Don’t count on broccoli compounds bailing out a high-fat diet’s effects on gut microbiota

Two rodent studies of mature broccoli and broccoli sprouts’ effects on a high-fat diet, with the first from 2021 investigating broccoli florets and stalks:

“Addition of broccoli florets to a HFD ameliorated insulin sensitivity. Florets further promoted gut microbiota diversity and low-grade inflammatory-associated strains.

Stalk supplementation also altered gut microbiota, leading to increased Bacteroidetes/Firmicutes ratio and levels of communities that preserve mucus layer and gut integrity while simultaneously decreasing levels of potentially harmful species.

Addition of broccoli to a HFD did not ameliorate body and tissues weight gain or food intake. Both broccoli stalks and florets did not affect fat accumulation, carbohydrate, or lipid metabolism-related parameters.”

https://www.frontiersin.org/articles/10.3389/fnut.2021.680241/full “Broccoli Florets Supplementation Improves Insulin Sensitivity and Alters Gut Microbiome Population – A Steatosis Mice Model Induced by High-Fat Diet”


A 2020 study cited by this first study investigated compounds extracted from 1-day-old broccoli sprouts:

Bioaccessibility of aliphatic glucosinolates was shown to 76.2 ± 0.6%:

aliphatic glucosinolate bioavailability

Glucoraphanin was the predominant glucosinolate with the highest bioaccessibility in broccoli, and could effectively prevent HFD-induced body weight gain in mice, especially increases in liver weight and the accumulation of lipids in adipocytes. Furthermore, supplementation with glucoraphanin reduced the level of oxidative stress, regulated genes of FAS, PPARα, CPT1 and ACOX associated with lipid metabolism, and might be associated with changes in composition of gut microbiota.”

https://www.frontiersin.org/articles/10.3389/fnut.2021.680241/full “Effect of glucoraphanin from broccoli seeds on lipid levels and gut microbiota in high-fat diet-fed mice”

This study’s title was “Effect of glucoraphanin from broccoli seeds..” although its Materials and methods section disclosed:

“1 day after germination from broccoli seeds, sprouts were boiled in water for 30 min. The resulting aqueous extract was processed by liquid solid separation and condensation and was subsequently spray-dried to yield an extract powder containing 249 mg glucoraphanin.”


Eat broccoli sprouts every day and its predecessor study demonstrated that broccoli intake every day had beneficial effects during shorter periods than either of these studies.

Both studies had many “may”, “could”, and “might” statements. Not sure that broccoli compounds / gut microbiota relationships are adequately investigated by choosing a few out of tens of thousands of gut microbiota species as both studies attempted to do.

There are too many additive / antagonistic / synergistic combinations to analyze even before reaching twenty gut microbiota species. But researchers aren’t often sponsored for studies unless they conform to existing research.


I haven’t made headway in understanding my top 10 of 42,156 gut microbiota species’ exact causes, effects, and interactions. The top three by themselves are considered beneficial:

top 1-10 species

Uncertainty is fine for now, though, with a 40-hour work week interfering. Finding out what my gut microbiota generally want and giving that to them has been a productive approach this year.

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