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:
- KSK (a polyherbal formulation from India’s Siddha system of medicine) 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. Larger, multi-centric trials can strengthen the current findings.
- There is currently insufficient evidence to determine the benefits and harms of vitamin D supplementation as a treatment of COVID-19.
- Herbal supplements may help patients with COVID-19, zinc sulfate is likely to shorten the duration of olfactory dysfunction. DS therapy and herbal medicine appear to be safe and effective adjuvant therapies for patients with COVID-19. These results must be interpreted with caution due to the overall low quality of the included trials. More well-designed RCTs are needed in the future.
- No significant difference with vitamin-D supplementation on major health related outcomes in COVID-19.
- there is not enough evidence on the association between individual zinc status and COVID-19 infections and mortality.
- Omega-3 supplementation improved the levels of several parameters of respiratory and renal function in critically ill patients with COVID-19.
- A 5000 IU daily oral vitamin D3 supplementation for 2 weeks reduces the time to recovery for cough and gustatory sensory loss among patients with sub-optimal vitamin D status and mild to moderate COVID-19 symptoms. The use of 5000 IU vitamin D3 as an adjuvant therapy for COVID-19 patients with suboptimal vitamin D status, even for a short duration, is recommended.
- In this 2-sample MR study, we did not observe evidence to support an association between 25OHD levels and COVID-19 susceptibility, severity, or hospitalization. Hence, vitamin D supplementation as a means of protecting against worsened COVID-19 outcomes is not supported by genetic evidence.
- These antiviral and immune-modulating activities and their ability to stimulate interferon production recommend the use of probiotics as an adjunctive therapy to prevent COVID-19. Based on this extensive review of RCTs we suggest that probiotics are a rational complementary treatment for RTI diseases and a viable option to support faster recovery.
- In this randomized clinical trial of ambulatory patients diagnosed with SARS-CoV-2 infection, treatment with high-dose zinc gluconate, ascorbic acid, or a combination of the 2 supplements did not significantly decrease the duration of symptoms compared with standard of care.
- These findings neither support nor refute the claim that 3M3F alters the severity of COVID-19 or alleviates symptoms. More rigorous studies are required to properly ascertain the potential role of Chinese Herbal Medicine in COVID-19.
- NSO (Nigella sativa oil) supplementation was associated with faster recovery of symptoms than usual care alone for patients with mild COVID-19 infection. These potential therapeutic benefits require further exploration with placebo-controlled, double-blinded studies.
- The clinical application of LQ (Lianhua Qingwen Granules or Capsules ) on the treatment of COVID-19 has significant efficacy in improving clinical symptoms and reducing the rate of clinical change to severe or critical condition. Nevertheless, due to the limited quantity and quality of the included studies, more and higher quality trials with more observational indicators are expected to be published.
- The study identified some important potential traditional Indian medicinal herbs such as Ocimum tenuiflorum, Tinospora cordifolia, Achyranthes bidentata, Cinnamomum cassia, Cydonia oblonga, Embelin ribes, Justicia adhatoda, Momordica charantia, Withania somnifera, Zingiber officinale, Camphor, and Kabusura kudineer, which could be used in therapeutic strategies against SARS-CoV-2 infection.
- Shenhuang Granule is a promising integrative therapy for severe and critical COVID-19.
- Low-certainty or very low-certainty evidence demonstrated that oral CPM (Chinese patent medicine) may have add-on potential therapeutic effects for patients with non-serious COVID-19. These findings need to be further confirmed by well-designed clinical trials with adequate sample sizes.
- XYP (Xiyanping) injection is safe and effective in improving the recovery of patients with mild to moderate COVID-19. However, further studies are warranted to evaluate the efficacy of XYP in an expanded cohort comprising COVID-19 patients at different disease stages.
- Our meta-analysis of RCTs indicated that LH (Lianhuaqingwen) in combination with usual treatment may improve the clinical efficacy in patients with mild or moderate COVID-19 without increasing adverse events. However, given the limitations and poor quality of included trials in this study, further large-sample RCTs or high-quality real-world studies are needed to confirm our conclusions.
- Reduning injection might be effective and safe in patients with symptomatic COVID-19.
- In light of the safety and effectiveness profiles, LH (Lianhuaqingwen) capsules could be considered to ameliorate clinical symptoms of Covid-19.
- QPT (Qingfei Paidu Tang) was associated with a substantially lower risk of in-hospital mortality, without extra risk of acute liver injury or acute kidney injury among patients hospitalized with COVID-19.
- This community-based RCT found that the use of a herbal medicine therapy (Jinhaoartemisia antipyretic granules and Huoxiangzhengqi oral liquids) could significantly reduce the risks of the common cold among community-dwelling residents, suggesting that herbal medicine may be a useful approach for public health intervention to minimize preventable morbidity during COVID-19 outbreak.
- Based on unresolved controversies and inconclusive findings, it could be said that generally, a single and specific therapeutics to COVID-19 is still a mirage.
- Keguan-1-based integrative therapy was safe and superior to the standard therapy in suppressing the development of ARDS in COVID-19 patients.
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
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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.
Thank you. I agree and would add that the rest is much the same.
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
see, for instance, these recent reviews
https://pubmed.ncbi.nlm.nih.gov/33641060/
https://pubmed.ncbi.nlm.nih.gov/32900213/
https://pubmed.ncbi.nlm.nih.gov/33294991/
https://pubmed.ncbi.nlm.nih.gov/31826654/
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):
In the conclusion (emphasis mine):
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
Talk to a doctor. I mean a real medical doctor, not a quack doctor.
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 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.