Now that summer is over and colder weather is on the way, we’re sure to notice an increase in the number of colds, chills and other viral infections knocking about. For most of us, a cold is a moderately depressing inconvenience that at worst keeps us in bed for a day or two, but for the elderly and the sick, a simple viral infection like a cold can leave them open to attack from more dangerous illnesses.

Many people wonder why there are no cures for colds and influenza. Surely, they reason, with all that modern medicine can do, curing a simple disease like a cold should be easy. The problem is not that we don’t understand how viruses like colds and flus work (we understand them completely) but how rapidly they mutate – in other words how quickly one type of cold can change into a different one.

Let’s start by looking at what a virus is. Viruses have been amusingly described by one biologist as ‘a little piece of genetic code wrapped up in bad news.’ Viruses themselves are not technically alive – they don’t have cells or all the machinery necessary to sustain life and are entirely parasitic. Viruses work simply by entering a living cell (depending on the virus, this could be a bacterium, a plant cell, fungal cell or animal cell, such as a human cell) and essentially taking over the machinery of that cell. The cell is then forced to produce more copies of the virus, until there are so many copies that the cell bursts, and all the little copies are free to attack neighbouring cells.

Viruses are extremely simple. A typical virus contains just a small length of DNA or RNA (genetic material) encased in a tough protein coat (the bad news). This protein coat is of a very specific shape, and it is this that allows the virus to enter a cell. In simple terms, the protein coat binds to structures on the surface of the cell it is attacking, allowing the virus (or at least its genetic material) to enter the cell. Once inside, the virus’ genetic material takes over the cell, and millions of new copies are produced.

For the most part, these copies are identical to the original virus, but every so often (about one copy in a billion) there is a mutation. Because the shape of the virus’ protein coat is determined by the order of its genes, a slight change in genetic order caused by a single mutation can lead to the virus having a different shaped protein coat. Most of these mutations will have coats that are now useless (the wrong shape to bind to cells) but some will have a differently shaped coat that allows them to bind to a different structure on their hosts cells. This new mutated virus will spread and produce more copies of itself, and we have a new strain of virus. This truly is evolution in action.

This is why we are unlikely ever to find a definitive ‘cure’ for colds and other common viruses. It may surprise you to know that you are now immune to every cold you have ever had in your life. If your body encounters a virus that has previously infected it, it is able to recognise it and destroy it before it can infect you, but because viruses like colds are constantly mutating, there are always new types of cold around that you haven’t previously encountered, and you are always at risk of infection from these new strains.

This is why it is a good idea to ensure that your immune system is working as effectively as it can be. The immune system is an incredibly complex and powerful set of tools that our bodies use to defend against infection and to destroy invading viruses or bacteria. It works on many levels, but is easiest to consider in terms of being a small standing army of different specialist cells. These cells patrol your body, identifying alien invaders such as viruses and attempting to destroy them. When a new invading virus is found, your immune system first needs to discover the right shaped protein molecule – or antibody – that will destroy the virus, and this can take a couple of days. During this time, the virus will be producing billions of copies of itself, spreading through your system and beginning to make you feel ill.

Perhaps surprisingly, it is not often invading viruses themselves that make us feel ill, but the body’s efforts to destroy them. Once the right kind of antibody has been discovered, the immune system goes into overdrive, manufacturing millions upon millions of copies of it, and this uses a lot of energy, leading to the fatigue that is a common symptom of colds.

Boosting the immune system and making sure it has all the vitamins and minerals it needs to work effectively can dramatically reduce the risk of becoming ill. If the immune system is able to quickly identify and destroy new invaders before the infection becomes widespread, we can tackle viral infections sometimes without even realising we’ve had one. In other words, we get a cold and get over it without ever actually becoming ill.

Antiviral supplements contain vitamins and herbs that stimulate and support the immune system. When the body is manufacturing antibodies and immune cells, it uses a lot of vitamin C and zinc, and taking a daily supplement containing these substances can help to keep your immune system functioning correctly. An antiviral supplement will also typically contain a strong antioxidant such as Elderberry extract. Antioxidants help to reduce the damage done by so-called ‘free radicals’ – chemicals that are often produced as a by product of illness – that attack healthy cells. Finally, most antiviral supplements also contain Echinacea extract, which has been shown in some trials (others have been less conclusive) to stimulate the production of immune cells and antibodies.

Antiviral supplements alone are no substitute for a healthy diet and a healthy lifestyle, but they can help to promote optimal immune system function, and to ensure that your body is ready to tackle any new invader more effectively than would otherwise be the case.