Revealed: the gut microbiome varies through the day and through the seasons

[bennevisplace]

The balance of microbes in the human gut varies substantially from morning to night and even more by season, completely transforming the microbiome from summer to winter, says recently reported research insideprecisionmedicine.com...

This finding has implications for the increasing number of chronic conditions with which the gut microbiome is associated nature.com/articles/s41430-... as well as for research, and for the diagnosis and treatment of gut disorders.

We have to wait until 7 May for the team's study to be presented, but Precision Medicine reports:

For this study, the UCSD researchers reviewed data for about 20,000 stool samples collected by the American Gut Project, the world’s largest citizen science microbiome project, from countries around the world between 2013 and 2019.

Analyzing the collection time, date and location, the team found nearly 60% of the phyla— related groups of bacteria—have a distinct 24-hour cycle. Seasonal fluctuations were even more pronounced, with certain types of bacteria following one of two distinct patterns over the course of a year.

Zarrinpar and his colleagues think that diet and sleep are likely big factors in daily fluctuations.

Seasonal variation is harder to explain, but researchers are exploring data by latitude and climate, which could indicate whether light and temperature play a role. Pollen and humidity are among other possible influences.

On that last point, one hopes that the research also covered community antibiotic consumption, which tends to be higher in the winter months, and would lead to seasonally raised levels of gut dysbiosis and associated illness within the community ncbi.nlm.nih.gov/pmc/articl... and sciencedirect.com/science/a...

[MGirl-Aust]

Wow, that’s really interesting! There’s still so much to discover about the gut microbiome. I try and eat a wide range of vegetables, fruits, grains, legumes and fermented foods every week to support diversity in my gut - hopefully it’s doing some good 😊

[LeoPa]

Wow this is a very interesting study. I feel like it just blew a hole into the conventional wisdom of eat the rainbow because you need the fiber because your friendly gut bacteria need those to feed on. Looks like the whole thing is much more complicated. I wonder whether the seasonability can have something to do with people eating seasonal foods which might support different kinds of gut bacteria in different seasons. Albite these days with everything available in supermarkets all year round if people eat the same way all through the year that might not be the case. From my own at-home bacteriological experiments (making homemade sour cream at least twice a week) 🙂 I know how quickly bacteria can multiply. One day it's a fresh cream, the next day it's so thick you can stick a teaspoon in it and it stands erect.

[bennevisplace in reply to LeoPa]

Granted, there is a degree of seasonal variation in most people's diet. The degree here is probably typically modern western with supermarket access, as the data base for this study is heavily US biased plus NW Europe and minor Australia journals.asm.org/doi/10.112...

[LeoPa]

"Recent links have been made between dietary intake of short-chain fatty acids (SCFAs) and autoimmune arthritis in mice, wherein SCFAs play an important role in the suppression of inflammation in RA [13, 14]."

Oh my, the second link is also very interesting. I have been convinced for quite a while that our food intake has a profound role in how our microbiome looks and the composition of the microbiome has a deep impact on gut permeability and the development of autoimmune conditions. I can't go into the details here but those who want to know more please read this book:

amazon.de/Giulia-Enders/dp/...

And as far as butyrate is concerned, here is an interesting study on the effects of intermittent fasting:

ncbi.nlm.nih.gov/pmc/articl....

My takeaway: do not eat if not hungry and no snacking between meals.

Just to clear up the seemingly contradictory opinion about does it or does it not matter what we eat. As long as one follows the conventional wisdom and eats the rainbow all year round it seems like it does not matter much.

But in case of a radical dietary change and dumping the eat the rainbow paradigm coupled with intermittent fasting it does matter a lot. But that's just my opinion and I am no doctor, so I could be wrong.

[bennevisplace in reply to LeoPa]

the composition of the microbiome has a deep impact on gut permeability and the development of autoimmune conditions.

You bet. See also healthunlocked.com/meandcfs... and especially the very last reference, a seminal paper on the regulation of gut permeability.

[bennevisplace]

You're suggesting that seasonal changes in the gut microbiome are baked in by evolution?

[The-Man-with-a-Plan]

Bennevis:

Does this research support or dispute the time-honored phrase: "You are what you eat!"

'You are what you eat' emerged in English in the 1930s. That is when the American nutritionist Victor Lindlahr, who was a strong believer in the idea that food controls health, developed the Catabolic Diet. That view gained some adherents at the time and the earliest known printed example is from an advert for beef in a 1923 edition of the Bridgeport Telegraph, for 'United Meat Markets':

"Ninety per cent of the diseases known to man are caused by cheap foodstuffs. You are what you eat."

In 1942, the phrase entered into the public consciousness when Lindlahr published You Are What You Eat: how to win and keep health with diet. Lindlahr is likely to have also used the term in his radio talks in the 1930s to 50s (now lost unfortunately), which would also have reached a large US audience.

The phrase wasn't much used in the years after Lindlahr stopped his radio broadcasts in 1953 but got a new lease of life in the 1960s hippie era. The food of choice of the hippie champions of the 'you are what you eat' idea was macrobiotic whole-food and the phrase was adopted by them as a slogan for healthy eating.

Man-with-a-Plan

[bennevisplace in reply to The-Man-with-a-Plan]

I've always thought of that as a neat catchphrase with some wisdom behind it, which may or may not withstand rigorous analysis. It certainly makes a good book title. There are probably some solid epidemiological studies linking diet with obesity etc. I'm sure you could find hundreds of diet-health studies.

None of this really interests me I'm afraid. Apart from avoiding gluten, I eat what I like. My wife and I like a variety of foods and both enjoy cooking. My weight is the same as 50 years ago. My parents were much the same into old age. You are what you eat and what your genes determine.

[LeoPa in reply to bennevisplace]

You are genetically lucky then! Do you eat processed stuff like gluten free cookies, shortenings etc. with trans fats and added sugars?

[bennevisplace in reply to LeoPa]

Ha! Most commercial products branded Gluten Free are horrendous, the cookies as you describe, the breads dry and tasteless. Pricewise, a complete rip-off.

There's one brand of pasta made with brown rice that's good. My wife bakes fabulous GF bread, a skill she learned from a one day course in London that was a gift from me to her. Best investment I ever made 😋

[The-Man-with-a-Plan]

Thanks for responding. I agree completely. Like you, I pretty much eat what I want but most of it is 'good' foodstuffs. In addition to diet and good genes, I'll add regular, rigorous exercise!