jfinlay at nyx10.cs.du.edu
Sun Mar 5 02:04:18 EST 1995
I was interested in the post on uptake of calcium and
vit D and osteoporosis, etc. I was a graduate student
in a vitamin D lab. Milk among other foods contains
calcium which is important for properbone formation an
maintainance. The active form of vit D acts on the
intestine to increase calcium uptake. It is not known
if simply injesting mor calcium will actually increase
bone strenghth since calcium uptake is highly regulated
and the blood levels of calcium must remain constant.
My thesis advisor, Hector DeLuca told me that he feels
calcium supliments probably won't do any good. However
it is known that weight bearing exercise will help
streghthen bones. This is probably becasue this causes
microfractures in the bones. When the bones are
subsequenly remodeled by the bone reforming cells this
makes the bones more strong. So for older women exercise is probably more
important thant calcium suppliments and most of us are not vitamin D
deficient. However ther was one study that showed that highschool girls
given Ca supplements had a higher bone density when they reached their
mid 20s. It is not yet know if these women will be less likely to
jet14 at columbia.edu (J Thompson) writes:
>On Feb 16, Kristine <k.vaaler at ic.ac.uk> **my other post had this wrong** wrote:
>>As much as I am aware of, the problem with skimmed milk is that it *does*
>>contain calcium, but not the fat soluble vitamin (cannot remember whether it is
>>A or D) that is required for an efficient absorption of the calcium.
>Well, if you were to just skim the fat off of milk and drink it, you would
>lose _both_ the vitamin A and the vitamin D which are normally present in
>cow's milk (the vit. D is what you need to best absord calcium). However,
>the USDA thought of that a long time ago, and requires anyone who processes
>skim milk to re-add the A and D which had been lost (you can read the exact
>amount off of any carton of skim milk). Now, to be really nitpicky, by doing
>that, they also add in a tiny amount of fat for the vitamins to float in,
>but 'dietarily' that fat doesn't add up to anything.
>>It seems there is a good reason that fat is present in milk in the first place.
>While the fat in milk carries the fat-soluble vitamins, it's really there as
>a compact energy source. If you look at the new food labels, sugars and
>proteins both give 4 Cal/gram, while fats give 9. Thus, if you want to give
>a growing baby energy without requiring it to spend even _more_ of it's time
>eating, then it makes sense to load it's food with fat. Once we grow up,
>however, that much energy from fat isn't so good for us (thus the benefit of
>skim or 1% milk).
>J Thompson jet14 at columbia.edu
> Class of 1997, Columbia University P&S (a.k.a. Columbia Med)
>Avoid strong drink. It can make you shoot at a tax-collector... and miss!
> -Lazarus Long (Robert A. Heinlein)
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