Fermented foods shown to protect against the flu

The flu season has hit America especially hard this year. Though influenza peaks in February, 37 children have died already; overall mortality for 2017-2018 was doublelast year’s numbers before midwinter even arrived.

Eyebrows were raised a few months ago when researchers realized this year’s flu vaccine does not prevent against H3N2, the dominant strain. While anecdotally it seems people are recovering (at least here in Los Angeles), the Centers for Disease Control and Prevention (CDC) announced that numbers are still rising.

With all of these troubling conditions, a little bit of positive news from Georgia State University: fermented foods appear to help protect against the influenza virus, and even prevent a secondary infection. 

During the worst years the flu affects three to five million people in the United States; when an epidemic strikes, it can claim up to half a million lives. Lead author Sang-Moo Kang, professor at the Institute for Biomedical Sciences at Georgia State, writes that fermented vegetable and dairy products help us deal with a variety of ailments: “Studies have found some lactic acid bacteria strains provide partial protection against bacterial infectious diseases,” she said, “such as Streptococcus pneumoniae, as well as cold and influenza viruses.”

A Map of flu activity in the United States for the week ending January 20, 2018. Source: CDC. Image: Hilary Fung, NPR.

During the worst years the flu affects three to five million people in the United States; when an epidemic strikes, it can claim up to half a million lives. Lead author Sang-Moo Kang, professor at the Institute for Biomedical Sciences at Georgia State, writes that fermented vegetable and dairy products help us deal with a variety of ailments: “Studies have found some lactic acid bacteria strains provide partial protection against bacterial infectious diseases,” she said, “such as Streptococcus pneumoniae, as well as cold and influenza viruses.”

For this study, Kang and team were able to prevent rapid weight loss and death in a group of mice that were pretreated with heat-killed Lactobacillus casei DK128 bacteria. This not only protected them from lethal primary infections, but secondary infections as well. Pretreated mice experienced a stunning 100 percent survival and weight loss prevention record. 

Incredibly, pretreated mice had 18 times less virus in their lungs than the control group. While none of these mice died, all of the mice in the control group were dead by the end of the study. It should be noted that every mouse involved in the study was injected with a lethal dose. 

This research offers hope that the lactic acid bacteria might be a beneficial preventive food:“These findings would significantly improve our understanding of mechanisms by which hosts can develop innate and adaptive immunity against lethal viral infections,” said Kang. “It suggests a potential usage of LAB as antiviral probiotics.”

Fermented foods have long been considered healthy. One 1990 study mentions that benefits include “improved nutritional value of food, control of intestinal infections, improved digestion of lactose, control of some types of cancer, and control of serum cholesterol levels.”

Foods fermented using lactic acid bacteria include yogurt, kimchi, cultured butter, sauerkraut, cheese, tempeh, kefir, cured sausages and fish—pretty much everything we eat that has a bit of funk. Our ancestors long ago realized the benefits of fermentation; it was our primary method of food preservation and storage before refrigeration.

As I’m writing up this study, I mention the results to my wife. We’ve both had numerous co-workers get the worst of the flu this year, some of whom were in close proximity to us in our respective workplaces. She reminded me of all the kombucha we’ve been drinking—she started brewing a scoby weeks ago right outside my office door. Each time I walk in here to write I get a whiff of vinegar in the hallway.

Anecdote, of course, but I’ll certainly continue drinking my daily brew in hopes of boosting my immune system and gliding through peak flu season unscathed. There is no silver bullet to a virus as perplexing as influenza, but research shows the benefits of ingesting fermented foods are well worth it. 

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Derek Beres is the author of Whole Motion: Training Your Brain and Body For Optimal Health. Based in Los Angeles, he is working on a new book about spiritual consumerism. Stay in touch on Facebook and Twitter.