Clams and Heme (was Re: organic beer and ale)

[Guest guest]

Hi ,

> How would you suggest doing that -- replacing beef and lamb by weight,

> calories, or protein content? Do clams have roughly the same amount,

> or more? Are some types of clam more heme-rich than others?

I don't know, they probably are, but I haven't seen anything like that

in a database. I only looked at the USDA one a while back, which

showed clams having I think some 2-3 times as much heme iron as beef.

You could check nutritiondata.com to see if they have different

varieties.

> Do clams have the same types of heme that red meat does? Will it

> survive digestion, or will its constituents be readily recombined into

> heme?

As far as I know, there is only one type of heme, but I haven't really

seen anything that specifically addressed the issue.

Heme survives digestion and is absorbed into the intestinal enterocyte

in tact. However, according to an iron textbook chapter I just

finished, the heme is broken down in the enterocyte and the iron mixed

with nonheme iron. There is a heme-carrying protein in the blood

called hemopexin, but according to this chapter it is for carrying

heme released during hemolysis of RBC's, and even the heme it carries

is destroyed and the iron released.

I had seen data indicating that vegetarian diets boosted ferritin

levels but decreased hematocrit or other indicators of hemoglobin

synthesis, so I had assumed that the heme was more usable as heme per

se. But if this textbook chapter is correct, the data would probably

be explained by the presence of other nutrients in a meat-inclusive

diet that are used for heme synthesis.

In any case, heme iron is much more absorbable than other types of

iron, so it could be that your requirement is simply for iron per se.

So it would still be worth trying to substitute clams for a bit and

see if they satisfy your need.

Chris