Determining dietary patterns accompanying egg intake and its impact on glucose homeostasis and satiety hormones

Date

2019-08

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Abstract

Recent studies have shown that under free-living conditions higher egg consumption is associated with poor glycemic control and an increased risk of developing diabetes. However, higher egg intake could simply be a marker for other dietary indiscretions such as high energy intake and saturated fat intake. We hypothesized that the purported association of eggs and alterations in glycemic control is due to dietary patterns associated with egg consumption rather than the egg consumption per se. We specifically aimed to 1) examine the association between egg consumption and total energy and saturated fat intake measured using a validated objective method; and 2) compare and contrast the acute effects of the intake of eggs and saturated fat on appetite and glycemic control in normal healthy individuals. Experiment 1: Forty-eight non-diabetic subjects (age 18-65 years; Body Mass Index ≥ 20 ≤ 60 kg/m2; fasting glucose < 126 mg/dl; consume ≥ 1 egg per week) were recruited via advertisement. The subjects captured photographs of all the meals they consumed including snacks and beverages for seven days via a smartphone app called SmartIntake© (i.e., Remote Food Photography Method; RFPM). The images were analyzed for mean daily nutrient and energy intake. Experiment 2: In a randomized controlled partial crossover clinical trial, the 48 subjects from Experiment 1 received two of four iso-caloric, macronutrient composition matched test breakfasts composed of either eggs (EB), saturated fat (SB), eggs with saturated fat (ES) or a control breakfast (CB) in two testing sessions spaced at least seven days apart. Subjects presented for each testing session after fasting for 10 hours. A pre-breakfast blood sample was obtained on admission, and one of the four breakfasts were administered. Subsequently, five post-breakfast blood samples were obtained at 30, 60, 90, 120, and 180 minutes. Data were analyzed using mixed effects models accounting for within-subject nature using the lme4 and lmerTest packages in R statistical software. Daily egg intake, as measured by RFPM, was significantly associated with cholesterol intake, but not with the daily energy and saturated fat intake or measures of glycemic control (i.e., fasting glucose, fasting insulin, HOMA-IR, and HbA1c). The area under the curve of glucose, insulin, ghrelin, PYY, or GLP-1 measured following EB, ES, and SB did not significantly differ from CB. Therefore, higher consumption of eggs in free-living conditions, when measured using an objective method, is unlikely to be associated with undesirable profiles of macronutrient intake, total energy intake, or a deranged glycemic profile in this study population. Similarly, when experimentally controlled for macronutrient composition, total energy content and glycemic index, consumption of eggs, saturated fat or their combination are unlikely to affect glycemic control or objective measures of hunger and satiety in healthy individuals at an acute setting. Thus, the purported associations between egg consumption and undesirable profiles of energy and macronutrient intake and deranged glycemic control need to be questioned.

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Keywords

Eggs, Remote food photography method, Insulin, Dietary patterns

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