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