Nutrition · Protocol 6 of 7
Feed your gut with fermented foods
1In 30 seconds
Each day, enjoy two to four small helpings of fermented food that is low in sugar, such as plain curd, chaas, kefir, kanji or sauerkraut. They appear to widen the variety of helpful bacteria in your gut and calm inflammation.
2Picture it
3Why do it
- 1
In a ten-week trial, people eating more fermented foods saw 19 markers of inflammation fall.
- 2
A more varied gut microbiome is linked to better digestion and may support mood through the gut-brain link.
- 3
Plain curd and buttermilk are cheap, easy and already part of most Indian meals.
4How to do it
- Each day, eat two to four helpings of low-sugar ferments, such as plain curd, kefir, sauerkraut, kimchi, miso, natto or brine pickles kept in the fridge.
- Choose versions with no added sugar, and keep kombucha moderate because it holds some sugar and a little alcohol.
- Skip pickles and sauerkraut sold unrefrigerated on the shelf, since they have usually not been fermented with live cultures.
- Spread your servings across the day, for example curd at breakfast, chaas at lunch and a spoon of fermented vegetables with dinner.
- If you make ferments at home, follow a trusted recipe exactly and keep jars and hands clean to avoid harmful bacteria.
5Make it work in India
- Set dahi at home every day; it costs little more than the milk and counts fully. A glass of salted chaas with roasted jeera is an easy lunch serving.
- Winter kanji, made from black carrots, mustard seed and water, is a classic North Indian ferment. Make it in a clean glass jar and keep the finished drink in the fridge.
- Most oil-based achar is very salty and is not a reliable source of live bacteria, and idli and dosa are cooked, which kills their microbes. Enjoy them, but do not count them towards your servings.
6The long read: the science1 min read · tap to open
Trillions of bacteria live in your gut, and together they are called your gut microbiome. This community starts forming before birth and keeps changing with what you eat, the people and pets around you, the air, the soil and even exercise. Scientists now agree that variety matters most. A gut with many different kinds of helpful bacteria tends to be a healthier one.
The gut also talks to the brain. Gut bacteria help make serotonin, a mood chemical, when they get enough of its raw material, tryptophan. When the community is out of balance, it may push up inflammatory proteins called cytokines, some of which are linked to depression. These links are still being worked out.
The headline study came from Justin Sonnenburg’s lab at Stanford. Thirty-six adults were split into two groups for ten weeks. One group ate much more fibre. The other ate more low-sugar fermented foods like yoghurt, kefir, sauerkraut, kimchi and kombucha. The fermented group’s gut bacteria became more varied, and 19 markers of inflammation dropped. The fibre group did not see the same jump in variety.
Best of all, the change lasted. Four weeks after the trial ended, the fermented group still had the richer mix. The researchers described it as the gut ecosystem being remodelled, not just visitors passing through.
Early evidence A small 36-person Stanford trial found fermented foods raised gut bacteria variety and lowered inflammation markers, and the larger studies are mostly observational, so this is promising but not yet proven.
Questions people ask
Does sweetened yoghurt or lassi count?
Not really. The protocol asks for low-sugar ferments, so choose plain curd, unsweetened chaas or salted lassi, and add fresh fruit if you want some sweetness.
Fermented foods make my eyes itch or my head foggy. Why?
Some people react to histamine in fermented foods. The author takes an enzyme called diamine oxidase (DAO) before such meals; talk to your doctor before trying it or any other supplement.
Are fermented foods expensive?
Some imported ones are. Plain curd and apple cider vinegar are cheap and easy to find, and home-set dahi costs almost nothing extra.
7Be careful
If you have a weakened immune system, are pregnant or have a histamine intolerance, ask your doctor before adding home ferments. Throw away any batch that smells wrong, turns slimy or grows mould.
8Try it for 7 days
Tap a day each time you had two fermented servings.
From the book: “Consume Low-Sugar Fermented Foods” (Nutrition Protocol 6). Evidence rating and India notes are our own.