Kefir and yogurt can both offer health benefits because of the beneficial bacteria they contain.
However, kefir may be the better choice, as it has a wider variety of microorganisms.
Kefir and yogurt are both cultured foods that commonly come from dairy products. That said, nondairy alternatives of both foods are now widely available.
This article looks at the differences between kefir and yogurt, their health benefits and nutritional value, how to use them, and whether or not they have any side effects.
Kefir and yogurt have a similar sour, fermented taste, but there are many differences between them.
These differences include:
Production
For centuries, people have made kefir using kefir grains and cow’s milk. It is also possible to make it with goat or sheep milk. Kefir grains resemble tiny cauliflower florets.
Manufacturers add the grains to the milk to ferment it, then they remove them. The remaining product is kefir. The grains are reusable in the next batch.
They can also make kefir dairy-free, by fermenting the grains with water or coconut water and sugar.
On the other hand, commercial producers make yogurt by heating a yogurt mix, then cooling it and adding the helpful bacteria.
Current standard procedures and regulations for yogurt production require the addition of both Streptococcus thermophilus and Lactobacillus bulgaricus as the starter culture.
This is the best starter culture due to the symbiotic relationship between the two species.
Bacteria and yeasts
Both kefir and yogurt can help populate the gut with good bacteria. The difference is that kefir contains a wider variety of bacteria, and it also contains beneficial yeasts.
Two of the most common beneficial yeasts in kefir are Saccharomyces cerevisiae and Saccharomyces unisporus.
According to research, kefir may:
- have antimicrobial and antifungal properties
- help the immune system
- be anti-allergenic and antitumor
- be beneficial for lactose malabsorption
However, the variation in microorganisms in each batch make it difficult to verify the health effects of different products.
Yogurt often contains the probiotics Lactobacillus acidophilus and Bifidobacteria. Probiotics are bacteria that can be beneficial to a person’s health. Kefir also contains probiotics, as well as yeasts.
Research suggests that probiotics may help treat or prevent:
It is important for probiotics to survive the acidic environment in the gut. The authors of a 2017 review suggest that if Bifidobacterium strains are in fermented products such as kefir and yogurt, they should be acid resistant.
A 2019 study of people with metabolic syndrome who drank kefir for 12 weeks found some favorable changes to their gut bacteria.
However, the authors suggest that research into the probiotic potential of the fermented drink is limited at the moment.
Yogurt, low fat yogurt, and fat-free yogurt contain “at least 3.25% milk fat, between 0.5% and 2% milk fat, and less than 0.5% milk fat,” respectively.
Plain low fat yogurt and plain low fat kefir have similar nutritional values. The table below shows these values per 100 grams (g) of the product:
| Plain low fat kefir | Plain low fat yogurt | |
| Calories | 43 | 63 |
| Protein | 3.79 g | 5.25 g |
| Fat | 1.02 g | 1.55 g |
| Carbohydrates | 4.77 g | 7.04 g |
| Total sugars | 4.61 g | 7.04 g |
Both products also contain a wide range of vitamins and minerals.
There are also many different flavored products on the market that might contain high amounts of added sugars.
For example, one study that evaluated dairy products — including kefir and yogurt — in Poland found that 71% of products exceeded the permissible sugar content set by the World Health Organization (WHO).
Ready-to-eat kefir and yogurt are widely available in supermarkets. People with a lactose intolerance and those who wish to avoid dairy can try an alternative made with soy, coconut, or oats.
Some people who are intolerant to lactose are often able to consume fermented dairy products such as yogurt and kefir safely. This is because the process of fermentation reduces the lactose content.
A person can make their own yogurt or kefir at home using starter cultures. There are many sources and suppliers available online.
Once a person has fermented the milk or other liquid using kefir grains, they strain it and remove the grains. They can then use them again to start the next batch. This can be a cost effective way of maintaining a supply of kefir.
People can eat or drink kefir and yogurt as it is. They can also add the products to smoothies or breakfast cereals. It is vital not to heat kefir or yogurt, as this process can destroy the beneficial bacteria.
People should always keep fermented dairy products in the fridge and not use them after the expiry date on the packaging.
Fermented foods such as kefir and yogurt contain high levels of a substance called histamine.
Some people are intolerant to histamine and can experience symptoms such as:
- headaches
- skin irritation
- diarrhea
If a person knows that they are intolerant to histamine, or if they have any of the symptoms of intolerance, it may be best for them to avoid yogurt and kefir.
Some people can experience gas and bloating when they first consume foods that contain probiotics. These tend to subside once the person’s gut gets used to the new foods. It can help to introduce these foods gradually.
Fermented foods may have an effect on the immune system, so people who are taking immune-modulating drugs and those who have compromised immune systems should speak to a doctor before trying new products.
Sometimes, fermented foods are responsible for outbreaks of food poisoning. According to the authors of one 2019 review, manufacturers can help prevent these outbreaks by ensuring the product’s acidity.
Kefir and yogurt can be healthful additions to a person’s diet. Kefir may have more health benefits than yogurt due to the wider variety of bacteria and yeasts it contains.
People have the choice of buying convenient products in stores or making their own kefir or yogurt at home, which can be rewarding and more cost effective.
Over time, the production of yogurt and other cultured dairy foods has evolved from basic procedures to more controlled processes. Advances in scientific understanding of bacteria and the human microbiome mean that companies can develop new products to benefit people’s health.
A person who is trying fermented foods for the first time should do so gradually to decrease the risk of any side effects.
People with a health condition and those taking immune-modulating medication should speak to a doctor first.