How ‘old’ is your immune system?

Clinical Nutritionist Di McCauley (BHSc (comp.med), MH)

With Covid-19 causing death, disruption & disconnection across the globe, it has also introduced us to many new terms that we have become all too familiar with; Lockdown, self-isolation, social distancing, co-morbidity, epidemic, pandemic, outbreak, panic buying, PPE, Covid-19, Coronavirus, community transmission, quarantine.

Also, relevant with a slightly more positive context is the term ‘Immune Age’!   It’s more important than ever to keep our immune systems fit and healthy so I briefly discuss; what is immune age? and how does is benefit us?

When it comes to the avoiding viral transmission most of us are well versed with the preventative measures such as washing hands for 20 seconds, sneezing into your elbow, avoid touching your face etc., basic hygiene practices that go along way to keeping ourselves and our community healthy.

But ultimately, the most important factor standing between you and any viral infection is your immune system.

Immunologists now know that our immune system gets weaker with age which is a key reason those over the age of 70 are at more risk of disease.  It is also becoming clear that immune health doesn’t always correlate with age.  Some people have an immune system that is older or younger than their chronological years.  The good news is that there are some simple ways to turn back the immunological clock!

If you are younger than 60, in good health and don’t have too many bad habits, then your immune system is probably functioning well enough to keep you safe from almost any infectious disease.

What is Immunosenescence?

The bad new is that as we age, our immune system gradually deteriorates.  This is referred to as “immunosenescence” (changes to the immune system associated with age) which starts to affect people’s health at about 60 years of age.   Therefore, the older you get the weaker your immune system becomes and the more likely you are to get ill.  As is typical with acquiring a virus such as the seasonal flu, how well you recover comes down to immunosenescence.  However, the ability to turn back your immunological clock becomes important as through life we continue to be exposed to ‘invaders’ and therefore our immune system needs to be ready when the next one comes along.

Is Your Immune System Aging Faster Than You?

Immune decline can be accelerated by many lifestyle factors.   The following  are identified as significant causative factors that cause an immune system to become older than your chronological years;

  • Smoking
  • Obesity
  • Sedentary lifestyle

This understanding has led to this new concept called ‘immune age’ and is similar to ‘biological age’.  Determination of biological age uses chemical tags progressively added to genes throughout life to measure how far down the trajectory of ageing somebody has travelled.  Biological years & chronological years are usually similar but can diverge by as much as 20 years either way as a result of deliberate lifestyle changes.

Although recent scientific development has established how to measure immune age, commercial testing is still in development therefore currently unavailable.

However, you don’t need to know exactly what your immune age is in order to take steps now to lower it and improve the health & fitness of your immune system.

Immune Surveillance

A key aspect of immunosenescence is that some of our immune cells start to misbehave as we age and this relates to a class of immune cells called neutrophils (a common white blood cell).  These are the body’s first line of defence against infection and this army of immune cells are on constant surveillance for harmful bacteria.  They seek and destroy just like a Pac-Man as they tunnel from the bloodstream through tissues in a process called chemotaxis.  This process, however, becomes increasingly erratic as we age.   Older neutrophils can still detect invaders but become ineffective at hunting them down effectively losing their navigation system.

Not only does this lose the speed & efficiency in which our immune system responds but the disordered neutrophil response causes inflammation referred to as ‘inflammaging’ (the general low level inflammation that affects our bodies as we age).

Scientists have discovered that the root cause of the problem is an overactive enzyme involved in directional control and currently research is still developing on pharmaceuticals drugs that are effective in dialling down this enzyme.

Good News

However, here comes the good news!  A 2016 study revealed that there is a drug free way to rejuvenate your neutrophils with EXERCISE!  The study showed those maintaining 10,000 daily steps on average had neutrophils as good as young adults.

Just to clarify also, neutrophils are not anti-viral so won’t prevent you from catching a virus.   They will protect you from pneumonia which is a common secondary infection occurring as a result of viral illness and often becomes the biggest risk to health and recovery.

Vital Vitamins

T-cells are another class of immune cells whose effectiveness are also blunted by immunosenescence.  Just like neutrophils signalling pathways go awry & they are inhibited by inflammaging.  Immunologist have reported research on the efficacy that Vitamin E provides as a simple solution to undo this damage.   Vitamin E daily doses showed strong positive immune system responses with a decrease in the rate of upper respiratory infections.

In 2017 a review of Vitamin D research concluded this vitamin appears to positively influence the innate immune system and it’s responses in preventing upper respiratory tract infections.  Vitamin D efficacy is dose dependent & I advise many of my clients to have levels checked first to ascertain the appropriate dose needed to achieve therapeutic functioning levels.

A third supplement with good evidence for immune boosting efficacy for viral infections is Zinc.  Again, dose and the dosing window for efficacy is important.

Getting Physical to Maintain Health & Immunity

Your thymus organ (located beneath your breastbone) is a patch of lymphatic tissue where your T-cells go to mature before being released into your immune army for active duty.

Unfortunately, it shrinks with age and by middle age we barely have any left and T-cell count therefore declines which affects our ability to fend off novel pathogens.

Thymus regeneration is an active area of anti-aging research and to date has revealed that a large part of thymus decline could be down to physical inactivity!

Exercise also has other immune-boosting effects.   Skeletal muscle is a profound immunoregulatory tissue which not only stimulates aspects of our immune system but also provides anti-inflammatory effects and effectively supports a normal body composition.

Maintaining muscle has significant benefits for maintaining health and a fit immune system therefore, it’s a no-brainer to ensure you take steps to avoid losing it as you age (sarcopenia).

Simple Steps Count

Increasing your steps (activity) to 10,000 per day in the face of our current viral landscape (even in lockdown!) is more important than ever to maintain a fit and healthy immune system.


Your immune system is critical to your lifespan therefore looking after it provides a direct route to your longevity and maintaining regular exercise is a key aspect.

Hopefully lockdown for you has initiated some positive lifestyle adjustments;  quality time, connection, regular exercise & real food.  If so, then think about how you can carry this framework forward to support your immune system.

Your lifestyle serves to maintain the fitness of your immune system so what lifestyle choices will you make to ensure you look after it?