Ben,
the $4000 lion story is a nice one.
Anyway I would very strongly support the concept of liver as an essential
nutrient for man, too. There surely are many vitamins and trace elements
contained in liver that make it a complement to meat (and milk in babies).
And there are continuously discovered new vitamin-like constituents, like
the RXR-receptor hormone phytanic acid [1,2].
But there is one component that alone makes liver essential for man under
paleolithic conditions: copper. Before science was pushed onto the
slippery greasy road, there has been much work on copper and
arteriosclerosis. You can look for Klevay, Leslie M, in medline and take
his papers as a starting point. It could be shown that copper deficiency
leads to arteriosclerosis in many animals, because the copper dependent
integrity of the internal elastic lamina (IEL), a thin elastic layer that
is separated by only one endothelial cell layer from blood, is crucial for
the development of intimal thickening. I can confirm this notion
completely from my own experiences. We are developing coronary stents. One
unsolved problem with these devices is the development of restenosis. In
many experimental setups 80% of the restenosis is to be explained by the
way, the stent tortures the IEL. The IEL is a protein polymer, polymerized
from monomers that are secreted by the surrounding cells. But the
polymerizing enzyme, lysyl oxidase (LOX), contains copper and its
production depends on copper supply [3]. Copper is needed for many
biochemical reactions, e.g. for the necessary jodide-oxidation in the
thyroid gland (EC 1.11.1.8, think of the thyroxin dependency of
cholesterol metabolism!) and the iron utilization for heme-production.
Milk produkts are free of copper (and iron). So babies cannot thrive on
milk if they have used up the maternal iron and copper deposits in their
liver, especially if already the mother was copper deficient. This is
experimentally proven in rodents [4]. Meat is copper deficient, too.
Rodents become copper deficient if fed with meat as the sole copper
source. Safe copper intake is 1,5-3 mg [5], but many western people have
less than 1 mg a day. But where does one get even this much from? Most
foods are poor in copper. Only some invertebrates (possibly because of
their hemocyanine-copper containing blue blood) and some nuts (cocoa)
contain enough of it, and - liver. But where did our hand-ax throwing
ancestors get their cocoa or shellfish from, living near the glacial edge
a million years ago? The only reliable copper source, at all times and at
all places humans could survive, was liver. Especially that of lambs and
other ruminants.
Do you remember that key scene in "Dances with Wolves?" After a long
period of famine the bisons came back and the first thing, the red man
took out of the first bison was the liver, offering it to the white man
as a sign of esteem.
There is at least one multicenter study (FOODCUE) on its way to look for
copper effects [6].
What the protein ceiling discussion concerns, it is quite usual for
bodybuilders to eat 5g/KgBW protein together with very low fat, e.g. 50%
of calories. Look at the end of the table at
http://www.gunters.net/Diets/DietsFsetG.htm
Prot: 619,8 g, 52%
Carb: 412 g, 35%
Fat: 69 g, 13%
kcal: 4823.
This is not unusual for a top body builder
(m = 134 kg, essentially muscle
http://www.gunters.net/Diets/DiaryMrO2001G.htm ).
But liver seems not a very typical foodstuff for body builders.
[1] McCarty M, The chlorophyll metabolite phytanic acid is a natural
rexinoid--potential for treatment and prevention of diabetes.
Med Hypotheses 2001 Feb;56(2):217-9.
[2] Heim M, Phytanic acid, a natural peroxisome proliferator-activated
receptor agonist, regulates glucose metabolism in rat primary
hepatocytes. FASEB J 2002 Mar 26.
[3] Rucker RB, Copper, Lysyl oxidase, and extracellular matrix protein
cross-linking. Am J Clin Nutr 1998;67(suppl):996S-1002S.
[4] Hunsaker HA, Marginal copper deficiency in rats; Atherosclerosis,
51(1984):1-19.
[5] Klevay LM, Lack of a RDA for copper may be hazardous to your health.
J Am Coll Nutr 1998;17(4):322-326.
[6] Turley E, Copper supplementation in humans .... FreeRadBiolMed 2000,
29(11): 1129-34.
roro
NNNN NNNN roland rohde, md, +49 (511) 906 35- Tel -03 FAX -69
NN N NN mailto:[log in to unmask]
NN N NN NN Leibniz Research Labs for Biotechnology
NN N NN and Artificial Organs (LEBAO)
NN N NN
NN NN Hannover Medical School (MHH)
NN http://www.mh-hannover.de
NN LEBAO Department of Cardiovascular Surgery
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