When Is a Billion Not So Many?

Ellen Kanner of the McClatchy Newspapers writes a column called The Edgy Veggie. This week's is about foods with added probiotics.

There's even a probiotic cereal, Kashi Vive ($4.49, 12 ounces). It's whole grain (wheat, rye, triticale, brown rice, barley, buckwheat, oats plus freeze-dried broccoli sprouts) with a masterly 12 fiber grams per 1-\ cup serving.

Vive's probiotics come from cultured nonfat dry milk and yogurt, appearing as little white puffballs among the flakes. It's crunchy-munchy and mildly sweet, with 170 calories, 2.5 fat grams and a billion probiotics.

A billion's nothing, babe. Lifeway, your kefir king, has developed SoyTreat ($3.40, 32 ounces), an organic soy kefir with up to 10 billion probiotics per 8-ounce serving.

Kanner is clearly impressed by big numbers, and at first glance 10 billion sounds like a mighty big number.

It isn't. It's probably nowhere big enough.

The bacteria in cultures are incredibly tiny. Ten billion of them is less than a pinpoint. Spreading those ten billion out over eight ounces means that the number per gram - the more usual scientific measure - gives you a number too small to be impressive. I'll do the math. One ounce equals 28.375 grams. Eight ounces is 227 grams. That puts the count at about 44 million per gram.

For comparison I looked up some random yogurts and probiotic capsules to see what their counts were.

Dr. Thomas E. Radecki gave the results of tests on his Modern Psychiatry site:

Astro BioBest yogurt - 794 million live bacterial cultures per gram (175 grams per container or 139 billion per container

Organic Meadow yogurt - 100 million per gram

Danone yogurt 180 million per gram or 32 billion per container

These counts were for the freshest possible yogurt. You can assume that a minimum of two-thirds of the cultures will die off by the end of the shelf life printed on the carton.

Probiotics capsules have far higher concentrations. Of course they have to: you're only going to take one capsule, not eat a whole container.

A site called Custom Probiotics came up first in a Google search. These are merely their claims on their site, which I am using for comparison, not as an endorsement in any way.

1. L. Acidophilus, 150 billion per gram.
2. L. Rhamnosus 200 billion per gram.
3. L. Salivarius, 100 billion per gram.
4. L. Plantarum, 400 billion per gram.
5. B. Lactis, B. Bifidum or B. Infantis, 400 billion per gram.

44 million a gram? Piffle. These contain almost a thousand times as many.

So don't get taken in by mere large numbers. If you're not getting your probiotics by the multiple billions, you're probably not getting enough to do you any good.