Antioxidant effect of amaranth flour or protein isolate incorporated in high-fat diets fed to Wistar rats. Influence of dose and administration duration.
Study Goal
The researchers aimed to evaluate the effects of amaranth flour and protein isolate on oxidative status in Wistar rats fed high-fat diets, focusing on intestinal and liver cells.
Results Summary
Amaranth flour and protein isolate showed dose- and time-dependent effects on oxidative stress biomarkers, increasing antioxidant activity (e.g., GSH, SOD, GPx) in intestinal cells but mixed effects in liver cells (some reductions in GSH and SOD but large increases in GPx). The effects were more pronounced at higher doses (50% protein replacement) and shorter administration (1 week).
Population
Wistar rats fed high-fat diets with added cholesterol and porcine fat.
Effective Dosage
25% or 50% protein replacement with amaranth flour or protein isolate.
Duration
4 weeks for most groups, 1 week for high-dose groups.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Chol+F+AF1 diet (25% protein replacement with amaranth flour) | increase | reduced glutathione (GSH) content in intestinal cells | Wistar rats | 56% | produced an increment | #1 |
Chol+F+AI2 diet (50% protein replacement with amaranth protein isolate) | increase | reduced glutathione (GSH) content in intestinal cells | Wistar rats | 39% | produced an increment | #2 |
Chol+F+AF2 diet (50% protein replacement with amaranth flour) | increase | superoxide dismutase (SOD) activity in intestinal cells | Wistar rats | 25% | induced an increment | #3 |
Chol+F+AF2 diet (50% protein replacement with amaranth flour) | increase | glutathione peroxidase (GPx) activity in intestinal cells | Wistar rats | 46% | induced an increment | #4 |
Chol+F+AF2 diet (50% protein replacement with amaranth flour) | decrease | superoxide dismutase (SOD) in liver | Wistar rats | 19% | produced a decrease | #5 |
Chol+F+AF2 diet (50% protein replacement with amaranth flour) | decrease | reduced glutathione (GSH) in liver | Wistar rats | 36% | produced a decrease | #6 |
Chol+F+AF2 diet (50% protein replacement with amaranth flour) | increase | glutathione peroxidase (GPx) activity in liver | Wistar rats | 255% | produced an increase | #7 |
Chol+F+AI1 diet (25% protein replacement with amaranth protein isolate) | decrease | reduced glutathione (GSH) in liver | Wistar rats | 36% | produced a decrease | #8 |
Chol+F+AI1 diet (25% protein replacement with amaranth protein isolate) | increase | glutathione peroxidase (GPx) activity in liver | Wistar rats | 273% | produced important increments | #9 |
Chol+F+AI2 diet (50% protein replacement with amaranth protein isolate) | decrease | reduced glutathione (GSH) in liver | Wistar rats | 24% | produced a decrease | #10 |
Chol+F+AI2 diet (50% protein replacement with amaranth protein isolate) | increase | glutathione peroxidase (GPx) activity in liver | Wistar rats | 2,900% | produced important increments | #11 |
This study evaluated the effect on Wistar rat's oxidative status of incorporating amaranth flour (AF) and protein isolate (AI) in increased-fat diets. Five of the groups were fed for 4 weeks with either BD (basal diet), Chol+F (2% cholesterol, 10% porcine fat), Chol+F+E (0.005% α-tocopherol), Chol+F+AF1 or Chol+F+AI1 (25% of protein replacement) diets. The other two groups were fed for 4 weeks with Chol+F and then 1 week with Chol+F+AF2 or Chol+F+AI2 diet (50% of protein replacement). Various effects on the oxidative stress biomarkers in tissues (intestine and liver) were observed. These effects were dependent on the ingredients, dose, and administration time. In the intestinal cells, Chol+F+AF1 and Chol+F+AI2 produced an increment in the reduced glutathione (GSH) content (56% and 39%, respectively), while Chol+F+AF2 induced an increment in the superoxide dismutase (SOD) (25%) and glutathione peroxidase (GPx) (46%) activities. The presence of certain components in flour (e.g., fiber, polyphenols, squalene) could explain the higher activity recorded for AF. In the liver, Chol+F+AF2 produced a decrease in SOD (19%) and GSH (36%), as well as an increase in GPx (255%); Chol+F+AI1 and Chol+F+AI2 also produced a decrease in GSH (36% and 24%, respectively) and important increments in GPx activity (273% for Chol+F+AI1 and 2,900% for Chol+F+AI2 ). These effects were dependent on the AI dose and were probably produced by absorbed peptides. PRACTICAL APPLICATIONS: It is known that redox imbalances are involved in the genesis of many chronic diseases. Therefore, it is possible to prevent them or limit their severity by improving the body's antioxidant defense mechanisms through dietary incorporation of antioxidant substances. The results suggest that amaranth protein isolate and amaranth flour have the potential for regulating intestinal and liver cells redox balance; effects were more evident when they contributed 50% of the diet's protein content and were administered for 1 week. Both amaranth ingredients could be used as ingredients in the development of functional foods with beneficial antioxidant properties.