Is Kefir Good for Gas?

Partly: kefir may reduce gas for some people who have trouble digesting lactose because fermentation and live cultures help break down the milk sugar. The evidence is limited, and kefir can also cause gas. For other food choices, see the best foods for gas.

Can kefir help with gas?

Kefir may be worth trying if ordinary milk seems to give you gas. A small clinical trial found that adults with lactose maldigestion reported less severe flatulence after kefir than after milk, even when the test meals contained the same amount of lactose.

That does not mean kefir helps everyone. Gas has many possible causes, and the study did not establish that kefir relieves gas unrelated to lactose. If you are comparing options, see the best drinks for gas.

How might kefir affect gas?

Milk kefir is a fermented drink made using bacteria and yeasts. During fermentation, some of the lactose in milk is broken down; live cultures may also help digest lactose that remains.

When lactose is not fully digested, microbes in the colon ferment it and produce gas. Kefir may therefore be easier to tolerate than regular milk for some people with lactose maldigestion. However, many milk kefirs still contain lactose, and the amount and types of cultures vary by product.

Kefir can also make some people feel gassy or bloated. An individual reaction does not necessarily mean the drink is harmful, but it is a reason to reconsider it if the discomfort continues.

What does the evidence say about kefir and gas?

In a small clinical trial of adults with lactose maldigestion, 15 participants had test meals containing milk, kefir or yogurt. Each meal contained 20 g of lactose, and symptoms were monitored for 8 hours.

Participants reported less severe flatulence after kefir than after milk. Plain kefir also produced a lower breath-hydrogen response than milk, consistent with improved lactose digestion. The flavored kefir had an intermediate breath-hydrogen response, so results should not be assumed to apply equally to every product.

This was a small study of gas associated with lactose maldigestion. It compared kefir with milk, not with having no kefir, and does not establish that kefir treats other causes of gas.

A study of water kefir in 40 healthy adults reported mild, temporary flatulence in 32% of participants and bloating in 24% during the intervention. Water kefir is different from milk kefir, and this study does not show that it prevents gas. Together, the studies show that responses can vary.

How should you try kefir for gas?

Start with a small sip of plain kefir and see how you feel. If you tolerate it, increase the amount gradually rather than starting with a large serving. There is no established kefir serving that reliably prevents gas.

Check the label for live cultures and, if lactose is a concern, whether the product is labeled lactose-free. Plain kefir may make it easier to identify what you tolerate: some flavored products contain added ingredients, such as certain sweeteners or added fibers, that can cause gas in some people.

Keep the rest of your routine reasonably consistent while you try it. Note whether symptoms follow kefir or another food, and stop or reduce it if it makes you uncomfortable. Carbonated water kefir may add to a feeling of bloating, and it has not been shown to have the same effects as milk kefir.

Who should be careful, and when should you see a doctor?

If you have a milk allergy, avoid milk kefir, including lactose-free milk kefir: removing lactose does not remove milk proteins. If you have lactose intolerance or irritable bowel syndrome, introduce kefir cautiously and stop if it worsens symptoms.

If you are pregnant, choose milk kefir made from pasteurized milk. People with weakened immune systems, serious illness or those taking immune-suppressing medicines should ask a clinician before consuming products with live cultures. Ask a pediatrician before using kefir to manage a young child’s symptoms.

See a doctor if gas is persistent, keeps returning or comes with a change in bowel habits, blood in the stool or unexplained weight loss. Seek urgent care for severe or worsening abdominal pain, especially with vomiting or an inability to pass gas or stool.