The human body’s immune system is responsible for fighting off infection and disease. It is a very complex system that involves skin, gut, blood, specialised white blood cells, antibodies, and more. Nobody wants to be sick and so we have long sought ways to strengthen our immunity. Pandemics like HIV and Covid-19 certainly highlight the importance of good immunity, but it has always been important (e.g. seasonal flu kills millions worldwide every year).
We’ll try to keep this brief:
There is some evidence (not as much as we’d perhaps think, but some) that healthy living supports immune-health. So yes, we do advise not-smoking, drinking moderately or not at all, being active, eating a balanced diet, maintaining a healthy weight, etc.
Sleeping for 7-8 hours a night helps with overall health, and with immune-system health.
Stress, especially long-term stress, can weaken immunity and disease-resistance. So managing stress can help.
If your diet is not well balanced you may benefit from a multivitamin supplement, although most adults can get all the nutrition they need from a balanced diet.
Most vaccines in modern use are effective and safe. Vaccines boost immunity (against specific infections only). Two good examples are season flu vaccine (typically offers about 60-70% protection) and pneumococcal vaccine (typically offers 50-80% protection to susceptible elderly patients).
General hygiene and hand-washing is very important in reducing the spread of many illnesses. As simple as it is, this is a habit worth developing.
As you can see, this is mainly common-sense healthy living.
What does not work?
Here we can help with a little “myth-busting”:
Most commercial products and the claims they make, are unproven. To be fair and clear, when we say “unproven” we mean that there is no solid peer-reviewed published evidence (the sort you’d read in reputable medical journals like Lancet, NEJM, BMJ, etc.). There may be anecdotal “evidence” and there may be tiny studies with mixed/possibly positive findings, but this is not what we call proof.
Mega-doses of single-vitamins (e.g huge doses of Vitamin C) have not been to shown to improve infection-resistance, in most reputable studies.
There is no reputable published evidence to support claims made for garlic, Rooibos tea, apple-cider-vinegar, and many other “folk remedies”. There are a great-many anecdotal stories and many people believe in these sort of “natural” remedies. At moderate doses there is almost certainly no harm in using these sort of products if you want to, but be careful, read packaging carefully (not all natural products are safe and side-effect free), and do not expect too much.
Extreme exercise does not build immunity. As a general guideline, exercise (sweaty and short of breath exercise) is healthy in almost every way, up to about 6-8 hours of training per week. More than this, which is common among competitive or professional athletes but rare otherwise, can actually weaken immunity.
Avoiding cold does not protect you from infections like the cold or flu. Despite what your mother may have told you (How many of us were told “put your jacket on before you catch a cold”?) the real reason why winter if “flu season” is almost entirely because we spend more time indoors, and closer together, in winter. Close contact aids infection spread and so we get more flu spreading in winter.
So there you have it – immune health, it turns out, is closely tied to general health and is achieved the same way, more or less. Live well, stay well! You may already have known or at least suspected this truth, but we hope we have at least helped to clarify a few things and perhaps bust a few myths. One further note: this is an area of ongoing research so we yet learn more in time.