Eating fermented foods may have various long- and short-term positive impacts on brain function, such as reducing stress. These foods naturally provide us with probiotics—good bacteria that mostly live in our digestive system. But which fermented foods are the best? The popular notion is that a few well-known fermented foods, such as khimchi and kombucha, are good for the gut and brain but a new research shows that, out of 200 fermented foods, almost all showed some potential to improve gut and brain health. The research was done at APC Microbiome, University College (Cork), and Teagasc (Ireland’s agriculture and food development authority) in Moorepark (Cork, Ireland). The researchers are currently working on a large study to finally answer the question which fermented foods are the best. The team compared sequencing data from 200+ foods from all over the world, looking for a variety of metabolites that are known to be beneficial to brain health.
Fermented foods are those that are left for many hours until the sugars and carbs that the food naturally contains interact with bacteria, yeast and microbes. This changes the chemical structure of the food yielding healthy probiotics. Some of the most widely available include: kombucha, kimchi, sauerkraut, yogurt, some types of cheese, miso, tempeh, pickles and natto. Other healthy common foods that are fermented are: wine, apple cider vinegar, cottage cheese, coconut kefir, and sourdough bread. Fermented rice has been used as meal in parts of rice-eating states of India. Health benefits of fermented foods and probiotics include: improving digestion/gut health, promoting brain health and boosting immunity.
One of main benefits of fermented foods is that they are a source of tryptophan, an amino acid key to the production of serotonin, a messenger in the brain which influences several aspects of brain function, including mood. Such foods may also contain other brain messengers (known as neurotransmitters) in their raw form. They are also helpful in treating gut issues such as irritable bowel syndrome. Fermented foods are supposed to provide minerals that build bone density, helping fight allergies and killing harmful yeast and microbes that cause issues like Candida.
The Irish study is still in its initial stages, but researchers, led by Ramya Balasubramanian, are already surprised by the preliminary results. Fermented sugar-based products and fermented vegetable-based products are like winning the lottery when it comes to gut and brain health. Though sugar-based products are seen to be bad for health, fermented sugar takes the raw sugar substrate and converts it into metabolites that can have a beneficial effect. Ramya plans to put the fermented foods through rigorous testing using an artificial colon and various animal models to see how these metabolites affect the brain.