Clinical trial NCT01792648: Effects of Almond Intake on Atherogenic Lipoprotein Particles
Official title: Effects of Almond Intake on Atherogenic Lipoprotein Particles in Individuals With Increased Abdominal Adiposity
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Dyslipidemia
Obesity, Abdominal
Keywords: Almond
Carbohydrate
Diet
Cholesterol
Lead sponsor: UCSF Benioff Children's Hospital Oakland
Sponsor class: OTHER
Collaborators: name: Almond Board of California
First posted: 2013-02-15
Enrollment: 24
Sex: ALL
Minimum age (years): 20
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

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.


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

Primary outcomes:
measure: Change in Total and LDL cholesterol
timeFrame: 3 weeks, 8 weeks, 13 weeks
measure: Change in small and medium LDL particles
timeFrame: 3 weeks, 8 weeks, and 13 weeks
measure: Change in apolipoprotein B
timeFrame: 3 weeks, 8 week, 13 weeks
Secondary outcomes:
measure: Change in total/HDL-cholesterol ratio
timeFrame: 3 weeks, 8 weeks, 13 weeks
measure: Change in LDL peak particle diameter
timeFrame: 3 weeks, 8 week, 13 weeks
measure: Change in plasma triglycerides
timeFrame: 3 weeks, 8 weeks, 13 weeks
measure: Change in HDL-cholesterol
timeFrame: 3 weeks, 8 weeks, 13 weeks
measure: Change in large HDL particles
timeFrame: 3 weeks, 8 weeks, 13 weeks
measure: Change in apolipoprotein AI
timeFrame: 3 weeks, 8 weeks, 13 weeks
measure: Change in HOMA-IR
timeFrame: 3 weeks, 8 weeks, 13 weeks
Other outcomes:
Locations:
city: Berkeley
country: United States
facility: Cholesterol Research Center
state: California
Study officials:
affiliation: UCSF Benioff Children's Hospital Oakland
name: Ronald M Krauss, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.