A lot of press recently has been about the benefits of fermented foods. Fermented foods are full of probiotics, the beneficial bacteria that aid in digestion. Proper digestion means fully breaking down all of the food we eat so the body can disperse those nutrients for maximum functioning of both body and brain. This is referred to as “gut health” and there is some speculation that good gut health is more important for good mental health than previously realized. This microbiata, or gut microbiome, communication between the gut and the brain is being referred to as “psychobiotics” and has been linked to disorders such as depression, anxiety and even autism. It appears that people with a richer microbiome – having more and greater variety of gut bacteria – are healthier, both physically and mentally.
Eating fermented foods is one of the best ways to increase the amount and variety of beneficial bacteria in the gut. Some examples of fermented foods and drinks are:
- Sour cream
- Brewed ginger ale
- Cottage cheese
- Soy sauce
- Yeasted breads (sourdough breads have unique yeasts that are different from commercial yeast)
- Tabasco sauce
- Worcestershire sauce
- “Aged” cheeses like parmesan, bleu cheese, and feta cheese
The last item, vinegar, is what makes pickled things technically qualify as fermented foods. There is a bit of a distinction however. Fermented vegetables like “pickles” and sauerkraut were traditionally fermented in brine by covering with water, adding salt, and leaving at room temperature for several days, or longer, until they were bubbling with proliferating bacteria that fed on the naturally occurring sugar in the vegetables. This creates a plethora of bacteria, varying with differing foods. You can still find things that have been fermented this way at health food stores and specialty stores in the refrigerated section. Typically, commercially pickled items like sauerkraut and cucumber pickles are pickled with vinegar. While the vinegar is fermented, the vegetables have not been fermented. So, the probiotics contained in the jar will primarily be from the vinegar. If the vegetables were fermented the traditional way using water and salt, they would create a wider variety of bacteria than what is contained in the vinegar. Vinegar will also kill a lot of other bacteria, both good and bad bacteria. This makes it good for preserving food because it prevents bad bacteria from growing which would spoil the food. However, when you add vinegar to fermented foods, it destroys much of the good bacteria also. While pickled foods offer some probiotic benefit, it is best to eat a variety of traditionally fermented foods to increase the variety of good bacteria in your gut microbiome.
Another thing that complicates the probiotic issue is cooking the fermented food. Bacteria are destroyed by high and prolonged heat. Because of this, it is best to eat fermented food that has not been heated after the fermentation process has occurred. Sourdough bread produces many different types of bacteria during the fermentation process, which is when the dough “rises”. But once the bread is cooked in the oven, the remaining probiotic benefit is questionable. This is also true of pickled items in cans and jars. Depending on how they have been processed after the vinegar is added, they may have lost some of their probiotic benefit. For this reason, it is best to eat raw fermented foods or foods that have been fermented after any heating has occurred. Yogurt, sour cream, and some cheeses for instance may have been pasteurized at the milk stage, which involves heating it to the point of destroying bacteria, but then the active “cultures”, which are the various beneficial bacteria we want, are added and the fermentation process occurs. This allows the probiotic bacteria to be alive and active when we consume them.
Recent studies of Amazonian hunter-gatherer tribes, like the Matses and Yanomami, have found a much richer biodiversity in their gut microbiome than is found in the guts of Americans. Not only do the Amazonian’s digestive tracts have 50% more bacteria, they have dozens of strains of bacteria, some of them associated with anti-inflammatory activity, that are completely absent in the microbiome of American’s. This is likely due to the amount of processed food in the typical American diet versus the fresh, natural food consumed in the Amazon rainforest. Processed food is often refined and heated at high temperatures, making it void of bacteria as well as much of the original nutrition. Fresh food on the other hand, is brimming with naturally occurring bacteria. Fresh vegetables and fruit also contain fiber that is woefully lacking in processed food. Fiber acts as a prebiotic, which is a non-digestible food that creates a friendly environment for probiotics to grow. This makes a fiber rich diet crucial to a healthy gut microbiome. Less than 3% of Americans consume the government recommended amount of fiber. Even though fiber is sometimes added back in to processed food, Justin L. Sonnenburg, PhD, associate professor in the department of microbiology and immunology at Stanford University School of Medicine and author of “The Good Gut” explains that loading up on fiber-fortified processed foods isn’t likely a good way to increase the kind of fiber that benefits the gut. Studies done on single fibers—those, like inulin, which are added to foods—haven’t shown to have the same effects as fiber that occurs naturally in whole foods. “All of the vegetables we’re encouraged to eat by our mothers and by the government guidelines, these are all filled with fiber, and filled with a diversity of fiber, and probably the best route for encouraging a diverse microbiota.”
Increasing healthy gut flora can decrease your risk of disease, inflammation, depression, anxiety, and other disorders. The best way to do that is to eat a diet rich in fresh whole foods, especially high fiber vegetables, fruits, nuts and seeds, eaten raw and minimally cooked and including a variety of traditionally fermented and probiotic cultured foods.