There are more than 200 types of viruses that cause colds with the most common called the Rhinovirus. Other common cold viruses include the coronavirus and respiratory syncytial virus (RSV).

While vaccines can help against certain strains of viruses, mostly we have no direct way of tackling them (apart from symptomatic relief). Our best line of defence against these little attackers is our immune system.

A common question I get is – ‘What supplements can I take to prevent cold/viruses?’

The most common supplement we think of is Vitamin C with it being the marketed go-to supplement for treating colds. I thought I would look at the research to see if there is any truth to this well known claim. I also will discuss one other supplement that I found has surprising effects on our respiratory health. Lastly, I will go over some day to day things that have proven to be effective in keeping our immune system functioning well.

Vitamin C

Vitamin C is thought to support various cell functions, enhances white blood cells ability to fight infections and improves the skin’s ability to keep out pathogens.

A 2013 Cochrane meta-analysis of human studies, looked at around 11,000 participants from the general public from marathon runners, skiers to soldiers.

Main findings:
– In adults the duration of colds was reduced by 8% and in children by 14%.
– In children, 1 to 2 g/day vitamin C shortened colds by 18%.
– This didn’t stop people getting colds.
– They only included studies that subjects were given more than 0.2g of Vitamin C daily, with it compared to placebo.

Another study found:
– Vitamin C administration does not decrease the average incidence of colds in the general population.
– Yet it halved the number of colds in physically active people.
– Regularly administered vitamin C shortened the duration of colds.

A 2018 meta-analysis also supports the idea that vitamin C can shorten colds and lessen symptoms.

Vitamin C can reduce the duration of colds (and even help ward them off, if you’re an athlete), but only if you’ve been supplementing regularly. If you start when you’re sick, it’s probably too late.

Vitamin D

Various studies have linked deficiencies in vitamin D linked it to impaired immunity. This was thought to be due to Vitamin D role in the regulation of immune cells during infection.

From 25 Random Controlled Trials from 14 countries, including the UK, were included. This included 11,321 participants, aged from 0-95 years.

Vitamin D supplementation was found to reduce the risk of acute respiratory tract infection by 12%.

Looking further into the research:
Splitting the participants into smaller subgroups, a statistically significant protective effect was seen for those who had daily or weekly vitamin D supplementation without large one-off doses but not for those receiving one or more large one-off doses.

Among those receiving daily or weekly vitamin D, protective effects were stronger for those with lower vitamin D levels at the start of the study and people with asthma.

So people who are at risk are more likely to benefit but might not extend to the general healthy public.

Other Things you can do.

I made a checklist that you can view with my top eight tips to how to keep your immune system functioning well. You can view or download this and use it daily to make sure you are doing everything you can.

So there is some evidence to suggest that the vitamins may be effective at fighting off viruses. It seems if you’re a sporty individual, then you may benefit from vitamin C supplementation. Vitamin D may reduce your chances of getting a cold and might be worth taking in the winter months or if you don’t get outside often.. The studies in both cases had strengths but have some limitations. Remember to follow the checklist.

Quick survey! Any comments feel free to message me below..