Egg consumption and carotid atherosclerosis in the Northern Manhattan Study
Introduction
Diet is a complex and irrefutable risk factor for cardiovascular disease (CVD). In keeping with the diet-heart hypothesis which invoked dietary cholesterol as a major CVD risk factor, dietary guidelines have advised limiting the intake of cholesterol rich foods. Egg is a significant source of cholesterol, containing an average of 213 mg per egg. Since the 1970's, egg consumption in the United States has been particularly discouraged by health stakeholders in the absence of empirical data. The American Heart Association guidelines no longer restrict egg consumption, but the allotted cholesterol allowance of <200 mg/day for individuals at high risk of CVD, and <300 mg/day for otherwise healthy individuals, precludes significant egg intake when guidelines are followed in the context of an omnivorous western diet. European and Canadian guidelines, in contrast, do not restrict cholesterol, as the literature suggests that saturated and trans-fat restriction is a more effective means of CVD risk reduction [1], [2].
Egg is a low glycemic index, whole-food that has been part of the human diet since early mankind. It is an inexpensive source of protein, essential fatty acids, antioxidants, vitamins, and minerals, and is one of the few dietary sources of choline, a potent anti-oxidant. Benefits of egg consumption are well described in the literature, including: the formation of larger, less atherogenic LDL and HDL particles [3], [4], increased HDL-C formation [5], [6], and protection against macular degeneration and cataracts [40], [41], [42].
A growing body of evidence supports the claim that egg consumption ≤1/day in healthy individuals is not associated with increased risk of CVD, yet inconsistent data remains. A recent study by Spence et al. described increased carotid plaque area, an imaging biomarker of atherosclerosis, in high risk individuals for CVD, consuming 3 or more eggs per week [7]. The study concluded that regular consumption of egg yolk should be avoided by individuals at high risk for CVD. This study contrasts starkly with the findings of other large, well-controlled, population based cohort studies which concluded that consumption of up to one egg per day does not increase CVD risk [8], [9], [10].
Because of conflicting evidence, guidelines, and the declining overall health and nutritional status of North Americans, it is important to understand the effect of egg consumption in a healthy, ethnically diverse population. The relationship between egg consumption and atherosclerosis in particular requires further study. Stroke and other vascular events are etiologically heterogeneous and atherosclerosis is likely an important pathway linking diet with clinical vascular events. Therefore, in this cross sectional study we examined the association between egg consumption with carotid atherosclerosis phenotypes, including carotid plaque cIMT, and with clinical vascular events in an urban, multi-ethnic population-based cohort.
Section snippets
Study population
NOMAS is a prospective cohort study designed to determine stroke incidence, risk factors, and prognosis in a multi-ethnic urban population. Study details have been published previously [11].
Eligible subjects: a) had never been diagnosed with ischemic stroke; b) were >40 years old; and c) resided in Northern Manhattan for ≥3 months, in a household with a telephone. Subjects were identified by random-digit dialing, and interviews were conducted by trained bilingual research assistants. The
Results
In the subcohort with carotid ultrasound measured, the mean age was 65.8 ± 8.8 years, 40% were male, 18% white, 20% black, and 60% Hispanic. In response to the frequency of whole egg consumption with a medium portion size of 2 eggs, 23% of the cohort reported that they consumed eggs less than once per month, 26% 1 time/month, 16% 2–3 times/month, 30% 1 times/week, 3% 2 times/week, 2% 3–4 times/week, 1% 5–6 times/week, and nobody reported consuming eggs daily. Table 1 shows the distribution of
Discussion
In this multi-ethnic population-based cohort study, we observed an inverse association between egg consumption and several distinct imaging biomarkers of carotid atherosclerosis including carotid IMT, plaque presence, plaque thickness, and total plaque area. The inverse association persisted without attenuation after adjustment for demographics, traditional vascular risk factors, dietary habits, and inflammation. Our results suggest that egg consumption, in the low to moderate range, is not
Funding sources
This work was supported by the National Institute of Neurological Disorders and Stroke [R37 NS 29993]; NIH [K24 to T.R. and RO1 013094 to M.E.]; and Evelyn McKnight Brain Institute.
Disclosure
Responsibility for (a) the accuracy of statements of fact, (b) the authenticity of scientific findings or observations, and (c) expressions of scientific or other opinion published in the journal rests solely with the author(s) of the article. No responsibility for such matters is assumed by the journal or its owners, publishers, reviewers or staff.
Acknowledgment
We wish to thank the staff of the Northern Manhattan Study, particularly the project manager Ms.Janet DeRosa.
References (41)
- et al.
Exploring the factors that affect blood cholesterol and heart disease risk: is dietary cholesterol as bad for you as history leads us to believe?
Adv Nutr Int Rev J
(2012) - et al.
Eggs distinctly modulate plasma carotenoid and lipoprotein subclasses in adult men following a carbohydrate-restricted diet
J Nutr Biochem.
(2010) - et al.
Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate-restricted diet
J Nutr
(2008) - et al.
Egg yolk consumption and carotid plaque
Atherosclerosis
(2012) - et al.
Food, plant food, and vegetarian diets in the US dietary guidelines: conclusions of an expert panel
Am J Clin Nutr
(2009) - et al.
Mediterranean-style diet and risk of ischemic stroke, myocardial infarction, and vascular death: the Northern Manhattan Study
Am J Clin Nutr
(2011) - et al.
Egg consumption in relation to cardiovascular disease and mortality: the Physicians' Health Study
Am J Clin Nutr
(2008) - et al.
Egg consumption, serum cholesterol, and cause-specific and all-cause mortality: the National Integrated Project for Prospective Observation of Non-communicable Disease and its Trends in the Aged, 1980 (NIPPON DATA80)
Am J Clin Nutr
(2004) - et al.
Eggs, serum cholesterol, and coronary heart disease
Am J Clin Nutr
(1982) - et al.
Dietary fat and cholesterol and risk of cardiovascular disease in older adults: the Health ABC Study
Nutr Metab Cardiovasc Dis
(2011)
Vascular effects of dietary l-arginine supplementation
Atherosclerosis
Dietary choline and betaine intakes in relation to concentrations of inflammatory markers in healthy adults: the ATTICA study
Am J Clin Nutr
R1-The role of vitamin D in cardiovascular disease: from present evidence to future perspectives
Atherosclerosis
Maintenance of the LDL cholesterol: HDL cholesterol ratio in an elderly population given a dietary cholesterol challenge
J Nutr
Plasma lipid and lipoprotein responses to dietary fat and cholesterol: a meta-analysis
Am J Clin Nutr
Egg consumption and endothelial function: a randomized controlled crossover trial
Int J Cardiol
Egg consumption in relation to risk of cardiovascular disease and diabetes: a systematic review and meta-analysis
Am J Clin Nutr
A 12-wk egg intervention increases serum zeaxanthin and macular pigment optical density in women
J Nutr
Consumption of 2 and 4 egg yolks/d for 5 wk increases macular pigment concentrations in older adults with low macular pigment taking cholesterol-lowering statins
Am J Clin Nutr
European guidelines on cardiovascular disease prevention in clinical practice (version 2012) The Fifth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of nine societies and by invited experts) Developed with the special contribution of the European Association for Cardiovascular Prevention & Rehabilitation (EACPR)
Eur Heart J
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Shared first authorship.