Probiotics or microbes? KHNI unpacks science behind fermented foods

01 Apr 2020 --- The term “probiotic” risks overextension when discussing microbes in fermented foods. This was flagged during a NutritionInsight webinar, called Fermented Foods: Stacking Up the Science and presented by Kerry Health and Nutrition Institute (KHNI). The webinar comes as fermented foods have become an industry priority in a very short period of time, with fermentation starting to step outside the realm of just cultured foods and probiotics. 

“Some fermented foods can increase the number of microbes in our gut by a fold of 100 to 10,000. We don’t know exactly what this means, but there is some correlation between the rise of allergic disease and our increasingly sanitized lives. Just because we’re consuming living microbes, we aren’t necessarily consuming probiotics. Probiotic means that when microbes are consumed in adequate amounts, they confer a health benefit,” says Dr. Maria Marco, Professor at the Department of Food Science and Technology at the University of California Davis.

She explains that because fermented foods typically contain undefined microbial strains that have not been found to show a health benefit, these foods should not be considered probiotic. Instead, she proposes that “live and active cultures” is a term more regularly applied to fermented foods.

Nonetheless, there are notable health benefits to fermented foods, including those going beyond the digestive tract. Previous studies have explored the connection between fermented foods and areas like obesity, Type 2 diabetes, mood and behavior, immunity and cardiovascular disease (CVD). However, Dr. Marco flags that research is still lacking as there are usually only one or two human studies in each area of fermented foods. These often have small sample sizes or are observational. 

Kombucha is a trending fermented food known for its vast array of health benefits.“What we know about how fermented foods can benefit our health has come through dairy – generally yogurt, although also cheese to some extent. Observational studies and a few randomized controlled trials have found that fermented dairy is associated with stemming inflammation and reducing Type 2 diabetes and cardiometabolic disease risks,” states Dr. Marco. 

She provides the example of a 2011 study using data from three cohorts to examine the relationship between diet, lifestyle factors and weight change. This was done every four years between 1986 and 2006. The researchers found that each increased daily serving of yogurt was found to be associated with just under a pound of weight loss. This was interesting because it was on par with other foods typically associated with reducing body weight, including vegetables, whole grains and nuts. 

Innova Market Insights data show that rising consumer interest in functional beverages and fermented products has moved out of the specialty sector and into the mainstream. Fermented, lightly effervescent black or green tea drinks, such as kombucha, contain multiple species of yeast and bacteria along with organic acids, active enzymes, amino acids and polyphenols produced by these microbes. They are positioned as a sustainable and healthful alternative to artificial soft drinks.

Transforming food through fermentation
Fermentation is also spotlighted as a natural way of preserving foods, which has been practiced for millennia. According to Dr. Marco, fermentation can also be used to improve food safety by lowering the pH. Additionally, fermentation can be used to make a food healthier or more tolerable, for example, in the case of lactose. While a serving of milk may have 12 g of lactose, an equivalent serving of cheese would only have 1 g. 

Dr. Marco continues that fermentation can also be used to synthesize new bioactive compounds, which may be another way to boost the health profile of a food. For example, making vinegar increases the amount of acetic acid, which is linked to increased insulin sensitivity and satiety and decreased gastric emptying. Acetic acid can also aid health by impacting other microbes in the gastrointestinal tract, as well as affecting intestinal cells and metabolism beyond the intestine. 

Looking ahead, Emma Cahill, Senior Manager of Food Protection & Fermentation at KHNI, predicts that kefir is a major emerging fermented food, stating that it could be “the next kombucha.” Other niche products, including kvass and fermented coffee, are also set for growth in the future. 

Cahill also highlights that growth in drinking vinegar is being aided by a combination of healthy halos and improved taste. Similarly, kombucha NPD is also seeing taste improvements, which are helping make the category mainstream. 

To learn more about these insights, including why the yogurt category is in decline and the role of sustainability, tune into the webinar here. 

By Katherine Durrell