Let us say there is 1 pint of blood getting to the Brain each hour for the sake of conversation ?
Now in this 1 pint of Blood it may carry Less than 20% oxygen or it may carry more than 80% Oxygen for conversation sake ?
The Blood that carries 80% Oxygen to the brain may have a better chance of supplying the brain the Oxygen it needs vs blood that "Only" carries 20% Oxygen in it, would you not say ?
So, "IF" ones Blood is "ONLY" carrying 20% Oxygen it may need to have "4" times as much Blood to be pumped to the Brain as if the blood was carrying the 80% Oxygen levels ?
Thus it may be more Important as to the ratio of Oxygen the Blood is able to carry vs how much blood is being pumped to the brain ?
Do you start to see the Importance of Top Quality Blood, which is able to carry more Oxygen, because of "NOT" having too much Ammonia, which may Cause the Blood to "NOT" be able to carry the higher ratio of Oxygen in it ?
And because of the problem of Excess Nitrogen in the Isotope form of ammonia, being in the Blood, because of the Funny Proteins people are eating and thus causing Damage to the Liver etc, the Rabbit Hole just gets deeper !