Management of dietary essential metals (iron, copper, zinc, chromium and manganese) by Wistar and Zucker obese rats fed a self-selected high-energy diet

Abstract

The balances and content of essential elements (iron, copper, zinc, chromium and manganese) in the body of Wistar, Zucker lean and Zucker obese rats fed a reference or cafeteria diet from day 30 to 60 after birth have been studied. Intestinal iron absorption compensated for low iron content of the cafeteria diet and the extra needs of growth and fat deposition. It can be assumed that the altered energy regulation processes that afflict the genetically obese rat are not directly related to altered iron metabolism. Obese Zucker rats had lower copper tissue concentrations than lean rats, but when fed a cafeteria diet the differences between Zucker rats strains disappear. This cannot be traced to large differences in diet copper concentration. A low diet availability of zinc--such as that of cafeteria-fed fa/fa rats--is easily compensated for by increasing absorption. So, as a consequence, we can conclude that genetic obesity did not impair zinc absorption. There was no deficit of zinc in any of the groups studied; the rats have enough capacity to extract zinc within a wide range of dietary concentrations. The absorption of dietary chromium was inversely proportional to its concentration. The ability to extract chromium from the diet and the very low urinary losses are a consequence of its scarcity in most dietary items. Despite wide variations in the manganese of the diets, the absorption rates were practically unchanged except for obese rats fed the cafeteria diet. It seems that this low absorptive capacity is enough to supply the rat with the manganese it needs, since a sizeable--but subjected to 8-fold-span variations--proportion is lost in the urine. This alone points towards a considerable excess of manganese in both diets studied. Obesity does not have a significant effect on the abilities to absorb and retain minerals, since these processes were more related to dietary availability. Management of essential metals by obese rats depends whether this condition is genetic or induced by diet. Most of the differences observed can be related to differences in diet concentration, to the excess fat content or different metabolic attitude to use substrates of obese animals. The data presented show that the cafeteria diet used adequately serves the mineral needs of the rat, since the rat adapts its absorbing and retaining strategies to match the dietary availability of these minerals.

Obesity and age-related alterations in the gene expression of zinc-transporter proteins in the human brain

“…Such increased zinc uptake occurred irrespective of the amount of food ingested, indicating that in this form of obesity, there is an altered intestinal absorption of zinc. 41 , 42 It is unclear whether this increased uptake of zinc has a causative role in this form of obesity, or is an epiphenomenon. A later study by Chen et al 43 did, however, find that zinc supplementation significantly increased body fat accumulation in both the ob/ob mice and the obese ICR mice.…”

Use of Alcalase in the production of bioactive peptides: A review

“…It is extensively known that nutritional disorders often come from a deficit in the intestinal absorption of metals which are essential for the organism [544,545]. To prevent it, many researchers have been trying to improve the chelating activity of functional foods increasing the bioavailability of these metals [546].…”

Dietary Interaction of High Fat and Marginal Copper Deficiency on Cardiac Contractile Function

“…However, whether copper deficiency results in the development of distinctive signs of lipotoxic dysfunction, such as accumulation of ceramide and triglycerides, alteration in NO, and nitrosative damage (6), has not been elucidated. Given that the lipotoxic model ( fa/fa obese rats) contains reduced tissue copper levels (21)(29), the aim of this study was to examine the concurrent impact of high‐fat diet and marginal copper deficiency on cardiomyocyte contractile function and intracellular Ca 2+ [Ca 2+ ] i handling. Isolated cardiomyocytes offer an immediate assessment of cardiac function independently of fibroblasts and connective tissues, although myocytes may lose the true in vivo physiological environment.…”