Can we really ‘boost’ our immune system to fight COVID-19?

stanley moffatt To date, the 1918 Spanish flu pandemic has the unenviable tag as the most humanly devastating in history, infecting more than 500 million people, and killing at least 50 million people worldwide. Unfortunately, the pandemic also came with opportunities for self-styled chemists and medics to make regular appearances in the news media, with alarming and sensational headlines.

Sadly, not much has changed in 2020. Even though the COVID-19 pandemic is separated from the Spanish flu by more than 100 years, with a commendable advancement of scientific discoveries, there are still thousands of so-called medical remedies floating around. The current theme by the herbal and other drug peddlers is “boosting” the immune system. And as always, social media is inundated with nutritional advice. This time, we’re being advised to seek out foods rich in Onions, Garlic, Antioxidants, Zinc and Vitamin C, while “nutritional and medical experts” are also peddling nutritional products such as probiotics.

According to another “nutritional expert”, green tea and cayenne pepper can even provide better protection against COVID-19 than face masks – albeit, a bold and questionable claim, considering that some face masks reduce your risk of coronavirus infection by a factor of five.

“Boosted” immunity doesn’t exist

Unfortunately, the idea that nutritional pills or supplements or some wellness habits provide a shortcut to a healthy immune system is a myth. In fact, the entire notion of “boosting” one’s immune system doesn’t have any medical or scientific meaning or relevance.

For a start, there are three main barriers to infection, which also provide the three keys to unravel the concept of immediate immunity. These are the mucus membrane, the airways, and the skin.

Once the virus succeeds in going past these defences, then you have to induce the ‘innate’ or non-specific immune response, which primarily consists of cells, physical and chemical barriers. The innate immune system is elicited first, but does not retain memory of previous responses. The main purpose of the innate immune response is to rapidly fight off the invading pathogen(s) in the body.

When that is not enough, then the adaptive immune system kicks in. This response involves Lymphocytes (B-cells and T-cells) and antigen presenting cells (B-cells, dendritic cells and macrophages). While the innate immune response is immediate, the adaptive immune response is not (takes a few days or weeks to emerge).

However, the effect of the adaptive immune response is long-lasting, and is sustained long-term by memory T cells. Importantly, the adaptive immune system is pathogen-specific, so for example, a T-cell specific to SARS-CoV-2 will not respond to common cold or the measles virus. Eventually, almost all viral infections will trigger adaptive immunity.

The current usage of the term “boosting the immune system” presumably denotes making these responses stronger or more active.

In actual fact, you don’t want to make the immune system more active.

If you take the symptoms of the common cold – fever, body aches, copious amounts of phlegm – these symptoms aren’t actually caused by the virus itself. Instead, they’re part of the innate immune response that are triggered purposefully by the body.

In this case, the rise in temperature that comes along with fever helps to create an uncomfortable environment for the virus to replicate, the aches are by-products of the inflammatory cytokines that run through your veins telling immune cells what to do and where to go (perhaps also signalling the brain to slow down and allow the body to recover), and the mucus helps to flush out the pathogen.

The mucus and chemical signals are part of inflammatory responses, which is the real indicator of a healthy immune response. But since this biochemical process is exhausting, you wouldn’t want to have it in an overdrive. And most viruses, including SARS-CoV-2, will trigger it anyway. What this means is, if any of the various “immune-boosting” supplements being advertised today had any impact on the immune system, they would give you almost nothing extra but a runny nose and more phlegm.

Furthermore, making the adaptive immune system generally “more active” could also be extremely unwelcome. For example, allergies occur when overactive immune cells treat even innocuous antigens, such as pollen, as though they are extremely harmful. Each time they find the pollen, they trigger the innate immune response too – itchy eyes, lots of sneezing, and general malaise. This is probably not what the advocates of these remedies have in mind.

But let’s give the advocates of the “immune system boosters” the benefit of the doubt, and assume they mean that their products can enhance the immune response – rather than literally “boost” it. The overarching problem with these claims, however, is that they don’t have any grounding in evidence. So what are these claims based on? – and is there anything that can help support the immune system?

For healthy individuals, forget the supplements – except vitamin D

Many multivitamins claim to help “maintain healthy immune function” but research indicates that multivitamins don’t work in already healthy people, and some may even be harmful.

Let’s take vitamin C. The health effects of this antioxidant have been hyped ever since Linus Pauling (a two-time Nobel Prize winner) became fascinated with its ability to fight the common cold. After extensive studies on vitamin C, he started taking 18,000 mg per day – around 300 times the recommended daily dosage!

There is however very little evidence to support the claim that vitamin C can fight off colds and other respiratory infections. Indeed, a review by Cochrane – an organisation noted for objective and unbiased research – reported that in adults, vitamin C administration at high doses after the onset of symptoms, showed no consistent effect on either the duration or severity of common cold symptoms. Since then, various infectious disease experts and nutritional immunologists from prominent labs around the world have asserted that vitamin C supplements aren’t beneficial unless you are immune-deficient!

Let’s look at vitamin D. In the advanced world, most people already have enough vitamins from their diets, unless they are restricted. The only exception may be that of Vitamin D, in […]

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