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Because of egg cholesterol content, reduction in egg consumption is generally recommended to reduce risk of cardiovascular disease. Recently, however, evidence has been accumulating to suggest that dietary cholesterol is less relevant to cardiovascular risk than dietary saturated fat. This randomized controlled crossover trial was conducted to determine the effects of egg ingestion on endothelial function, a reliable index of cardiovascular risk. Forty-nine healthy adults (mean age 56 years, 40% females) underwent a baseline brachial artery reactivity study (BARS), and were assigned to two eggs or oats daily for 6 weeks in random sequence with a 4-week washout. A BARS was done at the end of each treatment phase, measuring flow-mediated vasodilation (FMD) in the brachial artery using a high-frequency ultrasound. FMD was stable in both egg and oat groups, and between-treatment differences were not significant (egg -0.96%, oatmeal -0.79%; p value >0.05). Six weeks of egg ingestion had no effect on total cholesterol (baseline: 203.8 mg/dl; post-treatment: 205.3) or LDL (baseline: 124.8 mg/dl; post-treatment: 129.1). In contrast, 6 weeks of oats lowered total cholesterol (to 194 mg/dl; p = 0.0017) and LDL (to 116.6 mg/dl; p = 0.012). There were no differences in body mass index (BMI), triglyceride, HDL or SBP levels between egg and oat treatment assignments. Short-term egg consumption does not adversely affect endothelial function in healthy adults, supporting the view that dietary cholesterol may be less detrimental to cardiovascular health than previously thought.
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Egg consumption and endothelial function: a randomized
controlled crossover trial
David L. Katz*, Marian A. Evans, Haq Nawaz, Valentine Yanchou Njike, Wendy Chan,
Beth Patton Comerford, Martha L. Hoxley
Yale Prevention Research Center, 130 Division Street, Derby, CT 06418, USA
Received 14 August 2003; accepted 16 November 2003
Available online 19 July 2004
Abstract
Background: Because of egg cholesterol content, reduction in egg consumption is generally recommended to reduce risk of cardiovascular
disease. Recently, however, evidence has been accumulating to suggest that dietary cholesterol is less relevant to cardiovascular risk than dietary
saturated fat. This randomized controlled crossover trial was conducted to determine the effects of egg ingestion on endothelial function, a
reliable index of cardiovascular risk. Methods: Forty-nine healthy adults (mean age 56 years, 40% females) underwent a baseline brachial artery
reactivity study (BARS), and were assigned to two eggs or oats daily for 6 weeks in random sequence with a 4-week washout. A BARS was done
at the end of each treatment phase, measuring flow-mediated vasodilation (FMD) in the brachial artery using a high-frequency ultrasound.
Results: FMD was stable in both egg and oat groups, and between-treatment differences were not significant (egg 0.96%, oatmeal 0.79%; p
value > 0.05). Six weeks of egg ingestion had no effect on total cholesterol (baseline: 203.8 mg/dl; post-treatment: 205.3) or LDL (baseline:
124.8 mg/dl; post-treatment: 129.1). In contrast, 6 weeks of oats lowered total cholesterol (to 194 mg/dl; p= 0.0017) and LDL (to 116.6 mg/dl;
p= 0.012). There were no differences in body mass index (BMI), triglyceride, HDL or SBP levels between egg and oat treatment assignments.
Conclusion: Short-term egg consumption does not adversely affect endothelial function in healthy adults, supporting the view that dietary
cholesterol may be less detrimental to cardiovascular health than previously thought.
D2004 Elsevier Ireland Ltd. All rights reserved.
Keywords: Egg consumption; Endothelial function; Randomized controlled crossover trial
1. Introduction
Restricted egg consumption is widely recommended in
efforts to lower blood cholesterol and mitigate risk of heart
disease. However, there has been little if any evidence that
egg consumption is directly related to cardiovascular risk
[1,2]. On the contrary, large epidemiological studies have
found that consumption of one egg per day is unlikely to
have any substantial effect on cardiovascular disease risk in
healthy subjects [3,4]. Moreover, there has been a lack of
consistent literature to support the notion that regular or
near-regular egg ingestion leads to substantial elevation in
serum lipids and total cholesterol levels [1,5].
Because there are many serum moieties used to gauge
cardiac risk, a physiologic measure that captures their
aggregate influence is desirable. Endothelial function, which
refers to arterial vasomotor responses mediated through
release of chemical mediators including nitric oxide (vaso-
dilating) and endothelin (vasoconstricting) from the vascular
endothelium [6], is generally viewed as such a measure.
Impaired release of nitric oxide results in endothelial dys-
function which can be detected non-invasively by use of
ultrasound as the propensity of vessels to constrict and
impede flow in response to stimuli that should lead to
dilatation and flow augmentation [7]. One method of
assessing endothelial function non-invasively is by the
induction of hyperemic flow and sheer stress to stimulate
nitric oxide release [8]. Due to the strong correspondence
between peripheral and coronary endothelial responses [9],
measurement of flow-mediated dilatation (FMD) of the
brachial artery using high-resolution ultrasound is a standard
assessment method [10].
Endothelial dysfunction anticipates the development of
anatomically overt coronary artery disease [9], correlates
0167-5273/$ - see front matter D2004 Elsevier Ireland Ltd. All rights reserved.
doi:10.1016/j.ijcard.2003.11.028
* Corresponding author. Tel.: +1-203-732-1265; fax: +1-203-732-
1264.
E-mail address: katzdl@pol.net (D.L. Katz).
www.elsevier.com/locate/ijcard
International Journal of Cardiology 99 (2005) 65 – 70
strongly with both coronary disease and its risk factors [11]
and reverses in response to risk modification efforts [12].
While a definitive association between endothelial function
and clinical events awaits the results of an on-going multi-
center trial, endothelial dysfunction has increasingly been
viewed as an indicator of coronary risk [9], and its amelio-
ration as an indicator of risk reduction [12,13].
Endothelial function testing has been used extensively to
evaluate the acute and chronic effects of foods and nutrients
on cardiac risk [14 17]. In previous studies, oat ingestion
has produced favorable effects on endothelial function in
healthy adults challenged with a high-fat test meal [18,19],
and in adults with features of insulin resistance [20].We
therefore used oat ingestion as a positive control and
conducted a randomized controlled crossover trial of
short-term (6 weeks) daily ingestion of eggs on endothelial
function and lipid levels in healthy adults.
2. Materials and methods
2.1. Subjects
A total of 50 healthy adult men (n= 31) and women
(n= 19) were recruited from the greater Lower Naugatuck
Valley, CT, primarily through mass media (newspaper
advertisements, press releases) and posters. The sample
size was determined to allow for 10% attrition and provide
at least 80% power to detect a minimal difference of 4.0%
in FMD between treatment groups at a two-tailed alpha
level of 0.05. Inclusion criteria were: (1) age greater than
35 for males; (2) post-menopausal and not currently using
hormone replacement therapy for females; (3) non-smok-
ers; (4) no known coronary artery or other vascular disease;
(5) no vasoactive medication use; (6) no regular use of
high dose vitamin E or fiber supplements. Subjects from all
ethnic and minority groups were equally eligible for study
participation.
Individuals failing to meet inclusion criteria, including
those with hypercholesteremia (total cholesterol (T
chol
)
greater than 240, or T
chol
/HDL ratio greater than 4.5 for
women, or 5.5 for men), or anticipated inability to complete
the study protocol for any reason were excluded. Those
subjects (n= 107; m= 57, f= 50) who responded to recruit-
ment efforts were prescreened using a semi-structured
telephone interview. Subjects who met initial prescreening
criteria (n= 94) underwent a clinical screening examination
(height, weight, body mass index (BMI), waist, hip and
blood pressure measurements) performed by the clinical
research specialist, and laboratory testing (fasting total
cholesterol, HDL, LDL and triglyceride levels). The 50
eligible subjects enrolled were randomly assigned to six
groups. Each group was then randomly assigned to a
treatment sequence. Subjects could not be blinded to treat-
ment assignment; however, the ultrasonographer was strictly
blinded to treatment assignment. All subjects provided
informed consent prior to randomization. Participants were
compensated monetarily for their time.
2.2. Methods
Subjects first presented for baseline brachial artery reac-
tivity studies (BARSs), lipid panel and weight measure-
ments following an overnight fast. Subjects then returned
for 3 consecutive weeks and underwent BARS following
oatmeal ingestion, egg ingestion and ingestion of a sausage
and cheese sandwich (comparable to McDonald’s Sausage
McMuffink)[15] high in saturated fat, in random se-
quence. These single acute doses of egg, oats and sau-
sage/cheese sandwich were administered before the start of
the sustained intervention to gain some preliminary insight
into the direction of effect on FMD of a single dose of each
study treatment (eggs and oats) relative to the high-saturated
fat breakfast sandwich.
Subject assignment to treatment groups was performed
by the data manager using block randomization with one
subject per block. Groups were randomly assigned to each
of the two treatment assignments (eggs or oatmeal) daily for
a period of 6 weeks, followed by BARS and laboratory
testing, a 4-week washout period, then crossover to the other
treatment, again followed by BARS and laboratory testing.
The daily oat treatment during the sustained phase consisted
of 60 g uncooked whole oats. The daily egg treatment
consisted of two eggs. Subjects were at liberty to prepare
the treatment foods according to preference, but were
encouraged to consume them as part of the breakfast meal.
On the day of testing, BARS, lipid panel, and weight
measurement were performed in the morning following an
overnight fast. Immediately after the baseline scan, each
subject received the assigned treatment; eggs were prepared
hard boiled, oatmeal was served plain. BARS testing was
repeated exactly 3 h post-prandially for each subject.
Subjects were instructed to return all egg and oatmeal
containers to confirm compliance. Subjects also completed a
3-day food diary during each treatment period, including the
4-week washout, as well as a side-effects survey.
Informed consent was obtained from each subject and the
study protocol conforms to the ethical guidelines of the
1975 Declaration of Helsinki as reflected in a priori approv-
al by the Griffin Hospital Institutional Review Board.
2.3. Vascular reactivity testing: brachial artery reactivity
studies
Each vascular reactivity test consisted of pre- and post-
prandial BARS. Endothelial function was measured non-
invasively in the right brachial artery by means of a high
frequency ultrasound machine (Phillips Medical Systems;
Sonos 4500) in accordance with published guidelines [10].
Subjects were required to lie at rest in the quiet, temper-
ature-controlled, softly lit room for at least 15 min before
scanning was initiated. The baseline diameter of the bra-
D.L. Katz et al. / International Journal of Cardiology 99 (2005) 65–7066
chial artery was measured from two-dimensional ultra-
sound images using a high frequency, 10– 15 MHz, vas-
cular ultrasound transducer (Phillips Medical Systems 15-
6L L7540 linear array transducer). Arterial flow-velocity
was measured by means of a pulsed Doppler signal at a
70jangle to the vessel, with the range gate in the center of
the artery. Flow is determined by multiplying the arterial
cross-sectional area (pr
2
) by the Doppler flow velocity. The
timing of each image frame with respect to the cardiac
cycle is determined with simultaneous ECG gating during
image acquisition via the high-quality mainframe ultra-
sound system. Measurements were taken from the anterior
to the posterior ‘‘m’’ line in diastole. The brachial artery
was imaged at a location 37 cm above the antecubital
fossa in the longitudinal plane. A segment with clear
anterior and posterior intimal interfaces between the lumen
and vessel wall was selected for continuous 2D gray scale
imaging. The transmit (focus) zone was set to the depth of
the near wall because of difficulty in differentiating the
near from the far wall ‘‘m’’ line (the interface between
media and adventitia). Images were acquired on videotape
and magnetic optical disk for evaluation and analysis.
Diameter was obtained from m-line to m-line, over a
consistent segment of vessel at least 1015 mm in length.
To create a flow stimulus in the brachial artery, a sphyg-
momanometer (blood pressure cuff) was placed on the
upper arm proximal to the transducer. The cuff was inflated
for 5 min. Repeat scans were obtained at 15, 60 and 120 s
post-deflation. At each scanning interval, both cross-sec-
tional vessel diameter and flow velocity were recorded.
Measures of vessel diameter and flow velocity were
obtained by a single dedicated vascular clinical research
specialist blinded to subject treatment status. Velocity
measures were generated automatically, while the arterial
diameter was measured at a fixed distance from an ana-
tomical marker, such as a bifurcation, with ultrasonic
calipers recorded on magneticoptical disk. A random
sample of 30 BARS were provided to the clinical research
specialist for a blinded second reading. The resultant
coefficient of intraobserver reliability was 0.95.
2.4. Statistical analysis
All data were entered and stored by a dedicated data
manager using Microsoft Excel 2000. Data were manually
checked for entry accuracy. Flow-mediated dilatation, or
FMD, was calculated as the percent change in diameter
post-occlusion of brachial artery at 60 s relative to the
measurement at baseline before cuff inflation {[(response
baseline)/baseline] 100}. FMD was calculated during the
pre-prandial state and post-prandial state. A difference
measure between post-prandial FMD and pre-prandial
FMD was calculated to determine the value of post-prandial
FMD after adjusting with pre-prandial FMD.
All data analysis was conducted using SAS software
(Version 8.1 of the SAS System for Windows; SAS Insti-
tute, Cary, NC). A two-tailed pvalue of < 0.05 was
considered statistically significant. The change in hyperemic
response among the two treatment groups was measured
using repeated measures ANOVA. To control for type I
comparison-wise error rate, Duncan’s Multiple Range Test
for treatments was included. In the analysis, treatment and
time are considered as the main effects to compare treat-
ment-specific measures while accounting for time differ-
ences. Paired ttests were performed to compare pre- and
post-prandial vascular responses within treatments. To ac-
count for variability in the strength of the stimulus that
triggered endothelial reactivity (i.e., the hyperemic flow
Table 1
Baseline clinical characteristics of study population by gender
Variables (not including one male Mean FS.D.
dropout in acute phase) Male (n= 30) Female (n= 19)
Age (years) 54.1 F9.9 59.2 F8.5
BMI (kg/m
2
) 28.1 F3.5 29.5 F10.7
Total cholesterol (mg/dl) 196.2 F31.1 215.7 F28.4
HDL (mg/dl) 46.1 F10.2 63.1 F14.7
LDL (mg/dl) 120.8 F24.7 131.2 F24.2
Triglycerides (mg/dl) 146.2 F80.9 118.8 F68.7
Reference diameter (cm) 0.40 F0.07 0.32 F0.05
Diameter change 60 s to baseline (cm) 0.04 F0.03 0.03 F0.04
% Diameter change 60 s to baseline 11.0 F9.4 11.1 F12.8
Systolic blood pressure (mm Hg) 129.8 F11.7 131.9 F16.0
Diastolic blood pressure (mm Hg) 79.2 F9.5 79.7 F13.1
S.D. = Standard deviation.
Table 2
Flow-mediated dilatation (FMD) after an acute treatment with egg, oatmeal,
or sausage and cheese (n= 49)
Treatment Pre-prandial* Post-prandial* % Change
Egg 13.7 F11.0 9.6 F11.5
yz
4.04
z
Oatmeal 8.3 F13.0 8.4 F10.3
yz
0.14
z
Sausage and cheese 10.9 F7.6 10.4 F9.9
yz
0.50
z
* Mean FS.D.
y
pValue >0.05 adjusting with pre-prandial (paired ttest).
z
pValue >0.05 compared to other treatments (ANOVA).
Table 3
FMD after 6 weeks of treatment with egg or oatmeal (n= 49)
Treatment Pre-prandial* Post-prandial* % Change
Egg
Reference diameter (cm) 0.43 F0.08 0.43 F0.08 –
Hyperemic diameter
at 60 s (cm)
0.47 F0.08 0.44 F0.07 –
Flow-mediated
vasodilation (FMD)
8.66 F9.69 8.32 F6.33
yz
0.96
z
Oatmeal
Reference diameter (cm) 0.43 F0.07 0.43 F0.07 –
Hyperemic diameter
at 60 s (cm)
0.46 F0.08 0.47 F0.07 –
Flow-mediated
vasodilation (FMD)
6.98 F8.45 6.56 F7.99
yz
0.79
z
* Mean FS.D.
y
pValue >0.05 adjusting with pre-prandial (paired ttest).
z
pValue >0.05 compared to different treatments (ANOVA).
D.L. Katz et al. / International Journal of Cardiology 99 (2005) 65–70 67
induced to stimulate endothelial response), FMD was divid-
ed by flow at 15 s post-cuff deflation to create a stimulus-
adjusted response measure. The study was powered at a
minimal level of 80% to test the primary hypothesis that egg
ingestion differs from oat ingestion with regard to effects on
endothelial function.
3. Results
Subjects ranged in age from 36 to 73, with a mean age of
55.7 years. Demographic data for the study population are
provided in Table 1. A total of 49 subjects completed the
study. One male subject dropped out for unknown reasons.
With acute administration, both egg and the sausage/
cheese breakfast sandwich resulted in a non-significant
decline in FMD, while oat ingestion produced a non-
significant increase (see Table 2). The treatments did not
differ significantly from one another, nor were there inter-
treatment correlations in FMD response.
With daily ingestion of eggs or oats for 6 weeks, there
were no statistically significant differences in endothelial
function between treatment groups. FMD following egg
treatment did not differ from baseline with regard to the
pre-prandial or post-prandial measures. In a paired ttest
analysis, the mean FMD difference (between pre-and post-
prandial responses) for egg treatment was not significant
(0.96; P>0.05).
Results following oat treatment were similar, with no
differences from baseline in pre-prandial FMD, post-pran-
dial FMD or the difference between pre- and post-prandial
measures (see Table 3). These findings persist after control-
ling for type I comparison-wise error. There was no signif-
icant difference between treatment groups for stimulus
adjusted response measures.
Ingestion of egg for 6 weeks had no effect on total
cholesterol (baseline: 203.8 mg/dl; post-treatment 205.3) or
LDL (baseline: 124.8 mg/dl; post-treatment: 129.1). In
contrast, ingestion of oat treatment for 6 weeks lowered
total cholesterol to 194 mg/dl ( p= 0.0017) and LDL to
116.6 mg/dl ( p= 0.012). Post-treatment total cholesterol
(p= 0.0008) and LDL ( p= 0.0006) were both lower follow-
ing treatment with oat than with egg. There were no differ-
ences in body mass index, triglyceride, HDL or SBP level
between the egg and oat assignments (see Table 4).
4. Discussion
To our knowledge, this is the first study to demonstrate
the effect of egg ingestion on endothelial function. Our
findings provide evidence that short-term egg consumption
(6 weeks) does not adversely affect endothelial function in
healthy adults. Moreover, consuming two eggs daily did not
alter serum cholesterol or other measures of the lipid profile.
The prevailing view has long been that dietary choles-
terol contributes to elevated serum cholesterol, thereby
increasing heart disease risk [2123]. The association
between dietary cholesterol and serum cholesterol, indepen-
dent of dietary fat, is at best controversial, however [24,25].
Concern over egg consumption and potential adverse effects
on cardiovascular health stems from the high cholesterol
content (approximately 213 mg of cholesterol) of egg yolk.
However, there is limited if any epidemiological evidence
that egg consumption is directly related to cardiovascular
disease or mortality risk [1,3,4]. On the contrary, a recent
large epidemiologic study concluded that consumption of
one egg per day is unlikely to have any substantial effect on
cardiovascular disease risk in healthy subjects [3]. Analysis
of Framingham data for 912 subjects revealed no relation-
ship between the incidence of coronary heart disease and
tertile of egg intake [4]. Other studies investigating choles-
terol effects of egg consumption failed to show significant
increase in serum cholesterol levels [26], LDL or triglycer-
ides [27]. However, others report finding mild increases in
LDL and total cholesterol [28,29].
Egg ingestion is associated with mild increases in HDL
[27,30]. Homeostatic control of cholesterol absorption and
elimination may physiologically adapt to increasing dietary
cholesterol intake by limiting the amount of cholesterol
absorbed at higher dietary intake levels and by down-
regulation of cholesterol biosynthesis [31,32]. In the aggre-
gate, the evidence supports an important role for internal
metabolic control over serum cholesterol levels, with dietary
fat (quality and quantity) influencing plasma cholesterol far
more than dietary cholesterol [25].
The relative importance of dietary cholesterol to car-
diovascular risk, and the association between dietary and
serum cholesterol are both subject to ongoing debate
[24,33,34]. The association between dietary cholesterol
and coronary events and mortality is generally positive
but rather weak, and derived largely from ecological and
prospective cohort studies with variable follow-up [33,
Table 4
Outcome variables after 6 weeks of treatment with egg or oatmeal
Variables Mean FS.D.
Baseline Egg Oatmeal
BMI (kg/m
2
) 28.7 F7.2 28.1 F5.8 28.5 F5.7
Total cholesterol (mg/dl) 203.8 F31.5 205.3 F35.6 194.0 F30.5*
HDL (mg/dl) 52.6 F14.6 51.2 F15.1 53.3 F16.5
LDL (mg/dl) 124.8 F25.0 129.1 F32.2 116.6 F30.8*
Triglycerides (mg/dl) 135.6 F77.3 126.6 F72.8 122.5 F75.7
Reference diameter (cm) 0.37 F0.07 0.44F0.07 0.43 F0.07
Diameter change 60 s to
baseline (cm)
0.04 F0.04 0.48 F0.07 0.48 F0.07
% Diameter change 60 s
to baseline
11.0 F9.5 8.3 F6.3 6.6 F8.0
Systolic blood
pressure (mm Hg)
129.8 F11.7 124.9 F10.9 124.1 F12.5
Diastolic blood
pressure (mm Hg)
79.4 F9.1 77.4 F7.0 77.5 F8.7
*pValue < 0.05 compared to baseline value.
D.L. Katz et al. / International Journal of Cardiology 99 (2005) 65–7068
35,36]. In most such studies, covariance of dietary fat and
cholesterol intakes makes it difficult to un-bundle their
effects reliably.
While rich in cholesterol, eggs are also rich in monoun-
saturated fatty acids, polyunsaturated fatty acids and micro-
nutrients, and provide relatively little total fat and
proportionately little saturated fat compared to other sources
of animal protein [37,38]. Data from NHANES III reveal that
egg consumption is an important nutritional contribution to
the average American diet [2], providing a relatively inex-
pensive source of amino acids and essential fatty acids [39].
Eggs provide arginine, a precursor to nitric oxide, which, in
turn, plays a central role in endothelial function [40].
While providing valuable, preliminary data regarding
egg ingestion and cardiovascular health, this study naturally
has limitations. The sample size was relatively small and
derived from the population of one confined geographic
area in CT. Dietary intake data, including compliance to the
treatment assignment, were tracked by food diaries and
suggest no significant unintended changes in dietary pattern
during the study. Nonetheless, changes in diet or behavior
that were not captured might have contributed to the
findings observed. Subjects were not instructed to eliminate
either of the two treatment assignments from their normal
diets during the study. The duration of egg consumption
during this study limits the ability to project long-term
effects of egg ingestion. The study cohort was limited to
healthy adults; the implications for other groups are uncer-
tain. However, the strong correlation between endothelial
function and clinical risk factors for coronary heart disease,
coronary atherosclerosis, myocardial infarction and unstable
angina [41], suggests that these findings are of considerable
potential importance.
In conclusion, short-term, sustained ingestion of two
eggs daily did not adversely affect endothelial function or
cholesterol levels in healthy adults. Our findings are
consistent with the view that dietary cholesterol may be
less detrimental to cardiovascular health than previously
thought. Investigation of the differences between saturated
(and trans) fat and dietary cholesterol effects on diverse
measures of cardiac risk is warranted, as is further study of
the health effects of habitual egg ingestion in diverse
populations. In the interim, there appears to be no clear
reason to exclude moderate intake of eggs from the dietary
patterns of healthy adults.
Acknowledgements
Funding for this study was provided by the American
Egg Board*Egg Nutrition Center/U.S. Department of
Agriculture and by grant number U48/CCU115802-03 from
the Centers for Disease Control and Prevention. We
gratefully acknowledge Quaker Oats for providing the oats
used in this study. The technical assistance of Michelle
Larovera is greatly appreciated.
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... Finally, seven trials [24,32e37] were included, which were published between 2005 and 2018 (Table 1). Included studies were conducted in US [24,32,33,37], Poland [34], Netherlands [35] and Ireland [36]. The three studies included in this systematic review were double blinded randomized controlled trials (DBRCTs) [34e36]. ...
... The three studies included in this systematic review were double blinded randomized controlled trials (DBRCTs) [34e36]. A crossover design was applied in five studies [24,32,33,36,37]. Two studies were single-blind trial [24,33]. ...
... Whole eggs were used as the intervention in the four studies [24,32,33,37]. Skorkowska-Telichowska et al. [34] used egg-derived phospholipids in their study. ...
Article
Full-text available
Background & Aims Cardiovascular diseases (CVDs) are considered as a major cause of health loss for all regions of the world. Atherosclerosis is one of the most important underlying causes of CVDs. Vascular dysfunction is the primary marker of atherosclerosis. Various studies have investigated the effect of egg intake on CVDs. This study aimed to determine the effect of egg and its derivatives consumption on vascular function. Methods Using a comprehensive search strategy, the searching was conducted on PubMed, Scopus and Google Scholar search engines resources (from inception up to Feb 2020). Intended exposure and outcome were egg or its derivatives intake, and vascular function measuring methods, respectively. Results A total of 35 papers were found through search databases. Finally, seven trials were included, which were published between 2005 and 2018. Results showed that acute and chronic consumption of whole eggs did not have a significant adverse effect on flow-mediated dilatation (FMD). Also, lutein-enriched egg yolk and egg ovalbumin-derived protein hydrolysate did not have significant positive effects on FMD and pulse wave velocity (PWV), respectively. However, one month egg-yolk-derived phospholipid (PL) preparation intervention increased FMD by 3.4% (p< 0.05), and replacing a portion of a glucose challenge with whole eggs or egg whites improved postprandial FMD (p< 0.05). Conclusions We concluded that consumption of whole egg, despite being rich in cholesterol, has no adverse effect on vascular function, and even some of egg derivatives may improve vascular function. Further research is needed to justify the potential effects of egg or its derivatives on vascular function.
... This fear that if too much eggs are eaten, it could pose health risks is, however, unfounded because studies have shown that consuming 2 eggs per day for 6 weeks causes no health related diseases. 29,30 Out of the 54 egg consumers, majority (63.64%) of them were willing to consume more eggs if available and affordable. Similar responses have been obtained in past studies. ...
... Cardiovascular diseases, therefore, may not necessarily be the result of eating eggs or excess of it. 29,30 Due to the associated cholesterol content of the oils used in the preparation of eggs, boiled eggs were more prevalent among the consumers. ...
... We included 17 randomized clinical trials [7,36,[40][41][42][43][44][45][46][47][48]51,[53][54][55][56][57]. Table below shows an overview of the characteristics of the included studies. ...
... Six studies were RCTs [40,42,47,53,54,56]. Eleven studies were crossover studies [7,36,41,[43][44][45][46]48,51,55,57]. The intervention time ranged 21-84 days ( Table 1). ...
Article
Full-text available
The association of egg consumption and serum cholesterol concentrations in healthy people has been discussed for a long time. In this study, we aimed to explore association of egg consumption with on low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) concentrations and the LDL-c/HDL-c ratio through meta-analysis. This systematic review only included randomized controlled trials (RCTs) investigating egg consumption in healthy populations without combination therapy. We extracted mean and standard deviation for LDL-c/HDL-c ratio, LDL-c/HDL-c. The extracted data were pooled in a random-effects model and were presented as mean difference (MD) with 95% confidence interval (CI). Moreover, subgroup analyses were conducted for understanding effects of more egg consumption (MEC) on different intervention periods, egg-consumption levels, classification of responders. Overall, 17 RCTs met the eligibility criteria and pooled results showed MEC group had a higher LDL-c/HDL-c ratio than the control group (MD = 0.14, p = 0.001, I 2 = 25%). The MEC group also had higher LDL-c than the control group (MD = 8.14, p < 0.0001, I 2 = 18%). Moreover, for the subset of intervention over two months, the MEC group seemed to have a larger effect size than the subset of intervention within two months. This synthesis, the largest meta-analysis on this topic, shows the impact of egg consumption on lipid profiles among healthy subjects. Notably, longer time with MEC may lead to higher LDL-c/HDL-c ratio and LDL-c. However, RCTs with long tern follow-up are needed to guarantee the association between egg consumption and human health.
... Therefore, the inclusion of eggs in the context of PBDs could be considered as an adjuvant to enhance the overall diet quality in those at risk of T2DM adopting PBDs. Our findings regarding EF and lipid profiles in adults at risk of T2DM are consistent with findings of our prior studies involving healthy adults, adults with dyslipidemia, and adults with established ischemic vascular diseases (19)(20)(21). In 3 large prospective studies (22), egg consumption was not associated with major CVD and lipid profile. ...
Article
Background Plant-based diets (PBDs) are typically recommended to those at risk of type 2 diabetes mellitus (T2DM). Objectives We examined how including eggs, compared with excluding them from PBDs, affected cardiometabolic risk factors in adults at risk of T2DM. Methods This was a randomized, controlled, single-blind, crossover trial of 35 adults (mean age: 60.7 y; 25 women, 10 men) at risk of T2DM assigned to 1 of 2 sequence permutations of 2 dietary treatments (plant-based plus eggs, and exclusively plant-based), with a 4-wk washout period. A dietitian counseled participants to exclude or include 2 eggs daily in the context of PBDs for a 6-wk interval. Our primary outcome measure was endothelial function (EF) measured as flow-mediated dilatation. Secondary outcome measures included lipid profile, blood pressure, insulin sensitivity, anthropometry, and dietary intake. Data were analyzed using generalized linear models. Results Compared with egg exclusion, egg inclusion in the context of PBDs did not adversely affect EF (−1.7% ± 6.5% compared with −1.8% ± 7.5%; P = 0.9805). Likewise, egg inclusion, compared with egg exclusion, did not adversely affect (P = 0.1096–0.9781) lipid profile, blood pressure, insulin sensitivity, or anthropometry. Egg inclusion, compared with egg exclusion, improved reported intakes of selenium (23.1 ± 30.3 μg/d compared with 2.3 ± 34.9 μg/d; P = 0.0124) and choline (172.0 ± 96.0 mg/d compared with −3.4 ± 68.1 mg/d; P < 0.0001). Conclusions Consuming 2 eggs daily in the context of PBDs does not adversely affect cardiometabolic risk factors among adults at risk of T2DM. Eggs could be used as an adjuvant to enhance PBDs that are typically recommended for those at risk of T2DM. This trial was registered at clinicaltrials.gov as NCT04316429.
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The purpose of this research was to investigate whether the consumption of lutein and DHA enriched eggs can improve visual function among older adults at risk of age-related eye disease. A total of 30 Caucasian older adults (64.0 ± 3.4 years) consumed enriched eggs (0.87 mg lutein/day, 220 mg DHA/day) daily for 6-weeks. Retina function was assessed by full-field electroretinogram along with plasma DHA, plasma lutein, lipid profiles, and lipoprotein subfractions at day 0 (PRE) and 6 weeks (POST). At POST, maximum amplitude of scotopic a-wave and photopic b-wave significantly increased (P < 0.001); and plasma DHA levels increased by 35.4% (P < 0.001). Plasma lipid parameters, lutein and LDL sub-fractions remained unchanged, with a significant increase in large HDL particles and a decrease in intermediate sized HDL particles. Overall, the consumption of two lutein and DHA enriched eggs daily improves electrophysiological retina function without adversely altering plasma lipids in Caucasian older adults.
Article
The current review examines the totality of the evidence to determine if there exists a relationship between β‐glucan and body weight and adiposity and whether such a relationship is a consistent, causal and plausible one. Observational studies suggest an association between oat (i.e., β‐glucan) intake and reduced body weight, waist circumference and adiposity. High and moderate quality randomized controlled trials that were specifically designed to evaluate the efficacy of β‐glucan on anthropometric outcomes were given the highest weight. Several of these studies indicated a causal relationship between β‐glucan consumption and reduction in body weight, BMI, and at least one measure of body fat within diets that were not calorie-restricted. A review of additional animal and human evidence suggests multiple plausible mechanisms by which β‐glucan may impact satiety perception, gastric emptying, gut hormones, gut microbiota and short chain fatty acids in the complex interplay of appetite and energy regulation.
Chapter
In many countries, the area of Food for Health has been recognized as a research priority. This concept is based on the prodigious potential for improving health through foods. While egg has become a vital staple food, numerous studies on characterizing chemical composition, exploring biological function, and seeking nutraceutical and industrial applications have been conducted in the past two decades. In Western society, particularly in the Europe and North America, cardiovascular disease continues to be a leading cause of death in spite of progress in prevention, detection, and treatment. The 21st century is the age of disease prevention, and nature's numerous, beautiful gifts are being used for the purpose of human health. Egg is such a product, having a complete set of human building blocks. An egg product, reduced in cholesterol content, enriched with PUFAs, Cu, and Mn and having anti-ROS activity, anti-ACEI activity, platelet inhibition, anti-coagulation, and anti-inflammation components, would be ideal to protect our heart health. Recent research has progressed at a great pace to substantiate this goal.
Article
冠心病是全球死亡的首要原因。作为均衡膳食的一部分,食用全 谷物和谷物纤维可以降低罹患冠心病的风险。食品包装上的健康声称 可以有效地帮助消费者选择健康的饮食。1997 年,美国食品和药品管 理局首次批准了一项健康声称,燕麦、燕麦麸和全燕麦粉来源的b-葡 聚糖可溶性纤维可以降低罹患冠心病的风险。目前,只有少数国家批 准了类似的声称。自1997 年以来,针对燕麦b-葡聚糖与冠心病关系的 证据被大量证实并发表。为了帮助其他国家使用该声称,本文综述了 支持该声称的全部数据(包括美国食品和药品管理局用来证实该声称 的证据和自1997 年以来发表的49 项临床试验的结果),也讨论了基于 科学证据的健康声称需要考虑的很多复杂因素,包括加工过程对b-葡 聚糖降低胆固醇功效的影响。
Article
Coronary heart disease (CHD) is the leading cause of death globally. Consumption of whole grains and cereal fiber, as part of a healthy diet, can lower the risk of CHD. Health claims on food products are effective in helping consumers select healthful diets. The US Food and Drug Administration was the first to approve a health claim, in 1997, between beta-glucan soluble fiber from whole oats, oat bran, and whole oat flour and reduced risk of CHD. Only a few countries have approved similar claims. Since 1997, a significant amount of additional evidence has been published on the relationship between oat beta-glucan and CHD. To assist other jurisdictions in potentially utilizing this claim, the full extent of data that supports this claim (ie, the evidence utilized by the US Food and Drug Administration to substantiate the claim, as well as the results of 49 clinical trials published since 1997) are reviewed here. The complexities involved in authoring evidence-based health claims, including the impact of processing on beta-glucan cholesterol-lowering efficacy in approving eligible beta-glucan products, are also discussed.
Article
The misperception that dietary cholesterol determines blood cholesterol is held by many consumers in spite of evidence to the contrary. Many studies reported over the past 2 years have shown that dietary cholesterol is not a significant factor in an individual's plasma cholesterol level or cardiovascular disease (CVD) risk. Reports from the Lipid Research Clinics Research Prevalence Study and the Framingham Heart Study have shown that dietary cholesterol is not related to either blood cholesterol or heart disease deaths. In a similar manner, 10 clinical trials (1994 to 1996) of the effects of dietary cholesterol on blood lipids and lipoproteins indicate that addition of an egg or two a day to a low-fat diet has little if any effect on blood cholesterol levels. This observation was noted in young men and women with normal cholesterol levels as well as older subjects with elevated plasms cholesterol concentrations. The consistency of the clinical and the epidemiological data demonstrating that dietary cholesterol has little effect on plasma cholesterol in most individuals raises a number of questions regarding the justification of population wide restrictions on dietary cholesterol intake and egg consumption.
Article
Context Reduction in egg consumption has been widely recommended to lower blood cholesterol levels and prevent coronary heart disease (CHD). Epidemiologic studies on egg consumption and risk of CHD are sparse. Objective To examine the association between egg consumption and risk of CHD and stroke in men and women. Design and Setting Two prospective cohort studies, the Health Professionals Follow-up Study (1986-1994) and the Nurses' Health Study (1980-1994). Participants A total of 37,851 men aged 40 to 75 years at study outset and 80,082 women aged 34 to 59 years at study outset, free of cardiovascular disease, diabetes, hypercholesterolemia, or cancer. Main Outcome Measures Incident nonfatal myocardial infarction, fatal CHD, and stroke corresponding to daily egg consumption as determined by a food-frequency questionnaire. Results We documented 866 incident cases of CHD and 258 incident cases of stroke in men during 8 years of follow-up and 939 incident cases of CHD and 563 incident cases of stroke in women during 14 years of follow-up. After adjustment for age, smoking, and other potential CHD risk factors, we found no evidence of an overall significant association between egg consumption and risk of CHD or stroke in either men or women. The relative risks (RRs) of CHD across categories of intake were less than 1 per week (1.0), 1 per week (1.06), 2 to 4 per week (1.12), 5 to 6 per week (0.90), and ≥1 per day (1.08) (P for trend=.75) for men; and less than 1 per week (1.0), 1 per week (0.82), 2 to 4 per week (0.99), 5 to 6 per week (0.95), and ≥1 per day (0.82) (P for trend=.95) for women. In subgroup analyses, higher egg consumption appeared to be associated with increased risk of CHD only among diabetic subjects (RR of CHD comparing more than 1 egg per day with less than 1 egg per week among diabetic men, 2.02 [95% confidence interval, 1.05-3.87; P for trend=.04], and among diabetic women, 1.49 [0.88-2.52; P for trend=.008]). Conclusions These findings suggest that consumption of up to 1 egg per day is unlikely to have substantial overall impact on the risk of CHD or stroke among healthy men and women. The apparent increased risk of CHD associated with higher egg consumption among diabetic participants warrants further research.
Article
Context. —Much has been written about the potential role of antioxidants in the prevention of atherosclerosis.Objective. —To assess the short-term effect of a single high-fat meal with and without pretreatment with antioxidant vitamins on endothelial function in healthy, normocholesterolemic subjects.Design. —Observer-blinded randomized trial.Setting. —University hospital.Participants. —Twenty healthy, normocholesterolemic (total and low-density lipoprotein cholesterol <5.2 mmol/L and <3.4 mmol/L [<200 mg/dL and <130 mg/ dL], respectively), male (7) and female (13) hospital employee volunteers, aged 24 to 54 years.Intervention. —Three randomly administered breakfasts: (1) a high-fat meal (3766 J [900 calories], 50 g of fat); (2) a low-fat meal (3766 J [900 calories], 0 g of fat); and (3) a high-fat meal and pretreatment with oral administration of vitamins C (1 g) and E (800 IU) (high-fat meal with vitamins). A subgroup of 10 subjects also ate the low-fat meal with the same vitamin pretreatment (low-fat meal with vitamins).Main Outcome Measure. —High-resolution ultrasound assessed flow-mediated (endothelium-dependent) brachial artery vasodilation measured as percent diameter change before and hourly for 6 hours following each meal.Results. —Flow-mediated vasodilation fell from a mean±SD of 20%±8% before to 12%±6%, 10%±6%, and 8%±9% at 2, 3, and 4 hours, respectively, after the high-fat meal (P<.001). No significant changes in flow-mediated vasodilation occurred after the low-fat meal, high-fat meal with vitamins, or low-fat meal with vitamins. The change in flow-mediated vasodilation after the low-fat and high-fat meals correlated inversely with the 2-hour postprandial change in triglyceride levels (r=-0.54; P<.001).Conclusion. —A single high-fat meal transiently reduces endothelial function for up to 4 hours in healthy, normocholesterolemic subjects, probably through the accumulation of triglyceride-rich lipoproteins. This decrease is blocked by pretreatment with antioxidant vitamins C and E, suggesting an oxidative mechanism.
Article
The influence of whole fresh eggs on the serum cholesterol level in men and women was studied independently in hospitalized patients in Sofia, Prague and Urbana-Champaign. The patients were fed two eggs or the equivalent of two eggs in a custard base or milk shake in addition to the foods that were consumed in their diet pattern. The serum cholesterol level was determined before and at periods varying from 5 hr to 54 days after the consumption of the eggs. The mixed fatty acid composition of the total lipids in the serum and the erythrocytes was also determined. In the majority of patients, the serum cholesterol level did not change significantly 5 hr after the consumption of 465 mg of cholesterol in an egg custard base or milk shake or after up to 54 days of continued consumption of two whole eggs per day. The serum cholesterol level of some subjects increased and others decreased at all three experimental sites. A comparison of the mixed fatty acid composition of the total serum lipids obtained from men and women who had received treatment for other reasons than cardiovascular disease with those that had been treated for cardiovascular disease indicated that the serum from both groups contained a substantial amount of polyunsaturated fatty acids. The lipids extracted from the red blood cells obtained from patients in Urbana-Champaign and Sofia did not differ significantly in linoleic and arachidonic acid content.
Article
The endothelium plays a pivotal role in modulating the reactivity of vascular smooth muscle through the formation of several vasoactive substances. We examined the effects of endothelium-dependent and independent vasodilators on forearm blood flow in 29 patients with Type 2 (non-insulin-dependent) diabetes mellitus and in 21 control subjects, using venous occlusion plethysmography. Via a brachial artery cannula, increasing amounts of acetylcholine and glyceryl trinitrate were infused in doses of 60, 120, 180 and 240 mmol per min and 3, 6 and 9 nmol per min respectively. NG monomethyl-L-arginine, a stereospecific inhibitor of endothelium derived relaxing factor, was infused to inhibit basal and stimulated release of this dilator substance. Reactive hyperaemic forearm blood flow did not differ between groups. Forearm blood flow responses to each dose of acetylcholine were significantly greater in control than diabetic subjects (p less than 0.01 for all doses). NG monomethyl-L-arginine attenuated forearm blood flow from maximal stimulated values when responses were compared with the natural decline to acetylcholine in forearm flow in both control and diabetic subjects (p less than 0.05 for both groups), but had no effect on basal blood flow responses. Forearm blood flow responses to each dose of glyceryl trinitrate were significantly greater in control than diabetic subjects (p less than 0.05 for all). These data provide evidence for endothelial and smooth muscle dysfunction in diabetes which may have important therapeutic implications.
Article
Experiments were designed in a bioassay system to analyze the effect of elevated (from 5.9 mM to 7.5-45.9 mM) extracellular K+ concentration on the release of endothelium-derived relaxing factor. Segments of canine femoral artery with endothelium (donor segment) were mounted in an organ bath and perfused with modified Krebs-Ringer bicarbonate solution; the effluent from the donor segment was used to superfuse a canine coronary artery ring without endothelium (bioassay tissue). Elevation of perfusate K+ concentration by 1.6-15 mM by intraluminal infusion of potassium chloride upstream of the donor segment evoked further contractions of bioassay rings contracted with prostaglandin F2 alpha. In contrast, the bioassay rings progressively relaxed when increasing concentrations of potassium chloride (10-40 mM) were added extraluminally to the organ bath where the perfused segment was mounted. Extraluminal application of phenylephrine or prostaglandin F2 alpha did not evoke relaxations in the bioassay ring. Removal of the endothelium from the donor segment or selective exposure of the segment (but not the bioassay ring) to Ca2+-deficient solution prevented the K+-induced relaxations. Treatment of the donor segment and the bioassay ring with inhibitors of known endogenous vasoactive substances (acetylcholine, norepinephrine, adenine nucleotides, and prostanoids) had no significant effect on the relaxation of the bioassay ring evoked by extraluminal application of potassium chloride. Simultaneous measurements of changes in isometric force in the donor segment and bioassay ring revealed that extraluminal elevation of K+ concentration relaxed the segments as well and that the relaxations could not be prevented by simultaneous intraluminal infusion of potassium chloride.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Indirect and direct experimental evidence demonstrates that both the entry of extracellular calcium and the liberation of calcium from intracellular stores can contribute to an increase in free cytoplasmic calcium concentration in endothelial cells, which seems to be an essential step in the synthesis and/or release of endothelium-derived relaxing factors(s). A variety of Ca2+ transport mechanisms may be involved in the regulation of cytoplasmic calcium in endothelial cells. Ca2+ entry may occur via voltage-operated Ca2+ channels. If they do exist, these channels may have characteristics different from those in underlying vascular smooth muscle cells. Sustained activation of the release of EDRF by various receptor agonists (e.g., acetylcholine, adenine nucleotides, and bradykinin) is also dependent on Ca2+ entry, but it is insensitive to organic Ca2+ channel antagonists. These findings indicate that, when used clinically in various cardiovascular diseases, organic calcium channel antagonists are not expected to interfere with endothelium-dependent relaxation evoked by endogenous vasoactive substances (e.g., ADP, serotonin). Since amiloride and its analogues blocked endothelium-dependent relaxations in different arterial preparations, Na+ transport and Na+/Ca2+ exchange were suggested to play a role in calcium-dependent release of EDRF. The exact nature of Ca2+ transport mechanisms and also the calcium-sensitive cellular processes that lead to the synthesis/release of endothelium derived relaxing factor(s) remain to be determined. However, the available data suggest that calcium handling by the vascular smooth muscle and endothelial cells may be different, allowing potentially selective modulation of Ca2+ activation in these two cell types.
Article
To analyze the potential mediator(s) involved in flow-induced endothelium-dependent vasodilation, we measured the wall tension of intraluminally perfused canine femoral artery segments and compared the content of 6-ketoprostaglandin F1 alpha (determined by radioimmunoassay) and the relaxing activity of the effluent (determined by bioassay on canine coronary artery rings). During perfusion at a steady flow of 2 ml/min the effluent contained 6-keto-prostaglandin F1 alpha and relaxed the bioassay rings. Sudden increase in steady flow rate to 4 ml/min, or the introduction of pulsatile flow, increased the release of 6-keto-prostaglandin F1 alpha and induced further relaxations of the bioassay ring. No relaxations were observed with the effluent passing through a femoral artery segment without endothelium. Indomethacin significantly depressed the release of 6-keto-prostaglandin F1 alpha during increases in flow but had no significant effect on the relaxing activity of the effluent. In the presence of indomethacin, increases in flow produced significant relaxation in the perfused femoral artery segments with endothelium. Superoxide dismutase restored the relaxing activity of the effluent during increases in flow at a transit time of 30 seconds. These data demonstrate that in addition to prostacyclin, flow triggers the release of another relaxing substance (or substances) from vascular endothelial cells that has characteristics similar to the endothelium-derived relaxing factor released by acetylcholine.