How ultraprocessed foods affect gut microbiome and health


A number of research have demonstrated a possible hyperlink between ultra-processed meals (UPF) and persistent irritation. One latest evaluation printed in The Lancet Gastroenterology & Hepatology describes the mechanistic affiliation between the consumption of UPF and persistent medical circumstances, particularly these involving the intestine microbiome.

Research: Ultra-processed Foods and Human Health: From Epidemiological Evidence to Mechanistic Insights. Picture Credit score: Dawid Rojek /


Many strategies have been developed for processing meals over the previous a number of centuries to protect meals and improve its style and digestibility. Fashionable industrially processed meals exploit the provision of salt, sugar, vegetable oils, animal fats, and flour.

Usually, the manufacturing of those merchandise makes use of mechanical and bodily strategies resembling curler milling, extrusion, and stress rendering, in addition to chemical strategies like hydrogenation. Synthetic flavoring brokers and preservatives, anticaking brokers, and different components are additionally used to attain the ultimate desired texture, colour, and style of those meals merchandise.

These strategies allowed large-scale manufacturing and manufacturing of massively produced processed meals, making them obtainable all year long.”

Such extremely processed meals are sometimes hygienic, handy, reasonably priced, and accessible, thereby making them very best merchandise for a lot of high-income nations (HIC). Extra just lately, low- and middle-income nations (LMIC) have additionally grow to be more and more dependent upon these meals merchandise.

Coincident with this pattern, there was a rise within the variety of persistent inflammatory circumstances, together with metabolic syndrome and inflammatory bowel illness (IBD). The present paper explores the proof for a correlation between fashionable UPFs and persistent illness that’s mediated by the intestine microbiota.

Forms of processed meals

There are a number of classification programs used to explain meals primarily based on their processing. Essentially the most generally used is NOVA, which categorizes meals into teams 1 by means of group 4.

Group 1 contains unprocessed or minimally processed meals, resembling contemporary, chilled, dried, frozen, fermented, or pasteurized merchandise. Group 2 consists of processed components like vegetable oils, sugar, salt, butter, or different meals extracts added to group 1 meals.

Group 3 contains all typical processed meals, resembling salted canned meals, candied dry fruits, salted meats, cheeses, and contemporary bread. In brief, group 3 describes group 2 merchandise added to group 1 meals.

Group 4 contains UPFs which have undergone a number of of the aforementioned industrial processes. These might include non-domestic components, together with these used for flavoring, coloring, sweetening, or emulsification.

UPF consumption has elevated HICs, whereby they account for as much as 30%, 50%, and nearly 60% of caloric consumption in France, the UK, and the USA, respectively.

Research findings

Virtually 50% of the 100 potential research analyzed within the present research examined the affiliation between UPFs and numerous well being or mortality outcomes.


Seven research indicated a hyperlink between UPFs and dying from any trigger, with a rise in danger from 20% to 60% within the highest UPF consumption class as in comparison with the bottom. 5 research confirmed an elevated danger of sickness or dying from heart problems or stroke. 4 research confirmed a better danger of sort 2 diabetes, whereas one reported an elevated danger of gestational diabetes.


4 research reported an elevated danger of hypertension by as much as 30%, one with most cancers danger, and several other with chubby and weight problems. Many of those research additionally reported an affiliation with elevated weight, waist circumference, and elevated serum lipid ranges in kids.


Within the 2021 Potential City Rural Epidemiology (PURE) research, UPF consumption was related to a better danger of IBD, particularly for Crohn’s illness however not ulcerative colitis. Different research have linked UPF consumption to an elevated danger of despair, irregular lipid ranges, a decline in kidney operate, and fatty degeneration of the liver.

Weight acquire

Quick-term randomized intervention trials are at present being carried out, whereby UPFs and unprocessed meals are assigned to totally different cohorts for brief durations. Following this, the researchers noticed elevated power consumption by a mean of over 500 kcal per day and a imply weight acquire of 0.8 kg within the UPF group. Conversely, a mean weight lack of over 1 kg was reported within the unprocessed meals cohort. 

The mechanisms behind persistent irritation with UPFs

There are quite a few mechanisms that may be attributed to the load acquire and persistent irritation noticed with increased UPF consumption. One instance contains the poor dietary high quality of many UPFs.

In accordance with the French Open Meals Information database, just one in 5 UPFs had a excessive dietary rating. Even when the power consumption from UPFs is standardized for the sake of comparability with unprocessed meals, the antagonistic well being outcomes proceed to point out a powerful affiliation, thereby indicating that “components past dietary features have a task.”

One other difficulty is the presence of doubtless poisonous substances in UPFs, resembling polycyclic fragrant hydrocarbons, furans, superior glycation finish merchandise, trans fatty acids from the hydrogenation of fat, and acrylamide from the cooking of starchy meals at excessive temperatures. The latter chemical could be present in frequent meals like French fries, crisps, and biscuits, whether or not made at dwelling or industrially; nevertheless, acrylamide ranges are sometimes increased in these industrial merchandise.

Different contaminants resembling phthalates, bisphenols, mineral oils, and microplastics can leach into meals from the packaging, particularly when the meals stays involved for lengthy durations. This doubtless happens in meals merchandise which are shelf-stable for prolonged durations.

Prepared-to-eat meals are sometimes UPFs and require microwave heating, which can improve the leaching of bisphenols from polycarbonate packaging or improve acrylamide formation.

The end result of such exposures is unknown; nevertheless, prior analysis suggests a hyperlink with most cancers, cardiovascular ailments, insulin resistance, sort 2 diabetes, weight problems, and endocrine aberrations.

One other difficulty is the structural change that arises within the numerous elements of a meals product because of processing, which might impression its bioavailability by means of altered digestibility, satiety, charge of consuming, and chewing, all of which can contribute to the elevated power consumption with UPFs. This space is severely under-researched.

Over 300 meals components are permitted in Europe, of which a number of could also be implicated in persistent irritation, maybe by means of their results on the intestine microbiome. Landmark research have established that dietary patterns affect intestine microbiota profiles, which might subsequently alter host metabolism and promote weight problems.

Intestine micro organism are sometimes able to ingesting and processing easy sugars when uncovered to excessive dietary fats. Intestinal stressors embody sure meals colorants, emulsifiers, synthetic sweeteners, and nanoparticles like E171 (titanium dioxide).

These components alter the ratio of key bacterial genera within the intestine, whereby they have an effect on the protecting mucosal layer and expression of necessary defensive molecules like ­β-defensins, in addition to enable microbes to succeed in the sterile zone of the mucosa. This triggers endotoxin accumulation that subsequently results in metainflammation and IBD.

Concurrently, modifications within the molecular profile promote elevated power extraction from ingested meals, thus inflicting metabolic dysregulation and weight problems.

This hyperlinks caloric extraction from the meals eaten to metabolic aberrations induced by the weight loss plan. This dysregulated metabolism is marked by low-grade irritation and modifications within the intestine microbiome. The end result is a leak of bacterial merchandise like lipopolysaccharides (LPS) from the intestine into the host system.

LPS from Gram-negative bacterial cell partitions include lipid A, which is a molecule that crosses the intestine mucosa. As soon as lipid A reaches the blood, it will possibly set off irritation of varied goal tissues just like the liver and fatty deposits of the physique.

This cycle has been known as “metainflammation.” Metainflammation could be outlined as a metabolic inflammatory state outlined by low-grade persistent irritation created by metabolic cells and stress sensors.

This implies the necessity for interventions in UPF consumption to provide a helpful change within the intestine microbiome that may promote the manufacturing of ‘good’ bacterial metabolites by means of applicable gene expression by intestine mucosal cells. These embody anti-inflammatory short-chain fatty acids (SCFAs).


The research findings emphasize the necessity for enhancing the present understanding of how meals processing impacts human well being. Massive-scale research can be wanted to determine elements causally linked to metainflammation and weight problems.

Public schooling can be essential to assist the consumption of more healthy meals, ideally these which are minimally processed and with out components. Such dietary selections are emphasised by the United Nations Meals and Agriculture Group (FAO) suggestions, in addition to a number of nationwide dietary directives.

Utilizing measures resembling monetary incentives, laws, and cell phone functions that present proof of meals selections, federal insurance policies should shift in the direction of favoring the manufacturing and distribution of wholesome and good-quality meals merchandise.

Governments and the meals trade ought to be a part of efforts to determine insurance policies fostering a more healthy meals setting for customers to assist battle effectively in opposition to the rising incidence of persistent inflammatory circumstances.”

Journal reference:

  • Srour, B., Kordahi, M. C., Bonazzi, E., et al. (2022). Extremely-processed Meals and Human Well being: From Epidemiological Proof to Mechanistic Insights. The Lancet Gastroenterology & Hepatology. doi:10.1016/S2468-1253(22)00169-8.
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