The Japanese diet contains elements that are known to positively influence intestinal microflora. Obviously there is a significant intake of omega-3 fatty acids from fish and seafood, lots of vegetables, and plenty of roots such as wasabi, daikon, and renkon. The three aforementioned roots are part of the Brassica family of vegetables, which have been shown to exert quite a specific growth of friendly bacteria in the human gut. The Japanese are known to be frequent consumers of Brassica family vegetables, and most often these are eaten with minimal cooking and have low AGE content.
Indeed, some specific items in the Japanese diet would normally escape consideration as promoters of good bacteria. For example, research shows that green tea promotes the growth of Bifidobacteria. How about all that fresh ginger that accompanies sushi? It has been reported that despite ginger’s strong antimicrobial properties, it may actually contribute to the growth of Lactobacilli.
Honey is also a great way to sweeten foods because it contains antioxidant polyphenols, and at least two studies have shown that it can selectively promote the growth of Bifidobacteria and Lactobacilli. The dietary fiber, the omega-3 fatty acids from fish, the green tea, the Brassicas, and a host of other colorful phytonutrients within the Japanese diet may influence intestinal microflota in a beneficial way.
Because Japan is home to the oldest living people on Earth, researchers have spent quite a bit of time studying the genetics, diet, and lifestyle of the Japanese. Undoubtedly, many aspects of the Japanese diet may promote longevity and healthy skin through the aging process. Since intestinal microflora have been theorized to influence the aging process, it would be interesting to note any major differences between the intestinal microflora of Japanese and North American adults. Researchers from the University of Tokyo and the Ludwig Institute of Cancer in Toronto compared the fecal microflota of Japanese Tokyoites consuming a typical Japanese diet to that of healthy Toronto residents consuming a typical Western diet. As you may have imagined already, the levels of Lactobacilli and Bifidobacteria were significantly higher among the Japanese.
Looking even a little bit more deeply, researchers found that the overall levels of Bifidobacteria were much higher among rural dwellers of the Japanese region known for great longevity than among Tokyo adults. The levels of Bifidobacteria in the rural region, where residents adhere more strictly to the traditional Japanese diet, were higher than those of a Tokyo resident twenty years younger. Bifidobacteria levels usually drop through the aging process, and some consider levels of this bacteria to be a reliable marker of aging.
Note that rural Japanese are the least likely to use conventional and microwave ovens. Foods, even meats and fish, are prepared with water on a regular basis so the preformed AGE content is almost certainly lower among these residents. The bottom line is that a more healthy profile of intestinal bacteria is associated with longevity, which is in turn associated with fewer processed foods, more fiber, and fewer AGE-containing foods.