Nothing has been ruled out in the fight against coronavirus by a group of researchers who think cabbage could control symptoms.
A world wide research team has examined the role diet could play in helping to control the symptoms of coronavirus, and even think what people eat could be behind varying death rates.
The Usher Institute of Population Health Sciences and Informatics at Edinburgh University took part in the research, which includes scientists from across the world.
They point out that the recent spikes in Europe and the USA doesn't seem to have hit Asia and Africa, and speculate people's diet could be one of the reasons for this.
They paper's authors write: "Although there are many pitfalls in analyzing death rates for COVID-19, death rates during the Spring pandemic were low or very low in Central European countries, Eastern Asian countries, many sub-Saharan African countries, the Middle East, India, and Pakistan as well as in Australia and New Zealand.
"This geographical pattern is very unlikely to be totally due to reporting differences between countries.
"Some very low death rate settings (but not in Australia or New Zealand) have a common feature of eating large quantities of fermented vegetables such as cabbage and, in some continents, various spices."
The study explains how spices known to have a "beneficial effect on human health" could be interacting with Covid-19 in a number of different ways.
"Three phases of COVID-19 have been described: (i) a viral infection lasting for 1–2 weeks; (ii) a second phase characterized by an intertwined cytokine and oxidative stress storm, independent of infection; and (iii) a recovery phase that may last for some months.
"Spices may interact differently during these 3 phases."
But the researchers think these spices, and a number of "pungent" foods could also be activating nutrients, known at TRPA1/V1 in the body which reduces the severity of the virus.
Early, limited studies have also had promising results, with seven Covid patients given a mixture of broccoli with TRPA1/V1 and paracetamol.
And the results showed these nutrients reduced cough, gastrointestinal symptoms, and nasal symptoms very rapidly.
"Fatigue was usually largely improved [one hour] after ingestion," the paper says.
But the affect was limited, and symptoms usually returned again between four and eight hours later.
The researchers stress in their hypothesis that whilst there is a suggestion these foods could help, it will be important to prove the theory with scientific study.
"Before any conclusion can be drawn and these treatments recommended for COVID-19, the data warrant confirmation.
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"In particular, the benefits of the foods need to be assessed in more severe and/or hospitalized patients through large and properly designed studies with a double-blind, placebo-controlled design. These immediate effects cannot be related to the blockage of the virus entry into the cells," they say.