Cardiovascular Disease Clinical Trial
Official title:
The Effect of Almonds on Coronary Heart Disease Risk Factors: Dose Response Study.
To assess the effects of almonds on coronary heart disease (CHD) risk factors (serum lipids, measurements of oxidative stress and nitric oxide production) when added to the diets of subjects with high cholesterol. Also, to assess whether the amount of almonds consumed (i.e. almond dose) decreases CHD risk factors in a dose dependent manner. We hypothesize that since almonds have been shown to reduce serum lipids, we believe they will also increase nitric oxide levels related to their high levels of arginine and reduce markers of oxidative stress related to their content of bioactive phenolics. We anticipate that a dose-dependent relationship will be observed resulting in greater reductions in risk factors for coronary heart disease when greater doses of almonds are consumed.
Previous studies have shown that nuts, specifically almonds, result in an improved coronary
heart disease (CHD) lipid risk profile. Part of the reason has been ascribed to their high
content of monounsaturated fat. However in a previous study we have done, the almond
supplement, in comparison with an olive oil and dairy protein based supplement, still showed
a significant reduction in total cholesterol (total-C) and low density lipoprotein
cholesterol (LDL-C). We wish to use this paradigm to confirm the lipid lowering effect of
almonds, to establish a similar relationship for the apolipoproteins and so add further
support for the cardiovascular risk reduction associated with an almond diet. In addition,
in view of the relatively high arginine content of almonds, we believe higher levels of
nitric oxide (NO) will be produced, as indicated by increased NO in expired air from
perfused olfactory mucosa. With this technique, we have found higher levels of NO in
preliminary studies of subjects on soy diets. These data would further add to interest in
nuts in relation to cardiovascular disease risk reduction. Furthermore, phenolics are
present in high concentrations in oil seeds and nuts, and are known to have antioxidant
activity. As yet, they do not appear to have been emphasized in relation to almonds. We will
therefore determine the effect of feeding almonds on measures of oxidative stress, including
oxidized LDL-C, considered to be of direct relevance to CHD; and oxidized DNA, of potential
importance to neoplastic transformation and carcinogenesis.
These studies could lead to assessment of postprandial effects of almonds to determine a
mechanism, and to studies of cardiovascular effects of almonds including exercise stress
tests and measures of vascular reactivity (e.g. forearm blood flow) in conjunction with NO
measurements.
Protocol: All subjects underwent three 4-week treatments in a randomized crossover trial.
Background Diet: Subjects were instructed to follow the National Cholesterol Education
Program (NCEP) Step 2 dietary guidelines. Nuts, soy and dietary supplements (vitamins,
minerals or herbal remedies) were excluded in the background diet during all phases of the
study.
Treatments: The three phases were all weight maintaining, self-selected diets: control, full
almond and half almond. Almond: Raw almonds were added as supplements to the subject's usual
diet. Subjects with calorie needs of 2,400 kcal or greater, assessed by LRC tables, received
the full almond supplement (100 g/d, approximately 600 kcal). Subjects requiring between
1,600-2,400 kcal daily received 75% of the full supplement (75 g/d, approximately 450 kcal).
Subjects requiring less than 1,600 kcal daily received 50% of the full supplement (50 g/d,
approximately 300 kcal). Control: The full control supplement was four 150 kcal muffins.
Control supplements was matched with the energy content of the nut supplements; i.e. either
600 kcal/d (4 muffins); 450 kcal/d (3 muffins) or 300 kcal/d (2 muffins). The macronutrient
composition of the muffins conformed to an NCEP Step 2 diet with 25% total fat, <7%
saturated fat (by use of corn oil as the oil commonly used in healthy baked goods), with 18%
protein (the average for our subject population using added skim milk powder), and zero
cholesterol. Muffins were made with wheat flour. Half Portion: The Half Portion was matched
with the energy content of the other two treatment periods. However on this treatment, half
of the energy was derived from almonds and half from the control muffins.
Design: Randomized crossover design.
Duration: The study consisted of three months subject recruitment and selection; three
4-week treatment periods where supplements are provided, and at least two-week washout
periods between supplements. (Total duration: approximately 7.5 months per subject).
Study Details: Subjects came after a 12h overnight fast to the Risk Factor Modification
Center at St. Michael's Hospital (Toronto) immediately prior to commencement of each study
and at weekly intervals during the course of each study period. Prior to the start of the
study, subjects were instructed on details of the study diet protocol. They were also asked
to maintain a constant level of physical activity throughout the course of the study. At all
visits, body weight (in kg) was obtained in indoor clothing, without shoes.
Measurements: Bloods were taken at baseline and at weeks 2 and 4 of each phase. Pulmonary
air was collected at baseline and at week 4 of each phase. Diet histories were recorded
during the last week of each phase.
Compliance:Compliance was assessed from completed one-week diet records where supplement
intake is recorded. Diet records were reviewed by the dietitian with the subject at the end
of the week. In addition, uneaten supplements were returned, weighed and noted on the menu
plans by the dietitian.
;
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Single Blind, Primary Purpose: Treatment
Status | Clinical Trial | Phase | |
---|---|---|---|
Completed |
NCT02122198 -
Vascular Mechanisms for the Effects of Loss of Ovarian Hormone Function on Cognition in Women
|
N/A | |
Completed |
NCT02502812 -
Bioequivalence Study of Clopidogrel 75 mg in Two Tablet Formulations Relative to Reference Tablet in Healthy Subjects
|
Phase 1 | |
Recruiting |
NCT04216342 -
Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Fx-5A in Healthy Volunteers
|
Phase 1 | |
Completed |
NCT03654313 -
Single and Multiple Ascending Doses of MEDI6570 in Subjects With Type 2 Diabetes Mellitus
|
Phase 1 | |
Completed |
NCT03646656 -
Heart Health Buddies: Peer Support to Decrease CVD Risk
|
N/A | |
Completed |
NCT02081066 -
Identification of CETP as a Marker of Atherosclerosis
|
N/A | |
Completed |
NCT02147626 -
Heart Health 4 Moms Trial to Reduce CVD Risk After Preeclampsia
|
N/A | |
Not yet recruiting |
NCT06405880 -
Pharmacist Case Finding and Intervention for Vascular Prevention Trial
|
N/A | |
Recruiting |
NCT03095261 -
Incentives in Cardiac Rehabilitation
|
N/A | |
Completed |
NCT02711878 -
Healing Hearts and Mending Minds in Older Adults Living With HIV
|
N/A | |
Completed |
NCT02998918 -
Effects of Short-term Curcumin and Multi-polyphenol Supplementation on the Anti-inflammatory Properties of HDL
|
N/A | |
Completed |
NCT02589769 -
Effects of Reduction in Saturated Fat on Cholesterol and Lipoproteins in Lean and Obese Persons
|
N/A | |
Not yet recruiting |
NCT02578355 -
National Plaque Registry and Database
|
N/A | |
Completed |
NCT02868710 -
Individual Variability to Aerobic Exercise Training
|
N/A | |
Recruiting |
NCT02885792 -
Coronary Artery Disease in Patients Suffering From Schizophrenia
|
N/A | |
Completed |
NCT02272946 -
Effect of IL--1β Inhibition on Inflammation and Cardiovascular Risk
|
Phase 2 | |
Completed |
NCT02640859 -
Investigation of Metabolic Risk in Korean Adults
|
||
Completed |
NCT02652975 -
Anticancer Treatment of Breast Cancer Related to Cardiotoxicity and Dysfunctional Endothelium
|
N/A | |
Completed |
NCT02657382 -
Mental Stress Ischemia: Biofeedback Study
|
N/A | |
Recruiting |
NCT02265250 -
Pilot Study-Magnetic Resonance Imaging for Global Atherosclerosis Risk Assessment
|