Because of spam, I personally moderate all comments left on my blog. However, because of health issues, I will not be able to do so in the future.

If you have a personal question about LI or any related topic you can send me an email at I will try to respond.

Otherwise, this blog is now a legacy site, meaning that I am not updating it any longer. The basic information about LI is still sound. However, product information and weblinks may be out of date.

In addition, my old website, Planet Lactose, has been taken down because of the age of the information. Unfortunately, that means links to the site on this blog will no longer work.

For quick offline reference, you can purchase Planet Lactose: The Best of the Blog as an ebook on or Almost 100,000 words on LI, allergies, milk products, milk-free products, and the genetics of intolerance, along with large helpings of the weirdness that is the Net.

Friday, August 14, 2009

More on the History of Lactose Intolerance

Everything old is new again, as the ancient phrase goes. (Or is it ancient? I got sidetracked to do a search on that phrase's origin and I didn't find anything earlier than the song written by Peter Allen and Carole Bayer Sager in the film All That Jazz, which came out in 1979. Then I found a 1975 song on Anne Murray's Together album. And a search of Newspaper Archive reveals absolutely nothing before that? Shouldn't the phrase be far older?)

Geneticists have been plunging deep into the DNA of humans and multiple other species to search for the historic information that is encoded there.

Dave Munger, for example, wrote about the history of lactose tolerance in his new column in Seed magazine.

The researchers say the lactase gene evolved in Europe because Europeans don’t get enough sun to produce Vitamin D, which in turn is needed for humans to take in calcium. Since lactose also assists in the uptake of calcium, adult milk drinking helped northern Europeans meet that deficiency.

Gerbault’s team developed a computer model demonstrating that, in order for the adaptation to persist, lactose-tolerant northern Europeans would need to have 1.8 percent more children. In other words, milk drinkers would need to be more successful in reproducing—and this is indeed what is observed there.

That's cool, right? A startling bit of history revealed in our genes. A new understanding of the world.

Except it isn't. That "discovery" is merely an affirmation of knowledge that is now more than 30 years old. I wrote exactly the above scenario in my 1996 book Milk Is Not for Every Body, based on academic work existing and easily findable. Everything else covered in Munger's column is in my book as well. All I did was read the literature, which nobody today seems to bother to do.

DNA evidence is a marvel. Many roads to the truth exist, though, and even the crude methods of the past managed to ferret out some relationships that hold true today.

Never forget the past when you cast your eyes toward the future.

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