What’s in store-bought yogurt? – Dr. William Davis

I get this question frequently: “I don’t want to make the L reuteri (or other) yogurt. Can’t I just eat the stuff in the grocery store?”

So what’s in store-bought yogurt? From the standpoint of microbes, very little.

By FDA guidelines, to call something yogurt, it must be fermented with the microbes Lactobacillus bulgaricus and Streptococcus thermophilus, two species that are ho-hum in biological effect. (Have you ever heard anyone claim that consuming store-bought yogurt transformed their life and health? I don’t think so.) Some manufacturers add additional species, but without specifying bacterial strain, we really don’t know if the added strains do anything beyond providing generic effects such as increase intestinal mucus and inhibit pathogens. If, for instance, Bifidobacterium longum is included, is it the strain that has been shown to reduce depressive thoughts? You can’t tell because no strain is specified. And pay no attention to the websites that claim that all the benefits attributable to probiotics are also attributable to commercial yogurts—this is simply not true.

The FDA does specify that a minimum bacterial count of 10 million microbes (CFUs, or colony-forming units) per gram be present at time of manufacture, one million per gram at the end of specified shelf-life, meaning a half-cup serving yields 1.23 billion CFUs at its peak. That sounds like a lot, but those of you following these discussions recognize that we have been aiming for hundreds of billions of live microbes per serving. And these values on commercial yogurt apply only if “live cultures” are specified. Some manufacturers pasteurize after fermentation, killing off the microbes, a practice permitted by FDA guidelines.

Recall that commercial yogurt-making is typically a 4 hour-long process, the briefest possible time to hasten production. We have been fermenting for 36 hours–8 times longer. If L reuteri doubles every 3 hours at 100 degrees F, you can appreciate that 4 hours yields very little, while 36 hours permits 12 doublings. The biggest increase in counts occurs between 24 and 36 hours (that we document via flow cytometry), meaning that a 4-hour fermentation period is not even close to the amount of time required to yields hundreds of billions of microbial counts.

The brief fermentation time used commercially means that the end-result is thin, necessitating the addition of thickening agents such as gellan gum, xanthan gum, guar gum, and carageenan. They also often start with non- or low-fat dairy and therefore pre-heat to improve texture. We do none of this. We start with the 18% fat of half-and-half, ferment to maximum bacterial numbers (after 36 hours there is no further increase), have no need for thickening agents, and enjoy a thick and rich end-result that can yield often spectacular health effects. Of course, we also do not add sugar, high-fructose corn syrup, artificial flavors or colorings, cornstarch, or preservatives like potassium sorbate (which is antibacterial and disrupts the intestinal microbiome) added to “maintain freshness.”

There is no commercial product fermented only with L reuteri to high counts—if there were, it could not be labeled “yogurt” by FDA guidelines. (I call it “yogurt because it looks, tastes, and smells like yogurt,” but I am not selling you anything.) You are left with fermenting it yourself if you desire the incredible benefits we obtain from restoring this microbe.

If you are interested in fermenting other microbial species for other benefits, such as:

Reduced arthritis pain–ferment Bacillus coagulans

Smaller waist circumference–with reduced visceral fat, ferment L gasseri

Healthier infants–that are more likely to sleep through the night, have less colic, fewer diaper changes, and less likely to have asthma, irritable bowel syndrome, and other conditions as older children, along with higher IQ, ferment B infantis.

And others. If these sorts of fermentation projects and benefits interest you, I invite you to get the Super Gut book in which I show you how to ferment each microbe: how to obtain, which strain, what temperature and how long to ferment.

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