CALIFORNIA AVOCADO ASSOCIATION 



25 



no means all, even of our commonest ones, furnish as much of the min- 

 eral nutrients as animals need." 



"Can it be that such an important matter as the provision of the 

 body with mineral nutrients has not been adequately provided for by 

 natural selective processes ? Have not animals' food-habits and digestive 

 processes been adapted to the provision of the body with all those nutri- 

 ents which it needs ? 



In a general way we may answer these questions in the affirmative, 

 but when we consider them with care we see many exceptions and quali- 

 fications becoming necessary. 



"It is doubtless true that in his aboriginal state man's food habits 

 provided his body with all those nutrients which his simple life required, 

 but civilization has set up new standards, unnatural ones in the sense that 

 natural selection has not been able to accomplish new adaptations as 

 fast as they were required by changed habits and so we find ourselves 

 living somewhat out of harmony with our physiological processes. 



"Civilization requires specialized efficiency, and so the organism is 

 put upon a strain by the severity of the tax upon some functions; cer- 

 tain it is that the twentieth-century American has need for more food 

 of a sort capable of developing his nervous system than had aboriginal 

 man. Indiscriminate eating may sustain life at low-pressure, but keen 

 competition and highly specialized activity call for definite adaptation of 

 the food, both as to kind and quality, to the necessities for nutriment." 



Time will not permit entering into detail regarding the use made by 

 the body of each of the different minerals above mentioned. The sulphur, 

 however, that is found in the protein in foods is mainly metabolized into 

 sulphuric acid, the phosphorus into phosphoric acid, etc. It is very nec- 

 essary that there be some base to take up or unite with these acids in 

 order to preserve the neutrality or faint alkalescence of the blood and 

 tissues. Many illustrations could be cited indicating that the continued 

 use of a so-called mineral-free diet will product acidosis resulting from 

 the lack of the base-forming elements in the food. A mineral-free diet 

 is one that consists of proteins, fats, and carbohydrates, but that has 

 been freed from mineral matter and leaves no appreciable residue on 

 burning in the air. Such a combination of foods is termed an acid- 

 forming diet because in the body there will be furnished from the metabol- 

 ism of proteins sulphuric and phosphoric acids. As stated by Sherman: 



"A diet in which the acid-forming elements greatly predominate must 

 result in a withdrawal of fixed alkalies from the blood and tissues or an 

 increased circulation of ammonia salts in the body, neither of which can 

 be regarded as advantageous. While such a diet is more or less habitual 

 with camivora and may not be dangerous to man, it must put upon the 

 body accustomed to a mixed diet a tax, which, however, small, might better 

 be avoided, especially as we have no reason to anticipate any disadvan- 

 tage from a predominance of base-forming elements, which if not used to 

 neutralize stronger acids, would take the form of bicarbonates and thus 

 aid in the maintenance of the normal and necessary neutrality or faint 

 alkalescence of the blood and tissues. It therefore seems desirable that 

 in constructing a dietary the foods in which the acid-forming elements 



