The question of whether Kefir is lactose-free can have controversial answers.
Some producers insist that their Kefir may be considered lactose-free, and some of them even advertise Kefir made with low-fat milk as a “100% lactose-free” product.
On the other hand, most dieticians are unanimous: milk Kefir is not lactose-free since it is a dairy product that inevitably contains certain amounts of lactose even when fermented.
The truth is slightly more complex and lies somewhere in-between.
Even the shortest answer to the question “Is Kefir lactose-free?” should be divided into three points:
- Milk Kefir is not lactose-free as even after fermentation, it still contains remains of lactose.
- However, Kefir is much better accepted by lactose-intolerant people because most of the lactose in milk is converted into lactic acids during fermentation. Thanks to this process, the lactose content of Kefir is significantly lower compared to fresh milk.
- Fully lactose-free alternatives to traditional milk kefir can be obtained by replacing dairy milk with non-dairy types like coconut milk, almond milk, soy milk, or cashew milk.
Additionally, it would be worth reminding that water Kefir is indeed 100% lactose-free. However, we consider that water and milk Kefir’s nutritional values and probiotic properties are too different and therefore incomparable. Although water Kefir is still a highly beneficial probiotic drink, its probiotic virtues are considerably inferior to milk Kefir, so it cannot be considered an equivalent alternative.
Let’s analyze the various aspects related to the presence of lactose in milk Kefir.
What is lactose?
Lactose is a type of sugar contained in milk. It is also known as a disaccharide because it is composed of two substances: galactose and glucose. Lactose constitutes around 2–8% of total milk weight.
After birth, all mammals, including humans, feed on their mothers’ milk, containing large quantities of lactose. However, the metabolization (or digestion) of lactose requires the presence in the body of an enzyme called lactase. Lactase is found in abundance in all infant mammals, including human babies. Lactase breaks down lactose into its two components – galactose and glucose, making them digestible.
In the absence of the enzyme lactase, the milk sugar lactose cannot be digested and may cause digestive problems.
Over time, however, the synthesis of lactase in the human body tends to decrease as, with age, humans usually rely less on milk.
That is especially valid when no milk or milk products are consumed for more extended periods. In such cases, the quantity of lactase present in the human body decreases drastically, and the gastrointestinal tract can no longer digest lactose. Then, any intake of fresh milk can lead to general digestive problems like bloating and flatulence, identified as lactose malabsorption or lactose intolerance.
How does Kefir help with lactose in fresh milk?
Lactose (or milk sugar) is the main food for the probiotic bacteria of Kefir. Once immersed in fresh milk, Kefir’s bacteria start to feed on lactose and transform it into lactic acid. And lactic acid is, of course, the reason why fermented Kefir has a slightly sour and sometimes even acidic taste.
As expected, this conversion of lactose into lactic acid during fermentation results in a drastic decrease in the amount of lactose in fermented Kefir. So, for the metabolization of Kefir, the lactase is no longer needed, and the absence of this enzyme may no longer impair digestion.
After fermentation, Kefir contains drastically less lactose than fresh milk and is much better tolerated by people affected by lactose hypersensitivity, lactose malabsorption, or lactose intolerance.
But there’s even more: scientific studies suggest that the presence of Kefir’s probiotic bacteria in the guts can stimulate the secretion of the enzyme lactase, thus inhibiting lactose intolerance.
As a result, Kefir is not only better accepted by lactose-intolerant people but can also act as a remedy for their health condition.
How to reduce lactose in Kefir to a minimum?
Simply put, lactic fermentation is a metabolic process in which lactose is converted into lactic acid and cellular energy. Fermentation of Kefir makes no exception.
The longer fermentation lasts, the more lactose gets converted into lactic acid, and the less lactose remains in the product. Kefir that has fermented and matured, say 48 hours, will contain less lactose than relatively fresh Kefir fermented for 8 or 10 hours.
So, the first and most natural way to minimize residual lactose in milk is to prolong fermentation time.
One of the simplest ways to make fermentation last longer is to extend the secondary fermentation or, as we call it, the maturation of Kefir. As we already know from the kefir-making recipe, the secondary fermentation starts after the Kefir grains are removed from the brew and is usually carried out in a refrigerator. This secondary fermentation is also called maturation or ripening.
At this stage, while the Kefir grains are already missing, fermentation processes continue but at a slower pace. Kefir’s bacteria and yeasts will keep on “eating” lactose and converting it into acids, but low temperatures in the fridge will prevent our Kefir brew from over-fermenting and separating.
In other words – our fridge creates the ideal conditions for the maturation of Kefir, during which remaining lactose will decrease to a minimum. That will certainly not make our Kefir 100% free from any lactose but will make it tolerable for almost anyone having troubles with lactose intolerance or malabsorption.
So, let’s sum up the advice on how to decrease the amount of residual lactose in Kefir:
- First of all, go for a long fermentation period with an extended phase of secondary fermentation. The longer milk ferments in the presence of the Kefir’s bacteria, the less lactose it will contain.
- Fermenting Kefir at lower temperatures may also contribute to lowering the residual lactose content in Kefir. Relatively low temperatures favor the development of Kefir’s bacteria, at the expense of the development of yeasts. Since the Kefir’s bacteria are the ones that are mainly responsible to convert lactose into acids, Kefir that has fermented at lower temperatures usually contains less lactose. Additionally, low temperatures require longer fermentation, and this is another contributing factor for lowering the amounts of lactose in Kefir.
Although, as a dairy product, traditional milk Kefir cannot be 100% lactose-free, processes involved in fermentation allow its lactose content to be reduced to acceptable levels for people affected by lactose intolerance.
Further decrease of lactose levels in Kefir to almost nil can be achieved through prolonged maturation after the initial fermentation period.
It is also recommended to ferment Kefir at lower temperatures (for instance – in the fridge) which would inhibit the development of Kefir’s yeasts and stimulate the development of Kefir’s bacteria – the microorganisms responsible for converting lactose into lactic acids.
A 100% lactose-free Kefir can be obtained by using non-dairy types of milk like coconut milk, almond milk, soy milk, or cashew milk. In such cases, however, Kefir grains should be periodically returned into dairy milk as they need the lactose of milk to feed. Repeated fermentations of Kefir grains in non-dairy kinds of milk can negatively affect or even kill them.
On the other hand, very few lactose-intolerant people demonstrate any adverse reactions to Kefir, and most people affected by this health condition usually react very well to the consumption of Kefir.