Dietary Intake of Whole Walnuts in Adult Subjects Under Low Cardiovascular Risk

NCT ID: NCT03227497

Last Updated: 2017-07-24

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 52 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-04-21
• Study Completion Date: 2017-07-15

Brief Summary

This cross-over study investigates health effects of dietary intake of whole walnuts towards cardiovascular risk factors in adults under low cardiovascular risk.

Investigators hypothesize that daily intake of whole nuts as a replacement meal, would improve cardiovascular risk factors, including traditional risk factors and molecular biomarkers.

The participants are randomly assigned to receive either study treatment, or no treatment, and are crossed after five weeks.

The study subjects are instructed to continue with their habitual diet and physical activity.

Detailed Description

Recent literature data raise important questions on the beneficial effect of dietary fats. Dietary intake of nuts, although with high caloric burden, is however characterized with high intake of fatty acids with known beneficial health effects. Those fatty acids include mono- (MUFA) and polyunsaturated fatty acids (PUFA), to whom beneficial health effects are ascribed.

Among nuts, walnuts are characterized with comparatively high levels of MUFA and PUFA, especially content of alpha-linolenic PUFA, considered essential fatty acid, since not synthesized endogenously in humans. Dietary intake of alpha-linolenic acid is shown to be inversely related with cardiovascular risk factors, both in interventional studies and epidemiological cohorts. Molecular background of alpha-linolenic actions is bidirectional, and includes the action itself, as well as beneficial endogenous conversion towards long-chain fatty acids, including eicosapentaenoic and docosahexaenoic fatty acid.

Although high caloric intake is indicated with intake of walnuts, literature data suggest that consumption of walnuts does not increase body weight.

Dietary intake of walnuts has been shown to decrease cholesterol fractions, triglycerides and apolipoproteins in adult population. Also, consumption of walnuts was associated with decrease in blood pressure.

The study design is cross-over, controlled, randomized nutritional intervention. The participants are randomly assigned to receive either study treatment, or no treatment, and are crossed after five weeks.

The study subjects are instructed to continue with their habitual diet and physical activity. Additionally, study subjects are instructed to avoid walnuts and nuts other then study treatment, during the complete study period of 10 weeks.

Sample size calculation was conducted by use of online calculators, and was based on the low density lipoprotein (LDL) cholesterol. Namely, in order to achieve decrease in 0.5 mmol/L, in a sample with projected standard deviation of 0.7 mmol/L, and type I and II errors being 0.2 and 0.05, respectively, 62 subjects are needed.

Conditions

Cardiovascular Risk Factor; Metabolic Syndrome; Hypertension

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

Walnut

At the beginning of the study, subjects are randomly assigned to receive either intervention treatment (whole walnuts) or no treatment (control arm).

Treatment arm includes 56 g of whole walnuts daily.

Group Type: ACTIVE_COMPARATOR

Whole Walnuts

Intervention Type: DIETARY_SUPPLEMENT

Intervention arm includes whole walnuts taken as dietary replacement meal during the day, and between breakfast and lunch, and/or lunch and dinner. Importantly, none of the main meals, including breakfast, lunch and dinner are to be replaced by study intervention, and the study subjects are instructed to do so. Walnuts are provided with the same producer at the Belgrade market.

Control

At the beginning of the study, subjects are randomly assigned to receive either intervention treatment (whole walnuts) or no treatment (control arm).

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

Whole Walnuts

Intervention arm includes whole walnuts taken as dietary replacement meal during the day, and between breakfast and lunch, and/or lunch and dinner. Importantly, none of the main meals, including breakfast, lunch and dinner are to be replaced by study intervention, and the study subjects are instructed to do so. Walnuts are provided with the same producer at the Belgrade market.

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

Inclusion Criteria

Presence of at least one of the following criteria, formerly assessed through routine medical examination:

• dyslipidemia, defined as the presence of either: elevated total cholesterol (>5.2 mmoL/L), and/or elevated LDL-cholesterol (>3.4 mmoL/L), and/or elevated triglycerides (>1.7 mmoL/L), and/or decreased HDL-cholesterol (<1.6 mmoL/L)
• elevated blood pressure (systolic/diastolic ≥120/80 mmHg), or regular anti-hypertension therapy

Exclusion Criteria

• presence of allergy on any nuts
• presence of any chronic disease, excluding following conditions: hypertension and diabetes mellitus type 2
• smoking
• statin therapy
• pregnancy and/or lactation

• Minimum Eligible Age: 30 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Centre of Research Excellence in Nutrition and Metabolism

UNKNOWN

Sponsor Role: collaborator

University of Belgrade

OTHER

Sponsor Role: lead

Responsible Party

Manja Zec

Dr

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Maria Glibetic, Prof

Role: PRINCIPAL_INVESTIGATOR

Center of Research Excellence in Nutrition and Metabolism, Institute for Medical Resaerch

Locations

Center of Research Excellence in Nutrition and Metabolism, Institute for Medical Research, University of Belgrade

Belgrade, , Serbia

Countries

Serbia

Other Identifiers

EO120/2017

Identifier Type: -

Identifier Source: org_study_id