Brazil Nuts Effects on Selenium Status and Cognitive Performance

Effects of Brazil Nuts Consumption on Selenium Status and Cognitive Performance in Older Adults With Mild Cognitive Impairment: a Randomized Controlled Pilot Trial

Some studies reported that selenium status is associated with cognitive function. However only a few reports have investigated whether selenium supplementation can benefit cognitive performance and in most of them selenium supplementation was not exclusive. Also, none of those reports have used foods rich in selenium as a source of supplementation. Thus, the aim of our study was to investigate whether the consumption of Brazil nuts improves cognitive function. We hypothesized that the daily consumption of Brazil nuts would have benefits on selenium status, increase antioxidant enzyme activity and improve cognitive function in older adults with MCI.

Study Overview

• Status: Completed
• Conditions: Mild Cognitive Impairment
• Intervention / Treatment: Dietary supplement: Brazil nut; Dietary supplement: selenium

Detailed Description

We enrolled older patients with MCI who attended the Memory and Aging Unit of the Geriatrics Division, University of São Paulo Medical School (Brazil). All participants fulfilled the criteria proposed by the International Working Group on Mild Cognitive Impairment (Winblad et al., 2004), which include the following: (1) the person is neither normal nor demented; (2) there is evidence of cognitive deterioration shown by subjective report in conjunction with objective cognitive deficits; and (3) activities of daily living are preserved and complex instrumental functions are either intact or minimally impaired. The diagnosis of MCI was based on a comprehensive neuropsychological assessment which included the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery (Welsh et al., 1994; Bertolucci et al., 2001). Participants were recruited from May 2011 to August 2012. Eligible subjects were aged 60 years or older, fluent in Portuguese, and free of any other significant neurologic or psychiatric diseases. None of them presented major depression or psychosis, had a regular intake of Brazil nuts, used supplements with selenium, or had intolerance to oleaginous food. An informed consent was obtained before the interview from all participants. The research protocol was approved by the Research Ethics Comittee of the Faculdade de Ciências Farmacêuticas da Universidade de São Paulo.

• Study Type: Interventional
• Enrollment (Actual): 31
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Brazil
  • SP
    • São Paulo, SP, Brazil, 05508000
      • University of Sao Paulo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 60 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• aged 60 years or older,
• fluent in Portuguese,
• free of any other significant neurologic or psychiatric diseases

Exclusion Criteria:

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control Group; This group did not receive any intervention.
Experimental: Treatment Group; This group took one Brazil nut daily during 6 months.	Dietary supplement: Brazil nut; Participants of the treatment group were instructed to take one Brazil nut daily during 6 months. Brazil nuts were supplied in 2-month allowances at no cost together with written nutritional information and a calendar to monitor the compliance. Compliance was monitored in intervals of 2 months by checking the calendar and counting returned nuts. Compliance was considered to be adequate if ≥85% of Brazil nuts were consumed. All subjects were instructed to maintain their normal diet and to avoid additional Brazil nuts during the study.; Dietary supplement: selenium

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Selenium level in plasma and erythrocyte	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
cognitive performance	Cognitive performance was measured by using six sub-testes from the CERAD neuropsychological battery have been administered to assess fundamental cognitive abilities.	6 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oxidative stress parameters	Oxidative stress was evaluated by measuring glutathione peroxidase activity, Oxygen radical absorbance capacity (ORAC) and Malondialdehyde (MDA).	6 months

Collaborators and Investigators

• Sponsor: University of Sao Paulo
• Investigators: Study Director: Silvia F Cozzolino, PhD, University of Sao Paulo

Study record dates

Study Major Dates

• Study Start: May 1, 2011
• Primary Completion (Actual): August 1, 2012
• Study Completion (Actual): August 1, 2012

Study Registration Dates

• First Submitted: April 21, 2014
• First Submitted That Met QC Criteria: April 22, 2014
• First Posted (Estimate): April 23, 2014

Study Record Updates

• Last Update Posted (Estimate): April 23, 2014
• Last Update Submitted That Met QC Criteria: April 22, 2014
• Last Verified: April 1, 2014

More Information

Terms related to this study

• Keywords: oxidative stress; cognitive performance; selenium; brazil nuts
• Additional Relevant MeSH Terms: Mental Disorders; Neurocognitive Disorders; Cognition Disorders; Cognitive Dysfunction; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Protective Agents; Trace Elements; Micronutrients; Antioxidants; Selenium
• Other Study ID Numbers: Doutorado-2014