100 Ways
to Boost Your
Immune System
Theresa Cheung

Collins gem

Table of Contents

Cover Page

Title Page

INTRODUCTION

Part One: Understanding Your Immune System

What is your immune system

Components of your immune system

How your immune system works

Meet the bugs

Signs of infection

The common cold

Flu

Is it a cold or flu?

A word about bird flu

Auto-immune disorders

Allergies

Improving your immunity

Vaccination

The flu jab

Immunity enemies

Is your immune system in trouble?

Making immune-boosting diet and lifestyle choices

Part Two: 100 Immune System Boosters

Boosting immunity with nutrition

Boosting immunity with lifestyle changes

Boosting immunity with supplements

Boost immunity with a fighting spirit

Part Three: Fighting Infection

Working out your immune system

DIY home remedies for colds and flu

Take probiotic supplements

Don’t fly unless necessary

Take good care of yourself

Index

Copyright

About the Publisher

INTRODUCTION
YOUR INVISIBLE ARMY

Without a strong immune system you can’t live younger or longer. Your immune system is your invisible army, working tirelessly around the clock to keep you fit and healthy, and fighting off invasion by foreign organisms that can lead to premature ageing and disease.

A vigorous immune system is vital to good health, both physical and mental. Tiredness, frequent colds and other infections, allergies, mood swings and premature ageing are sure-fire signs of a weakened immune system. Learning how to protect and support your immune system is therefore the most important thing you can do for your health and well-being. Fortunately, there are many ways in which you can strengthen and support your immune system – and keep your troops in peak condition – without resorting to the use of antibiotics.

This book gives you all the advice you need to achieve this healthy state of affairs.

So be good to yourself. Read on to discover everything you need to know to stay free from disease and maximise your potential for high-level health, happiness and vitality.

Drawing on a variety of disciplines in medicine and natural health, each immune booster in this book will provide practical strategies you can use in your daily life to strengthen your resistance to illness. And if you do get sick you’ll find information that will help you get well faster.

PART ONE: UNDERSTANDING YOUR IMMUNE SYSTEM

What is your immune system

Your immune system is a complex interrelated network of organs, blood cells and chemical reactions that are your body’s basic – and mostly highly effective – defence mechanism against invasion from the hordes of bugs (bacteria, viruses, parasites and fungi) that are constantly trying to get inside you.

Every day a healthy body with a fully functioning immune system sees off potentially dangerous organisms that can trigger illness, as well as protecting against quirks in your cellular system that might potentially develop into cancerous growths. If your immune defences are working at their optimum level of efficiency, your health is likely to be good. If, however, you feel under par or constantly unwell, this suggests that your immune system is compromised.

Compromised immunity can leave you vulnerable to premature ageing and disease, and impair your ability to heal properly and live your life to the full. It’s no surprise that a recent study of healthy centenarians found they had one thing in common: a healthy immune system. A healthy immune system is therefore the key to good health and a long life.

Components of your immune system

The key components of your immune system are the thymus and the lymph system, together with the spleen, bone marrow, white blood cells and antibodies.

The thymus is the source of T cells. T cells – a type of white blood cell or lymphocyte – are the foot-soldiers of your immune system. They destroy invaders that have been detected by B cells, another type of white blood cell. The lymph system transports nutrients to cells and filters waste. Lymph nodes are collections of lymphoid cells found throughout the body, including the neck, armpits and groin. They are connected by a network of lymph-carrying vessels and are the main sites of storage, activation and production of white blood cells.

The spleen filters the blood, looking out for invaders, and also carries out regular ‘MOT checks’ on red blood cells. Bone marrow is the source of new red and white blood cells. White blood cells are actually a collection of cells that work together to destroy bacteria and viruses. There are numerous types of white blood cells: leukocytes, helper T cells, natural killer cells and so on. Finally, there are five primary types of antibody, known as ‘immunoglobins’, each of which responds and binds to a specific invader, preventing it from entering host cells. We need huge quantities of antibodies to protect us from the constant and daily bombardment of bacteria we unknowingly inhale or digest in our food.

How your immune system works

Your immune system is an elaborate, interactive system of cells, chemicals and tissues located throughout your body. When any of its components come into contact with cells or substances – such as bacteria or viruses – to which they are programmed to respond, a series of reactions is triggered that destroys the invaders or renders them harmless.

A cell or chemical that triggers an immune reaction is called an antigen, and that reaction can be either innate or adaptive. The innate immune response produces an immediate, nonspecific immune response to disease-causing antigens that enter or appear inside the body. An army of scavenging white blood cells constantly roams around your body on the lookout for bugs; if a white blood cell detects an ‘enemy’, then it is immediately transported to the nearest lymph node, situated in your neck, armpits and groin, and destroyed without mercy. You can feel this process happening every time your glands become swollen because innate immunity also includes the inflammation or swelling process.

While the innate response is working on the front lines, the adaptive response system is quietly working behind the scenes to find a defence specifically tailored to deal with the antigen. Typically, the adaptive response takes about five to seven days to get completely mobilised; if the antigen works faster than that, you’re in trouble.

Although the immune system is capable of diversifying its defence plan to meet a wide variety of invading antigens – and once immunity to a specific antigen has been developed that immunity will protect against future attacks by antigens that produce similar diseases – it’s important to point out that each antigen requires an individual response. So, if you’ve developed immunity to the chickenpox virus, you still need to develop immunity to deal with the measles virus and if you’ve developed immunity to one strain of flu virus you still need to develop immunity to deal with countless other cold and flu viruses.

Meet the bugs

Your body is under daily attack from infectious agents doing their best to get inside your body. To a bug, your body offers warmth, safety and food; these make it a very attractive proposition.

Bacteria, viruses and other infectious agents live everywhere. You can find them in the air; on food, plants and animals; in soil and in water; and on almost every surface, including those of your own body. They range in size from microscopic single-cell organisms to parasitic worms that can grow to several centimetres in length.

Most of these agents won’t make you ill, but others can cause infection and harm you. Even though your hard-working immune system is powerful and usually successful at defending you from invaders, it does face the constant threat of viruses and bacteria that are forever mutating, and seeking new ways to attack and break down your immune defences. Let’s take a look at the constant threats your immune system faces:

Bacteria and viruses

Among the earliest life forms on Earth, bacteria are self-sufficient, one-celled organisms that are visible under a microscope. Not all bacteria, however, are harmful. Some bacteria that live in your body are actually good for you, such as Lactobacillus acidophilus, the healthy bacteria that reside in your intestines and help you digest food. But when unhealthy bacteria enter your body they can make you ill by rapidly reproducing and secreting toxic chemicals that can damage cells in the tissue they have invaded. Common conditions caused by bacteria include strep throat and gastrointestinal illness triggered by E. coli bacteria, which are often linked to undercooked meat.

Even smaller than bacteria, viruses can only be seen through electron microscopes, high-powered instruments that are used to study very small objects. Unlike bacteria, viruses are not self-sufficient; they need a suitable host in which to reproduce. When a virus such as influenza enters you it takes over healthy cells and spreads through your body, causing illness.

Fungi and parasites

Slightly larger than bacteria, fungi live in the air, water, soil and on plants. Moulds and yeasts are types of fungi that can live in your body but don’t always cause illness. Some fungi such as penicillin – an antibiotic which kills harmful bacteria – have health benefits, but other fungi are not so good for you and can cause illness; an example might be Candida, which can cause yeast infections and oral thrush.

Protozoa are single-celled organisms that spend part of their life cycle outside humans living in food, soil, water or insects, and part of their life cycle living within your body as a parasite. Many protozoa inhabit the intestinal tract and are harmless, but others can cause digestive problems and disease.

Helminths are larger parasites that can enter your body, taking up residence in your intestinal tract where they live off the nutrients in your body. The most common helminths are tapeworms and roundworms.

Signs of infection

Diseases and infections are not the same thing. Infection is the first step to disease when bacteria, viruses or other antigens enter your body and try to multiply and take hold. Disease or illness occur when the cells in your body are damaged by infection, and signs and symptoms of illness will become evident.

Common symptoms of infection, such as sweating, chills, fever, runny nose, sore throat, coughing and sneezing, are all indications that your immune system is doing its job and fighting back. In most cases the natural healing response your immune system offers is effective in warding off invading antigens but sometimes things don’t work so efficiently. Bacteria, a virus or other antigens make it past your immune defences and you get ill. And the most common way to get ill is with a cold or flu virus.

The common cold

It’s called the common cold for a reason; you are more likely to get a cold than any other type of illness. More than 200 different viruses can cause the common cold and there are very few people who escape the infection each year. Most adults get between two and four colds a year and most children get between three and seven as their immune systems are less well developed.

Colds can occur year round but are most common in winter. Symptoms generally include a runny nose, nasal congestion and sneezing, but you may also have a sore throat, cough, headache and mild fever. When someone is down with a cold, his or her nose is teeming with cold viruses and sneezing, nose blowing and nose wiping all spread the virus. You can catch a cold by sitting close to someone with a cold and inhaling the virus or by touching your eyes, nose and mouth after you have touched something contaminated with the virus. People are typically most contagious for the first three days of the cold and not contagious at all after a week.

Once you have caught a cold, symptoms appear within a few days and typically begin with a scratchy throat, followed by sneezing and watery nasal secretions that gradually turn thicker, becoming yellow and green. Most colds are over in a week, with perhaps a few symptoms – such as a cough – lingering on for a further week.

If you get a cold you don’t need antibiotics to treat it unless you have yellow or green nasal discharge for more than 10–14 days. Over-the-counter remedies can offer relief but they won’t cure it. It’s important to rest and drink plenty of fluids.

Flu

Caused by the influenza virus which gives it its name, the ‘flu’ which typically arrives in the winter months is a contagious infection of the nose, throat and lungs. It often begins with a fever, raising your body temperature to 39–41ºC (about 102–106 ºF), and other common symptoms such as body aches, dizziness, lack of energy and a flushed face. The fever can last for up to five days but normally subsides after a day or two. Sometime around day four of the illness the ‘whole body’ symptoms subside and respiratory symptoms, such as coughs, sore throats, runny or blocked noses and sneezing, take centre stage. These symptoms tend to continue for about a week, but coughs and tiredness can linger for weeks after the rest of the illness is over.

The influenza virus is airborne and can be caught by breathing in droplets from coughs or sneezes. Most often, however, it is caught when you touch a tap, phone or door handle with the infection on it, and then touch your mouth, nose and eyes.

Millions of people get influenza every year; most recover but for some the symptoms are so severe that they need to be hospitalised. All ages are at risk of serious complications with flu, but those most at risk include babies, children, pregnant women, people over the age of 60, and anyone with diabetes or a chronic heart, lung or kidney condition.

In most people who are otherwise healthy, influenza subsides within seven to ten days. If you do get flu and are not in a high-risk category, resting, using over-the-counter medications that relieve symptoms, drinking plenty of water and avoiding alcohol, tobacco and antibiotics are the best ways to treat it. (For more advice on DIY methods to ease symptoms of colds and influenza, see ‘Part Three: Fighting Infection’.)

Is it a cold or flu?

Most people get a cold several times a year but fortunately, influenza strikes only once every few years. The flu virus is often mistaken for a cold virus since both these infections share similar symptoms, but the two diseases are very different. For one thing colds tend to go away without causing trouble but influenza can lead to complications such as pneumonia. Being able to spot a case of flu quickly also opens up the possibility of taking antiviral medications, such as Tamiflu and Relenza, which can kill the virus and speed recovery. Once flu is diagnosed, your doctor can determine which one is best for you.

If you aren’t sure if you have a cold or a case of the flu, bear in mind that colds tend to come on gradually. The first sign is often a sore or scratchy throat, followed by a runny nose and sneezing. Other symptoms include coughing, headaches and stuffiness. Also colds don’t usually cause fevers in adults, although they can sometimes do so in children. The flu, on the other hand, leads quickly to a high fever and the symptoms tend to be far more severe. You might feel weak, tired and drained of all energy, and you might also experience chills, a sore throat, strong headaches and aches and pains (including eye pains).

A word about bird flu

Known as ‘avian influenza’, bird flu is a viral disease caused by different strains of the influenza virus. It mostly infects birds. Recent outbreaks in Europe have largely been caused by a highly contagious and virulent strain of the virus known as ‘H5N1’. At present, H5N1 is only mildly infectious to humans who have been in contact with infected birds and it cannot be transmitted from one human to another. However, virus experts fear that the H5N1 virus could mutate and be transferred to humans, or combine with other influenza viruses already infecting humans, causing a 21st-century flu pandemic on the scale of the ‘Spanish flu’ that followed World War I, which killed over 50 million people worldwide.

Research suggests that flu drugs, such as Relenza and Tamiflu, are effective treatments for the disease, although there is concern that such drugs may not be as readily available or as effective as hoped if the virus mutates. In addition, a number of companies are trying to develop a vaccine, although this is proving difficult as the flu virus mutates frequently and the vaccines need to be constantly modified.

Despite growing concern, health experts strongly advise the public not to panic as there is no immediate threat to humans. The World Health Organisation (WHO) has effective disease-control measures in place in areas where outbreaks have occurred or are likely to occur. Currently, the WHO is also creating an emergency plan to handle a pandemic and governments are stockpiling antiviral medications. The best way to protect yourself is to keep your immune system as strong as possible by following the guidelines in this book and by staying away from infected birds.

Auto-immune disorders

A weakened immune system will not only increase your susceptibility to colds and flu, it can also increase your risk of auto-immune disorders in which the immune system attacks healthy body cells.

Normally the immune system is capable of telling the difference between ‘self’ and ‘non-self’ tissue, but auto-immune disorders occur when it can no longer differentiate between the two. Why this happens is still uncertain. Some experts believe that these disorders occur following infection by some kind of organism that looks similar to particular cells in the body, which are later mistaken for the organism and targeted for attack.

In many cases, auto-immune disorders cause the destruction of body tissue, resulting in the decreased functioning of an organ or tissue, or several organs or tissues. Examples of auto-immune disorders include:

Chronic fatigue syndrome: A condition of prolonged weariness and fatigue that is not relieved by rest or caused by other medical conditions. Experts aren’t sure what causes it but one theory is that it is caused by some sort of auto-immune response.

Diabetes (Type 1): A disease that occurs when the pancreas produces too little insulin to regulate blood sugar. Symptoms include increased thirst, weight loss, fatigue and increased urination.

Multiple sclerosis: An auto-immune disease that affects the central nervous system (brain and spinal cord). Symptoms include fatigue, tremors and weakness in one or more extremities.

Pernicious anaemia: Caused by the lack of a substance needed to absorb vitamin B12 from the gastrointestinal track. Symptoms include fatigue, unsteady gait and bleeding gums.

Rheumatoid arthritis: A painful long-term disease that causes inflammation of the joints and surrounding tissues.

Most auto-immune disorders are chronic but can be controlled with medication. The outcome of treatment will vary with the disorder but the aim is to reduce the immune response against normal body tissue while leaving intact the immune response against invading antigens.

Allergies

Allergic disorders occur when the immune system over-reacts to exposure to substances in the environment and triggers defence mechanisms such as swelling, watery eyes and sneezing. The substances that provoke this over-reaction are called allergens, and over-reactions to allergens are typically controlled by medications called antihistamines.

When an allergen enters the body of a person with a sensitive immune system, histamine and other chemicals are released by certain cells. It is these that cause itching, swelling, watery mucus production, skin rashes and other symptoms. Such symptoms are inconvenient and unpleasant but are not life-threatening; treatment generally involves the use of medications, such as antihistamines. Sufferers can also take steps to reduce their exposure to known allergens.

The most common allergic disorders include:

Asthma: A respiratory disorder that involves an allergic response by the lungs and can cause breathing problems. If the lungs are sensitive to certain allergens, such as pollen or dust mites, this can trigger a narrowing of the breathing tubes in the lungs, making it hard for the person to breathe. Asthma symptoms can also be triggered by respiratory infections, exercise, cold air, stress, smoke and other pollutants.

Eczema: An over-sensitive reaction that occurs in the skin and causes a scaly, itchy rash. Exposure to environmental irritants can worsen symptoms, as can dry skin, exposure to water, temperature changes and stress. Consult your doctor for a diagnosis of eczema because it can be hard to differentiate from other skin disorders.

Food allergies (to products such as nuts), seasonal allergies (such as hay fever) and environmental allergies (to organisms such as dust mites). All of these are also caused by an over-sensitive immune system, which leads to an incorrect immune response when the immune system reacts to allergens or substances that are generally harmless.

Improving your immunity

A large number of health problems can be linked to an under-par immune system. On the surface, the symptoms of hay fever may seem quite different from the painful, inflamed joints of arthritis or the wheezing of asthma. They are all triggered, however, by an immune system that is struggling to cope with the pressures being placed on it.

There are a number of reasons why your immune system may be compromised or struggling. It is important to understand that in the majority of cases your immunity can be weakened or strengthened by factors within your control. Although the immune system is less efficient in children and the elderly, even the most susceptible person can boost their immune system by:

 keeping up to date with vaccinations

 avoiding common enemies of immunity

 heeding the warning signs of an immune system under pressure

 making the right diet and lifestyle choices.

Vaccination

Your doctor can help you stay healthy by offering you appropriate vaccinations to reduce your risk of getting infected with diseases that are potentially life-threatening. Many vaccines are given in childhood, but adults can also be vaccinated to prevent illness such as tetanus and influenza.

Your body can become immune to bacteria, viruses and other germs by getting a disease – this is called natural immunity. Immunity can also be developed through vaccines – vaccine-induced immunity. Vaccines work by stimulating an immune response without causing disease. Several doses of a vaccine may be needed for a full immune response and it should be noted that vaccines are not free of possible side effects, which often include swelling at the injection site or a mild fever.

Vaccines are the first line of defence against diseases such as polio, measles, tetanus, mumps, rubella, influenza and diphtheria. Were it not for the widespread use of vaccines, a far greater number of deaths would have occurred in childhood, and a great many more people would be living with the chronic and crippling after-effects of disease.

Despite the proven benefits of vaccines there is public concern about their safety and possible side effects, but vaccination continues to be strongly recommended by doctors because gaining natural immunity involves considerable risk.

Vaccination is generally considered by health experts to be the right thing to do as it protects you as well as others. If you have any concerns about vaccinations for which you or your child are eligible, however, it is important to discuss them with your doctor before you come to an informed decision. You can also look at the following website: www.immunisation.nhs.uk. This is an up-to-date source of information on vaccines, disease and immunisation in the UK. Whatever you decide, remember that the overwhelming majority of evidence and research suggests that vaccinations save lives.

The flu jab

Catching flu is tough for most people but for some, especially the elderly, it can lead to serious illnesses such as bronchitis and pneumonia that may lead to hospital treatment and – in severe cases – death. That’s why doctors advise all people over the age of 65, and those with long-term medical conditions, to have a yearly flu vaccination.

The best time to have a flu jab is between late September and early November, to prepare for the winter months. The flu virus mutates frequently, which is why yearly jabs are advised to guarantee protection against the latest strain of the virus. If you think you need a flu vaccination, check with your doctor or ask your local pharmacist for advice. Bear in mind that it takes between seven and ten days for the vaccine to take effect, and that the flu jab doesn’t stop you catching the many other viruses that appear every winter.

Immunity enemies

Although compromised immunity can be triggered by accidents and medication (or in rare cases, immuno-deficiency disease viruses such as HIV), the most common causes of below-par immunity are in fact related to diet and lifestyle choices. In other words, the strength of your immune system is strongly influenced by factors within your control.

A healthy immune system forms the basis of your well-being, so making it more efficient by avoiding anything that might compromise or weaken it is fundamental to good health. Listed below are factors that clinical experience and modern research have shown to have the most damaging influence on immunity, and which should be avoided to ensure good health.

Nutritional deficiencies: The immune system works best when you keep it supplied with a full range of micronutrients such as vitamins and minerals. A poor diet increases the likelihood of nutritional deficiencies and therefore weakens immunity. (For advice on optimising your immunity through diet choices, see ‘Part Two: Boosting immunity with nutrition’.)

Stress: Chronic stress causes the adrenal glands to secrete higher levels of corticosteroids, which depress immune function. (For advice on boosting your immunity through stress management, see ‘Part Two: Boosting immunity with lifestyle changes’.)

Depression: Research shows that people who are negative, moody, nervous and easily stressed have a weaker immune response than those who are more positive. (For advice on boosting your immunity with a positive attitude, see ‘Part Two: Boosting immunity with a Fighting spirit’.)

Lack of quality sleep: Lack of sleep seems to impair the healthy functioning of the immune system. (For advice on getting a good night’s sleep, see ‘Part Two, pages 92–93’.)

Sedentary lifestyle: Exercise enhances the overall functioning of the immune system, and protects against heart disease, cancer and osteoporosis, as well as being an effective way to relieve stress. Research has shown that people who exercise regularly are less likely to get colds than those who are not active. (For advice on immune boosting and exercise, see ‘Part Two, pages 94–95’.)

Over-exertion: Too much exercise can be as damaging as too little. Over-exertion suppresses T-cell function and other immune responses. (For advice on boosting immunity with a regular, moderate exercise plan, see ‘Part Two, pages 94–101’.)

Weight gain: Obesity increases the risk of cancer and heart disease, so maintaining a healthy body weight is a sensible way to encourage long-term immune health, as well as general well-being. (For advice on boosting immunity through weight management, see ‘Part Two, pages 102–103’.)

Alcohol, cigarettes and drugs: Alcohol in excess, together with smoking and taking recreational drugs are simply not compatible with a healthy immune system. The odd drink now and again is fine, but more than one drink a day depresses the immune system; drug use is a major cause of poor nutrition, which damages immunity further; and cigarette smoke contains high levels of dangerous chemicals, including cadmium, which is a powerful immune system depressant. (For advice on quitting smoking, see ‘Part Two, page 126’.)

Over-use of antibiotics: Over-use of antibiotics can cause unintentional suppression of normal immune system responses. (For advice on the sensible use of antibiotics, see ‘Part Three: Fighting Infection’.)

Environmental pollutants: All of the following three categories can compromise immunity and although it is impossible to avoid them completely, sensible use and taking the recommended precautions are advised.

 Radiation: From mobile phones, televisions, microwaves, radio transmitters and computers.

 Chemicals: From engine exhaust fumes, pesticides, herbicides, smoke, aerosols, paints and household products such as air fresheners, cosmetics, deoderants, detergents and furniture polish. Food additives, preservatives and colourings also fall into this category.

 Biological: From house dust, dust mites and mould.

(For advice on avoiding environmental pollutants that can compromise immunity, see ‘Part Two, pages 146-167’.)

Is your immune system in trouble?

The earlier you recognise the signs and symptoms of weakened immunity, the faster you can take corrective action and decrease your risk of illness or poor health. Your immune system may be invisible but there are ways to tell if it is in trouble. Use the checklist below to see if your immune system is in need of a boost.

 Do you feel as if you have lost your energy or get-up-and-go?

 Do you feel the cold more than other people?

 Do you get more than two or three colds a year?

 Have you noticed a loss of libido?

 Are you overweight?

 Do you smoke?

 Is your job sedentary?

 Do you spend little time in natural sunlight?

 Is your diet high in sugar and refined processed foods?

 Do you feel stressed, up and down or just below par?

 Are you forgetful?

 Is it ages since you had a good night’s sleep?

 Do you need coffee or other stimulants to get you through the day?

 Is your skin dry or dull?

 Do you suffer from indigestion, constipation or bouts of diarrhoea?

 Is your neck stiff and sore when you move?

 Does your breath smell?

 Do you suffer from bleeding gums?

 Do you suffer from eye strain?

 Do you suffer from frequent headaches?

 Can you sometimes hear high-pitched sounds in your ears?

 Do you suffer from allergies?

 Do you get food cravings or feelings of intense hunger?

 Are you prone to thrush or cystitis?

 Do your cuts or wounds heal slowly?

 Do you suffer from anaemia?

 Does your hair lack shine?

 Do you often feel fed-up and run down?

If you ticked more than 5 boxes and you can’t find any logical explanation (for example, a stiff neck is to be expected if you slept in a draught; hunger is normal if you haven’t eaten for a few hours and so on), your immune system is definitely in need of a boost. Follow as much of the advice as you can in ‘Part Two: 100 Immune System Boosters’.

If you answered ‘yes’ to only a few questions, your immune system is doing its job well, but it’s still worthwhile reviewing ‘Part Two’ to find ways to turn any ‘yes’ answers you gave into ‘no’ answers.

Making immune-boosting diet and lifestyle choices

Danger comes when your immune system is weakened, and invaders remain undetected and start to multiply. Some invaders are so powerful that they trample your body’s immune system, but in the great majority of cases research has shown that making the right diet and lifestyle choices is the most effective way to boost your immunity and protect your health.

Although vaccinations are a good insurance policy against disease, and medications can save lives, the first line of defence against unpleasant illnesses – such as colds and influenza – is to make sure your immune system is as strong and healthy as possible. The 100 immune-system boosters that follow will give you all the information you need to keep your body’s defences strong through informed diet and lifestyle choices. And whether you decide to incorporate one or all 100 boosters into your life, bear in mind that each one is designed not only to keep you as free from illness as possible, but to also help you feel great, look better and live longer.

PART TWO: 100 IMMUNE SYSTEM BOOSTERS

Boosting immunity with nutrition
1 Go Mediterranean

If you keep your body well nourished with a healthy, balanced diet, you can literally ‘eat yourself well’.

Nutrients are needed for every part of your immune system, and for renewal, repair and defence against infection and illness, so its strength will depend on the quality of your diet. It is therefore important to maintain a healthy, balanced diet that provides an adequate intake of vitamins, minerals and dietary fibre.

But what is a healthy, balanced diet? Studies have shown that the so-called ‘Mediterranean diet’ can offer protection against obesity, heart disease, osteoporosis, cancer and diabetes.

The Mediterranean diet is rich in fruits, vegetables and wholegrains, and contains adequate amounts of oily fish, nuts, seeds, legumes, diary products, lean meat or meat substitutes. Saturated fat, salt and sugar intake are limited, and processed, refined foods are off the menu entirely. Olive oil, the primary source of fat in the Mediterranean diet, is an excellent source of monounsaturated fatty acids that help to lower cholesterol. It is also rich in vitamins and antioxidants that fight cancer and lower the risk of developing degenerative diseases.

In a nutshell, research suggests that the Mediterranean diet, with its emphasis on a wide variety of fresh whole foods – along with the odd glass of antioxidant-rich red wine – is the template for a healthy immune-boosting diet.

2 Double take

The nutritional benefit that you receive from fruits and vegetables is unparalleled. Experts advise eating five to nine servings of fruits and vegetables per day; one way to maximise the variety of immune-boosting vitamins, minerals, fibre and antioxidants, is to make sure you eat two different colours of vegetables and fruits with each meal.

Each different-coloured fruit and vegetable contains unique health components that are essential to our health. The phrase ‘eating a rainbow of fruits and vegetables’ is a simple way of remembering to get as much colour variety in your diet as possible, so that you can maximise your intake of a broad range of nutrients.

Red: Tomatoes, berries, peppers and radishes contain nutrients that can reduce the risk of prostate cancer, lower blood pressure, reduce tumour growth and cholesterol levels, eliminate harmful free radicals, and support joint tissue in arthritis cases.

Orange and yellow: Carrots, yams, squash, oranges, papayas and other orange and yellow fruits and vegetables contain nutrients that can reduce age-related macular degeneration and the risk of prostate cancer, lower cholesterol and blood pressure, promote collagen formation and healthy joints, fight harmful free radicals and work with magnesium and calcium to build healthy bones.

White: Mushrooms, pak choi and pumpkins contain nutrients that can activate natural killer B and T cells, reduce the risk of colon, breast and prostate cancers, and balance hormone levels, reducing the risk of hormone-related cancers.

Green: Kale, spinach, cabbage, alfalfa sprouts, mustard greens and collard greens are all examples of green vegetables that contain nutrients that can reduce cancer risk, lower blood pressure and cholesterol levels, boost digestion, support retinal health and vision, fight harmful free radicals, and boost immune system activity.

Blue and purple: Blueberries, pomegranates, grapes, elderberries, aubergines and prunes contain nutrients that boost healthy digestion and act as anti-carcinogens in the digestive tract.

3 Drink your lemons

Drinking a glass of lemon juice diluted with filtered water every morning is the perfect way to kick-start your digestion and boost your immunity at the same time.

Lemons contain bioflavonoids, a group of nutrients that boosts immunity by protecting the cells of your body against environmental pollutants. Along the membrane of each cell there are microscopic parking spaces, called receptor sites. Pollutants, toxins or germs can park here and gradually eat their way into the membrane of the cell, but when bioflavonoids fill up these parking spots there is no room for toxins to park. Bioflavonoids also reduce cholesterol’s ability to form plaques in arteries and lessen the formation of microscopic arterial blood clots, which can lead to heart attacks and strokes. Studies have shown that people who eat the most bioflavonoids have less cardiovascular disease.

Lemon is also the ideal food for restoring the acid–alkali balance in your body. Drinking freshly squeezed lemon juice in water first thing in the morning or adding it to tea, salad dressings (in place of vinegar), baking or cooking, helps maintain your body’s internal balance at a pH that supports healthy bacteria, instead of the viruses and harmful bacteria that thrive in more acidic environments. Apple cider vinegar is another great way to improve your body’s alkalinity, but the taste of lemons is much more pleasant!

Fresh lemon juice drink

To make a glass of fresh lemon juice, squeeze the juice of one lemon into a glass, add 300 ml (10 fl oz) pure, filtered, slightly warm water and 1 teaspoon of maple syrup for sweetness. Stir and drink immediately. Remember, first thing in the morning about fifteen minutes before breakfast is the optimum time to drink lemon juice.

4 Alkalise, alkalise, alkalise

Your immune system is strongest in an alkaline environment. Many bacteria and viruses love an acid environment, but cannot survive in a healthy alkaline state. If you’re feeling run down, eating lots of green vegetables and drinking plenty of water will boost alkalinity and therefore your immunity.

Your immune system relies on water. It carries nutrients to the cells, carries waste, bacteria and toxins away from the cells and out of the body, keeps body temperature stable, protects joints and keeps the lining of your mouth hydrated and moist, reducing susceptibility to colds.

Don’t wait until you’re thirsty to drink water, as thirst is – along with headaches and dark yellow urine (healthy urine is pale yellow) – a sign of dehydration. Your body’s need for water is constant and experts recommend that you drink six to eight glasses a day, more if you are sweating, exercising or if the weather is hot. And it’s best to drink filtered water only, as tap water may be contaminated by lead and other toxins that your body doesn’t want or need.

5 A yoghurt a day

Look for yoghurt that contains live active cultures indicating helpful bacteria and try to eat one every day for breakfast or dessert, or use live yoghurt in salad dressings, smoothies and dips.

A live natural yoghurt per day might help keep infections at bay. That’s because these yoghurts contain probiotics – bacteria that stimulate immunity cells in the gastrointestinal tract (GI). Normal, healthy bacteria that colonise the GI tract help you resist bad bacteria and detoxify harmful substances. In addition to their protective effect in the GI tract, probiotics may also help stimulate immune-cell production system-wide. In a recent study of 33 women from the University of Vienna, those who ate yoghurt daily for two weeks raised their immune-boosting T-lymphocyte cell count by nearly 30 per cent. (See ‘Part Three, pages 217–19 for advice on taking probiotic supplements.)

6 FOS power

A bowl of oatmeal porridge or shredded wheat for breakfast will give your immune system a much-needed prebiotic fix.

We need both pre- and probiotics in our body. Probiotics are many and varied. The most commonly known is called Lactobacillus acidophilus, found in natural live yoghurt, but more are being discovered all the time.

Prebiotics – also known as FOS (Fructo-oligo-saccharides) – on the other hand, are a kind of natural fibre that nourishes and supports the good work of friendly bacteria, or probiotics. Prebiotics occur naturally in foods such as garlic, onions, leeks, shallots, asparagus, spinach, Jerusalem artichokes, chicory, peas, beans, lentils, oats and bananas. Including more of these foods in your diet will therefore be giving both your digestive system and your immunity a boost. One of the best ways to ensure you are getting enough FOS power in your diet is to have oatmeal, shredded wheat or another wholegrain cereal for breakfast.

7 Good coffee habits

Coffee doesn’t help your immune system do its job efficiently, so keep your coffee consumption down to no more than two cups a day.

The caffeine in coffee can temporarily boost alertness, perk up performance and possibly even improve concentration. But before you pour yourself another cup, experts say it’s important to remember coffee’s main ingredient, caffeine, is a drug and not a nutrient necessary for good health, such as vitamins and minerals. Caffeine can also dehydrate you and leach important immune-boosting nutrients, such as bone-boosting calcium, out of your body. In fact, too much caffeine may also lead to health problems, such as high blood pressure, brittle bones, sleep disorders and just plain irritability.

You don’t have to stop drinking coffee altogether, but, if you are drinking more than three cups of coffee a day, you do need to cut it down to one or two cups. Here are some tips to make sure your coffee-drinking habits are healthy:

 When you drink your coffee, make sure you add an additional glass of water to your daily water intake per cup of coffee to avoid its dehydrating effects.

 Drinking one to three cups of coffee a day (up to 300 mg of caffeine) does not seem to have any negative effects in most healthy people. However, pregnant women, children, people with heart disease or peptic ulcers and the elderly may be more susceptible to the effects of caffeine, and are therefore advised to restrict their intake.

 Be aware that the caffeine content of coffee varies widely depending on roasting and brewing methods, as well as the size of the cup from which you’re drinking. For example, a recent study showed that a 475 ml (16 fl oz) cup of the house blend at a leading coffee chain had a massive average of 259 mg of caffeine.

 Put back some of those lost nutrients by adding two tablespoons of milk to your coffee or making your espresso a latte.

Coffee is the main source of caffeine for many people, but other items, such as soft drinks, tea, chocolate, and cold and headache medicines also contain caffeine and can add substantially to your daily caffeine quota. As for chocolate (another source of caffeine), make sure that the type you eat is quality dark chocolate, containing at least 70 per cent cocoa solids.

Some people feel the buzz of caffeine more than others. Listen to your body and know when to say ‘no’ to that extra cup of coffee, even if you are surrounded by people who drink it like water.

It is important to bear in mind that coffee drinkers who skip their daily fix may experience temporary caffeine withdrawal (usually in the form of a headache or drowsiness), but that these symptoms will disappear within 24–48 hours.

8 Sugar shut down

The next time you’re tempted to grab a bar of chocolate, down a sugary drink or tuck into a sugary cereal, give your immune system a break and have a piece of fruit or a bowl of oatmeal instead.

The impact of refined white sugar on your immune system can be enormous. Eating or drinking 100 grams (8 tablespoons) of sugar – the equivalent of about two cans of a full-sugar fizzy drink – can reduce the ability of your white blood cells to kill germs by 40 per cent. The immune-suppressing effect of sugar starts less than 30 minutes after ingestion and may last for up to 5 hours. On top of all this, a diet high in sugar increases your risk of blood-sugar imbalances that can trigger mood swings, weight gain, fatigue, headaches, hormonal imbalances and a host of other unpleasant symptoms.

If you do only one thing to boost your immune system, eliminating sugar will do the trick. Sugar gives you no nutrients, just calories. You will see noticeable results in your energy levels, weight distribution, immunity and ability to think clearly when you break the cravings and stop eating refined sugar.

Cutting down on your sugar intake may seem daunting at first, but it is easier than you think if you follow these tips to total sugar shut-down:

Sweet substitutes: Try fruits and unsweetened fruit juices more often in meals and snacks to cut down on sugar. Fruits have natural sugars, but they also give you important vitamins and minerals. Plan to have fresh fruit in season for desserts. Use dried fruits to sweeten cereals and baked goods. Slice a banana or fresh peach instead of using jam on a peanut butter sandwich. Make your own fizzy drinks with unsweetened fruit juice and sparkling water.

Pass on the sugar: Take the sugar bowl off the table and, if you add sugar to your tea, gradually cut down until you need none at all. Persevere with this because once your taste buds get used to tea and other hot drinks without sugar, you’ll never want to switch back. And while you are cutting down, reduce the amount of sugar you use in baking as well.

Don’t ban sugar altogether: Some sugar, judiciously added to wholesome foods, may make them more appetising; a sprinkling of brown sugar on oatmeal or grapefruit, or a teaspoon of maple syrup on winter squash enhances the taste of these healthy options. It is better to avoid sugar substitutes, as some studies suggest that they can also have an adverse effect on your health.

Cereal killer: Some breakfast cereals have four or more teaspoons of sugar added to each serving! When you buy unsweetened cereals you may be saving money and you can add your own sweetener at home, if you choose. Sprinkle fresh, canned or dried fruit on your cereal to sweeten.

Read labels: When food shopping, read ingredient labels to find the amount and types of sugars that have been added to the food. There are many kinds of sugar that are used to make a food sweet and crisp. Look for words that end in ‘ose’ or ‘ol’, such as dextrose, fructose, maltose, sucrose, glucose, lactose, mannitol and sorbitol. These are all forms of sugar. Syrups such as corn sweetener, sorghum syrup and high-fructose syrups are sweeteners that are often added to drinks. Brown sugar, molasses and honey may be ‘natural’, but they all give you the same calories as refined table sugar. Ingredients are listed in order by weight, from most to least, so when a type of sugar or syrup is the first ingredient, you will know there is more sugar in that food than any other ingredient. Some foods may contain many kinds of sugar. When they are added up, the total may be more than any other ingredient in that food.

Switch from white bread, pasta and rice to wholegrain alternatives: Wholegrains are packed with nutrients and fibre that can keep your blood-sugar levels and your appetite balanced for hours after eating, unlike sugar, which gives you a quick high followed by a long low.

9 Conquer your sweet tooth

If you have a sweet tooth and constantly crave something sweet, you need to conquer it. A diet rich in sugar depresses your immune system and stops it working efficiently.

To conquer your sweet tooth, first of all, make sure you always eat breakfast and never leave more than two or three hours between meals and snacks. This is because eating little and often and kick-starting your metabolism first thing will keep your blood-sugar levels balanced so you are less likely to suffer from cravings. Aim for a healthy breakfast, followed by a satisfying mid-morning snack (a piece of fruit and a handful of nuts and seeds, for example), a healthy lunch, a mid-afternoon snack, supper and a light snack before bedtime.

For blood-sugar balance and appetite control, your meals and snacks need to be a mix of fibre-rich carbohydrates (such as wholegrains, fruits and vegetables) and healthy protein (such as nuts, seeds or dairy products) that give your body and brain a sustained release of energy so you feel satisfied. Avoid sweets, cakes, crisps and other processed or refined foods; these give you a quick burst of energy followed by a long, drawn-out low.

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