Answers to Questions from Readers, part 4

Q. I'm planning on going to Samoa soon, and I need to know if there is lactose in coconut milk, as it is used in most Samoan dishes.

Coconut "milk" is just the white liquid found in a coconut. None of the nut "milks" or nut "butters" have any real dairy content.

(A warning for non-travelers. In this country coconut milk is often processed with cow's milk. I doubt this is much of a problem in Samoa, but here it wouldn't hurt to doublecheck that you are getting pure coconut milk, not some canned processed variety.)

For a big fun list of such similar sounding foods, none of which contain the slightest amount of lactose, go to my The Better Look Twice List of Supermarket Products That Appear To Contain Milk -- But Don't! page.

Q. I have SLI (Secondary Lactose Intolerance) that I got from a really bad undiagnosed intestinal infection that left me severely intolerant two years ago. Yes, there are people like me out there who really can't tolerate anything more than one teaspoon of butter a day. We want to be acknowledged too!

And here's your acknowledgment!

It's true that I have my doubts that there are very many people out there with normal LI due to aging who cannot have even a speck of lactose. But here's a big BUT. But I've always made an exception for people with damage to their intestines; I know that their intolerance can be much worse than what happens with normal aging.

Avoiding all dairy projects is a project. I know, I did it for years before lactase pills came along. It can be done, and there are many more products around now to help you. Check out my Product Clearinghouse for info on dozens of them.

Q. Can you tell me what percentage of the population is Lactose Intolerant and if it is more prevalent in different ethnic groups?

My book, Milk Is Not for Every Body, has a listing that runs a full 15 pages, summarizing the results of dozens of such studies from around the world.

Very briefly, LI is most prevalent (up to near 100% levels) in East Asians, Native Americans and most Africans. It runs around 50% in people who live around the Mediterranean -- from Arabs and Jews to Romanians and Italians. The farther north one goes in Europe, the less likely you are to be LI. Scandinavians run no more than 5% LI.

The same holds true for this country. If your ancestors come from northern Europe, you are unlikely to be LI. If your ancestors come from places where LI is universal, you are likely to become LI yourself.

Nobody has ever done an LI survey of the entire U.S. population. (That 50,000,000 LI figure you see tossed around a lot is sheer meaningless extrapolation off of insufficient data.) But generally, the LI percentages for groups are similar to those of their ethnic ancestors.

This is already changing, however. Intermixing of the population is rapidly blurring these distinctions in this country. In another few generations LI will be mostly a thing of the past in the U.S.

Q. I have been reading that LI is mostly seen in certain regional areas and ethnic groups. Why this is so? Is it perhaps those individuals' diets do not consist of dairy products?

I cover this in detail in my book, Milk Is Not for Every Body, but here is as brief as explanation as possible.

In most places in the world, humans were able to get enough of certain important nutrients, especially calcium, without using dairy products. As people moved toward less hospitable climates, like northern Europe, those alternate sources were hard to come by. People who could have dairy products after the age of weaning had a reproductive advantage. Lactase persistence (LP), the ability to produce lactase as an adult, is a known dominant genetic mutation, so it would easily spread through a population.

Those who had the mutation in places where it was not necessary to eat dairy products to survive had no reproductive advantage and LP remained rare.

The oddest case is in Africa, where many tribes who live on the edges of the Sahara and other deserts survive for many months almost entirely on milk and nothing else. The almost total lack of other food generates as severe genetic pressure as one can imagine. These tribes are the only ones in Africa who are LP.

Q. I am Chinese and in my family, we eat a lot of vegetables, fish, and rice--non-dairy products. And in the last few years I have developed Lactose Intolerance. Did I develop LI because I stopped eating foods with lactose thus, my lactase enzyme was depleted?

Nope. The loss of lactase is genetically regulated only. Nothing that an individual does or doesn't do is known to change the rate of loss in any way.

There is some evidence that a person can reduce the symptoms produced by LI, however. LI symptoms are produced by the gases created when the bacteria in your colon ferment the undigested lactose. Some bacteria do this more than others and it would seem to be possible to encourage more of the ones that don't by regularly eating certain dairy products, yogurt in particular. Your lactase levels remain as low as ever, even so.