Tim Campbell wrote:
> Cod Liver Oil: The Number One Superfood-
> from natural-health-forum"at"yahoogroups.com-
> By Krispin Sullivan, CN- - -
>
> Cod liver oil contains more vitamin A and more vitamin D per unit
> weight than any other common food. One hundred grams of regular cod
liver
> oil provides 100,000 IU of vitamin A, almost three times more than beef
> liver
And that is a problem. High intake of retinol (vitamin A) is associated
with
reduced bone mineral density, increased fracture risk and osteo****osis.
The
fact that cod liver oil is also a good source of vitamin D does not
mitigate
the harmful effects of vitamin A. It has been confirmed in animal studies
that vitamin A reduces bone mineral density even when vitamin D intake is
sufficient. Serum retinol levels are also strongly associated with higher
fracture risk.
http://content.nejm.org/cgi/content/abstract/348/4/287
Here is a full study of a population where the use of cod liver oil is
quite
common.
http://www.annals.org/cgi/content/full/129/10/770
Couple of excerpts:
"We found a doubled risk for hip fracture (odds ratio, 2.1 [95% CI, 1.1 to
4.0]) with dietary intake of retinol greater than 1.5 mg/d compared with
intake less than 0.5 mg/d."
"In Norway, which has some of the highest incidence rates of hip fracture
ever re****ted, mean intake in the adult population is even higher: 1.5 to
2.0 mg of retinol equivalents per day. Why is the consumption of retinol
excessive in northern Europe? A possible explanation is a high consumption
of cod liver oil"
http://www.annals.org/content/vol129/issue10/images/large/3TT6.jpeg
According to the study by Melhus et al I mentioned above the mean intake
of
vitamin A in the Norwegean adult population was 1.5 to 2.0 mg of retinol
equivalents per day in 1997. (I guess this includes betacarotene as well.)
Norway where the cod liver oil is used frequently has the highest rate of
hip fractures in the world. "Recent dietary surveys have shown that
cod-liver oil supplements were used by around 35% of the population in
Norway and more than half of the eldest age group of the population
surveyed
(Johansson et al, 1997; Johansson & Solvoll, 1999)."
http://www.nature.com/ejcn/journal/v58/n1/full/1601759a.html
If we try to figure out the optimal intake of retinol from the point of
bone
health I think that the optimal retinol intake might be somewhere around
0.5
to 1.0 mg (although the confidence intervals are quite wide). One easily
exceeds that by cod liver oil use.
http://www.annals.org/content/vol129/issue10/images/large/3TT6.jpeg
Finally, this meta-analysis finds a slight _increase in mortality_ with
vitamin A supplementation, not very encouraging:
http://jama.ama-assn.org/cgi/content/abstract/297/8/842
For these reasons I think that the safest policy is to supplement with
fish
oil capsules and vitamin D3. Not cod liver oil.
--
Juhana
http://ruohikolla.blogspot.com/
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