Can you prevent the flu? Sure you can. Don't come into contact with someone who has the flu, or get a vaccine.

Can diet do it? A group of researchers say bacteria found in a traditional Japanese pickle can - and they have primed mainstream science media for coverage by declaring it the next superfood.

Their study found immune-boosting powers of Lactobacillus brevis from Suguki, a pickled turnip popular in Japan, in mice that were exposed to a flu virus.

Suguki enthusiasts have often cited its protective powers but there has been no evidence beyond anecdotes - like buying magic rocks to ward off tigers, not getting the flu is not evidence a pickled turnip did it. Human clinical trials using a probiotic drink containing Lactobacillus brevis KB290 bacteria are underway.

What about the bacteria gives them this amazing property? The scholars behind the paper have no idea, that should be a warning sign, but they tangentially note it is tolerant to stomach juices, which are too acidic for many bacteria, largely due to a protective layer of sugars called exopolysaccharides.

Lead researcher, Naoko Waki of KAGOME CO., LTD. in Japan said, "Our results show that when a particular strain of Lactobacillus brevis is eaten by mice, it has protective effects against influenza virus infection. We know that exopolysaccharides have immune boosting effects in other similar bacteria, so we wonder if the exopolysaccharides of KB290 are responsible for the effects we see."  

The effects they see are an increase the production of immune system molecules in the body – IFN-α and flu-specific antibodies, - and enhanced activity to eradicate virus infected cells. In their paper, they find that these effects were sufficient to prevent infection by the H1N1 flu and the scientists think that there could also be protection against other viral infections, including the deadly H7N9 flu, which has recently emerged in China. 

Citation: N. Waki, N. Yajima, H. Suganuma, B.M. Buddle, D. Luo, A. Heiser and T. Zheng, 'Oral administration of Lactobacillus brevis KB290 to mice alleviates clinical symptoms following influenza virus infection', Letters in Applied Microbiology, 6 Nob 2013, DOI: 10.1111/lam.12160