Fermented Foods May Lower Risk of Death, Probiotics May Ease Depression

Creamy Sauerkraut with parsley, chives and potatoes

This article was previously published August 6, 2020, and has been updated with new information.

By Dr. Joseph Mercola | December 23, 2021

I’ve written many articles detailing lifestyle and dietary strategies that may decrease your COVID-19 risk by boosting your immune function and general health. Now we can add fermented foods to the list, which shouldn’t come as such a great surprise, considering the influence your gut health has on your immune system.

The study,1 posted July 7, 2020, on the pre-print server medRxiv, conducted by researchers in Berlin, Germany, looked at whether diet might play a role in COVID-19 death rates. Interestingly, mortality rates tend to be lower in countries where consumption of traditionally fermented foods is commonplace. As reported by News Medical Life Sciences:2

“The researchers say that if their hypothesis is confirmed in future studies, COVID-19 will be the first infectious disease epidemic to involve biological mechanisms that are associated with a loss of ‘nature.’ Significant changes in the microbiome caused by modern life and less fermented food consumption may have increased the spread or severity of the disease, they say.”

Could Fermented Veggie Consumption Lower COVID-19 Mortality?

The researchers obtained data from the European Food Safety Authority (EFSA) Comprehensive European Food Consumption Database and compared consumption levels with COVID-19 mortality statistics (deaths per capita) for each country, obtained from the Johns Hopkins Coronavirus Resource Center.

The EFSA database includes statistics on countries’ consumption of fermented vegetables, pickled or marinated vegetables, fermented milk, yogurt and fermented sour milk specifically.

They also looked at potential confounders, such as gross domestic product, population density, percentage of the population over the age of 64, unemployment and obesity rates. According to the authors:3

“Of all the variables considered, including confounders, only fermented vegetables reached statistical significance with the COVID-19 death rate per country.

For each g/day increase in the average national consumption of fermented vegetables, the mortality risk for COVID-19 decreased by 35.4%. Adjustment did not change the point estimate and results were still significant.”

Probiotics May Ease Depression

In related news, a review4 of seven small clinical trials has found probiotics and/or prebiotics may be helpful for those struggling with depression and anxiety. While these mental health challenges are epidemics in their own right, the global lockdowns certainly have not made the situation any better.

According to the authors,5 all of the studies “demonstrated significant improvements in one or more of the outcomes” compared with no treatment, placebo, or baseline measurements, leading them to conclude that “utilizing pre/probiotic may be a potentially useful adjunctive treatment” for patients with depression and/or anxiety.

The review builds on earlier studies that have shown people with depression tend to have higher amounts of specific gut bacteria than those who are not depressed.

While it seems the gut microbiome’s role in health is a very recent discovery, as early as 1898 — yes, 122 years ago — a paper6 in The Journal of the American Medical Association proposed that intestinal microbes might play a role in melancholia. As noted in the 2019 paper, “The Microbiome and Mental Health: Hope or Hype?”:7

“The primary tenet of FMT [fecal microbiota transplantation] is that dysbiosis within the human host gut microbiome predisposes an individual to disease. The exact mechanisms through which this occurs have not yet been established, but several potential direct and indirect pathways exist through which the gut microbiota can modulate the gut–brain axis.

These pathways include endocrine (cortisol), immune (cytokines) and neural (vagus and enteric nervous system) pathways, and the assumption is that introducing microflora from a healthy individual will help recolonize the system with a microbial pattern more in keeping with wellness either by establishing the new healthy microbiota or by allowing the host to ‘reset’ their own microflora to a pre-illness state.”

Bacteria Associated With Mental Health and Depression

Two types of gut bacteria in particular, Coprococcus and Dialister bacteria, have been shown to be “consistently depleted” in individuals diagnosed with clinical depression. According to the authors of a study published in the April 2019 issue of Nature Microbiology:8

“Surveying a large microbiome population cohort (Flemish Gut Flora Project, n = 1,054) with validation in independent data sets, we studied how microbiome features correlate with host quality of life and depression.

Butyrate-producing Faecalibacterium and Coprococcus bacteria were consistently associated with higher quality of life indicators. Together with Dialister, Coprococcus spp. were also depleted in depression, even after correcting for the confounding effects of antidepressants.”

The researchers went on to analyze and catalogue the neuroactive potential of these gut bacteria, finding that those associated with good mental health had the ability to synthesize the dopamine metabolite 3,4-dihydroxyphenylacetic acid, while those associated with depression produce γ-aminobutyric acid. Other studies have identified yet other microbial profiles associated with better or worse mental health. For example:

2016 research9 found the relative abundance of Actinobacteria was increased, and Bacteroidetes was decreased in depressed individuals compared to healthy controls.

A 2015 study10 found patients diagnosed with major depressive disorder had higher amounts of Bacteroidetes, Proteobacteria and Actinobacteria, and lower amounts of Firmicutes than healthy controls.

“These findings enable a better understanding of changes in the fecal microbiota composition in such patients, showing either a predominance of some potentially harmful bacterial groups or a reduction in beneficial bacterial genera,” the authors wrote.

A 2014 study11 found depressed individuals had an overrepresentation of Bacteroidales and an underrepresentation of Lachnospiraceae bacteria.

Lachnospiraceae are a family of beneficial bacteria that ferment plant polysaccharides into short-chain fatty acids such as butyrate and acetate.12 The genus Oscillibacter, and one specific clade within Alistipes were also significantly associated with depression.


Via https://alethonews.com/2021/12/24/fermented-foods-may-lower-your-risk-of-death-probiotics-may-ease-depression/

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