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Epidemiological studies have consistently associated nut consumption with reduced risk for coronary heart disease. Subsequently, many dietary intervention trials investigated the effects of nut consumption on blood lipid levels. The objectives of this study were to estimate the effects of nut consumption on blood lipid levels and to examine whether different factors modify the effects. We pooled individual primary data from 25 nut consumption trials conducted in 7 countries among 583 men and women with normolipidemia and hypercholesterolemia who were not taking lipid-lowering medications. In a pooled analysis, we used mixed linear models to assess the effects of nut consumption and the potential interactions. With a mean daily consumption of 67 g of nuts, the following estimated mean reductions were achieved: total cholesterol concentration (10.9 mg/dL [5.1% change]), low-density lipoprotein cholesterol concentration (LDL-C) (10.2 mg/dL [7.4% change]), ratio of LDL-C to high-density lipoprotein cholesterol concentration (HDL-C) (0.22 [8.3% change]), and ratio of total cholesterol concentration to HDL-C (0.24 [5.6% change]) (P < .001 for all) (to convert all cholesterol concentrations to millimoles per liter, multiply by 0.0259). Triglyceride levels were reduced by 20.6 mg/dL (10.2%) in subjects with blood triglyceride levels of at least 150 mg/dL (P < .05) but not in those with lower levels (to convert triglyceride level to millimoles per liter, multiply by 0.0113). The effects of nut consumption were dose related, and different types of nuts had similar effects on blood lipid levels. The effects of nut consumption were significantly modified by LDL-C, body mass index, and diet type: the lipid-lowering effects of nut consumption were greatest among subjects with high baseline LDL-C and with low body mass index and among those consuming Western diets. Nut consumption improves blood lipid levels in a dose-related manner, particularly among subjects with higher LDL-C or with lower BMI.
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ORIGINAL INVESTIGATION
Nut Consumption and Blood Lipid Levels
A Pooled Analysis of 25 Intervention Trials
Joan Sabate´, MD, DrPH; Keiji Oda, MA, MPH; Emilio Ros, MD, PhD
Background:Epidemiological studies have consis-
tently associated nut consumption with reduced risk for
coronary heart disease. Subsequently, many dietary in-
tervention trials investigated the effects of nut consump-
tion on blood lipid levels. The objectives of this study
were to estimate the effects of nut consumption on blood
lipid levels and to examine whether different factors
modify the effects.
Methods:We pooled individual primary data from 25
nut consumption trials conducted in 7 countries among
583 men and women with normolipidemia and hyper-
cholesterolemia who were not taking lipid-lowering medi-
cations. In a pooled analysis, we used mixed linear mod-
els to assess the effects of nut consumption and the
potential interactions.
Results:With a mean daily consumption of 67 g of nuts,
the following estimated mean reductions were achieved:
total cholesterol concentration (10.9 mg/dL [5.1%
change]), low-density lipoprotein cholesterol concen-
tration (LDL-C) (10.2 mg/dL [7.4% change]), ratio of
LDL-C to high-density lipoprotein cholesterol concen-
tration (HDL-C) (0.22 [8.3% change]), and ratio of total
cholesterol concentration to HDL-C (0.24 [5.6% change])
(P.001 for all) (to convert all cholesterol concentra-
tions to millimoles per liter, multiply by 0.0259). Tri-
glyceride levels were reduced by 20.6 mg/dL (10.2%) in
subjects with blood triglyceride levels of at least 150 mg/dL
(P.05) but not in those with lower levels (to convert
triglyceride level to millimoles per liter, multiply by
0.0113). The effects of nut consumption were dose re-
lated, and different types of nuts had similar effects on
blood lipid levels. The effects of nut consumption were
significantly modified by LDL-C, body mass index, and
diet type: the lipid-lowering effects of nut consumption
were greatest among subjects with high baseline LDL-C
and with low body mass index and among those con-
suming Western diets.
Conclusion:Nut consumption improves blood lipid lev-
els in a dose-related manner, particularly among sub-
jects with higher LDL-C or with lower BMI.
Arch Intern Med. 2010;170(9):821-827
DIETARY INTERVENTIONS TO
lower blood cholesterol
concentrations and to
modify blood lipopro-
tein levels are the corner-
stone of prevention and treatment plans
for coronary heart disease (CHD).1Re-
cently, consumption of nuts has been the
focus of intense research because of their
potential to reduce CHD risk and to lower
blood lipid levels based on their unique
nutritional attributes.2,3 Nuts are a nutrient-
dense food rich in plant protein (10%-
25%) and fat (50%-75%), mostly unsat-
urated fatty acids.2-4 They are a rich source
of additional nutrients, dietary fiber, min-
erals (eg, copper, magnesium, and potas-
sium), vitamins (eg, folic acid, niacin, vi-
tamin E, and vitamin B6), and other
bioactive constituents such as phenolic an-
tioxidants and phytosterols.2-4
Epidemiological investigations have con-
sistently shown that frequent nut consump-
tion reduces CHD risk.5In a summary es-
timate of 4 major epidemiological studies,6-9
the mean CHD risk was 37% lower among
subjects who consumed 4 or more serv-
ings of nuts a week compared with those
who seldom or never ate nuts, with a mean
reduction of 8.3% for each incremental serv-
ing per week of nuts consumed.5Based on
scientific data documenting the benefits of
nut consumption, the US Food and Drug
Administration10 issued a qualified health
claim in 2003 stating that eating 43 g/d (1.5
oz/d) of specific nuts (almonds, hazel-
nuts, pecans, pistachios, walnuts, and pea-
nuts) may reduce CHD risk. While many
mechanisms by which nuts exert this CHD
protective effect have been postulated,11,12
their lipid-lowering properties have been
studied extensively.
Author Affiliations:
Departments of Nutrition
(Dr Sabate´ ) and Epidemiology
and Biostatistics (Dr Sabate´ and
Mr Oda), Loma Linda
University, Loma Linda,
California; and Unitat de Lı´pids,
Servei d’Endocrinologia i
Nutricio´ , Institut
d’Investigacions Biomèdiques
August Pi Sunyer, Hospital
Clı´nic de Barcelona, and Centro
de Investigacio´ n Biome´ dica en
Red Fisiopatologı´a de la
Obesidad y Nutricio´ n, Instituto
de Salud Carlos III, Barcelona,
Spain (Dr Ros).
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More than 25 human dietary intervention studies have
been conducted investigating the effects of nut consump-
tion on blood lipid levels. These studies differ in the type
and amount of nuts consumed, study design, subject se-
lection criteria, and duration. Because analyses have also
varied, factors that may be responsible for inconsisten-
cies among studies and for dose-response relationships
have remained elusive.
We examined the effects of nut consumption on blood
lipid levels and further examined whether these effects
were consistent when stratified by different population
groups and variables, including sex, age, type of nut, type
of control diet, and body mass index (BMI [calculated
as weight in kilograms divided by height in meters
squared]) by pooling and analyzing raw data from 25 nut
consumption trials conducted in 7 countries. Results have
been published for 23 studies (1 study reported results
from 2 different studies),13-34 and 2 studies remain un-
published (M. Most, PhD, unpublished data, 2004; and
E.R., unpublished data, 2004).
METHODS
STUDY DESIGN
A comprehensive MEDLINE search was conducted for English-
language human studies between January 1, 1992, and Decem-
ber 31, 2004, that assessed the effects of nut consumption on blood
lipid levels. The cutoff (2004) was selected because of the changes
in standards of care that occurred on release of the “Third Re-
port of the National Cholesterol Education Program” Adult Treat-
ment Panel guidelines35 and the potential problems with con-
founding in patients who may be taking statin drugs. Search terms
included human,cholesterol,nuts,almond,cashew,peanut,pecan,
pine nut,pistachio nut,macadamia nut,hazelnut, and walnut. Al-
though peanuts are members of the legume family, we included
them in the analysis given their comparable nutrient profile to
nuts and their common identification as part of the nut food group.
The literature search yielded 25 articles, one of which reported
results from 2 different studies.26 We identified 2 unpublished stud-
ies, for a total of 28 studies, and contacted the authors of the pub-
lished and unpublished research to obtain disaggregated data for
inclusion in a pooled analysis.
Articles were selected for the pooled analysis based on the
following a priori inclusion criteria: (1) the study involved hu-
man subjects; (2) a control group existed, or stable baseline lipid
measurements were present before nut consumption; (3) the
dietary intervention was exclusively nuts; (4) the nut consump-
tion period was at least 3 weeks; (5) the subjects had no recent
exposure to lipid-lowering medications; and (6) there were no
body weight changes between diets at the end of the interven-
tion. Based on these inclusion criteria, 2 published studies36,37
were excluded because the intervention included other sources
of monounsaturated fat in addition to nuts. Another pub-
lished study38 was excluded because of differential weight loss
at the end of the intervention. In total, 25 studies (23 pub-
lished and 2 unpublished) were selected for inclusion.
STATISTICAL ANALYSIS
Each research team provided their original data sets electroni-
cally. On receipt, we conducted preliminary statistical analy-
ses to confirm appropriate transfer of data. In all cases, we were
able to reproduce the results presented in the original articles.
Data were then combined into a single data set and were ana-
lyzed using statistical software (SAS version 9.1; SAS Institute,
Cary, North Carolina).
Each subject contributed 1 data point for each dietary treat-
ment received. Therefore, subjects of crossover studies con-
tributed 2 or more data points to the data set. The final data
set contained 1284 observations contributed by 583 unique sub-
jects. Analyses were conducted using mixed linear models that
included a fixed-effects term for diet and random-effects terms
for study, diet nested in study, and subject nested in study. To
test for study heterogeneity, fixed-effects terms for study and
dietstudy interaction were included in the model.
We investigated whether sex, age, BMI, controlled vs uncon-
trolled study design, degree of investigator control over subjects’
diets, type of funding source, type of nut, and type of control diet
modified the effects of nut consumption by adding appropriate
fixed-effects terms for main effect diet interaction to the model.
For some analyses, subjects were stratified into the following 3
low-density lipoprotein cholesterol concentration (LDL-C) cat-
egories according to “Third Report of the National Cholesterol
Education Program” Adult Treatment Panel criteria35: less than
130 mg/dL (n=262), 130 to 160 mg/dL (n =125), or greater than
160 mg/dL (n =195) (to convert cholesterol concentration to mil-
limoles per liter, multiply by 0.0259). Subjects were also strati-
fied into 2 triglyceride level categories (150 mg/dL [n=410] or
150 mg/dL [n=145]) (to convert triglyceride level to milli-
moles per liter, multiply by 0.0113), and BMIs were classified as
normal weight (25 [n=244]), overweight (25-30 [n =181]), or
obese (30 [n=82]). One value for LDL-C, 28 values for triglyc-
eride levels, and 76 height measurements were missing from the
original data sets. Almonds (n=210) and walnuts (n =178) were
the 2 nuts most commonly used, and all other nut types were
grouped into a single category (n=195).
Each study was categorized according to its design. Cross-
over and parallel design studies were classified as controlled
(n=18), and consecutive design (preintervention and post-
intervention) studies were classified as uncontrolled (n=7).
Types of control diets were represented by the following 3 cat-
egories: Western (total fat 30% and saturated fat 10%), Medi-
terranean (monounsaturated fat 20% and saturated fat 7%),
and low total and saturated fat (total fat 30% and saturated
fat 7%). To estimate a possible dose-response effect of nut
consumption, individual nut consumption was recomputed and
expressed as percentage of total calories in the diet.
To assess the possible influence of the degree of dietary con-
trol on the results, each study was classified as having low, me-
dium, or high dietary control. The low dietary control cat-
egory included studies in which subjects consumed nuts without
dietary advice and there was no biologic measure of dietary com-
pliance. The medium dietary control studies gave dietary ad-
vice and used a biologic measure of dietary compliance. The
high dietary control category comprised studies and meta-
bolic trials in which nuts and all meals were provided. Last,
each study was classified as industry sponsored or as non–
industry sponsored based on the type of funding source.
RESULTS
Of 25 studies in the pooled analysis, 16 used a crossover
design, 7 used a consecutive design, and 2 used a parallel
design (Table 1). Sample size ranged from 10 to 49 sub-
jects (median, 20 subjects), and age ranged from 19 to 86
years (mean age, 46 years). All but 4 studies included both
sexes, and there were 307 men and 276 women. Subjects
in 9 studies had hypercholesterolemia (mean range, 236-
259 mg/dL for total cholesterol concentration [TC] and 154-
178 mg/dL for LDL-C), and subjects in 16 studies had nor-
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mocholesterolemia (125-222 mg/dL for TC and 67-142
mg/dL for LDL-C). Across studies, individual BMIs ranged
from 17 to 49 (mean, 27). Daily nut consumption ranged
from 23 to 132 g (mean, 67 g), which is approximately 0.8
to 4.8 oz/d (mean, 2.4 oz/d).
Compared with control diets, nut diets reduced TC,
LDL-C, ratio of LDL-C to high-density lipoprotein choles-
terol concentration (HDL-C), and ratio of TC to HDL-C
(P.001 for all) (Table 2). Nut consumption had no sig-
nificant effect on the mean HDL-C, nor was there an effect
on triglyceride level except in subjects with hypertriglyc-
eridemia. For all blood lipid levels and ratios evaluated, study
and dietstudy interaction were significant (P.001 for
all), suggesting heterogeneity among the studies.
The effects of nut consumption on blood lipid levels
were similar in men and women (P.2 for all nut
dietsex interactions) and across all age groups (P.2
for all nut dietage interactions). They were indepen-
dent of the specific type of nut consumed (P.45 for all
nut dietnut type interactions).
The estimated cholesterol-lowering effects of nut con-
sumption were greater for subjects with higher baseline
LDL-C (Table 3 and Figure 1). Responses differed be-
tween subjects with baseline LDL-C of less than 130 mg/dL
vs greater than 160 mg/dL (mean decrease, 12.5 mg/dL
for TC and 14.9 mg/dL for LDL-C). There was also a dif-
ferential cholesterol-lowering effect of nut consump-
tion depending on baseline BMI, with greater response
among subjects having lower BMI. A significant nut
dietBMI interaction was found for ratio of LDL-C to
HDL-C and for ratio of TC to HDL-C (P=.02 for both).
Similar trends existed for TC, LDL-C, and triglyceride
Table 1. Characteristics of 25 Intervention Trials Included in the Pooled Analysis
Source
No. of Subjects/
Sex/Mean Age, y
Subject
Characteristic
Daily Amount
of Type of Nut, g
Duration
of Dietary
Intervention,
wk
Study
Design
Control
Diet
Industry
Sponsored
Sabate´ et al,13 1993, USA 18/18M/30 Normocholesterolemia 79 Walnut 4 Crossover Low saturated fat Yes
Abbey et al,14 1994, Australia 16/16M/41 Normocholesterolemia 84 Almond,
68 walnut
3 Consecutive Western No
Colquhoun et al,15 1996,
Australia
14/7M, 7F/46 Normocholesterolemia 54 Macadamia 4 Crossover Low fat Yes
Spiller et al,16 1998, Canada 45/12M, 33F/53 Hypercholesterolemia 100 Almond 4 Parallel Western,
Mediterranean
Yes
Chisholm et al,17 1998,
New Zealand
16/16M/45 Hypercholesterolemia 78 Walnut 4 Crossover Low saturated fat No
Kris-Etherton et al,18
1999, USA
22/9M,
13F/unknown
Normocholesterolemia Unknown
peanut
3.4 Crossover Western Yes
Edwards et al,19 1999, USA 10/4M, 6F/46 Hypercholesterolemia 60 Pistachio 3 Crossover Western No
Durak et al,20 1999, Turkey 30/18M,
12F/unknown
Normocholesterolemia 69 Hazelnut 4.3 Consecutive Unknown No
Zambo´ n et al,21 2000, Spain 49/26M, 23F/56 Hypercholesterolemia 46 Walnut 6 Crossover Mediterranean Yes
Morgan and Clayshulte,22
2000, USA
19/4M, 15F/41 Normocholesterolemia 68 Pecan 8 Parallel Western Yes
Curb et al,23 2000, USA 30/15M,
15F/unknown
Normocholesterolemia Unknown
macadamia
4.3 Crossover Western Yes
Rajaram et al,24 2001, USA 23/14M, 9F/38 Normocholesterolemia 85 Pecan 4 Crossover Low saturated fat Yes
Almario et al,25 2001, USA 18/5M,
13F/unknown
Normocholesterolemia 52 Walnut 6 Consecutive Western, low
saturated fat
Yes
Lovejoy et al,26 2002, USA 30/13M, 17F/25 Normocholesterolemia 100 Almond 4 Crossover Low saturated fat,
Mediterranean
No
Lovejoy et al,26 2002, USA 20/10M, 10F/54 Normocholesterolemia 100 Almond 4 Consecutive Western No
Jenkins et al,27 2002, Canada 27/15M, 12F/64 Hypercholesterolemia 73 Almond
(high dose),
37 almond
(low dose)
6 Crossover Low saturated fat Yes
Iwamoto et al,28 2002, Japan 40/20M, 20F/24 Normocholesterolemia 51 Walnut 4 Crossover Low fat Yes
Hyson et al,29 2002, USA 22/10M, 12F/44 Normocholesterolemia 66 Almond 6 Consecutive Low saturated fat Yes
Sabate´ et al,30 2003, USA 25/14M, 11F/41 Normocholesterolemia 68 Almond
(high dose),
34 almond
(low dose)
4 Crossover Low saturated fat Yes
Garg et al,31 2003, Australia 17/17M/54 Hypercholesterolemia 48 Macadamia 4 Consecutive Western No
Alper and Mattes,32 2003, USA 15/8M, 7F/33 Normocholesterolemia 89 Peanut 8 Consecutive Western No
Ros et al,33 2004, Spain 20/8M, 12F/55 Hypercholesterolemia 55 Walnut 4 Crossover Mediterranean Yes
Sheridan et al,34 2007, USA 15/11M, 4F/60 Hypercholesterolemia 95 Pistachio 4 Crossover Western Yes
Most, 2004, USAa24/8M, 16F/46 Normocholesterolemia 87 Almond Unknown Crossover Western Unknown
Ros, 2004, Spaina18/9M, 9F/55 Hypercholesterolemia 58 Almond,
48 walnut
4 Crossover Mediterranean No
Abbreviation: USA, United States.
aUnpublished.
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level, but results of formal interaction tests did not reach
statistical significance.
Nut consumption had greater relative effects in re-
ducing TC and LDL-C (−7.4% and −9.6%, respectively)
when assessed against a Western control diet vs against
Mediterranean (−4.3% and −6.7%, respectively) or low-
fat (−4.1% and −6.0%, respectively) control diets
(Figure 2). The type of study design (controlled vs un-
controlled) did not modify the effects on blood lipid lev-
els; however, estimated differences were nonsignifi-
cantly greater for TC (P= .23) and for ratio of TC to HDL-C
(P=.28) in uncontrolled studies. No significant differ-
ence was noted in the effects of nut consumption by de-
gree of dietary control. For all blood lipid level fractions
given in Table 2, the type of funding (industry spon-
sored vs non–industry sponsored) did not have an effect,
except for triglyceride level, which showed a decrease
among industry-sponsored studies compared with no
change among non–industry-sponsored studies (P=.01
for nut diet–funding source interaction) (data not shown).
The estimated effects of nut consumption on blood
lipid levels were dose related (Figure 3). At 20% of di-
etary energy from nuts (equivalent to 71 g [2.5 oz] for a
2000-kcal diet), blood lipid levels were reduced by 9.9
mg/dL (4.5% change) for TC and by 9.5 mg/dL (6.5%
change) for LDL-C. At 12.2% of dietary energy from nuts
(equivalent to 43 g [1.5 oz]), the amount of nut con-
sumption recommended by the US Food and Drug Ad-
ministration,10 blood lipid levels were reduced by 7.1
mg/dL (3.2% change) for TC and by 7.2 mg/dL (4.9%
change) for LDL-C. At 10% of dietary energy from nuts
(equivalent to 35 g [1.2 oz]), blood lipid levels were re-
duced by 6.1 mg/dL (2.8% change) for TC and by 6.2
mg/dL (4.2% change) for LDL-C. Similar dose re-
sponses were estimated for ratio of LDL-C to HDL-C and
for triglyceride level in subjects with baseline triglycer-
ide levels of at least 150 mg/dL.
COMMENT
In this pooled analysis of 583 unique subjects in 25 clini-
cal trials, incorporating nuts into the diet lowered TC,
LDL-C, ratio of LDL-C to HDL-C, and ratio of TC to HDL-C.
Table 2. Estimated Changes in Blood Lipid and Lipoprotein Levels Among Subjects Consuming Nut Diets vs Control Diets
Variable Mean Change (95% Confidence Interval)a% Change PValueb
Concentration, mg/dL
TC −10.9 (−14.1 to −7.8) −5.1 .001
LDL-C −10.2 (−13.1 to −7.4) −7.4 .001
HDL-C 0.09 (−1.00 to 1.19) 0.2 .88
Ratio
LDL-C/HDL-C −0.2 (−0.3 to −0.1) −8.3 .001
TC/HDL-C −0.2 (−0.3 to −0.1) −5.6 .001
Triglyceride level, mg/dL −3.1 (−7.2 to 1.2) −2.8 .15
150 0.7 (−3.2 to 4.7) 0.7 .74
150 −20.6 (−30.7 to −9.9) −10.2 .05
Abbreviations: HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TC, total cholesterol.
SI conversion factors: To convert cholesterol concentration to millimoles per liter, multiply by 0.0259; to convert triglyceride level to millimoles per liter, multiply
by 0.0113.
aNut diet values minus control diet values.
bDifference between nut diet and control diet.
Table 3. Estimated Changes in Blood Lipid and Lipoprotein Levels by Baseline LDL-C Concentration and by Baseline BMI
Among Subjects Consuming Nut Diets vs Control Diets
Variable No.
Mean Change (95% Confidence Interval)
TC Concentration,
mg/dL
LDL-C Concentration,
mg/dL LDL-C/HDL-C TC/HDL-C
Triglyceride Level,
mg/dLa
LDL-C concentration, mg/dL
130 262 −5.0 (−9.2 to −0.9)b−3.5 (−7.5 to 0.5) −0.11 (−0.19 to −0.02) b−0.14 (−0.24 to −0.04)b−2.0 (−6.5 to 2.8)
130-160 125 −11.0 (−15.5 to −6.6)c−9.9 (−14.2 to −5.6) c−0.26 (−0.38 to −0.13)b−0.28 (−0.41 to −0.15)c−8.5 (−14.7 to −1.3) b
160 195 −17.5 (−22.0 to −13.0)c−18.4 (−22.7 to −14.1) c−0.38 (−0.52 to −0.24)c−0.35 (−0.48 to −0.20)c−0.6 (−7.1 to 6.3)
BMI
25 244 −12.0 (−15.9 to −8.1)c−11.9 (−15.4 to −8.4) c−0.24 (−0.32 to −0.16)c−0.24 (−0.33 to −0.15)c−5.8 (−9.8 to −1.6) b
25-30 181 −10.5 (−14.4 to −6.6)c−9.2 (−12.8 to −5.7) c−0.14 (−0.23 to −0.04)b−0.15 (−0.25 to −0.04)b−0.6 (−6.0 to 5.0)
30 82 −8.9 (−13.7 to −4.1)b−6.8 (−11.2 to −2.4) b−0.10 (−0.21 to 0.02) −0.12 (−0.25 to 0.01) −1.6 (−9.2 to 6.4)
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); HDL-C, high-density lipoprotein cholesterol;
LDL-C, low-density lipoprotein cholesterol; TC, total cholesterol.
SI conversion factors: To convert cholesterol concentrations to millimoles per liter, multiply by 0.0259; to convert triglyceride level to millimoles per liter,
multiply by 0.0113.
aMedian triglyceride levels for LDL-C cutoffs of less than 130, 130 to 160, and greater than 160 mg/dL were 95, 118, and 123 mg/dL, respectively. Median triglyceride
levels for BMI cutoffs less than 25, 25 to 30, and greater than 30 were 98, 129, and 146 mg/dL, respectively.
bP.05 for difference between nut diet and control diet.
cP.001 for difference between nut diet and control diet.
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Most important is the finding that the cholesterol-
lowering effects of nut consumption are dose related and
are more pronounced in subjects with higher baseline
LDL-C or lower BMI. Nut consumption also lowered tri-
glyceride levels in subjects with hypertriglyceridemia. Study
design, type of funding source, and degree of dietary con-
trol did not significantly affect these outcomes. This study
provides the best estimate of the effects of nut consump-
tion on blood lipid levels. Specifically, a mean daily con-
sumption of 67 g (2.4 oz) of nuts resulted in estimated mean
reductions of 10.9 mg/dL (5.1% change) in TC, 10.2 mg/dL
(7.4% change) in LDL-C, 0.22 (8.3% change) in ratio of
LDL-C to HDL-C, and 0.24 (5.6% change) in ratio of TC
to HDL-C. The estimated reductions in this pooled analy-
sis are almost identical to those obtained in a recent meta-
analysis39 of walnut consumption studies (−10.3 mg/dL for
TC and −9.2 mg/dL for LDL-C). The similarity of the re-
sults obtained by different methodologic approaches con-
firms the validity of our findings.
While the blood lipid level and lipoprotein results cor-
roborate those of previous clinical trials, the observed effect
of a nut dietBMI interaction on blood lipid level re-
sponses is a novel finding. In agreement with this obser-
vation, Mukuddem-Peterson et al40 recently reported that
high consumption of neither walnuts nor cashews was as-
sociated with blood lipid level changes in subjects with
obesity and metabolic syndrome. It is well established that
obese subjects have an attenuated cholesterol-lowering re-
sponse to dietary reduction of saturated fatty acids com-
pared with lean individuals, probably because obesity is char-
acterized by elevated endogenous production of cholesterol
in relation to insulin resistance.41 However, in most of the
nut consumption trials in our pooled analysis, nut diets and
0
4
2
6
8
12
10
% Change
ABaseline LDL-C concentration mg/dL
<
130 130-160 >
160
0
4
2
6
8
12
10
TC LDL-C LDL-C/HDL-C TC/HDL-C TG
% Change
BBaseline BMI
<
25 25-30 >
30
Figure 1. Estimated effects of nut consumption on blood lipid and
lipoprotein levels by baseline LDL-C concentration (A) and by baseline BMI
(B). *P.001 and †P.05 for difference between nut diet and control diet.
To convert cholesterol concentrations to millimoles per liter, multiply by
0.0259. BMI indicates body mass index (calculated as weight in kilograms
divided by height in meters squared); HDL-C, high-density lipoprotein
cholesterol; LDL-C, low-density lipoprotein cholesterol; TC, total cholesterol;
and TG, triglycerides.
10
0
5
5
10
15
TC LDL-C LDL-C/HDL-C TG
% Change
Type of control diet
Western Mediterranean Low fat
Figure 2. Estimated effects of nut consumption on blood lipid and
lipoprotein levels by type of control diet. *P.001 and †P.05 for
difference between type of control diet. HDL-C indicates high-density
lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol;
TC, total cholesterol; and TG, triglycerides.
0
10
9
8
7
6
5
4
3
2
1
TC LDL-C LDL-C/HDL-C TG
% Change
Dietary intake from nuts, %
10 12.220
Figure 3. Estimated effects of nut consumption on blood lipid and
lipoprotein levels by percentage of dietary energy from nuts. *Estimated
using values from participants with triglyceride levels of at least 150 mg/dL
(to convert triglyceride level to millimoles per liter, multiply by 0.0113).
Dietary intakes from nuts of 10%, 12.2%, and 20% are equivalent to 35, 43,
and 71 g, respectively, based on a 2000-kcal diet. †Recommended by the US
Food and Drug Administration10; 12.2% is equivalent to 43 g/d (1.5 oz/d).
HDL-C indicates high-density lipoprotein cholesterol; LDL-C, low-density
lipoprotein cholesterol; TC, total cholesterol; and TG, triglycerides.
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control diets were matched for saturated fat content. Obe-
sity and metabolic syndrome are each associated with re-
duced intestinal cholesterol absorption.42,43 Nuts are rich
in plant sterols, natural compounds that might contribute
to cholesterol lowering by interfering with cholesterol ab-
sorption,44 and this effect would be blunted when choles-
terol absorption rates are low. More research is needed to
answer the important question of why nuts are less effec-
tive in lowering blood cholesterol concentration among sub-
jects with obesity.
When the effects of diets incorporating increasing
amounts of nuts are compared with those of nut-free con-
trol diets, a dose-response effect is manifested. These find-
ings are consistent with results from 2 clinical trials spe-
cifically designed to assess dose response between nut
consumption and blood lipid levels. Sabate´etal
30 found
proportionally greater reductions in LDL-C with a 20%
energy (68 g [2.4 oz]) replacement of almonds into the
usual diet (9.0% reduction) than a 10% energy (34 g [1.2
oz]) replacement (3.3% reduction). Jenkins et al27 found
graded decreases in LDL-C with a “full dose” (73 g [2.6
oz]) of almonds (9.4% decrease) compared with a “half
dose” (37 g [1.3 oz]) (4.4% decrease). To achieve a clini-
cally relevant reduction in blood lipid levels, patients with
hyperlipidemia may benefit from higher amounts of nut
consumption than that recommended by the US Food
and Drug Administration10 for the general public.
Incorporating nuts into the diet of patients with hy-
perlipidemia provides cardiovascular benefits beyond low-
ering blood cholesterol concentration. The 7.4% esti-
mated mean reduction of LDL-C observed in this pooled
analysis is modest compared with the effect of statin
drugs.45 However, the value of regular nut consumption
for CHD prevention is unlikely due to the blood choles-
terol–lowering effect alone, as the 37% summary esti-
mate risk reduction from frequent nut consumption in
epidemiological investigations5is more than double that
attributable to lowering LDL-C by 7.4%.44 Nut consump-
tion exerts beneficial effects by improving endothelial
function,33 lowering oxidative stress,20,27,37 and reducing
lipoprotein(a) level.21,24,27 In addition, nut consumption
is associated with lower risk of developing type 2 diabe-
tes mellitus,46 and research has shown that frequent nut
consumption does not lead to weight gain.47-49
As expected, nut consumption led to more pro-
nounced reduction of TC and LDL-C compared with a
Western diet vs Mediterranean or low-fat diet. Greater cho-
lesterol-lowering effect is found when nuts replace satu-
rated fat than when olive oil or carbohydrates are re-
placed. This finding has important clinical and public health
applications. For patients with dyslipidemia and for the gen-
eral population consuming a Western diet, the incorpora-
tion of nuts into their daily diet will result in greater im-
provement of blood lipid levels than for individuals already
following a healthy Mediterranean or low-fat diet.
Although duration of the dietary intervention trials
pooled herein ranged from 3 to 8 weeks, other investi-
gators have found that favorable lipid levels resulting from
nut consumption are sustainable. One-year findings from
the Prevencio´n con Dieta Mediterra´ nea trial50 evaluat-
ing the effects of nut consumption in the context of a
Mediterranean diet on metabolic syndrome status showed
that mixed nut consumption of 30 g/d significantly re-
duced the prevalence of high waist circumference, hy-
pertriglyceridemia, and hypertension compared with a
control group receiving a nut-free low-fat diet. Tapsell
et al51 found significantly decreased LDL-C and signifi-
cantly increased HDL-C and ratio of TC to HDL-C in pa-
tients with type 2 diabetes mellitus consuming 30 g/d of
walnuts for 6 months as part of a modified low-fat diet
compared with those receiving nut-free, low-fat, or modi-
fied low-fat diets.
Our findings confirm the results of epidemiological
studies showing that nut consumption lowers CHD risk
and support the inclusion of nuts in therapeutic dietary
interventions for improving blood lipid levels and lipo-
proteins and for lowering CHD risk. Nuts are a whole
food that have been consumed by humans throughout
history. Increasing the consumption of nuts as part of an
otherwise prudent diet can be expected to favorably affect
blood lipid levels (at least in the short term) and have
the potential to lower CHD risk.
Accepted for Publication: October 19, 2009.
Correspondence: Joan Sabate´, MD, DrPH, Department
of Nutrition, Loma Linda University, Nichol Hall Room
1102, Loma Linda, CA 92350 (jsabate@llu.edu).
Author Contributions: Mr Oda had full access to all the
data in the study and takes responsibility for the integ-
rity of the data and the accuracy of the data analysis. Study
concept and design: Sabate´.Acquisition of data: Sabate´ and
Ros. Analysis and interpretation of data: Sabate´, Oda, and
Ros. Drafting of the manuscript: Sabate´. Critical revision
of the manuscript for important intellectual content: Sabate´,
Oda, and Ros. Statistical analysis: Oda. Obtained fund-
ing: Sabate´. Study supervision: Sabate´.
Financial Disclosure: Drs Sabate´ and Ros have received
research funding from the California Walnut Commis-
sion, the Almond Board of California, the National Pea-
nut Board, and the International Tree Nut Council; they
are also unpaid members of the Scientific Advisory Coun-
cil of the California Walnut Commission. Dr Sabate´ has
received an honorarium as a member of the Pistachio Sci-
entific Advisory Board.
Funding/Support: This research was partially funded by
a grant from the McLean Research Fund of the Depart-
ment of Nutrition, Loma Linda University, and by the
International Tree Nut Council Nutrition Research and
Education Foundation.
Role of the Sponsors: The funding sources had no role
in the design or conduct of the study; collection, man-
agement, analysis, or interpretation of the data; or prepa-
ration, review, or approval of the manuscript.
Additional Contributions: Jay S. Tanzman, MPH, as-
sisted with data analysis, and Michelle Wien, DrPH, RD,
CDE, edited the manuscript. We thank the trial investi-
gators who shared their original data with us, which made
this study possible.
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... Evidence from small, short-term randomized clinical trials in middle-aged individuals indicates a consistent but modest cholesterol-lowering effect of diets supplemented with nuts in general [6] or walnuts in particular [7], which is dose-related and greatest among those with high baseline low-density lipoprotein cholesterol (LDL-C) [8]. Most nut feeding trials have selected young or middle-aged adults [6][7][8], and few feeding studies have examined the effects of nuts on advanced measures of lipoprotein atherogenicity, such as subparticle number, size, and composition determined by nuclear magnetic resonance (NMR) spectroscopy. ...
... Evidence from small, short-term randomized clinical trials in middle-aged individuals indicates a consistent but modest cholesterol-lowering effect of diets supplemented with nuts in general [6] or walnuts in particular [7], which is dose-related and greatest among those with high baseline low-density lipoprotein cholesterol (LDL-C) [8]. Most nut feeding trials have selected young or middle-aged adults [6][7][8], and few feeding studies have examined the effects of nuts on advanced measures of lipoprotein atherogenicity, such as subparticle number, size, and composition determined by nuclear magnetic resonance (NMR) spectroscopy. Those who have reported such parameters have shown equivocal results [9]. ...
... First, higher consumption of total nuts and non-walnut nuts was associated with increased HDL-C. This finding is counter to known evidence on the null effect of nuts on HDL-C, as summarized in meta-analyses [6][7][8]. As large HDL-P contain more cholesterol, their increase with higher total nut consumption supports higher HDL-C. ...
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Background Scientific evidence has accumulated on the beneficial effects of nut consumption on cardiovascular risk and cholesterol reduction, but few studies have examined the effects of nuts on advanced measures of lipoprotein atherogenicity determined by nuclear magnetic resonance (NMR) spectroscopy. We analyzed associations between the amount and type of of nuts consumed and advanced measures of lipoprotein atherogenity and insulin resistance in older individuals at high cardiovascular risk. Methods The present observational study was carried out within the framework of the Prevención con Dieta Mediterránea (PREDIMED) trial. Cross-sectional and longitudinal analyses after 1-year of follow-up were conducted in 196 men and women recruited in the PREDIMED-Reus (Spain) center. Dietary intake was assessed using a validated semi-quantitative food questionnaire. Baseline and 1-year fasting plasma lipoprotein and metabolite profiling were performed in plasma using NMR spectra Vantera ® Clinical Analyzer. Associations by tertiles of nut consumption between baseline and 1-year changes and advanced measures of lipoprotein atherogenicity, branched chain amminoacids, and measures of insulin resistance were tested by multivariable-adjusted ANCOVA models. Results Compared to paticipants in the bottom tertile, those in the top tertile of total nut consumption showed higher levels of large HDL particles and HDL-cholesterol, lower levels of branched-chain amino acids (BCAA) and GlycA, and reduced lipoprotein insulin resistance and diabetes risk index. Participants in the top tertile of walnut consumption disclosed lower levels of very large VLDL, total LDL particles, LDL-cholesterol, and GlycA. Participants in the top tertile of non-walnut nut consumption displayed higher levels of total HDL particles, HDL-cholesterol and apoliporotein A1, lower BCAA and GlycA, and reduced lipoprotein insulin resistance. Participants in the top tertile of 1-year changes in walnut consumption showed increases in medium-sized HDL particles in comparison to the bottom tertile. Conclusions In older individuals at high cardiovascular risk, increasing nut consumption was associated with a shift of the NMR lipoprotein subfraction profile to a less atherogenic pattern, as well as lower circulating concentrations of BCAA and decreased insulin resistance. These results provide novel mechanistic insight into the cardiovascular benefit of nut consumption. Trial registration ISRCTN35739639; registration date: 05/10/2005; recruitment start date 01/10/2003.
... Key foods shared with these other dietary patterns [27,30] have also been shown to improve intermediate cardiometabolic outcomes. These foods include viscous fibres [108,109] from oats and barley [110,111], temperate fruit and berries [112,113], nuts [103,[114][115][116] and legumes [117][118][119][120][121][122][123][124][125]. Another possible explanation for the observed benefits of Nordic dietary patterns is because of weight loss induced by the interventions. ...
... We did not downgrade for indirectness here, as the prospective cohort studies did include a representative proportion of individuals with diabetes and the RCTs included individuals at risk for diabetes. The key components of Nordic dietary patterns have also been shown individually to lower cardiometabolic risk factors reliably in people with diabetes [108][109][110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126]. ...
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Aims/hypothesis Nordic dietary patterns that are high in healthy traditional Nordic foods may have a role in the prevention and management of diabetes. To inform the update of the EASD clinical practice guidelines for nutrition therapy, we conducted a systematic review and meta-analysis of Nordic dietary patterns and cardiometabolic outcomes. Methods We searched MEDLINE, EMBASE and The Cochrane Library from inception to 9 March 2021. We included prospective cohort studies and RCTs with a follow-up of ≥1 year and ≥3 weeks, respectively. Two independent reviewers extracted relevant data and assessed the risk of bias (Newcastle–Ottawa Scale and Cochrane risk of bias tool). The primary outcome was total CVD incidence in the prospective cohort studies and LDL-cholesterol in the RCTs. Secondary outcomes in the prospective cohort studies were CVD mortality, CHD incidence and mortality, stroke incidence and mortality, and type 2 diabetes incidence; in the RCTs, secondary outcomes were other established lipid targets (non-HDL-cholesterol, apolipoprotein B, HDL-cholesterol, triglycerides), markers of glycaemic control (HbA 1c , fasting glucose, fasting insulin), adiposity (body weight, BMI, waist circumference) and inflammation (C-reactive protein), and blood pressure (systolic and diastolic blood pressure). The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of the evidence. Results We included 15 unique prospective cohort studies ( n =1,057,176, with 41,708 cardiovascular events and 13,121 diabetes cases) of people with diabetes for the assessment of cardiovascular outcomes or people without diabetes for the assessment of diabetes incidence, and six RCTs ( n =717) in people with one or more risk factor for diabetes. In the prospective cohort studies, higher adherence to Nordic dietary patterns was associated with ‘small important’ reductions in the primary outcome, total CVD incidence (RR for highest vs lowest adherence: 0.93 [95% CI 0.88, 0.99], p =0.01; substantial heterogeneity: I ² =88%, p Q <0.001), and similar or greater reductions in the secondary outcomes of CVD mortality and incidence of CHD, stroke and type 2 diabetes ( p <0.05). Inverse dose–response gradients were seen for total CVD incidence, CVD mortality and incidence of CHD, stroke and type 2 diabetes ( p< 0.05). No studies assessed CHD or stroke mortality. In the RCTs, there were small important reductions in LDL-cholesterol (mean difference [MD] −0.26 mmol/l [95% CI −0.52, −0.00], p MD =0.05; substantial heterogeneity: I ² =89%, p Q <0.01), and ‘small important’ or greater reductions in the secondary outcomes of non-HDL-cholesterol, apolipoprotein B, insulin, body weight, BMI and systolic blood pressure ( p< 0.05). For the other outcomes there were ‘trivial’ reductions or no effect. The certainty of the evidence was low for total CVD incidence and LDL-cholesterol; moderate to high for CVD mortality, established lipid targets, adiposity markers, glycaemic control, blood pressure and inflammation; and low for all other outcomes, with evidence being downgraded mainly because of imprecision and inconsistency. Conclusions/interpretation Adherence to Nordic dietary patterns is associated with generally small important reductions in the risk of major CVD outcomes and diabetes, which are supported by similar reductions in LDL-cholesterol and other intermediate cardiometabolic risk factors. The available evidence provides a generally good indication of the likely benefits of Nordic dietary patterns in people with or at risk for diabetes. Registration ClinicalTrials.gov NCT04094194. Funding Diabetes and Nutrition Study Group of the EASD Clinical Practice. Graphical abstract
... However, other dietary differences could also contribute toward reduced CVD risk among vegetarians. Compared to meat-eaters, vegetarians tend to have a higher intake of fruit and vegetables, whole grains, nuts, and legumes [70], and such food groups have generally been shown to reduce the risk of CVD, IHD and stroke [61][62][63] and to have benefits on cardiovascular risk factors such as blood pressure [84][85][86], serum cholesterol [87][88][89], bodyweight [82] and risk of type 2 diabetes [90,91]. ...
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Purpose Vegetarian diets have been associated with reduced risk of ischemic heart disease (IHD). However, results regarding cardiovascular disease (CVD) overall and stroke are less clear. We conducted a systematic review and meta-analysis of prospective cohort studies on CVD, IHD and stroke risk among vegetarians or vegans versus nonvegetarians to clarify these associations. Methods PubMed and Ovid Embase databases were searched through August 12, 2021. Prospective cohort studies reporting adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for incidence or mortality from CVD, IHD and stroke, comparing vegetarians and vegans to nonvegetarians were included. Risk of bias (RoB) was assessed using ROBINS-I and the strength of evidence was assessed using World Cancer Research Fund (WCRF) criteria. Summary RRs (95% CIs) were estimated using a random effects model. Results Thirteen cohort studies (844,175 participants, 115,392 CVD, 30,377 IHD, and 14,419 stroke cases) were included. The summary RR for vegetarians vs. nonvegetarians was 0.85 (95% CI: 0.79–0.92, I ² = 68%, n = 8) for CVD, 0.79 (95% CI: 0.71–0.88, I ² = 67%, n = 8) for IHD, 0.90 (95% CI: 0.77–1.05, I ² = 61%, n = 12) for total stroke, and for vegans vs. nonvegetarians was 0.82 (95% CI: 0.68–1.00, I ² = 0%, n = 6) for IHD. RoB was moderate ( n = 8) to serious ( n = 5). The associations between vegetarian diets and CVD and IHD were considered probably causal using WCRF criteria. Conclusions Vegetarian diets are associated with reduced risk of CVD and IHD, but not stroke, but further studies are needed on stroke. These findings should be considered in dietary guidelines. Review registration No review protocol registered.
... In addition, peanuts contain up to 30% of protein in their dry weight. Furthermore, these nuts offer a cheap source of high-quality oil and dietary vegetable proteins [55][56][57]. Data from [1]; * data from [14]; ** data from www.nutritionvalue.org/seeds (accessed on 16 October 2020); N, precise quantity information is not available. ...
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India plays an important role in the production of oilseeds, which are mainly cultivated for future extraction of their oil. In addition to the energic and nutritional contribution of these seeds, oilseeds are rich sources of bioactive compounds (e.g., phenolic compounds, proteins, minerals). A regular and moderate dietary supplementation of oilseeds promotes health, prevents the appearance of certain diseases (e.g., cardiovascular diseases (CVDs), cancers) and delays the aging process. Due to their relevant content in nutraceutical molecules, oilseeds and some of their associated processing wastes have raised interest in food and pharmaceutical industries searching for innovative products whose application provides health benefits to consumers. Furthermore, a circular economy approach could be considered regarding the re-use of oilseeds’ processing waste. The present article highlights the different oilseed types, the oilseeds-derived bioactive compounds as well as the health benefits associated with their consumption. In addition, the different types of extractive techniques that can be used to obtain vegetable oils rich from oilseeds, such as microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE) and supercritical fluid extraction (SFE), are reported. We conclude that the development and improvement of oilseed markets and their byproducts could offer even more health benefits in the future, when added to other foods.
... For example, increased intakes of dietary fibers, plant proteins, whole grains and dairy products (i.e., calcium) and magnesium had beneficial effects on abdominal obesity, blood pressure, insulin resistance, insulin secretion and sensitivity, TG, and HDL-C [11,24,25,49,53e57]. Frequent consumption of nuts improved TG, LDL-C and WC [11,58], whereas increased plant protein intake reduced WC and overall risk of MetS [57]. Consumption of omega-3 fatty acids and polyphenols in plant oils and fish improved lipid profiles and available level of circulating antioxidants known to protect against metabolic oxidative stress [11,59]. ...
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Aims Whether early young adulthood dietary patterns predict the risk of metabolic syndrome (MetS) and diabetes-related endpoints prior to middle age remains unknown. We examined the prospective associations of dietary patterns in early young adulthood with MetS and diabetes-related endpoints at later young adulthood. Methods We used data of young adults from a long running birth cohort in Australia. The Western dietary pattern rich in meats, refined grains, processed and fried foods and the prudent dietary pattern rich in fruits and vegetables, whole grains and legumes were derived using principal component analysis at the 21-year follow-up from dietary data obtained by a food frequency questionnaire. Fasting blood samples at 30 years were collected from each participant and their blood biomarkers, anthropometric and blood pressure were measured. MetS, insulin resistance, and prediabetes were based on clinical cut-offs; increased β-cell function and insulin resistance were based on upper quartiles. Log-binomial models were used to estimate diet-related risks of each outcome adjusting for potential confounders. Results Greater adherence to the Western pattern predicted higher risks of MetS (RR: 2.32; 95% CI: 1.34, 4.00), increased insulin resistance (1.69; 1.07, 2.65), high β-cell function (1.60; 1.10, 2.31) and less likelihood of increased insulin sensitivity (0.57; 0.39, 0.84) in adjusted models. Conversely, adhering more to the prudent pattern predicted lower risks of MetS (RR: 0.47; 95%CI: 0.29, 0.75), increased insulin resistance (0.57; 0.39, 0.82), high β-cell function (0.69; 0.50, 0.93) and a greater likelihood of increased insulin sensitivity (1.84; 1.30, 2.60). Conclusion This prospective study of young adults indicates greater adherence to unhealthy Western diet predicted higher risks of MetS and increased insulin resistance, whereas healthy prudent diet predicted lower risks. Optimising diets to improve later cardiometabolic health needs to occur in early adulthood.
... Tree nuts overall intake were shown to lowers total cholesterol, LDL cholesterol, Apo B, and triglycerides (Del Gobbo, Falk et al. 2015). In addition, a pooled analysis of 25 trials indicated that blood lipids including TC, LDL-C and TG are improved after a daily consumption of 67g of nuts (Sabate, Oda et al. 2010). ...
Thesis
Among the physiological and metabolic changes occurring with ageing, the ageing of heart function is a key determinant of health. The death number from CVDs is expected to reach over 23.6 million by 2030. An estimated 17.9 million people died from CVDs in 2019 in the UK, representing 32% of all global deaths. Evidence suggested that the Mediterranean diet supplemented with extra virgin olive oil (EVOO) (25-50 ml/day) is highly reported as associated with a reduction of CV risk factors. However, the acceptability of the Mediterranean diet and the feasibility of this dietary pattern which includes consumption of olive oil remains unknown among Caucasians and East Asians in Northeast England. An Online Survey with two ethnicities in equal number and similar mean age and BMI that were undertaken for this PhD programme indicating that the acceptability and frequency of olive oil intake among East Asians is higher with a great MD score (8.02±SD1.8) (p<0.001) while Caucasians who consume olive oil were scored higher for MD score (6.51±SD2.2) (p<0.001), scored higher for MD acceptability (10.21±SD2.3) (p=0.017) and reported lower perceived barriers to healthy eating (PBHE) (1.81±SD4.0) (p=0.03) than non-consumers. Olive oil intake is likely to be positively associated with older age, higher MD score, higher MD acceptability and lower PBHE in both ethnicities. Evidence examining the effectiveness of nuts and olive oil, on both traditional and novel CV risk factors, in a comprehensive study in adults with different ethnic background is lacking. Our systematic reviews and meta-analysis of previous relevant literature on nuts that were undertaken for this PhD programme showed that nuts improve TC (MD: -7.54; 95% CI: -10.2 to -4.89; p < 0.00001; I2=59%, n=66), HDL (MD: 0.89; 95% CI: 0.04 to 1.75; P=0.04; I2= 53%; n=67), LDL (MD: -7.21; 95% CI: -9.38 to -5.04; P< 0.00001; I2= 68%; n=68), TG (MD: -8.83; 95% CI: -13.12 to -4.53; P< 0.0001; I2= 64%; n=65) and FMD (MD: 0.74; 95% CI: 0.09 to 1.39; P=0.03; I2=5%, n=10). The non-Asiangroup potentially tends to benefit more CV biomarkers with moderate nut consumption than Asian group. Olive oil systematic review reported that olive oil improves biomarker - PAI-1 (MD: -1.02ng/ml, 95% CI: -1.92 to -0.12; p = 0.03, I2 = 0%). Nevertheless, studies on olive oil on different ethnicities were lacking. A 6-week, cross-over, randomised controlled dietary interventional study with 2 weeks interventional duration was undertaken to test the effects of EVOO on cardiovascular health. Overall, this study provided evidence on the benefits of over a 2-week period produced a positive effect on 24-hour SBP including daytime SBP, night-time DBP and MAP and TC, LDL for all participants. For East Asians, olive oil exerts a beneficial effect on 24-hour SBP and daytime SBP, MAP while night�time DBP was improved among Caucasians following EVOO. EVOO intake also has a positive effect on blood lipids - TC and circulating biomarkers - sE-selectin in East Asians while LDL and non-HDL are improved among Caucasians after EVOO intake. The findings reported in the present thesis could be valuable to health professionals to develop more effective interventions and could also help the public to make better informed food choices relating to cardiovascular health
... While dietitians and nutritionists have expertise in nutrition, given that all health professionals are in a position to educate patients, it is beneficial for all professionals to improve their current knowledge and to ensure that accurate nutrition information is provided to patients. For example, in response to whether nuts can increase people's total blood cholesterol and risk of CVD, significantly more non-dietitians/nutritionists incorrectly believed that nut consumption could increase blood cholesterol and risk of CVD, contradicting the current evidence base for the effect of nut consumption on health outcomes [15][16][17]. Similar results were observed in New Zealand where GPs and practice nurses were twice as likely as dietitians to believe nut consumption could increase blood cholesterol [7]. ...
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Consumption of nuts and seeds is associated with a range of health outcomes. Summarizing the best evidence on essential health outcomes from the consumption of nuts is essential to provide optimal recommendations. Our objective is to comprehensively assess health outcomes associations related to the consumption of nuts and seeds, using a culinary definition including tree nuts and peanuts (registered in PROSPERO: CRD42021258300). Health outcomes of interest include cardiovascular disease, cancer, diabetes, obesity, respiratory disease, mortality, and their biomarker for disease. We present associations for high versus low consumption, per serving, and dose-response relationships. Medline, Embase, Cochrane, and Epistemonikos were searched and screened for systematic reviews and meta-analyses. Evidence was extracted from 89 articles on the consumption of nuts and relevant health outcomes, including 23 articles with meta-analysis on disease and mortality, 66 articles on biomarkers for disease, and 9 articles on allergy/adverse outcomes. Intake of nuts was associated with reduced risk of cardiovascular diseases and related risk factors, with moderate quality of evidence. An intake of 28 grams of nuts per day compared to not eating nuts was associated with a 21% relative risk reduction of cardiovascular disease (including coronary heart disease incidence and mortality, atrial fibrillation, and stroke mortality), 11% risk reduction of cancer deaths, and 22% reduction in all-cause mortality. Nut consumption was also inversely associated with mortality from respiratory diseases, infectious diseases, and diabetes: however, associations between nut consumption and diabetes incidence were mixed. Meta-analyses of trials on biomarkers for disease generally mirrored meta-analyses from observational studies on cardiovascular disease, cancers, and diabetes. Allergy and related adverse reactions to nuts were observed among 1–2% of adult populations, with substantial heterogeneity between studies. Overall, the current evidence supports dietary recommendations to consume a handful of nuts and seeds per day for people without allergies to these foods.
Chapter
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Macadamia nuts are a native Australian food rich in the monounsaturated fats, oleic acid and palmitoleic acid. A monounsaturated fatty acid-rich diet (MD), enriched with macadamia nuts (40% energy as fat, 20% energy from macadamia nuts) was compaared with a high-complex-carbohydrate diet (HC) for effects on serum lipid and lipoprotein levels. Subjects (7 female, 7 male) between 25 and 59 years of age were randomly allocated either to MD followed by HC, or vice versa. Each dietary phase lasted 4 weeks. Both diets lowered serum cholesterol by 7.9% (p<0.01) and low density lipoprotein cholesterol (LDL) by 10.7% (p<0.01) compared with baseline values. The MD led to a 20.9% decrease in serum triglyceride levels (p<0.01). Triglyceride levels were not affected by HC. High density lipoprotein cholesterol (HDL) decreased 13.1% with HC (p<0.05). MD and HC were equally effective in lowering serum cholesterol and LDL levels, and MD unlike HC lowered triglyceride levels without affecting HDL levels.
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Frequent consumption of nuts is associated with decreased risk of cardiovascular disease. We investigated the effect of pecans rich in monounsaturated fat as an alternative to the Step 1 diet in modifying serum lipids and lipoproteins in men and women with normal to moderately high serum cholesterol. In a single-blind, randomized, controlled, crossover feeding study, we assigned 23 subjects (mean age: 38 y; 9 women, 14 men) to follow two diets, each for 4 wk: a Step I diet and a pecan-enriched diet (accomplished by proportionately reducing all food items in a Step I diet by one fifth for a 20% isoenergetic replacement with pecans). The percentage of energy from fat in the two diets was 28.3 and 39.6%, respectively. Both diets improved the lipid profile; however, the pecan-enriched diet decreased both serum total and LDL cholesterol by 0.32 mmol/L (6.7 and 10.4%, respectively) and triglyceride by 0.14 mmol/L (11.1%) beyond the Step I diet, while increasing HDL cholesterol by 0.06 mmol/L (2.5 mg/dL). Serum apolipoprotein B and lipoprotein(a) decreased by 11.6 and 11.1%, respectively, and apolipoprotein A1 increased by 2.2% when subjects consumed the pecan compared with the Step I diet. These differences were all significant (P , 0.05). A 20% isoenergetic replacement of a Step I diet with pecans favorably altered the serum lipid profile beyond the Step I diet, without increasing body weight. Nuts such as pecans that are rich in monounsaturated fat may therefore be recommended as part of prescribed cholesterol- lowering diet of patients or habitual diet of healthy individuals. J. Nutr. 131: 2275-2279, 2001.
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Objective: To assess the association, in a Mediterranean population, between nut consumption and risk of weight gain (at least 5 kg) or the risk of becoming overweight/obese. Research Methods and Procedures: The Seguimiento Universidad de Navarra project is a prospective cohort of 8865 adult men and women who completed a follow-up questionnaire after a median of 28 months. Dietary habits were assessed with a previously validated semiquantitative food-frequency questionnaire. Results: Nine hundred thirty-seven participants reported a weight gain of ≥5 kg at follow-up. After adjusting for age, sex, smoking, leisure time physical activity, and other known risk factors for obesity, participants who ate nuts two or more times per week had a significantly lower risk of weight gain (odds ratio: 0.69; 95% confidence interval: 0.53 to 0.90, p for trend = 0.006) than those who never or almost never ate nuts. Participants with little nut consumption (never/almost never) gained an average of 424 grams (95% confidence interval: 102 to 746) more than frequent nut eaters. Nut consumption was not significantly associated with incident overweight/obesity in the cohort. Discussion: Frequent nut consumption was associated with a reduced risk of weight gain (5 kg or more). These results support the recommendation of nut consumption as an important component of a cardioprotective diet and also allay fears of possible weight gain.
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bkground.— Although dietary factors are suspected to be important determinants of coronary heart disease (CHD) risk, the direct evidence is relative-lse.Methods.— The Adventist Health Study is a prospective cohort investigation of 31 208 non-Hispanic white California Seventh-Day Adventists. Extensive dietary information was obtained at baseline, along with the values of traditional coronary risk factors. These were related to risk of definite fatal CHD or definite nonfatal- dial infarction.Results.— Subjects who consumed nuts frequently (more than four times per week) experienced substantially fewer definite fatal CHD events (relative risk, 0.52; 95% confidence interval [CI], 0.36 to 0.76) and definite nonfatal myocardial infarctions (relative risk, 0.49; 95% CI, 0.28 to 0.85), when compared with those who consumed nuts less than once per week. These findings persisted on covariate adjustment and were seen in almost all of 16 different subgroups of the population. Subjects who usually consumed whole wheat bread also experienced lower rates of definite nonfatal myocardial infarction (relative risk, 0.56; 95% CI, 0.35 to 0.89) and definite fatal CHD (relative risk, 0.89; 95% CI, 0.60 to 1.33) when compared with those who usually ate white bread. Men who ate beef at least three times each week had a higher risk of definite fatal CHD (relative risk, 2.31; 95% CI, 1.11 to 4.78), but this effect was not seen in women or for the nonfatal myocardial infarction end point.Conclusion.— Our data strongly suggest that the frequent consumption of nuts may protect against risk of CHD events. The favorable fatty acid profile of many nuts is one possible explanation for such an effect.(Arch Intern Med. 1992;152:1416-1424)
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Background— Although recent studies have indicated that nut consumption may improve levels of blood lipids, nuts are not generally recommended as snacks for hyperlipidemic subjects because of their high fat content. Furthermore, the effective dose is still unknown. Methods and Results— The dose-response effects of whole almonds, taken as snacks, were compared with low-saturated fat (<5% energy) whole-wheat muffins (control) in the therapeutic diets of hyperlipidemic subjects. In a randomized crossover study, 27 hyperlipidemic men and women consumed 3 isoenergetic (mean 423 kcal/d) supplements each for 1 month. Supplements provided 22.2% of energy and consisted of full-dose almonds (73±3 g/d), half-dose almonds plus half-dose muffins, and full-dose muffins. Fasting blood, expired air, blood pressure, and body weight measurements were obtained at weeks 0, 2, and 4. Mean body weights differed <300 g between treatments. The full-dose almonds produced the greatest reduction in levels of blood lipids. Significant reductions from baseline were seen on both half- and full-dose almonds for LDL cholesterol (4.4±1.7%, P=0.018, and 9.4±1.9%, P<0.001, respectively) and LDL:HDL cholesterol (7.8±2.2%, P=0.001, and 12.0±2.1%, P<0.001, respectively) and on full-dose almonds alone for lipoprotein(a) (7.8±3.5%, P=0.034) and oxidized LDL concentrations (14.0±3.8%, P<0.001), with no significant reductions on the control diet. No difference was seen in pulmonary nitric oxide between treatments. Conclusions— Almonds used as snacks in the diets of hyperlipidemic subjects significantly reduce coronary heart disease risk factors, probably in part because of the nonfat (protein and fiber) and monounsaturated fatty acid components of the nut.
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Context Nuts are high in unsaturated (polyunsaturated and monounsaturated) fat and other nutrients that may improve glucose and insulin homeostasis.Objective To examine prospectively the relationship between nut consumption and risk of type 2 diabetes.Design, Setting, and Participants Prospective cohort study of 83 818 women from 11 states in the Nurses' Health Study. The women were aged 34 to 59 years, had no history of diabetes, cardiovascular disease, or cancer, completed a validated dietary questionnaire at baseline in 1980, and were followed up for 16 years.Main Outcome Measure Incident cases of type 2 diabetes.Results We documented 3206 new cases of type 2 diabetes. Nut consumption was inversely associated with risk of type 2 diabetes after adjustment for age, body mass index (BMI), family history of diabetes, physical activity, smoking, alcohol use, and total energy intake. The multivariate relative risks (RRs) across categories of nut consumption (never/almost never, <once/week, 1-4 times/week, and ≥5 times/week) for a 28-g (1 oz) serving size were 1.0, 0.92 (95% confidence interval [CI], 0.85-1.00), 0.84 (0.95% CI, 0.76-0.93), and 0.73 (95% CI, 0.60-0.89) (P for trend <.001). Further adjustment for intakes of dietary fats, cereal fiber, and other dietary factors did not appreciably change the results. The inverse association persisted within strata defined by levels of BMI, smoking, alcohol use, and other diabetes risk factors. Consumption of peanut butter was also inversely associated with type 2 diabetes. The multivariate RR was 0.79 (95% CI, 0.68-0.91; P for trend <.001) in women consuming peanut butter 5 times or more a week (equivalent to ≥140 g [5 oz] of peanuts/week) compared with those who never/almost never ate peanut butter.Conclusions Our findings suggest potential benefits of higher nut and peanut butter consumption in lowering risk of type 2 diabetes in women. To avoid increasing caloric intake, regular nut consumption can be recommended as a replacement for consumption of refined grain products or red or processed meats.
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Background—Epidemiological studies suggest that nut intake decreases coronary artery disease (CAD) risk. Nuts have a cholesterol-lowering effect that partly explains this benefit. Endothelial dysfunction is associated with CAD and its risk factors and is reversed by antioxidants and marine n-3 fatty acids. Walnuts are a rich source of both antioxidants and-linolenic acid, a plant n-3 fatty acid. Methods and Results—To test the hypothesis that walnut intake will reverse endothelial dysfunction, we randomized in a crossover design 21 hypercholesterolemic men and women to a cholesterol-lowering Mediterranean diet and a diet of similar energy and fat content in which walnuts replaced 32% of the energy from monounsaturated fat. Participants followed each diet for 4 weeks. After each intervention, we obtained fasting blood and performed ultrasound measurements of brachial artery vasomotor function. Eighteen subjects completing the protocol had suitable ultrasound studies. Compared with the Mediterranean diet, the walnut diet improved endothelium-dependent vasodilation and reduced levels of vascular cell adhesion molecule-1 (P0.05 for both). Endothelium-independent vasodilation and levels of intercellular adhesion molecule-1, C-reactive protein, homocysteine, and oxidation biomarkers were similar after each diet. The walnut diet significantly reduced total cholesterol (4.47.4%) and LDL cholesterol (6.410.0%) (P0.05 for both). Cholesterol reductions correlated with increases of both dietary-linolenic acid and LDL-tocopherol content, and changes of endothelium-dependent vasodilation correlated with those of cholesterol-to-HDL ratios (P0.05 for all). Conclusions—Substituting walnuts for monounsaturated fat in a Mediterranean diet improves endothelium-dependent vasodilation in hypercholesterolemic subjects. This finding might explain the cardioprotective effect of nut intake beyond cholesterol lowering.
Article
Background—Although recent studies have indicated that nut consumption may improve levels of blood lipids, nuts arenot generally recommended as snacks for hyperlipidemic subjects because of their high fat content. Furthermore, theeffective dose is still unknown.Methods and Results—The dose-response effects of whole almonds, taken as snacks, were compared with low-saturatedfat ( 5% energy) whole-wheat muffins (control) in the therapeutic diets of hyperlipidemic subjects. In a randomizedcrossover study, 27 hyperlipidemic men and women consumed 3 isoenergetic (mean 423 kcal/d) supplements each for1 month. Supplements provided 22.2% of energy and consisted of full-dose almonds (73 3 g/d), half-dose almonds plushalf-dose muffins, and full-dose muffins. Fasting blood, expired air, blood pressure, and body weight measurementswere obtained at weeks 0, 2, and 4. Mean body weights differed 300 g between treatments. The full-dose almondsproduced the greatest reduction in levels of blood lipids. Significant reductions from baseline were seen on both half-and full-dose almonds for LDL cholesterol (4.4 1.7%, P 0.018, and 9.4 1.9%, P 0.001, respectively) andLDL:HDL cholesterol (7.8 2.2%, P 0.001, and 12.0 2.1%, P 0.001, respectively) and on full-dose almonds alonefor lipoprotein(a) (7.8 3.5%, P 0.034) and oxidized LDL concentrations (14.0 3.8%, P 0.001), with no significantreductions on the control diet. No difference was seen in pulmonary nitric oxide between treatments.Conclusions—Almonds used as snacks in the diets of hyperlipidemic subjects significantly reduce coronary heart diseaserisk factors, probably in part because of the nonfat (protein and fiber) and monounsaturated fatty acid components ofthe nut. (Circulation. 2002;106:1327-1332.)Key Words: hypercholesterolemia lipids lipoproteins diet antioxidants