I ran across something interesting today on the Scientific
American webpage. I often wondered why I heard that technically everyone
is lactose intolerant, yet some have symptoms worse than others. For example,
my father MUST drink milk brands such as Soy, Silk, or Lactaid to prevent
whatsoever from happening upon consumption of regular processed milk. I on the
other hand do not.
According to the article, some time ago
during the last glacial period, it was only children who could drink milk due
to having the lactase enzyme that broke lactose down, "the main sugar in
milk". Adults who did not posses this critical enzyme could fall victim of
the toxin.
Thousands of years ago, a genetic mutation
took over Europe that essentially lead to a change that branched from children
to adults as well; this change resulted in the production of lactase. If this
is so, then technically everyone as a result of this genetic mutation should be
able to tolerate milk, more so lactose, right? If we as Americans were discovered
by Europeans, is it not a possible thought that this mutation was descended to
us now?
I believe, despite my father's need of
milk that helps those who are considered lactose intolerant, it may be a mind
over matter idea. Maybe, symptoms of what one might consider to be lactose
intolerant are exaggerated, and in all honesty no one suffers from it. Placebo
effect anyone?
Maybe a few things about this that are problematic…
ReplyDelete”If this is so, then technically everyone as a result of this genetic mutation should be able to tolerate milk, more so lactose, right?”
Not necessarily. Remember that every mutation begins in the germ line of a single person. People who live at the same time as that person won’t have the mutation, nor will their offspring until one of them reproduces with a person that has the mutation.
SO…if the mutation arose when the human population was very small, it would have a higher probability of having become fixed in the current population. However, when this mutation occurred, people had already migrated considerably and established populations around the globe.
“If we as Americans were discovered by Europeans, is it not a possible thought that this mutation was descended to us now?”
Do you mean that Americans were descended from Europeans? Can you clarify this statement?
I was trying to draw a connection as to how this mutation could have reached the Americas. When I said descended from Europeans, that was my way of showing that although Natives were here initially, Europeans discovered the New World thus taking claims as their home. With this in mind, the mutation, according to the article happened thousands of years ago, therefore was present when the Age of Discovery occurred. As time went on relations eventually between the Europeans, Natives, and later slaves was something not uncommon. I took this information and concluded that the mutation could have been passed down to offspring in that manner whether some express it or not.
DeleteDid that help clarify or made matters worse?
All clear. Thanks.
DeleteIn Alicia Silverstone's book The Kind Diet, she states that as many as 80 percent of African Americans, 90 percent of Asian Americans, and 60 percent of Hispanics are lactose-intolerant to some degree. She also states that those of us who can digest cow's milk are thought to have a genetic mutation that occurred thousands of years ago so we could survive on a herd's milk under harsh conditions.
ReplyDeleteI agree with you, it is to some degree. But are the symptoms as bad as death? Like I stated, prior to this mutation, it was lethal to consume milk as an adult. I am simply stating facts and then trying to draw a conclusion. From what Silverstone has stated, it seems as if the large group of people who are still considered to be lactose-intolerant are minorities. That actually is something interesting I would like to look further into. Thank you!
DeleteLactose isn't lethal even for those who don't carry the mutation. I can tell you from experience. It causes no small degree of discomfort, but isn't lethal.
DeletePlacebo effect typically refers to an improvement after taking a control in a medical study, a ‘sugar’ pill basically. There are definite measurable responses to the placebo and not just in someone’s mind. Maybe a more apt descriptor in the instance of seemingly exaggerating symptoms would include those people who maybe have some degree OCD or hypochondria. Many people now self diagnose, what with the state of health care today and the ease of information gathered from the internet. Also, if there are varying tolerances to lactose depending on individual biology, then maybe that is where the skepticism comes into play: they can eat cheese, but not drink milk? As an aside, there is a related genetic metabolic disorder, galactosemia, in which drinking milk can have severe consequences. http://ghr.nlm.nih.gov/condition/galactosemia
ReplyDeleteYou have presented information in such a way that I was attempting to! I totally agree with the skepticism, and I believe my own skepticism is the basis of my blog.
DeleteIn addition to this, you have mentioned something I did not take into consideration, galactosemia. Is it possible that these are the few rare people who did not receive the mutated gene, considering galactose is a branch of lactose?