Fermented products and probiotics have been promoted in recent years as a way to improve digestion, healthy guts and getting complete nutrition.

Looking back at times before we had refrigeration, fermenting was one of the ways to preserve food. The need and the skills of preserving food have diminished in modern society due to it being replaced with other preserving techniques of refrigeration, dehydration, transportation, an example is how food is transported refrigerated from all around the world.

Fermentation is any energy-releasing metabolic process that takes place only under anaerobic conditions. It is a process of aging and ‘predigesting’ food with enzymes (bacteria) making its energy easier to extract during digestion.

Depending on the types of bacteria used for fermentation, it creates acids with distinctive flavor. For example, propionic acid in Swiss cheese, lactic acid found in yogurt, cheddar cheese, soy sauce, acetic acid in vinegar giving its biting flavor. Wine, alcohol, and beer are all products of fermentation too.

The bacteria produce byproducts during fermentation:

- ethanol like in wine and beer

- lactic acid, for example, during intense exercise where oxygen supply becomes limited lactic acid is produced.

- Hydrogen gas.

Ayurveda uses many ferments but only medicinally as Asavas and arishtas (alcoholic herbal preparations). Herbarized wine is used as a vehicle to deliver healing herbs, targeting the liver, the digestive system and the reproductive system and used for Vata.

The metabolic waste products of bacteria are generally acidic, sour and irritating. They require processing and are a burden to the liver (this is obvious with alcohol).

Fermented food has heating qualities (Pitta), to be taken in small doses by vāta and Kapha and during Vata and Kapha season, in the old days, this was the time fermented food was eaten.

Fermented food is contraindicated in post-surgery, post-partum, and in cases of bleeding or high pitta and all liver disorders. Overuse of ferments increases Pitta and spoils the quality of the blood.

Ingredients that are fermented:

Alcohol, Apple Cider Vinegar, Balsamic Vinegar, Beer, Black Tea, Chocolate (Cacao), Coffee, Dosa Mix, Fish Sauce, Kefir, Kombucha, Miso, Nutritional Yeast, Olives, Pickle (Cucumber), Red Wine, Red Wine Vinegar, Sake, Sauerkraut, Soy Sauce, Tamari, Tempeh, Tobacco / Nicotine, Tofu, Umeboshi Plums, White Vinegar, White Wine (Dry type), Yeast.

Ayurvedic fermented food: Common fermented or probiotic foods in India and Ayurveda include idli, dosa, pickle, yogurt, and herbarized wine.

To understand the effect of fermented food, think of the Gunas of the ingredients and the process of fermentation and how it will affect the Doshas.

For example, Kefir and sauerkraut fall under the same category, but kefir will be more heavy and cooling in nature {better choice for pitta} and sauerkraut is better for kapha.

Takra is a fat-free yogurt mixed with water, which is an Ayurvedic probiotic used in IBS.

For a probiotic to work correctly, they need to be fed with prebiotics food that is high in inulin, a polysaccharide. Examples are burdock root, dandelion root, Jerusalem artichokes, and root veggies like parsnips, leek, asparagus, and sweet potatoes.