When buying kvass, the doctor advises to pay attention to its expiration date – the shorter it is, the better.
In an interview with nutritionist Elena Solomatina, it was said opinion about the benefits of kvass:
“Natural kvass is very useful for the body, as it is a product of fermentation and fermentation that can improve the state of the intestinal microflora.”
At the same time, the specialist believes that store products can hardly be called natural and useful – such kvass contains undesirable artificial components, added sugar. It is preferable to prepare a drink on your own or purchase “live” kvass.
Solomatina shared her tips on choosing kvass. The doctor recommends focusing on the expiration date of the drink. “Live” kvass, due to the recipe, cannot be stored for a long time, but if the manufacturer promises its long-term preservation, then such a drink contains preservatives. , prolonging the shelf life of the drink, “kills” fermentation, and this is the most valuable thing in kvass, as well as in sour-milk products, ”explained Elena Solomatina.
The doctor clarified that sorbic acid or citric acid can be used as a preservative – such an option is quite acceptable. But if the drink, among other things, contains flavors, dyes, it is better to refuse to buy and drink it.
Earlier, the MedikForum.ru portal wrote about which vitamins can be very dangerous in case of an overdose. 
Elena Solomatina healthy lifestyle nutritionist