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August 2013

  • Avni Sali

Lifestyle is your best defence

In the quest for good health, one of the most fundamental wellness strategies we can consider is the development and maintenance of a strong immune system. Especially in winter, with its typical increase in the incidence of colds and ‘flus, we can be proactive with regards to our immunity. However, a healthy immune system is also an essential consideration every day of the year, as immunity plays an important role in the prevention and treatment of cancer and other immune disorders such as autoimmune illness. It also plays a major role in allergy disorders.

The immune system is a complex composite of tissues, cells and molecules with specialised roles in the defence against infection, and is vital in the body’s maintenance of health. Its complex interrelationship with the psychological, neurological, endocrinological, gastrointestinal and cardiovascular systems has provided many medical insights into the nature of disease and its pathology. Immune dysfunction may appear as an immune inactivity, such as cancer, or hyper-activity as in various allergies such as asthma or autoimmune diseases such as type 1 diabetes, Multiple Sclerosis and rheumatoid arthritis. Our immunity is also linked to recurrent infections of which the common cold and influenza are perhaps the most well known examples.

There are two types of immunity: the innate immune system (non-specific) and the adaptive (acquired) immune system. The innate system refers to our body’s first line of defence and includes physical barriers such as the skin and other mechanisms. We see the effect of innate immunity when, for example, redness occurs around a cut in the skin. The innate system releases cells that are responsible for inflammation (an initial part of the body’s protective mechanism) and natural killer cells which can destroy viruses, bacteria or cancer cells. This immune response will occur to the same extent regardless of how many times the infectious agent or trauma is encountered.

The second type of immunity is adaptive immunity. Adaptive immune responses improve on repeated exposures to a given infection or antigen. An antigen is any substance that causes the immune system to produce antibodies against it. An antigen may be a foreign substance from the environment such as chemicals, bacteria, viruses or pollen, or formed within the body, as with bacterial toxins. The body will produce either a cellular (T-cells, B-cells) or humoral (antibody) response. T-cells help B-cells make antibodies (produced in the bone marrow and thymus), which kill virally infected cells. After initial antigen exposure, immune memory develops and results in early recognition and stronger reactions to fight the antigen on subsequent exposure. This process of acquired immunity is the basis of vaccination. The innate and adaptive immune systems are not exclusive of one another – indeed they cooperate to remove pathogens and restore balance in the body.

Strategies for better health should ideally begin with taking care of the gut. Gastrointestinal mucosa is the major contact area between the human body and the external world of micro flora and is over 400 square metres in size. Gut bacteria (flora), of which there are approximately 100 trillion, are in constant communication with our immune cells with 70-80 percent of all immune cells in the human body located in the gastrointestinal-associated lymphoid tissue (GALT). Research now provides us with a better understanding of the interaction of bacterial species and the immune system. This represents a somewhat paradoxical shift – from the belief that the immune system controls microorganisms to the understanding that it is the microorganisms that control the immune system. Supporting GALT with optimised micro flora is therefore key to our ability to fight diseases and ward off common infections. A key problem with antibiotics and chemotherapy drugs is that they destroy the normal gut flora, which in turn leads to immune disturbance. The gut flora not only influences the immune system, but can also influence virtually all body systems, for example the brain and weight (metabolism).

All of the systems in the body, including the gastrointestinal system, are influenced by lifestyle, hence how we live affects how well our body responds to the threat of pathogens and disease. The connection between stress and depression and health is best explained through the disciplines of Psychoneuroimmunology (PNI) and Psychoneuroendocrinology (PNE). Stress and depression influence the body through the brain – PNI is the study of how the mind influences the immune system (to be normal, abnormal or hyperactive) and PNE describes how the mind influences the body’s hormones.

How is lifestyle influencing your immune system today?
Key risk factors for immunity include:
• Stress – chronic stress and depression 
• Lack of sleep 
• Lack of sunshine – vitamin D deficiency 
• Exercise – too little or too much (extreme) exercise 
• Obesity or being underweight 
• Poor nutritional intake and poor diets generally 
• Environment  – climate changes including overheating, poor housing and/or living conditions such as overcrowding 
• Environmental syndromes including chemical sensitivities 
• Chemical exposure and pollutants – occupational, industrial, pollution, smoking 
• Medications – especially immuno-supressors and chemotherapy medications 
• Exposure to infections – through poor water and food quality, and poor hygiene. Also exposure to bacterial, fungal, viral and parasitic infections 
• Nutrient deficiencies, for example, vitamins A, C, D, E, B6, B12, folate, zinc, iron and copper. However, all micronutrients are important for proper immune function. 

Any change in lifestyle that modifies the above risk factors will enhance immunity. Some general immunity tips include:

Manage your immune system with food
Many foods are immune-modulating based on whether they have an anti-inflammatory or pro-inflammatory effect. You can boost your anti-inflammatory food intake with: omega 3 EFA, as found in seafood; low-GI foods; antioxidant rich foods (especially those high in vitamins A, C and E); high fibre foods; increased monounsaturated fats (nuts and avocados are good); restricted total calorie intake; more fruit and vegetables; lean game meats; herbs such as garlic, ginger and turmeric; and drinking green tea.

Pro-inflammatory foods are those with: excess energy (high calories), high-GI, high trans fats, saturated fats, excessive salt and refined carbohydrates, as found in most processed and fast foods. Also excessive alcohol consumption, some dairy foods and food additives such as artificial colours, flavours and preservatives can be pro-inflammatory.

Make quality sleep a priority
Poor sleep is associated with a greater susceptibility to the common cold and most other illnesses. The natural sleep hormone melatonin is immune-modulating, so sleep disruptions have an immediate effect on the complex interrelationship between hormones and the immune system. Poor sleep is associated with a multitude of health problems and is a common complaint for Australians today. Over 50 percent of adults aged 65 and over have at least one sleep complaint. Sleep is essential for good physical and mental health. Immunity can be enhanced by ensuring regular and restorative sleep patterns are maintained. In some cases melatonin supplementation may also be of therapeutic benefit for the immune system.

Take a probiotic every day
It is understood that daily replenishment of gut bacteria is important for immunity. Supplements are ideal ways to ensure measured doses are taken; however, there are many foods that can be added to the diet that feed or replenish gut bacteria, such as yoghurt and fermented foods. (See July issue of The Melbourne Review for more information on gastrointestinal health.)

Vitamin D and the sunshine effect
Originally vitamin D deficiency was only regarded to be important for bone health. However, it is now understood that this vitamin is actually a complex vitamin that is intricately involved in the integrity of the innate immune system, plus every other body system. Vitamin D receptors exist in all tissue to regulate cell growth and decrease the risk of cells becoming malignant. Vitamin D deficiency has now been linked to numerous types of cancer, auto-immune diseases such as Multiple Sclerosis and many other chronic illnesses.

Of course at this time of year, there are additional immune strategies that may help us meet the challenges of the season. Research reveals several herbal, vitamin and mineral supplements that may be of particular benefit for boosting immunity in the cold and flu season.

Season Specific Supplements

Zinc is critical for cell function and directly influences the GALT and the mucosal barrier to inflammatory cells. It regulates the immune system and even a mild deficiency can result in immune dysfunction. Many studies have demonstrated the beneficial effects of zinc supplementation in the management of the common cold, cold sores, influenza and acute respiratory infections.

Vitamin C

Vitamin C can reduce the duration of a viral infection such as a cold. It is possible that a high dose of vitamin C may also prevent the onset of a cold. It has been found to improve components of the immune system such as antimicrobial and natural killer cell activities. Plus it can be antibacterial and antiviral at high doses.

There is preliminary evidence that echinacea may be beneficial in the early treatment of the common cold. The purple flower is a traditional cold remedy that has been used by Indigenous Americans for centuries. Studies indicate echinacea can decrease the length of a flu-like illness, as well as reduce the frequency and severity of upper respiratory tract infections. It can be used for both prevention and treatment.

Astralagus is a 2000-year-old Traditional Chinese Medicine herb used to enhance immunity and rejuvenate the body and its vitality in the recovery of illness. It is antioxidant, anti-viral and helps rebalance gut flora. Clinical trials showed astralagus reduced the incidence and duration of colds.

Olive Leaf Extract
Olive leaf extract can suppress a number of viruses, including those that cause the common cold. It has been reported to improve immunity by increasing natural killer cell function, and to be effective against viruses such as HIV, hepatitis B and C, and herpes. Preliminary research also shows benefits for artery disease, dementia prevention and other disorders.

The immune system changes as we age and has different demands placed upon it during different seasons. It is disturbed by malnutrition, the normal process of ageing, physical and mental stress and undesirable lifestyles. There are many ways we can improve our immunity, and effective changes can start today by improving dietary intake of immune-modulating foods and supporting the diet with proven immune boosting supplements. A strong immune system is a mirror of a healthy lifestyle. Preventative measures in the cold and ‘flu season will also support optimal health and wellbeing.


Professor Avni Sali is Founding Director of the National Institute of Integrative Medicine (NIIM). He oversees the facilitation of the practice of Integrative Medicine at the NIIM Clinic in Hawthorn, as well as the promotion of education and research.




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