Effects of Almond Intake on Atherogenic Lipoprotein Particles

NCT ID: NCT01792648

Last Updated: 2017-11-06

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 24 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2013-04-30
• Study Completion Date: 2016-04-30

Brief Summary

Increased abdominal adiposity is a key feature of metabolic syndrome, which describes a cluster of cardiovascular disease (CVD) risk factors that also includes insulin resistance, high blood pressure and an atherogenic lipoprotein phenotype characterized by increased plasma triglycerides, low HDL-C, and increased levels of small LDL particles. While lifestyle intervention remains the cornerstone for managing obesity and metabolic syndrome, the optimal dietary macronutrient distribution for improving blood lipids and CVD risk remains a topic of controversy. While both low carbohydrate diets and weight reduction are effective for managing atherogenic dyslipidemia, long-term compliance is low, and it becomes imperative to identify alternative dietary approaches.

Increased consumption of almonds has been shown to lower LDL-C, an effect that exceeds that predicted from changes in fatty acid intake. However, although LDL-C lowering by almonds has been demonstrated in patients with diabetes, there have been no trials in non-diabetic patients with abdominal obesity. Moreover, there is limited information of the effects of almond intake on LDL particle subclasses.

The overall objective of the present study is to determine whether lipoprotein measures of CVD risk in individuals with increased abdominal adiposity are reduced by almond supplementation in a diet with overall macronutrient content that conforms to current guidelines. Our main hypothesis is that in these individuals, almond consumption can reduce levels of small and medium LDL particles without the need to restrict dietary carbohydrates to levels below those currently recommended.

This hypothesis will be tested by comparing the lipoprotein effects of an almond-supplemented diet (20%E) with those of two reference diets that do not contain almond products: one with similar content of carbohydrate, protein, and fat (standard reference), and the other in which carbohydrate content is reduced by substitution of protein and monounsaturated fat (low-carbohydrate reference).

We will provide the diets for 3 weeks each in a randomized 3-period crossover design to 40 individuals with increased abdominal adiposity. We will test whether the almond supplemented diet will result in lower levels of lipoprotein measures of CVD risk, specifically LDL-C and small and medium LDL particles, compared to either the standard or low-carbohydrate reference diets.

Conditions

Dyslipidemia; Obesity, Abdominal

Keywords

Almond; Carbohydrate; Diet; Cholesterol

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Standard Reference Diet

Group Type: ACTIVE_COMPARATOR

Standard reference diet

Intervention Type: OTHER

50% energy as carbohydrate, 15% energy as protein, 35% energy as total fat

Almond Supplemented Diet

Group Type: EXPERIMENTAL

Almond supplemented diet

Intervention Type: OTHER

50% energy as carbohydrate, 15% energy as protein, 35% energy as total fat, 20% energy from almonds

Low Carbohydrate Reference Diet

Group Type: ACTIVE_COMPARATOR

Low carbohydrate reference diet

Intervention Type: OTHER

26% energy from carbohydrate, 29% energy from protein, 45% energy from total fat

Interventions

Standard reference diet

50% energy as carbohydrate, 15% energy as protein, 35% energy as total fat

Intervention Type: OTHER

Almond supplemented diet

50% energy as carbohydrate, 15% energy as protein, 35% energy as total fat, 20% energy from almonds

Intervention Type: OTHER

Low carbohydrate reference diet

26% energy from carbohydrate, 29% energy from protein, 45% energy from total fat

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Age 20 or older
• Increased abdominal adiposity as defined by waist circumference ≥102 for men or ≥88 for women.
• Fasting blood sugar (FBS) < 126 mg/dl
• Weight stable for > 3 months.

Exclusion Criteria

• History of coronary heart disease, cerebrovascular disease, peripheral vascular disease, bleeding disorder, liver or renal disease, diabetes, lung disease, HIV, or cancer (other than skin cancer) in the last 5 years.
• Taking hormones or drugs known to affect lipid metabolism or blood pressure.
• Systolic blood pressure > 160 mm Hg and diastolic blood pressure > 95 mm Hg.
• Body mass index (BMI) > 38 kg/m2
• User of nicotine products or recreational drugs
• Refusal to abstain from alcohol or dietary supplements during the study.
• Total- and LDL-C > 95th percentile for sex and age.
• Fasting triglycerides > 50mg/dl and > 500 mg/dl
• Abnormal thyroid stimulating hormone (TSH) levels.
• Pregnant or breast-feeding

• Minimum Eligible Age: 20 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Almond Board of California

OTHER

Sponsor Role: collaborator

UCSF Benioff Children's Hospital Oakland

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Ronald M Krauss, MD

Role: PRINCIPAL_INVESTIGATOR

UCSF Benioff Children's Hospital Oakland

Locations

Cholesterol Research Center

Berkeley, California, United States

Countries

United States

References

Williams PT, Bergeron N, Chiu S, Krauss RM. A randomized, controlled trial on the effects of almonds on lipoprotein response to a higher carbohydrate, lower fat diet in men and women with abdominal adiposity. Lipids Health Dis. 2019 Apr 3;18(1):83. doi: 10.1186/s12944-019-1025-4.

Reference Type: DERIVED

PMID: 30943980 (View on PubMed)

Other Identifiers

MM2222

Identifier Type: -

Identifier Source: org_study_id