Recent Blog Articles

Harvard Health Blog

Fermented foods for better gut health

May 16, 2018

About the Author

photo of Kelly Bilodeau

Kelly Bilodeau, Former Executive Editor, Harvard Women's Health Watch

Kelly Bilodeau is the former executive editor of Harvard Women’s Health Watch. She began her career as a newspaper reporter and later went on to become a managing editor at HCPro, a Boston-area healthcare publishing company, … See Full Bio
View all posts by Kelly Bilodeau


As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.


July 12, 2018

Assuming that the vinegar is added to introduce some starter cultures: if you use filtered (i.e. commercially available) vinegar it probably won’t work as intended. There are simply no bacteria in it. It probably will, however, prevent fermenting bacteria and fungi from growing (but also potentially harmful ones).

June 26, 2018

Remove the vinegar please. The lacto fermentation has nothing with vinegar but at the end can produce the vinegar.
I am born in north Europe where fermentation (lacto fermentation, without vinegar, please, forgive the vinegar, replace sugar with an apple or any fruit, there is simple ways!!) was the source of vegetable for 6 months of year and a daily component all the year.
There are several possibilities to increase the lacto bacillus and acidofilus and bulgaricus in your gut, for free, some without salt. Sourdough is a type of fermentation, beer and wine again (all these are with yeast and some lacto-bacillus, wild yeast for home made products) , lacto fermentation is in yougurt home made and needs 5 minutes of effort, sour milk or sour heavy cream (and fermented and NOT pasteurized cheeses) again are thanks to lacto fermentation and bacteria around us. East europe has kambucha (here sugar needed) or borch or kwass or elder-flowers juice or to not forget the kefir etc. Fermentation with salt solutions is great for vegetables and jars can resist all the winter.

Happy to have an immersion to simple and traditional food in France. Hope to spend a wonderful summer again, eating only in local markets from villages.

And not forget: all these bacteria live around us happily. Just to not destroy the ecosystem and keep the balance. The dirt is not so bad how it is promoted.

June 25, 2018

…The jars of pickles you can buy off the shelf at the supermarket are sometimes pickled using vinegar and not the natural fermentation process …
This piece of the text is contradicting to the recipe which recommends “2 tablespoons apple cider vinegar”. Is that ok?

May 30, 2018

In Cameroun West Africa we grew up eating a fermented breakfast porridge made from corn called pap, there is also fermented cassava for fufu etc These gut friendly foods has really helped in keeping us healthy.

May 30, 2018

You don’t need to add salt or vinegar. But a small amount of sugar might be helpful. I ferment cabbage regularly by cutting it up and putting in jar with enough water to cover. The first time I did this, I added some drops of the clear liquid i found on the top of some yogurt in a jar in my refrigerator. Now I add some liquid from the previous batch. This supplies the necessary micro-organisms to start the process.

I recently found a jar of fermented cabbage which had been sitting in my fridge for two years. It was still in perfect order.

May 28, 2018

This comment is in reply to J’s comment – migraines are principly due to lack of magnesium in your diet – consider reviewing this post

May 24, 2018

Except those with migraine, who find that avoiding foods with tyramine (all fermented and aged foods), to be beneficial in reducing frequency or severity of migraine symptoms and auras.
So no cheeses (except fresh like farmers, Havarti, cream cheese are OK), no red wine, no stout ales, no aged foods like sauerkraut or kimchi, no aged sauces (no Franks Red Hot, no Sriracha, etc.), no refrigerated leftovers (freeze portions instead).
There are some foods with naturally occurring tyramine but, except for fava beans, which have a very high amount, most can still be eaten in moderation. Avocado is good for you. But, maybe not a lot of it in one day for migraine suffers. Go easy on the guacamole dip at parties!
Cut out all tyramine foods and then add each in, starting with natural ones like avocado. When you see which bother you, edit them out of your diet. But most of us can live without most of these things just fine!
The fermented food craze, like all food crazes in the U.S., is overly promoted, overly hyped, and potentially ruinous to those with migraine.

May 24, 2018

All interesting comments. Like many cures, it’s a carefull rebalancing act. As the traditional saying goes: a little bit of bad is good, too. Sounds good!

N. Schultz
May 21, 2018

This is sad, if true. I just read your article and was writing down the ingredients when I looked at the posts below. If true, Harvard, you should retract, correct or stand by your article. Are the responses/posts correct?

May 21, 2018

I agree with Travis & Shane s replies. Well said & more completely explained.

May 21, 2018

Harvard Medical are amatuers in the ” Natural healing ” arena. They are trying to show a different image/reputation in order to attract more readers & subscribers.

They post some useable/ pertinent info, but are playing “catch up” with other countries in terms of alternative methods of wellness & healthcare.

P Worden
May 21, 2018

Way too much salt for my cardiac diet.

May 21, 2018

Maor Roffe:
You have no clue to what fermented foods are and what they do. Use some critical thinking and do som research.

Maor Roffe
May 21, 2018

This is ridiculous info, how can Harvard post something promoting items found to cause cancer? Last I read, there has been much evidence showing that cultures the frequently eat salty pickled food items have higher incidence of associated cancers.
Google “gastric cancer and pickled foods”, “stomach cancer and pickled foods” and you’ll find tons of data and research on the subject.
Im shocked. I’d expect Harvard to be so much more careful with the information the push out and promote.

May 17, 2018

You don’t need to add vinegar and if you do, you’ll thwart the natural succession of microbes that acidify and preserve. Instead of acetic acid, you want lactic acid created from lactobacillus for a traditional ferment.

Also, traditional ferments last almost forever under refrigeration, not a month.

Bubbles as a sign of being “natural fermented” is incorrect. At most, that will only tell you it’s a young ferment.

C’mon Harvard!

May 16, 2018

I’ve made my own kombucha before, and sugar is essential to the fermentation process in transforming tea -> kombucha.

I feel it would have been a similar situation for the recipe you shared – so I’m wondering why you decided to leave out the sugar?

I thought that the bacteria needed the sugar for the fermentation process.

Commenting has been closed for this post.

Free Healthbeat Signup

Get the latest in health news delivered to your inbox!

Harvard Health Publishing Logo

Thanks for visiting. Don't miss your FREE gift.

The Best Diets for Cognitive Fitness, is yours absolutely FREE when you sign up to receive Health Alerts from Harvard Medical School

Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health, plus the latest advances in preventative medicine, diet and exercise, pain relief, blood pressure and cholesterol management, and more.

Harvard Health Publishing Logo

Health Alerts from Harvard Medical School

Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss...from exercises to build a stronger core to advice on treating cataracts. PLUS, the latest news on medical advances and breakthroughs from Harvard Medical School experts.

BONUS! Sign up now and
get a FREE copy of the
Best Diets for Cognitive Fitness

Harvard Health Publishing Logo

Stay on top of latest health news from Harvard Medical School.

Plus, get a FREE copy of the Best Diets for Cognitive Fitness.