Source: {"pile_set_name": "USPTO Backgrounds"}

The importance of an adequate supply of trace elements zinc, chromium, manganese, iron and of the essential amino acid methionine in the diet of both animals and humans has long been recognized in the literature. Small amounts of trace minerals such as zinc, manganese and iron have also been documented as not only extremely important in dietary function, but for other reasons such as healthy skin, etc. It is common to feed animals such as domestic livestock feed supplements that contain essential amino acids and trace mineral mixes that contain zinc, manganese and iron.
It is also heretofore known that simply choice feeding of free essential amino acids, and conventional inorganic water soluble salts of zinc, chromium, manganese and iron is not the most efficient way for diet supplementation. This is true because neither the amino acid nor the transition metals are in their most bioavailable form in simple choice feeding of conventional simple salts such as zinc chloride, chromium chloride, manganese chloride, and iron chloride.
As a result of the above knowledge, the common assignee of the present application has in the past synthesized and patented certain 1:1 complexes of zinc, chromium, manganese and iron. See for example U.S. Pat. Nos. 3,941,818; 3,924,433: 3,950,372; 4,021,569; 4,067,994. Each of the above patents relate to 1:1 complexes of alpha amino acids, preferably methionine and of transition metals including zinc, chromium, manganese and iron. The complexes shown provided and claimed in the above patents are described as 1:1 complex salts because 1:1 complexes are more water soluble, are more bioavailable, and are more efficiently converted to provide maximum effective body usage of both the transition metal and the amino acid. Such has been demonstrated from data provided in some of the earlier referred to patents of the common assignee.
Each of the above patents describes, prepares and claims raecemic mixtures of the metal methionine complexed salts. That is to say the resulting salt as described is a 1:1 complexed salt which contains within the metal methionine complex, methionine that is a raecemic mixture of the D-form of methionine and the L-form of methionine. In recent times it has been discovered that only the L-form of methionine is bioavailable. In the past it has been believed that the D-form of methionine was converted to the L-form within the body's own biochemical systems. It is now known that this is not the case, and in fact the D-form of methionine is simply passed through and in effect wasted. This pass-through event carried along with it the associated transition metal such that it, too, is hither wasted or less efficiently utilized by the body system.
It has now been discovered that if the complexes are substantially pure L-form complexes, maximized bioavailability of both the transition metal such as zinc, chromium, manganese or iron, and the methionine is accomplished. As a result, dosages can be reduced by for example one-half the amount previously used, and the same bioavailability is achieved. The reason for this is simply that the supplement is in a 100% L-form, and therefore is 100% bioavailable.
Accordingly, it is a primary objective of the present invention to provide substantially pure 1:1 L-form transition metal methionine complexed salts of zinc, chromium, manganese and iron. By preparing only L-form the resulting compounds can be dosed in one-half the amounts now commonly used, and yet the same bioavailability and nutritional supplementation both from the standpoint of the amino acid and from the standpoint of the transition metal are achieved. Costs are reduced.
Another objective of the present invention is to provide a process of preparing substantially pure 1:1 L-form complexes of methionine with zinc, chromium, manganese and iron.
Another important objective of the present invention is to provide compositions for supplementation of diets of animals and humans which can be dosed up to 50% of the levels of the complexes previously known, and yet achieve the same levels of assimilation of zinc, chromium, manganese and iron and methionine into the body systems of the animal, as the earlier used higher doses of raecemic mixtures.
The method of accomplishing these and other objects will become apparent from the following description of the invention.