From:
sukiec@optonline.net
Date: 2005-08-06 17:52:52 UTC
Subject: RE: Raw Meat Question
To: ferrethealth@smartgroups.com
Message-ID: <4567514.1123350772790.JavaMail.root@thallium.smartgroups.com>
When mentioning ancestral or wild aspects of living it is essential to remember this salient point of evolutionary research:
What is optimal for the ancestors is NOT necessarily optimal for any current day individuals who live longer than most of the ancestors do.
Selection works only on factors which affect reproductive and survival success rates.
That means that except in those populations where the elderly play a critical role in survival of their relative's children there simply is no selective pressure that encourage/assists becoming elderly.
The diet which may be optimal for an animal that most commonly dies young after a year or three of reproducing can not be necessarily assumed to be a diet that is also optimal for an older animal.
In some types of animals where there is the pressure of limited shared resources the most successful lines can even be those in which the non-reproducing adults die off rapidly. When the elderly die off in those species the young have more food and space for themselves, so in such situations the families with the most offspring which survive to reproduce can be those in which the kidneys can't take the protein load after a few years, or where infection or infestation can no longer be combated, or...
Yet, in our households we WANT to keep ferrets who are past the typical years of reproduction and we want those seniors who are past their prime to be active and healthy. This is a goal which has NOTHING to do with their ancestral selective pressures.
All sort of things change over time. The immune system is not as effective so the negative results of parasites or infections can be greater. The kidneys may begin showing effects that indicate that reducing protein (or at least phosphorus impact on them) may have a strong effect on survival. In animals from lines which have been going through selective breeding for things other than health there may introduced vulnerabilities in greater rates, such as those presented by oncogenes.
In humans what we can deal with in diet in our prime differs from what registered dieticians are finding in studies are optimal for older people, and dietary needs may be different again in the old-old. One point in relation to that, though: it has been postulated in multiple studies that it may be that those who reach old-old actually already are more sturdy genetically so diet may have far less of an impact on them than it has on the more vulnerable individuals. In fact, over and over again gerontology researchers say in relation to the incredibly old humans that they simply have so much won the genetic lottery that it almost doesn't even matter what they do to themselves in daily life.
The point is that it is overly simplistic to assume that ancestral diets are optimal for all ages of animals which survive outside the reproductive ages of those ancestral animals, though it may be optimal for some ages.
It is also overly simplistic to assume that each aspect of that ancestral diet is essential.
That is not a criticism. I do not assume that you assume any such things in your question, but there may be those who do.
Basically, at this stage in what we do NOT know, we all take what facts exist now as we find them, we remind ourselves of what is NOT known (which is huge), we look at the pros and cons, and we make our own choices as best we can (and in doing so we need to be fair and kind to those who make other choices because putting belief in where facts are missing is more suited to religion than it is to nutrition, physiology, or biochemistry).
Personally, I suspect that over time diets will be more engineered to the individual, both in terms of age and personal vulnerabilities. Right now except in the most obvious cases we simply don't have enough information to do that.
So, anyway, now you know one of the ways in which the "ancestral diet" argument simply doesn't apply.