> Are you sure, Todd?  I know that grassfed beef contains ten times the
> beta carotene as grain fed.  Since the body can readily convert beta
> carotene to vitamin A, I'd think you'd be able to get more than
> sufficient amounts.  But I'd need to do the math.

Well, I'm never really sure of anything, but I accept the premise that
grassfed beef has a lot more beta carotene.  But the conversion to vitamin
A is lossy, and gets moreso as we age.  That may, of course, be due to
non-paleo diet and lifestyle, but I'm inclined to believe that getting
some dietary pre-formed vitamin A (and vitamin D) is important.  Although
we commonly think of vitamin A in terms of eye function, it is also very
important for immune system function and, interestingly, supports
testosterone production.  This is actually how I came to research it, a
couple of years ago.  Despite a pretty good paleo diet, at the time, a
routine checkup showed pretty low testosterone levels.  I was getting a
good amount of exercise too, so this seemed odd.  Since I was 53 and the
reading was at the low end of, but still within, the "normal" range (which
is quite wide), the doctor just shrugged.

I was unaware that sleep apnea also causes testosterone reduction, and
also unaware that I had severe sleep apnea, so looked around to see what I
could find out.  As you'd expect, the bodybuilding web sites have a lot of
info about testosterone boosting, and that's where I found the first
suggestion that vitamin A (not beta carotene) supplementation could help. 
I started using cod liver oil *and* pure vitamin A supplements, which are
dirt cheap anyway.  I was taking about 30,000 units a day.  About four
months later I had my levels checked again and they had tripled.  And
between then and now I haven't had a cold, a cough, a sniffle--nothing.

Of course, the other variable is the sleep apnea, which I found out about
a bit later, and have apparently had for a long, long time.  But that's
off-topic for this list.  My main point is that I think it's important to
get pre-formed vitamin A.  Weston Price thought so too, as I recall.

Todd Moody