Low Dose β-carotene Supplementation Diminishes Oxidative Stress in Type 2 Diabetics and Healthy Individuals
Study Details
Study Description
Brief Summary
Since diabetes has multiple etiologies and oxidative stress one of the proposed mechanisms, the objective is to determine the effect of supplementation with β-carotene to type 2 diabetics and healthy individuals, on iron metabolism, oxidative balance, and antioxidant plasma capacity, using doses similar to the daily nutritional requirement.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
N/A |
Detailed Description
Type 2 diabetes is a chronic, multifactorial disease, and oxidative stress one of the pathophysiological mechanisms associated with its appearance and development. The objective was to determine the effect of supplementation with β-carotene to type 2 diabetics and healthy individuals, on iron metabolism, oxidative balance, and antioxidant plasma capacity, using doses similar to the daily nutritional requirement.
A total of 117 volunteers participated in the study. Type 2 diabetics (34) and healthy individuals (24), received 6 mg β-carotene for 45 d, and were compared to similar non-supplemented diabetic (33) and control (26) groups. Blood samples were taken at the beginning, end and 30 days after finishing supplementation, to determine hemoglobin, hematocrit unsaturated iron binding capacity, total iron binding capacity, transferrin saturation, ferritin, glycemia, glycosylated hemoglobin, cholesterol, triglycerides, HDL, LDL, oxidized LDL, copper, zinc, TBARS, FRAP, nitrites, GPx, SOD, folates, retinol and β-carotene.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: Supplemented Diabetics (DB) Diabetics supplemented with betacarotene for 45 days |
Dietary Supplement: Betacarotene
6 mg betacarotene in caplets for 45 days (daily)and reevaluate parameters 30 days after finishing supplementation
Other Names:
|
| Experimental: Unsupplemented Diabetics (DS) Diabetics without betacarotene supplementation |
Dietary Supplement: Controls. No treatment
Evaluate at time 0, 45 days and 75 days, but without receiving betacarotene supplements
Other Names:
|
| Active Comparator: Supplemented Controls (CB) Controls supplemented with betacarotene for 45 days |
Dietary Supplement: Betacarotene
6 mg betacarotene in caplets for 45 days (daily)and reevaluate parameters 30 days after finishing supplementation
Other Names:
|
| Active Comparator: Unsupplemented Controls (CS) Controls without betacarotene supplementation |
Dietary Supplement: Controls. No treatment
Evaluate at time 0, 45 days and 75 days, but without receiving betacarotene supplements
Other Names:
|
Outcome Measures
Primary Outcome Measures
- Changes in oxidative status [Time 0, 45 days and 75 days after supplementation]
Secondary Outcome Measures
- Hemoglobin and hematocrit [Time 0, 45 days and 75 days after supplementation]
- Ferritin [Time 0, 45 days and 75 days after supplementation]
Enzyme linked immunosorbent assay (ELISA) with monoclonal antibodies
- Iron metabolism markers [Time 0, 45 days and 75 days after supplementation]
Serum iron, total iron binding capacity (TIBC) and unsaturated iron binding capacity (UIBC) were determined by the methods proposed by the International Committee of Standardization of Hematology.
- Blood Chemistry [Time 0, 45 days and 75 days after supplementation]
Glycemia, triglycerides, total cholesterol, LDL, and HDL were determined automatically in a Ciba Corning 550 Express autoanalizer, using classic enzymatic methods for the determination of these variables.
- Glycosylated Hemoglobin [Time 0, 45 days and 75 days after supplementation]
It was determined using a commercial kit (Bioscience, Caracas, Venezuela),
- Oxidized LDL [Time 0, 45 days and 75 days after supplementation]
Analyzed by a solid phase two-site enzyme immunoassay from Mercodia (Sweden), which contains 2 monoclonal antibodies directed against separated antigenic determinants on the oxidized apolipoprotein B molecule.
- Thiobarbituric Acid Reactive substances (TBARS) [Time 0, 45 days and 75 days after supplementation]
Were detected by the quantification of malondialdehyde present in the sample, by reacting 2 molecules of thiobarbituric acid with 1 molecule of malondialdehyde, which produces an abduct that is detected at 535 mn.
- Ferric Reducing ability of Plasma (FRAP). [Time 0, 45 days and 75 days after supplementation]
Measured after 4 and 10 min incubation, was used to determine the ability of plasma to reduce iron from ferric to ferrous state, based on the formation of a triazine-Fe+3 complex, that when reduced to Fe+2, generate a change in color that is measured at 593 nm.
- Activities of the enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx). [Time 0, 45 days and 75 days after supplementation]
Determined by commercial kits (Cayman Chemicals, Pittsburg) following the recommended protocols
- Serum zinc and copper. [Time 0, 45 days and 75 days after supplementation]
By flame atomic absorption spectrophotometry
- β-carotene. [Time 0, 45 days and 75 days after supplementation]
It was determined by HPLC, with a reverse fase C18 column.
- Serum retinol [Time 0, 45 days and 75 days after supplementation]
It was determined by HPLC, with a reverse fase C18 column, as an indirect measure of betacarotene metabolism.
- Serum nitrites [Time 0, 45 days and 75 days after supplementation]
Were determined as an indirect measure of the concentration of nitric oxide, since nitrites are the stable end products of its degradation. Nitrates were reduced to nitrites by activated cadmium. Then sulfanilamide and nitrites generate a chromophore that reacts with naftilethylenediamine, to generate a product visible at 540 nm.
- Serum and erythrocyte folates. [Time 0, 45 days and 75 days after supplementation]
The method is based in the folate-dependent controlled growth of a Lactobacillus strain that is measured spectrophotometrically and quantified against a standard curve.
Eligibility Criteria
Criteria
Inclusion Criteria:
Patients with a diagnose of Type 2 diabetes mellitus of at least 5 years of diagnosis, in treatment with oral hypoglycemics Patients in regular control (once a month) in the Hospital
Exclusion Criteria:
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Hospitalized patient
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Diabetic patient with diabetes related acute complications (ketoacidosis, hyperosmolar coma)in the 3 months previous to the study.
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Individuals with infections that required antibiotics in the 3 weeks previous to the study.
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Individuals with antibodies anti-insulin, autoimmune diseases or in treatment with immunosuppressive drugs.
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Individuals with viral infections such as hepatitis B, hematological, renal or hepatic diseases.
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Pregnancy
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Hospital Baudilio Lara | Barquisimeto | Lara | Venezuela |
Sponsors and Collaborators
- Instituto Venezolano de Investigaciones Cientificas
- Seguros Caracas Foundation
- National Fund for Science and Technology, Science Mission
Investigators
- Study Director: Maria N Garcia-Casal, PhD, Instituto Venezolano de Investigaciones Cientificas
- Principal Investigator: Jose M Moreno, PhD, Instituto Venezolanode Investigaciones cientificas
Study Documents (Full-Text)
None provided.More Information
Additional Information:
Publications
- Ford ES, Cogswell ME. Diabetes and serum ferritin concentration among U.S. adults. Diabetes Care. 1999 Dec;22(12):1978-83.
- Ford ES, Mokdad AH, Giles WH, Brown DW. The metabolic syndrome and antioxidant concentrations: findings from the Third National Health and Nutrition Examination Survey. Diabetes. 2003 Sep;52(9):2346-52.
- Song Y, Cook NR, Albert CM, Van Denburgh M, Manson JE. Effects of vitamins C and E and beta-carotene on the risk of type 2 diabetes in women at high risk of cardiovascular disease: a randomized controlled trial. Am J Clin Nutr. 2009 Aug;90(2):429-37. doi: 10.3945/ajcn.2009.27491. Epub 2009 Jun 2.
- Sugiura M, Nakamura M, Ikoma Y, Yano M, Ogawa K, Matsumoto H, Kato M, Ohshima M, Nagao A. The homeostasis model assessment-insulin resistance index is inversely associated with serum carotenoids in non-diabetic subjects. J Epidemiol. 2006 Mar;16(2):71-8.
- IVIC-HUMNUT-001