I came across this article via a German secondary report about it entitled “Scientists discover what else protects from severe symptoms” (Forscher finden heraus, was noch vor schweren Symptomen schützt). The article rightly stressed that vaccination is paramount and then explains that, once you have caught COVID, nutrition can prevent serious symptoms.
Even though I rarely discuss standard nutritional issues on my blog (nutrition belongs to mainstream not so-called alternative medicine [SCAM], in my view), this subject did attract my attention. Here are the essentials of the original scientific paper:
Australian scientists studied the association between habitual frequency of food intake of certain food groups during the COVID-19 pandemic and manifestations of COVID-19 symptoms in adult outpatients with suspected SARS-CoV-2 infection. They included 236 patients who attended an outpatient clinic for suspected COVID-19 evaluation. Severity of symptoms, habitual food intake frequency, demographics and Bristol chart scores were obtained before diagnostic confirmation with real-time reverse transcriptase PCR using nasopharyngeal swab.
The results of the COVID-19 diagnostic tests were positive for 103 patients (44%) and negative for 133 patients (56%). In the SARS-CoV-2-positive group, symptom severity scores had significant negative correlations with the habitual intake frequency of specific food groups. Multivariate binary logistic regression analysis adjusted for age, sex, and occupation confirmed that SARS-CoV-2-positive patients showed a significant negative association between having higher symptom severity and the habitual intake frequency of legumes and grains, bread, and cereals.
The authors concluded that an increase in habitual frequency of intake of ‘legumes’, and ‘grains, bread and cereals’ food groups decreased overall symptom severity in patients with COVID-19. This study provides a framework for designing a protective diet during the COVID-19 pandemic and also establishes a hypothesis of using a diet-based intervention in the management of SARS-CoV-2 infection, which may be explored in future studies.
So, the authors seem to think that they found a causal relationship: A CHANGE IN DIET DECREASES SYMPTOMS. In different sections of the article, they seem to confirm this notion, and they state that they tested the hypothesis of the effect of diet on SARS-CoV-2 infection symptom severity.
Yey, the investigation was merely a correlative study that cannot establish cause and effect. There are many other variables that might be linked to dietary habits which could be the true cause of the observed phenomenon (or contributors to it).
What’s the harm? If the article makes people adopt a healthier diet, all is pukka!
Perhaps, in this case, that might be true (even though one could argue that this paper might support anti-vax notions arguing that vaccination is not important if it is possible to prevent severe symptoms through dietary changes). But the confusion of correlation with causality is both frequent and potentially harmful. And it is unquestionably poor science!
I feel that we need to be concerned about the fact that even reputable journals let such things pass – not least because the above example shows what the popular press subsequently can make of such misleading messages.