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Lactose intolerance

  1. Dec 20, 2003 #1
    I was trying get more info about what causes lactose intolerance (caused by mutation or by inherited mutations?)
    and came across this link: http://www.eurekalert.org/pub_releases/2002-01/uoc--uaf011402.php which is part of what Dr. Peltonen was discussing in the 30 min. lecture link. (UCLA and Finnish scientists) My american ears haven't adjusted to her thick accent yet. That pedigree chart she had went back what about 500 years? That's a serious chunk of work. There's a lot of info to digest in that lecture.

    I think she said everyone was originally lactose intolerant- lactose tolerant was the mutation and lactose intolerant was original. The ancient human population in Africa couldn't tolerate milk before the humans migrated out of Africa. The a mutation hit the genome allowing a fraction that were lactose tolerant. This variant became more frequent in populations that were high users of dairy products. (selective advantage when humans started using the dairy products)
     
  2. jcsd
  3. Dec 20, 2003 #2
    Do not understand what difference it makes anyway. Milk was meant for infants - not adults. There is absolutely NO reason for adults to drink milk. There are so many better choices for protein and calcium. Save the milk for babies.

    Nautica
     
  4. Dec 20, 2003 #3
    I second that Nautica.. milk makes me sick! (literally :wink: )
     
  5. Dec 21, 2003 #4

    Monique

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    Well, the interesting thing is that everyone is lactose tolerant as a child, but a large proportion of the population looses that tolerance when they age.

    There thus certainly is a mechanism at work which prevent adults from steeling milk from children. That is probably why lactose intolerance was the norm so long ago.

    The interesting thing is that today blacks and asians have the highest percentage of lactose intolerance. It would indicate that a. the mutation took place after coming out of Africa and when the asians already had migrated to the East or b. that Asians and Africans never cultivated dairy farm and thus never got the required selection of the mutation.

    It is an interesting example though, how a mutation in a gene created a phenotype that was beneficial for survival: evolution at work

    Nautica, the ability to drink milk has played a large role in survival, maybe not that much today but certainly in the past. It is still a good source for nutrients, since a mother wants to give a baby the best material right?
     
  6. Dec 21, 2003 #5

    iansmith

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    There some african tribes with a diet based on milk. The masai is a good example
     
  7. Dec 21, 2003 #6

    Monique

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    Yes, but is that example an exception or a rule?
     
  8. Dec 21, 2003 #7

    iansmith

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    I know there a couple of other african group that have diet based mostly on milk but they tend do be concentrated round the dessert and plains in ethopia, kenya, somalia. I just can find my notes. Also I don't know the lactose tolerant:intolerant ratio. Maybe they have a high level of intorelance.

    The problem is to find what is the exception and what is the rule.
     
  9. Dec 21, 2003 #8
    Monique,

    While I agree that milk is "the best" source of nutrients for infants (due to the enzymes which allow them to digest milk properly), it has no place in the diet for adult humans. Let me qualify that statement, one should not think that they must have X number of servings of milk per day in order to have a healthy diet.

    Whole milk is loaded with fat and all that skim milk has to offer is a small portion of calcium and some protein - but most of the protein is not digested due to curdling; therefore it is of no use.

    I am not saying that there are not needed nutrients in milk, what I am saying is that there are much better choices. For example, for calcium - green leafy veggies and for protein there are endless choices.

    The slogan should be changed to:

    "Milk - it does the BABY good."

    Nautica
     
  10. Dec 21, 2003 #9

    Monique

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    What do you say about the following nutritional values of milk?
    http://www.milknutrition.org/media/milkfacts/nutrients_in_milk.html

    1% milk is supposed to have the same elements, just without the fat. Here is what the National Institute of Child Health and Human Development has to say:

    http://www.nichd.nih.gov/milk/whymilk/milk.cfm

    But green, leavy vegetables are a good replacement, but does an average person eat enough of those? And how readily is the calcium taken up from that source? But in general for the grown up population I guess you are right.
     
    Last edited: Dec 21, 2003
  11. Dec 21, 2003 #10

    selfAdjoint

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    Just went to a new doctor (I am 70). He says umm - calcium in your diet, do you drink milk? I say I used to have skim milk with breakfast, but quit because it gives me a blood sugar spike (I am a diabetic, type II). He says put some skim milk in your diet.
     
  12. Dec 21, 2003 #11

    Monique

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    You could also just eat some calcium supplement pills with added Vit.D, instead of taking milk which influences you negatively..
     
  13. Dec 21, 2003 #12
    Skim milk does have the same nutritional value as whole milk, which is not alot, especially after considering pasturazation techniques.

    You ask if the average person eats enough green leafy vegtables. Probably not, but the average person eats too many cheeseburgers and I can't do anything to fix that either.

    The calcuim is taken up just fine so long as the body has a sufficient amount of vitamin D, which 15 minutes per day in the sun will take care of. If a person needs more, calcium supplements are cheap.

    As far as the statement about a doctor telling his patient to include milk. Visit some of the medical school websites and see how many hours of nutrition a doctor has. At the most it is 3 hours and that is usually an elective. Doctors specialize in taking care of the sick not preventing people from getting sick.

    Nautica
     
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