Report From the LI Conference, part 21

We're in the final stretch of the conference, the Tuesday morning presentations, all of which were devoted to addressing the question "What Strategies Are Effective in Managing Individuals With Diagnosed Lactose Intolerance?"

To be honest, we didn't get much of an answer from the first presenter, although he covered some issues I wasn't familiar with, issues that touch on the answer tangentially.

Prebiotics and Lactose Intolerance
David S. Newburg, Ph.D.
Associate Professor of Pediatrics
Harvard Medical School
Director
Program in Glycobiology, Pediatric Gastroenterology and Nutrition
Massachusetts General Hospital

Prebiotics are any food component that promotes beneficial bacterial growth. I've covered them before, in Prebiotics and Probiotics, where I quoted a fuller definition:

Prebiotics ("before life") are nondigestible or fiber components of foods, usually complex carbohydrates that beneficially affect the host by stimulating the growth of intestinal bacteria. Certain bacteria prefer a particular prebiotic to use as a source of energy.

Lactose itself can be considered a prebiotic, because the changes in the bacteria that live in your colon from the types that ferment lactose and produce gas to the types that digest lactose and are symptom-free is certainly a beneficial change. If you read me regularly you know that the change usually requires both time and persistence. By having dairy in your diet regularly you can promote the beneficial bacteria. Or you can try taking probiotics - foods or medications that contain the good bacteria - and have them colonize your large intestine.

Why do you need to spend so much time on this? Dr. Newburg said that just introducing a new species of bacteria doesn't make a lasting change. Unless you keep reinforcing the switchover by constant application, your bacteria, known as your intestinal flora, go back to the way they were in a few days or weeks.

Report from the LI Conference, part 3

So where do you start a state of the science conference on lactose intolerance. At the beginning. Rimshot. But where's the beginning? Birth? Not early enough. How about with the fetus?

After the usual opening remarks, the conference began with an overview. Appropriately enough, the first presentation started with the basics.

Early Feeding, Human Milk, and the Transition
Josef Neu, M.D.
Professor of Pediatrics
Director of Neonatology Fellowship Training Program
Department of Pediatrics
Division of Neonatology
University of Florida College of Medicine

We're all designed to be introduced to lactose through mother's milk. That introduction happens shortly after birth. And that creates an unexpected dilemma. Since a fetus will never be exposed to lactose, there's no real reason for one to make any lactase. Yet that lactase has to be there and available when the mother's milk comes flowing in.

The body's response is to gradually ramp up lactase availability. Scientists first detect lactase at about 8 weeks of development. Even at 34 weeks, lactase is only at 30% of what will be needed.

That leaves about six weeks for it to reach the needed 100%. (Actually a tiny bit longer. Mothers make what is known as colostrum for the first couple of days of feeding, a special type of milk designed to add to and stimulate the infant's immune system. Colostrum is especially low in lactose.)

What about premature infants? They face a double whammy. Not only are they not fully developed but they are lacking in a critical enzyme to help digest the one food they can eat. No wonder that premature babies faced such long odds in the days before modern science.

Here's where the science gets weird. Despite all this, studies have shown that feeding lactose to premature infants will help them increase lactase levels faster. It's better to give them mother's milk than lactose-free formulas. (After a month or so, the difference disappears as the lactase-making ability increases naturally.)

Even weirder, the partial lactose intolerance that ensues is itself helpful. Some of the lactose reaches the colon, because there's not enough lactase to digest it all. Babies are born with sterile guts: no bacteria. The bacteria enter after birth because bacteria are everywhere and the world is far from sterile. Which bacteria are in the colon make all the difference. The presence of lactose selects for bacteria that are more beneficial. In other words, lactose acts as a prebiotic. "Prebiotics are non-digestible food ingredients that stimulate the growth and/or activity of bacteria in the digestive system which are beneficial to the health of the body."

Think about that. Food companies are spending millions to create prebiotics to add to foods to make them healthier. Humans do it naturally to help premature babies drink their mother's milk. Mind-boggling.

Making Sense of Yogurt Choices

An article by the American Institute for Cancer Research on FoodConsumer.org offers a quick tutorial on the multitude of claims that yogurts are making. Here's a shortened version.

Probiotics. All yogurts provide probiotics, live microorganisms (bacteria) that confer a wide range of potential health benefits. Research tentatively supports using probiotics to help resolve diarrhea and symptoms of irritable bowel syndrome, as well as to enhance immune system functions and reduce susceptibility to infections. But not all types of probiotic bacteria offer identical benefits. In the U.S., the starter bacteria for yogurt cultures (L bulgaricus and S thermophilus) have been shown to help with lactose intolerance, but research does not provide convincing evidence of the other proposed benefits.

Prebiotics. Several yogurt manufacturers now go a step further by adding prebiotics to their products. Prebiotics are carbohydrates that feed probiotic bacteria, supporting their growth or activity. Some types of dietary fiber are classified as prebiotics, but it’s not as simple as just looking for fiber on the Nutrition Facts panel. Prebiotics added to yogurt include inulin (made from chicory or table sugar), soy oligosaccharides and some types of maltodextrins and modified food starch. And don’t assume that prebiotics are listed on all labels; some yogurts contain one or more prebiotics without identifying the ingredient to the consumer. Other yogurts correctly note that they contain prebiotics, but each serving may contain only a quarter to a half of the amount that research identifies as effective.

Omega-3s and plant sterols. Omega-3 fats and sterols that promote heart health are now added to some yogurts. Omega-3 fat, which has received much attention for its purported role in reducing heart disease, is naturally abundant in fatty fish like salmon and mackerel. While yogurts fortified with omega-3s may convey some benefit, they often contain less than 10 percent of the amount found in a standard serving of salmon. Alternatively, many yogurts contain the plant form of omega-3s (the type of essential fatty acid supplied by flax), which does not seem nearly as potent as the compound found in seafood.