The Effects of Dietary Iron and Capsaicin on Hemoglobin, Blood Glucose, Insulin Tolerance, Cholesterol, and Triglycerides, in Healthy and Diabetic Wistar Rats

<div><p>Objective</p><p>Our aim was to assess the effects of dietary iron, and the compound capsaicin, on hemoglobin as well as metabolic indicators including blood glucose, cholesterol, triglycerides, insulin, and glucose tolerance.</p><p>Materials and Methods</p><p>Our animal model was the Wistar rat, fed a chow diet, with or without experimentally induced diabetes. Diabetic males were fed control, low, or high-iron diets, the latter, with or without capsaicin. Healthy rats were fed identical diets, but without the capsaicin supplement. We then measured the parameters listed above, using the Student t-test and ANOVA, to compare groups.</p><p>Results</p><p>Healthy rats fed a low-iron diet exhibited significantly reduced total cholesterol and triglyceride levels, compared with rats fed a control diet. Significantly reduced blood lipid was also provoked by low dietary iron in diabetic rats, compared with those fed a control diet. Insulin, and glucose tolerance was only improved in healthy rats fed the low-iron diet. Significant increases in total cholesterol were found in diabetic rats fed a high-iron diet, compared with healthy rats fed the same diet, although no statistical differences were found for triglycerides. Hemoglobin levels, which were not statistically different in diabetic versus healthy rats fed the high-iron diet, fell when capsaicin was added. Capsaicin also provoked a fall in the level of cholesterol and triglycerides in diabetic animals, versus diabetics fed with the high iron diet alone. In conclusion, low levels of dietary iron reduced levels of serum triglycerides, hemoglobin, and cholesterol, and significantly improved insulin, and glucose tolerance in healthy rats. In contrast, a high-iron diet increased cholesterol significantly, with no significant changes to triglyceride concentrations. The addition of capsaicin to the high-iron diet (for diabetic rats) further reduced levels of hemoglobin, cholesterol, and triglycerides. These results suggest that capsaicin, may be suitable for the treatment of elevated hemoglobin, in patients.</p></div

Effects of a low-iron diet on healthy rats.

<p>Healthy rats were analyzed after 8 weeks on a low-iron diet (n = 10), or control diet (n = 10). (A) Cholesterol levels. (B) Triglyceride levels. (C) Hemoglobin levels. (D) Area under the insulin tolerance test curve. E) Area under glucose tolerance curve. Bars represent the mean and standard error; p-values assessed with Student’s t-test; *p< 0.05, **p< 0.001.</p

Effects of a high-iron diet, with or without capsaicin, on rats with STZ-induced diabetes.

<p>Diabetic and healthy rats were analyzed after 4 weeks on a high-iron diet (n = 10), or a high-iron diet plus capsaicin (3mg/kg body weight/day) (n = 10) (A) Cholesterol levels. (B)Triglyceride levels. (C) Hemoglobin levels. Bars represent the mean and standard error; p- values assessed with ANOVA. For (A) p < 0.05 when comparing group 1 <i>vs</i>. groups 2, and 3; for (B) p < 0.001 when comparing group 2 <i>vs</i>. group 1, and 3 (C) p < 0.001 when comparing group 2 <i>vs</i>. groups 1, and 3. ** p < 0.001, *p < 0.05.</p

Effects of a low-iron diet on rats with STZ-induced diabetes.

<p>Diabetic rats were analyzed after 8 weeks on a low-iron diet (n = 8), or a control diet (n = 8). (A) Cholesterol levels. (B) Triglyceride levels. (C) Hemoglobin levels. (D) Area under insulin curve. (E) Area under glucose tolerance curve. Bars represent the mean and standard error; p-values assessed with Student’s t-test; *p < 0.05.</p

Study design.

<p>Study design.</p

Diabetic and healthy rats fed with high iron diet plus capsaicin.

<p>p value from paired Student t-test at the beginning and at the end of intervention. The dose of capsaicin used was 1 mg/kg body weight/day administered subcutaneously. Initial refers to values before intervention. Final refers to values after 4 weeks of intervention. To confirm the effects of diabetes on hemoglobin in the high-iron group, an additional group of seven rats were tested; those data have been added ^£n = 17. The paired Student t-test was calculated with the lower n indicated at the top of the Table. In diabetic rats plus capsaicin the differences between initial and final values corresponds to death of one rat. In healthy rats with high iron the missing values at the beginning were due to technical difficulties in the measurements.</p

Standard control diet^¥.

<p>The high-iron diet consists of 200 mg iron/kg diet (standard control diet) plus 3 mg polymalthosed iron, administered orally.</p