Establishing a Healthy Immune System

In these unprecedented times that we find ourselves in and as we approach the winter months whereby an increase in seasonal colds and flu are expected, it is of no surprise that there is a vast amount of information being circulated regarding the importance of “boosting” one’s immune system.  The truth of the matter is that one should not aim to “boost” their immune system, as an overactive immune system is undesirable and may be harmful to one’s health.

The ultimate goal is to achieve a strong, healthy immune system that functions effectively in order to protect humans from infections by pathogens such as harmful bacteria, viruses and fungi.  The immune system is however complexed and integrated, involving many different cells and chemical mediators throughout the body.

Babies are born with an immature immune system which develops during childhood reaching optimal function in adolescents and young adulthood.  A gradual decline in immunity is experienced in older people, however it’s important to note that age-related declines in immune function are compounded by lifestyle factors.  It is the immature immune systems in children and the decline in immune function in the elderly that places these two groups of people in a position of increased susceptibility to infections.

There are a number of factors that influence the immune system and it’s competence, with nutrition being one of the most vital influencers throughout all stages of life.  Nutrition however cannot be isolated when trying to establish or ensure a healthy immune system. The focus should be on lifestyle as a whole.  Other factors alongside a poor diet that play a huge role in compromising the immune system and are therefore of utmost importance to mention include pollution, cigarette smoke, chronic stress, excessive alcohol intake, prolonged excessive exercise and inadequate sleep.  It’s important to note that the risk of infection is also influenced by gender, vaccination history, pathogen exposure, specific health conditions and diseases.

Adequate nutrition is vital in ensuring the necessary supply of energy and nutrients required for the development, maintenance and overall functioning of the immune system. The role of nutrients are numerous and varied, and it is therefore important to note that there isn’t one single nutrient, food item, diet or supplement that will enhance immune function – it is a balanced variety of micronutrients that is required.  Vitamins and minerals of particular importance include vitamins C, D, A, E, B12, B6, B2, folic acid, iron, selenium and zinc.

Micronutrient deficiencies are common worldwide even in developed countries where access to food is not restricted.  The main reason for this specifically in developed countries is not related to food accessibility as much as it is due to food choices and an increased intake of micronutrient poor foods.

Other factors that may result in a poor diet and ultimately a sub-optimal nutritional status include aspects such as low income and a lack of nutritious food, restricted diets, busy stressful lifestyles which result in an increased intake of convenience meals and take-away foods and sedentary lifestyles that predispose people to lifestyle diseases such as obesity, type 2 diabetes and heart disease which result in compromised immune function.

Ensuring an adequate intake of essential macro and micronutrients involves eating a balanced diet consisting of food items from all food groups.  It is of utmost importance for the general, healthy population to avoid diets that recommend restricting various foods groups (exceptions are made for certain disease conditions and when recommended only by a qualified healthcare professional on a case by cases basis).

The basic guideline includes eating a diet that includes a variety of colourful vegetables and fruit on a daily basis ensuring an adequate intake of fibre, vitamins and antioxidants to counteract oxidative stress. Avoid processed and refined foods and consume more high fibre, wholegrain products such as oats, barley, brown rice, quinoa etc. These foods are good sources of fibre, iron, niacin and folic acid.

Low fat protein sources such as lean meat, chicken, fish, legumes, nuts, seeds and low fat dairy should be consumed daily to ensure the intake of iron, zinc, calcium, vitamin D and B vitamins.  Limit intake of saturated and trans fats and include more monounsaturated and polyunsaturated sources such as olives, olive oil, avocado pear, nuts and seeds.  When possible avoid the regular intake of high sugar containing foods and beverages and ensure an increased intake of water and herbal tea.

It is highly recommended and generally possible to obtain all necessary nutrients from a healthy, balanced diet, therefore supplements should only be considered in the event of needing to restore a deficiency and/or on the recommendations of a qualified health professional.  In the event of supplementing, to avoid negative side effects it is important to ensure the supplemented amount does not exceed the recommended tolerable upper intake levels.

As mentioned a healthy lifestyle is key to a healthy immune system and includes not only a nutrient rich diet but also daily physical activity, maintaining a healthy weight, ensuring adequate sleep, decreasing stress levels, practicing good hygiene such as regular hand washing, limiting alcohol intake, and avoiding smoking.

The decisions you make today will ultimately affect your future, so invest in yourself in all stages of your life to ensure longevity and productivity for years to come.

The dietary guidelines mentioned above are basic, general guidelines however nutrition recommendations should be assessed and individualised on a case by case basis by a registered dietitian.

Richelle Cavanagh
Registered Dietitian – KPSMC

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