Bacteria have lived along with the mankind for hundreds and thousands of years since the first human appeared on Earth. The bacteria that are found living on and inside the human body, in their totality, are called the human microbiome. Throughout human evolutionary history, the human gut microbiome has fluctuated and changed as a result of many internal (e.g. gut health) and external factors (e.g. diet, skin conditions). Recent evidence suggested that a change to a meat-based diet in recent decades has caused the human gut microbiome to be more streamlined and simple compared to that in our ancestral counterpart, which had a more diverse gut microbiome consisting of hundreds and thousands of different bacterial species (1).
Bacteria that live inside our gut system can play a number of important roles. For one, certain bacteria species are capable of converting the food that we eat but unable to digest into small molecules that the human body can more readily absorb and metabolize. It has now becoming increasingly clear that certain microbial species living inside the human guts are capable of modulating our emotion and state of health through the small molecules that they make and release into our blood stream (2). Discovery of the association between certain bacterial species to incidence of obesity suggests that diets are not only important in shaping the human gut microbiome, but more importantly, understanding interaction between diet and gut microbiome and their impacts on diseases states may one day help scientists to find ways to tackle human diseases through food or bacteria implantation (3).
Humans have been using bacteria to produce foods for hundreds and thousands of years. Many of the fermented food items that we are familiar with today like fermented fish sauce, kimchi, cheese, and yogurt rely on bacterial metabolism to convert food polymers to molecules, which can greatly impart and enhance texture, flavor and aroma in the finished products. Consumption of fermented dairy products containing probiotics are well known to have beneficial effects on gut health. Other sources of probiotics can be found in fermented vegetables and fruits such as sauerkraut, kimchi, gundruk, khalpi, and sinki which are similarly rich in the probiotic bacteria Lactobacillus spp. (4)
During food fermentation, some bacterial species can produce bioactive peptides with health benefits. For example, soy milk fermentation by Lactobacillus plantarum was found to contain bioactive molecules that can improve the conditions of hypertension (5). Because of the abundance of fermented foods and the benefits associated with the consumptions of these food items, there have been calls for their global inclusion in food guides (6). In essence, without the little bugs that are capable of fermentation, the world today would have been severely depleted of many delicious food items.
In a nutshell, there are many more ways where bacteria could influence our lives and improve our food security. Although there is a general misconception that most bacteria are bad, increasing awareness has shone a light on the good ones that are out there serving their purposes to create a livable environments for mankind.
1. H. Moeller et al., Rapid changes in the gut microbiome during human evolution. Proc. Natl. Acad. Sci. 111, 16431–5 (2014).
2. P. Ojeda, A. Bobe, K. Dolan, V. Leone, K. Martinez, Nutritional Modulation of Gut Microbiota – The Impact on Metabolic Disease Pathophysiology. J. Nutr. Biochem. (2015), doi:10.1016/j.jnutbio.2015.08.013.
3. J. R. Marchesi et al., The gut microbiota and host health: a new clinical frontier. Gut (2015), doi:10.1136/gutjnl-2015-309990.
4. M. R. Swain, M. Anandharaj, R. C. Ray, R. Parveen Rani, Fermented fruits and vegetables of Asia: a potential source of probiotics. Biotechnol. Res. Int. 2014, 250424 (2014).
5. Y.-Y. Liu, S.-Y. Zeng, Y.-L. Leu, T.-Y. Tsai, Antihypertensive Effect of a Combination of Uracil and Glycerol Derived from Lactobacillus plantarum Strain TWK10-Fermented Soy Milk. J. Agric. Food Chem. 63, 7333-42 (2015).
6. S. N. Chilton, J. P. Burton, G. Reid, Inclusion of fermented foods in food guides around the world. Nutrients. 7, 390-404 (2015).