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Completed

NCT Number: NCT01477112

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

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.

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Key information

Conditions

Diabetes Mellitus Diabetes Mellitus, Type 2 Endocrine System Diseases Glucose Metabolism Disorders Iron Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases Oxidative Stress

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Hospital Baudilio Lara

Barquisimeto, Lara, Venezuela

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Betacarotene

Dietary Supplement

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)

Controls. No treatment

Dietary Supplement

Evaluate at time 0, 45 days and 75 days, but without receiving betacarotene supplements

Other names: No supplements

Primary outcomes

  1. Changes in oxidative status

    Time frame: Time 0, 45 days and 75 days after supplementation

Secondary outcomes

  1. Hemoglobin and hematocrit

    Time frame: Time 0, 45 days and 75 days after supplementation

  2. Ferritin

    Time frame: Time 0, 45 days and 75 days after supplementation

    Enzyme linked immunosorbent assay (ELISA) with monoclonal antibodies

  3. Iron metabolism markers

    Time frame: 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.

  4. Blood Chemistry

    Time frame: 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.

  5. Glycosylated Hemoglobin

    Time frame: Time 0, 45 days and 75 days after supplementation

    It was determined using a commercial kit (Bioscience, Caracas, Venezuela),

  6. Oxidized LDL

    Time frame: 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.

  7. Thiobarbituric Acid Reactive substances (TBARS)

    Time frame: 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.

  8. Ferric Reducing ability of Plasma (FRAP).

    Time frame: 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.

  9. Activities of the enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx).

    Time frame: Time 0, 45 days and 75 days after supplementation

    Determined by commercial kits (Cayman Chemicals, Pittsburg) following the recommended protocols

  10. Serum zinc and copper.

    Time frame: Time 0, 45 days and 75 days after supplementation

    By flame atomic absorption spectrophotometry

  11. β-carotene.

    Time frame: Time 0, 45 days and 75 days after supplementation

    It was determined by HPLC, with a reverse fase C18 column.

  12. Serum retinol

    Time frame: 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.

  13. Serum nitrites

    Time frame: 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.

  14. Serum and erythrocyte folates.

    Time frame: 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.

Sponsors and collaborators

Lead sponsor

Instituto Venezolano de Investigaciones Cientificas

Other

Collaborators

  • National Fund for Science and Technology, Science Mission
  • Seguros Caracas Foundation

Registry information

Official study title

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

Important dates

Study start
2010
Primary completion
2010
Study completion
2010
First posted
Nov 22, 2011
Registry last updated
Nov 22, 2011

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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