The Diet Pattern Linked To 83% Lower Odds Of Kidney Stones
If you've ever passed a kidney stone, you probably don't need much convincing about wanting to avoid another one.
The pain can be intense, and kidney stones have a frustrating tendency to come back. So when it comes to prevention, hydration and diet are natural places to look.
Now, researchers are taking a closer look at something else that happens after you eat: what your food does for the bacteria living in your gut. New research suggests1 that people who eat more foods considered supportive of the gut microbiome may be less likely to have kidney stones.
About the study
The researchers used the Dietary Index for Gut Microbiota (DI-GM), a scoring system that looks at 14 parts of the diet.
Ten are considered beneficial for the gut, including fiber, whole grains, broccoli, chickpeas, soy, avocado, coffee, green tea, cranberry, and fermented dairy. Four are considered less supportive: red meat, processed meat, refined grains, and a high-fat diet.
The score ranges from 0 to 14, with a higher score reflecting a dietary pattern that's more supportive of beneficial gut bacteria. In this study, researchers divided participants into three groups: scores of 0 to 5, 6 to 7, and 8 or higher.
They compared 278 adults with kidney stones with 556 adults without them, all from a health cohort in China, and researchers used detailed food questionnaires to calculate their DI-GM scores.
A score of 8 or higher was linked to 83% lower odds
People with a DI-GM score of 8 or higher had 83% lower odds of kidney stones than those with scores between 0 and 5.
The researchers also saw a steady pattern. As DI-GM scores increased, kidney stone risk decreased. The association was similar across different age groups and between men and women.
That doesn't mean a score of 8 is a magic cutoff for kidney stone prevention. The researchers created those score groups for the analysis, and the DI-GM itself is a way of assessing dietary patterns rather than a clinical test with an established "good" score.
It's also important to remember that this was a case-control study. It can show that two things are associated, but it can't tell us that the diet caused the lower kidney stone risk.
What does your gut have to do with kidney stones?
The connection comes down, at least partly, to oxalate.
Many kidney stones contain calcium oxalate. Oxalate is a naturally occurring compound found in a variety of foods, and certain gut bacteria can break some of it down before your body absorbs it.
Less oxalate absorption could mean less oxalate reaches your urine, where it can combine with calcium and contribute to stones.
Your gut bacteria may also influence other processes involved in kidney stone formation, including inflammation and the way your body handles certain compounds.
Researchers are still figuring out exactly how much these pathways matter, but the gut-kidney connection is an active area of research.
Foods that support the pattern
You don't need to calculate your own DI-GM score to borrow some of the ideas behind it, and a couple of simple daily habits can cover a lot of ground. The foods that made up the beneficial side of the index are pretty familiar:
- Whole grains: Oats, brown rice, and whole wheat are sources of dietary fiber
- Chickpeas and soy: These provide fiber along with plant-based protein
- Broccoli: A fiber-rich vegetable that also contains compounds that interact with the gut microbiome
- Fermented dairy: Yogurt and kefir can provide live cultures
- Avocado: A source of fiber and unsaturated fat
- Coffee, green tea, and cranberry: These also counted toward the beneficial side of the index
If fermented foods rarely make it onto your plate, there are a few signs a probiotic supplement may be worth considering.
And don't let the gut angle distract from one of the basics of kidney stone prevention: Staying well hydrated helps dilute substances in your urine that can form stones, so what you drink still matters.
RELATED READ: Follow This Guide To Get 30+ Grams Of Fiber Daily
The takeaway
Eating gut-supportive foods may also be a helpful tool for preventing kidney stones. While there's no magic cure, it's a great dietary habit for whole-body health that may come with added kidney benefits, too.