Gut bacteria
Is curd a probiotic?
Curd contains live bacteria and is a useful food for the gut, but it is not a probiotic in the strict scientific sense. A probiotic is a specific, named strain given in a known dose, with a benefit shown in studies. Home-set curd contains a mix of bacteria that varies from house to house and from batch to batch. It is still well worth eating: curd is easier to digest than milk, it supplies protein and calcium, and it adds live microbes to the diet every day.
In short
- Curd is a fermented food with live bacteria. A probiotic is a defined strain with a tested benefit. The two overlap but are not the same.
- The bacteria in curd help to digest lactose, so many people who cannot take milk can take curd.
- A small bowl of plain curd or a glass of buttermilk once or twice a day suits most people.
- Heating curd, as in kadhi, kills the live bacteria. The nutrition remains.
How do curd, yoghurt and probiotic curd differ?
Curd
- A fermented food with live bacteria
- Its bacteria help to digest lactose
A probiotic
- A defined strain
- It has a tested benefit
| Product | How it is made | Is it a probiotic? |
|---|---|---|
| Home-set curd (dahi) | Warm milk is set with a spoonful of the previous batch | Not in the strict sense. The mix of bacteria is not defined. |
| Yoghurt | Milk is fermented with two defined bacteria | Its bacteria have a shown benefit for lactose digestion. |
| Probiotic curd or yoghurt | A named strain is added | Only if that strain, at that dose, has been shown to work. |
| Buttermilk (chaas) and lassi | Curd that is churned and diluted | The same as the curd it is made from. |
What does curd do for the gut?
It is easier to digest than milk
The bacteria use up part of the lactose during fermentation. Yoghurt bacteria also carry the enzyme that digests lactose, and it stays active in the intestine. See lactose intolerance.
It adds live microbes
In a ten-week trial, a diet high in fermented foods increased the diversity of gut bacteria and lowered several markers of inflammation.
It is nourishing
Curd supplies protein, calcium and B vitamins.
What it does not do
Curd does not treat an infection, and it does not replace a medicine or a probiotic that has been prescribed for a specific purpose.
How much curd, and when?
- A small bowl of curd or a glass of buttermilk, once or twice a day
- Plain, not sweetened or flavoured
- Freshly set, within a day or two
- With meals, or as buttermilk between meals
Who should take care with curd?
- Marked lactose intolerance: begin with small amounts. Most people tolerate curd better than milk.
- Milk protein allergy: this is different from intolerance. Avoid curd and other dairy.
- IBS on a low FODMAP diet: lactose is one of the FODMAPs. Small portions of curd are often tolerated, and your dietitian will guide you.
- People on chemotherapy or after a transplant: follow the food advice of your treating team.
Do I need a probiotic capsule if I eat curd?
For general health, no. Curd, buttermilk and a diet with plenty of fibre do more.
A probiotic product is a targeted tool. It is worth considering in defined situations, such as lowering the chance of diarrhoea during a course of antibiotics. See restoring gut bacteria after antibiotics and choosing a probiotic in India.
When should I see a doctor?
See a doctor if dairy of every kind, including curd, brings on bloating, cramps or loose stools, or if these symptoms have lasted more than three to four weeks. A breath test can confirm lactose intolerance before you restrict your diet for the long term.
Questions patients ask me
Is curd a probiotic or a prebiotic?
Strictly, neither. Curd is a fermented food that contains live bacteria. Prebiotics are fibres that feed the bacteria already in your gut.
Is curd or yoghurt better for gut health?
Both are good. Yoghurt is made with two defined bacteria and is consistent from pack to pack. Home-set curd has a more varied and less predictable mix. Choose the plain version of whichever you enjoy.
Is buttermilk as good as curd?
Yes. Buttermilk is curd that has been churned and diluted. It contains the same live bacteria, with less fat when the butter is removed.
Can I eat curd at night?
There is no scientific evidence that curd at night is harmful. If you have acid reflux, a heavy or late meal of any kind can worsen it.
Is curd good during loose motions or a course of antibiotics?
Curd rice and buttermilk are sensible foods in both situations. Some antibiotics should not be taken at the same time as dairy, so check the label or ask your pharmacist.
Sources
This page is written for patients and is based on the guidelines and studies below. It is for education and does not replace a consultation.
- International consensus statement on the term probiotic. Hill C et al. Nat Rev Gastroenterol Hepatol. 2014. PubMed 24912386
- International consensus statement on fermented foods. Marco ML et al. Nat Rev Gastroenterol Hepatol. 2021. PubMed 33398112
- Review of how yoghurt bacteria help lactose digestion. Savaiano DA. Am J Clin Nutr. 2014. PubMed 24695892
- Review of lactose malabsorption and intolerance. Misselwitz B et al. Gut. 2019. PubMed 31427404
- Trial of high-fibre and fermented-food diets and immune status. Wastyk HC et al. Cell. 2021. PubMed 34256014
- American Gastroenterological Association guideline on probiotics in digestive disorders. Su GL et al. Gastroenterology. 2020. PubMed 32531291