“Life is great. Cheese makes it better.”
— Anthony Bourdain
This week’s Study Spotlight focuses less on a specific clinical trial or issue and more on a holistic perspective. Of course, details matter, but too much focus on isolated data points can lead us astray, wandering down a reductionist rabbit hole where all the bits of information float as disconnected flotsam and jetsam. This week, the focus is on real food: cheese, which, as the inimitable Anthony Bourdain observed, simply makes life better.
It turns out that it is not just a personal opinion but a scientific fact. Building on one of the conclusions from last week’s analysis, evidence suggests that dairy-based foods are cardioprotective. At face value, this seems to contradict conventional wisdom and ongoing recommendations that dairy be avoided because so many products are high in dairy fat, highlighted by the poster child, butter. However, the health benefit, particularly for fermented dairy products like yogurt and kefir, is particularly compelling. That cardiovascular advantage extends to fermented dairy foods high in fat, like real cheese. And we don’t mean Day-Glo orange cheese-like food substance dispersed from a spray can that can turn skin transparent[1]. We mean naturally fermented, funky, and well-aged – like a culinary Keith Richards.
- The study performs a DNA microorganism analysis on Bronze Age kefir cheese from approximately 3500 years ago, produced by the Xinjiang Xiaohe people of ancient China, who are genetically related to East and West Eurasians.
- The data suggests that human beings played a proactive role in selecting the microbial composition of cheese.
- Naturally fermenting the milk into cheese increased the shelf-life of the milk product and significantly decreased lactose concentration, as the Xinjiang Xiaohe people were lactose intolerant.
- Feasting on such fermented food actively shapes the human gut microbiota by ingesting a large number of microorganisms (10,000 times higher in fermented foods than non-fermented foods) from the comestibles we eat.
- Such consumptive patterns in the past likely helped shape the co-evolution of the gut microbiome that plays a critical role in modern human immune function.
- The authors conclude that, “As part of human culture, the history of milk fermenting is an indispensable part of understanding the human past and its impacts on the lifestyle of present-day humans.”
The Caveat:
The human gut microbiome, its composition, and its interaction with our immune system is an area of intense investigation and inquiry. But to truly understand it and to examine the effects of our current consumer culture and how our modern industrial foods – like ultra-processed foods – impact it, it is helpful to have a viewpoint with perspective. We can easily lose sight of the fact that our modern human gut microbiota is the result of a co-evolution between host and microbiome, and that during the millennia that led to the development of its present-day character and composition, our forebears were active participants. We are the result of what they chose to eat.
This study demonstrates that bacterial species currently associated with good health, like certain Lactobacillus species, were intentionally propagated and widely “consumed by humans over thousands of years.” The widespread dissemination of such bacterial species was achieved through the trading and sharing of kefir cheese and kefir grains (the inoculum used in goat and bovine milk to make the kefir cheese) that occurred in the course of human interaction and commerce. Some of the very same species that are found in present-day kefir grains, Lactobacillus kefiranofaciens and Lactobacillus helveticus, were found in the cheese samples from 3500 years ago.
In addition, there were other beneficial bacterial species like Penicillium rubens. This bacterium produces medicinal penicillin, and it was Penicillium rubens (originally identified as Penicillium notatum) that Alexander Fleming first discovered in 1928, which led to the development of penicillin as the world’s first antibiotic. Our ancestors were consuming this natural antibiotic thousands of years ago.
While we often focus on the bacterial composition of our gut microbiota, it is, in fact, a diverse ecosystem that also includes viruses (see the previous post for more in-depth commentary on the viral aspect of the gut microbiota), yeast, and fungi. The ancient Bronze Age kefir cheese contained 41 species of the yeast Saccharomyces; including two species found in present-day kefir grains.
By understanding and appreciating the ancient cross-cultural and cross-regional interactions that occurred through the trading and sharing of food, we gain insight into “how human activities may impact microbial evolution through human-microbe interactions” and how our food choices today impact not only our individual health and wellness but that of generations to come.
[1] (Reardon, 2024)
The Study:
Additional resources:
Farnworth, E.R.T. (2008). Handbook of Fermented Functional Foods (CRC Press).
