinc and vitamin D and help increase the production of white blood cells. Shiitake, reishi and maitake mushrooms are possibly the most beneficial but all mushrooms are good for your immune system.

10. Enjoy all foods from the sea regularly

Sea foods are rich in zinc and selenium, which helps white blood cells produce cytokines—proteins that help eliminate flu viruses from the body.

Add a liberal dose of laughter

A study conducted by Dr Lee Berk of Loma Linda University School of Medicine in California showed that men who watched a comedy video for an hour had a significant reduction in cortisol – the stress hormone – and a ‘significant’ boost to immune function, including higher levels of antibodies and natural killer cells.


Of course I am not saying that these measures would be enough, on their own, to cure you of a major infection once it has taken hold.

But they are 10 ways to raise your ongoing immunity levels to help head off an attack in the first place.


If you enjoyed this article, please share it with family and friends (see buttons below).

CTA Register NewsletterAnd register now for a free e-newsletter on the latest in nutrition and health research.

You can follow us on or for daily headline health tweets.

Dr Paul Clayton designed NutriShield as a comprehensive healthbutton-2 supplement with OPTIMUM levels of essential nutrients, including ALL those mentioned above. See more detail elsewhere on this site or click on the button.

Health Defence bookDr Paul Clayton’s best-selling book Health Defence is available from most good bookstores. See the website for excerpts and links to buy direct from the publisher.