Low Dose β-carotene Supplementation Diminishes Oxidative Stress in Type 2 Diabetics and Healthy Individuals

Effect of the Supplementation With β-carotene to Type 2 Diabetic Patients and Healthy Controls on the Iron Status and Antioxidant Capacity of Plasma

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.

Study Overview

• Status: Completed
• Conditions: Diabetes Mellitus; Iron Metabolism Disorders; Oxidative Stress
• Intervention / Treatment: Dietary supplement: Betacarotene; Dietary supplement: Controls. No treatment

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 Type: Interventional
• Enrollment (Actual): 117
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Venezuela
  • Lara
    • Barquisimeto, Lara, Venezuela
      • Hospital Baudilio Lara

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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:

• Hospitalized patient
• Diabetic patient with diabetes related acute complications (ketoacidosis, hyperosmolar coma)in the 3 months previous to the study.
• Individuals with infections that required antibiotics in the 3 weeks previous to the study.
• Individuals with antibodies anti-insulin, autoimmune diseases or in treatment with immunosuppressive drugs.
• Individuals with viral infections such as hepatitis B, hematological, renal or hepatic diseases.
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: NONE

Number of Arms

4

Arms and Interventions

Participant Group / 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: β-carotene as a soft gel capsule (GNC, Pennsylvania-USA)
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: No supplements
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: β-carotene as a soft gel capsule (GNC, Pennsylvania-USA)
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: No supplements

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Changes in oxidative status	Time 0, 45 days and 75 days after supplementation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hemoglobin and hematocrit		Time 0, 45 days and 75 days after supplementation
Ferritin	Enzyme linked immunosorbent assay (ELISA) with monoclonal antibodies	Time 0, 45 days and 75 days after supplementation
Iron metabolism markers	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.	Time 0, 45 days and 75 days after supplementation
Blood Chemistry	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.	Time 0, 45 days and 75 days after supplementation
Glycosylated Hemoglobin	It was determined using a commercial kit (Bioscience, Caracas, Venezuela),	Time 0, 45 days and 75 days after supplementation
Oxidized LDL	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.	Time 0, 45 days and 75 days after supplementation
Thiobarbituric Acid Reactive substances (TBARS)	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.	Time 0, 45 days and 75 days after supplementation
Ferric Reducing ability of Plasma (FRAP).	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.	Time 0, 45 days and 75 days after supplementation
Activities of the enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx).	Determined by commercial kits (Cayman Chemicals, Pittsburg) following the recommended protocols	Time 0, 45 days and 75 days after supplementation
Serum zinc and copper.	By flame atomic absorption spectrophotometry	Time 0, 45 days and 75 days after supplementation
β-carotene.	It was determined by HPLC, with a reverse fase C18 column.	Time 0, 45 days and 75 days after supplementation
Serum retinol	It was determined by HPLC, with a reverse fase C18 column, as an indirect measure of betacarotene metabolism.	Time 0, 45 days and 75 days after supplementation
Serum nitrites	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.	Time 0, 45 days and 75 days after supplementation
Serum and erythrocyte folates.	The method is based in the folate-dependent controlled growth of a Lactobacillus strain that is measured spectrophotometrically and quantified against a standard curve.	Time 0, 45 days and 75 days after supplementation

Collaborators and Investigators

• Sponsor: Instituto Venezolano de Investigaciones Cientificas
• Collaborators: 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

Publications and helpful links

General Publications

• Ford ES, Cogswell ME. Diabetes and serum ferritin concentration among U.S. adults. Diabetes Care. 1999 Dec;22(12):1978-83. doi: 10.2337/diacare.22.12.1978.
• 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. doi: 10.2337/diabetes.52.9.2346.
• 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. doi: 10.2188/jea.16.71.
• 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.

Helpful Links

• American Diabetes Association
• Instituto Venezolano de Investigaciones Cientificas

Study record dates

Study Major Dates

• Study Start: January 1, 2010
• Primary Completion (ACTUAL): December 1, 2010
• Study Completion (ACTUAL): December 1, 2010

Study Registration Dates

• First Submitted: November 15, 2011
• First Submitted That Met QC Criteria: November 18, 2011
• First Posted (ESTIMATE): November 22, 2011

Study Record Updates

• Last Update Posted (ESTIMATE): November 22, 2011
• Last Update Submitted That Met QC Criteria: November 18, 2011
• Last Verified: November 1, 2011

More Information

Terms related to this study

• Keywords: Antioxidants; Type 2 diabetes; Oxidants; β-carotene; Oxidative balance
• Additional Relevant MeSH Terms: Metabolic Diseases; Iron Metabolism Disorders; Physiological Effects of Drugs; Micronutrients; Vitamins; Provitamins; Beta Carotene
• Other Study ID Numbers: IVIC-HUMNUT-001