MD, PhD, FMedSci, FRSB, FRCP, FRCPEd.

The global market for dietary supplements has grown continuously during the past years. In 2019, it amounted to around US$ 353 billion. The pandemic led to a further significant boost in sales. Evidently, many consumers listened to the sly promotion by the supplement industry. Thus they began to be convinced that supplements might stimulate their immune system and thus protect them against COVID-19 infections.

During the pre-pandemic years, the US sales figures had typically increased by about 5% year on year. In 2020, the increase amounted to a staggering 44 % (US$435 million) during the six weeks preceding April 5th, 2020 relative to the same period in 2019. The demand for multivitamins in the US reached a peak in March 2020 when sales figures had risen by 51.2 %. Total sales of vitamins and other supplements amounted to almost 120 million units for that period alone. In the UK, vitamin sales increased by 63 % and, in France, sales grew by around 40–60 % in March 2020 compared to the same period of the previous year.

Vis a vis such impressive sales figures, one should ask whether dietary supplements really do produce the benefit that consumers hope for. More precisely, is there any sound evidence that these supplements protect us from getting infected by COVID-19? In an attempt to answer this question, I conducted several Medline searches. Here are the conclusions of the relevant clinical trials and systematic reviews that I thus found:

Confused?

Me too!

Does the evidence justify the boom in sales of dietary supplements?

More specifically, is there good evidence that the products the US supplement industry is selling protect us against COVID-19 infections?

No, I don’t think so.

So, what precisely is behind the recent sales boom?

It surely is the claim that supplements protect us from Covid-19 which is being promoted in many different ways by the industry. In other words, we are being taken for a (very expensive) ride.

12 Responses to The dietary supplement industry is taking us for a (very expensive) ride

  • I followed the link for the first paper in your list.

    The authors looked at the effect on viral load after seven days of taking their supplement in individuals with coronavirus infection confirmed by PCR, and compared this with zinc plus vitamin C as a control in a randomised trial. They found that the viral load declined significantly in both groups after seven days. So far so good.

    They also found that the fall in viral load was greater in the treated group than the control group. There was no attempt at any statistical analysis of this difference, however, so I don’t know how they can justify their conclusion:
    “KSK significantly reduced SARS-CoV-2 viral load among asymptomatic COVID-19 cases and did not record any adverse effect, indicating the use of KSK in the strategy against COVID-19. ”

    At the start of the results section of the paper they state:
    “Except for age and gender, the study and control groups were almost similar in all the baseline characteristics”

    Presumably the authors don’t think that age or gender are relevant factors in the rate of fall of viral load in COVID, despite that fact that they are well established as the two factors which most strongly predict the outcome of the infection.

    You may be interested to know the number of subjects recruited – 30 in each arm, so not a very large trial at all.

    This trial shouldn’t even have made it past an ethics committee, though I don’t know whether Siddha hospitals have such a thing. It certainly shouldn’t have passed peer review. I don’t know what the journal “Trials” is, though, or whether it is a serious publication. The authors clearly have no idea how to conduct a trial let alone any kind of statistical analysis.

  • Professor EE

    I’d be interested to know your thoughts of the supplement NAC (N-AcetylCysteine). Do you have an opinion about this specific supplement ?

    Thank you

  • Professor EE

    So I take it your opinion is the same as NIH published findings.

    How about his one ?
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7649937/
    This evidence would indicate that NAC is beneficial.

    • I would not be so sure. I have to admit, however, that I have not looked closely at the evidence.

    • @Bart

      The paper you are citing is a review paper and for the the most part the authors are hypothesizing, not necessarily a bad thing. However, they never claim that NAC IS beneficial. If you pay attention to the language:

      In the abstract itself they say this (emphasis mine):

      NAC has antioxidant, anti-inflammatory and immune-modulating characteristics that may prove beneficial in the treatment and prevention of SARS-Cov-2.

      In the conclusion (emphasis mine):

      NAC administration in combination with other antiviral agents may dramatically reduce hospital admission rate, mechanical ventilation and mortality.

      I skimmed thru the references section and I did not see any references to large scale clinical trials that use NAC to treat COVID-19. The authors basically reviewed a bunch of literature and hypothesized that NAC may be a good candidate to treat COVID-19. In the end, they propose a strategy to treat COVID-19 with NAC. This review seems to be a precursor to a clinical trial that the authors might be considering. That is all there is to this review. It is not an end all be all evidence that NAC is effective against COVID-19.

      • Hello Django

        Hey now, I’m just attempting to find out if this supplement is beneficial. Evidently NAC was deemed to be beneficial at one time, I think perhaps it still has benefits. Evidently, it was an FDA approved drug for specific indications.

        https://anh-usa.org/fda-bans-critical-toxin-protection-supplement/

        https://acetylcysteine.com/

        https://www.who.int/selection_medicines/committees/subcommittee/2/acetylcysteine_rev.pdf

        https://en.wikipedia.org/wiki/Acetylcysteine

        • I’m just attempting to find out if this supplement is beneficial.

          Talk to a doctor. I mean a real medical doctor, not a quack doctor.

          Evidently, it was an FDA approved drug for specific indications.

          I don’t think it is approved for treating COVID-19, which is what you were alluding to when you were referring to this paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7649937/ and that paper itself is not conclusive as I mentioned earlier.

          • Wrong sir

            I asked the professor about his opinion of NAC… period.
            He responded with some NIH links.
            One of which was actually positive for the indication of Schiz. mental disorder, among other mental disorders.

            After that there is the issue that NAC has been both a prescribed and OTC substance, FDA approved in both cases.

            To the topic of NAC for treatment of covid (link), perhaps the supplement has not been studied sufficiently to be conclusive to treat covid virus with verified results. However, I refer you to Dr. Julian’s statement which holds true.
            “You may not be aware that acetyl cysteine has long been on the formulary as a mucolytic drug, used routinely in the treatment of respiratory conditions characterised by excessively viscous or inspissated mucus.”

            I think that would apply very well to covid treatment, to be beneficial to recovery of patients.

          • Bart,

            I think that would apply very well to covid treatment, to be beneficial to recovery of patients.

            I was thinking in particular of conditions such as chronic asthma, other chronic obstructive pulmonary diseases, bronchiectasis and cystic fibrosis, all of which are characterised by the production of excessive amounts of viscid sputum.

            I have no experience of treating covid, which didn’t exist until after I retired, but from what I know, mucus production isn’t particularly a problematic feature even in severe cases.

  • You may not be aware that acetyl cysteine has long been on the formulary as a mucolytic drug, used routinely in the treatment of respiratory conditions characterised by excessively viscous or inspissated mucus.

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