Thirty different plants a week changes your gut
The American Gut Project found microbiome diversity scaled with plant variety, not volume.
In brief
Gut bacterial diversity is one of the best predictors of long-term metabolic and immune health. The largest crowd-sourced microbiome study found plant variety, 30 different plants a week, mattered more than total fibre grams. Herbs and spices count.
Gut bacterial diversity is one of the strongest predictors of metabolic, immune, and even mental health outcomes in the current research base. Until recently the lever most clinicians recommended was simply total fibre. The American Gut Project, a citizen-science effort with over 11,000 stool samples, found something more useful: the strongest single dietary correlate with microbiome diversity was the number of different plant species consumed per week, not total fibre grams (McDonald, mSystems, 2018).
What counts as a plant
Anything plant origin counts: vegetables, fruit, legumes, nuts, seeds, whole grains, herbs, spices, teas, coffees, even dark chocolate. A salad with rocket, tomato, cucumber, red onion, sunflower seeds, and olive oil counts as six plants. A dal made with five different lentil types, ginger, garlic, jeera, dhania, and curry leaves counts as ten. Hitting 30 in a week is not difficult once herbs and spices are included; the obstacle is the same five vegetables on repeat.
Why variety beats volume
Different bacterial species feed on different fibre types: Bifidobacterium prefers inulin from garlic, onion, and chicory; Akkermansia is fed by polyphenols from berries, dark chocolate, and olive oil; certain Firmicutes specialise in resistant starch from cooled rice, cooked-and-cooled potato, or green banana. Eating one fibre source repeatedly grows the bacteria that eat it and starves the rest. Variety keeps the ecosystem broad, and a broad ecosystem produces a wider range of short-chain fatty acids and immune-regulating metabolites.
Key Takeaways
- •Aim for 30 or more different plant species per week, herbs and spices included.
- •Variety drives microbiome diversity more than total fibre volume.
- •Different bacteria need different fibres; rotating plant sources keeps the ecosystem broad.
This article is for informational purposes only and is not medical advice. Discuss any changes to your health, medication, diet or exercise with a qualified healthcare professional. Lifefy is a preventative wellness platform and does not diagnose, treat or cure any condition.