ALLERGY HOTLINE COLUMNS
Babies and LI
I recently received an e-mail from a women whose doctor told her that her baby couldn't have Lactose Intolerance (LI) because breastmilk doesn't contain any lactose. Incredible as this may seen, it's not the first such letter I've gotten. Back to basics.
Human milk has the highest lactose content of any mammal's milk, about 7% on average. Other primates are next, followed by members of the horse family. Cows and their relatives have just under 5% lactose in their milks. Cold climate animals need higher concentrations of energy than sugar can provide. Reindeer milk is 22% fat and only 2% lactose. Sea lions have no lactose whatsoever in their milk, which is a full 35% fat.
Humans are genetically programmed to be able to survive and thrive on mother's milk for years, without any other food source, even though they are also programmed to lose this ability sometime after the age of weaning, what is known as Primary LI. At first glance, claims of babies being LI may therefore seem to be ridiculous. It's never quite that simple.
Some babies are born without any ability to manufacture the lactase enzyme that digests lactose. This condition, known as Congenital LI, used to be fatal before artificial non-milk formulas were developed. Indeed, the very first mention of LI in the medical literature came from a family in Britain, all of whose children had Congenital LI. Fortunately, this problem is exceptionally rare, with no more than a few hundred cases known worldwide.
Cases of Congenital LI should be quickly diagnosed, at least after the rather low-lactose colostrum is replaced by true milk. But Primary LI is a natural part of aging for most peoples around the world. The real question that needs to be asked is, how early can someone start naturally losing their lactase-making ability?
This is a tough question to answer. Barely a handful of LI studies have ever been done on infants. Those that have been done agree on two points. Babies under six months old do not test as being LI. But studies in Jordan, Tunisia, Nigeria, Thailand, and Bangladesh that include infants up to 18 months of age all show from 10-32% LI among their subjects.
Since infants everywhere can become what is known as Temporary LI due to damage to their intestines, even from a bad case of a gastrointestinal disorder like "stomach flu," it's impossible to know whether these infants were Primary LI or Temporary LI. But Lactose Intolerance at an extremely early age is hardly unknown. If your child starts showing signs of diarrhea, general gas and bloating, and foul-smelling stools it may very well be milk-related, even if you are still breastfeeding. A milk protein hypersensitivity is also possible, of course. Either way, you may need to convince your doctor that the problem is real and that tests are in order. Don't let offhanded ignorance on doctors' parts stand in the way of your child's health.