Fibroids

A distinct bacterial signature, cause still unclear

Uterine fibroids, non-cancerous growths in the womb affecting more than a quarter of women worldwide, are strongly influenced by oestrogen and progesterone. An observational study comparing 29 women with fibroids to 38 without found a genuinely distinct bacterial pattern in the vaginal and cervical microbiome, including specific bacteria that were more or less common in women with fibroids, and less bacterial diversity in those with a greater number of fibroids.

Source: Dysbiosis of vaginal and cervical microbiome is associated with uterine fibroids

A specific, testable chain of events

Researchers have proposed a detailed mechanism connecting gut health to fibroid growth: low vitamin D levels can trigger gut inflammation, which shifts the balance of gut bacteria toward a higher ratio of Firmicutes to Bacteroidetes, which in turn increases the release of unbound, biologically active oestrogen into circulation, oestrogen that then feeds fibroid growth. This is a genuinely specific, mechanistically detailed hypothesis, though it remains a proposed model rather than something confirmed by human intervention trials.

Source: Gut and genital tract microbiomes: Dysbiosis and link to gynecological disorders

An honest caveat: association, not yet proven cause

A separate pilot study examining the uterine cavity, cervix, and stool in women with fibroids found no significant overall difference in bacterial diversity compared with women without fibroids, though it did find specific bacteria, including Lactobacillus iners, overrepresented in fibroid patients. This is a useful reminder that the gut-fibroid connection, while genuinely being investigated with detailed, testable mechanisms, hasn't yet been proven as a cause, only as an association worth continuing to study.

What this means for you

Fibroids causing heavy bleeding, pain, or fertility difficulties need proper diagnosis and treatment from a gynaecologist, since options range from monitoring to medication to surgical removal depending on size and symptoms. Given how early this research still is, correcting a vitamin D deficiency, if present, is a reasonable, well-evidenced step in its own right, and one that happens to align with this proposed gut-fibroid mechanism. A varied, plant-rich diet supports the same gut bacterial balance this research is investigating in relation to fibroid growth. That's the same idea behind GutLab, everyday gut health starts with regularly feeding the microbiome a broad range of plant-rich ingredients.