Взаимосвязь между утренним приемом пищи (завтраком) и инсулинорезистентностью у группы практически здоровых иракцев

Махди Сара Салах; Абдулгани Худа С.; Ханин Субхи Шахид

Резюме

Клетки человека в основном используют глюкозу в качестве источника энергии, и ее усвоение клетками в значительной степени зависит от инсулина. Таким образом, инсулиновая сигнализация имеет решающее значение для гомеостаза глюкозы в инсулиночувствительных тканях. Нарушение различных молекулярных путей может привести к снижению чувствительности к инсулину, к инсулинорезистентности (ИР).

Цель исследования - оценить влияние наличия или отсутствия завтрака на показатели ИР, независимо от состава потребляемой пищи.

Материал и методы. Исследование проведено с участием 40 практически здоровых иракских добровольцев (как женщин, так и мужчин) в возрасте от 20 до 50 лет с индексом массы тела (ИМТ) от 21 до 35 кг/м², которые были разделены на 2 группы. Участники 1-й группы (n=20) завтракали ежедневно, а представители 2-й группы (n=20) пропускали утренний прием пищи. Были измерены антропометрические параметры и биохимические показатели (уровень глюкозы натощак и уровень инсулина в сыворотке крови), рассчитан индекс инсулинорезистентности (HOMA-IR).

Результаты. Уровень глюкозы в крови натощак (85,6±4,4 мг/дл), концентрация инсулина в сыворотке крови (5,61±1,69 МЕ/мл) и индекс HOMA-IR (1,18±0,37) у лиц, завтракающих утром, оказались значительно ниже (p<0,01) по сравнению с показателями лиц, пропускающих завтрак (97,8±8,4 мг/дл, 14,20±2,82 МЕ/мл и 3,46±0,83, соответственно). Кроме того, ИМТ был достоверно выше (p<0,01) у лиц, пропускающих завтрак (33,4±4,3 против 23,1±3,4 кг/м²).

Заключение. Исследование подтверждает гипотезу о том, что употребление завтрака связано с более низкой ИР. Однако нерандомизированная выборка и значительные различия в ИМТ между группами ограничивают возможность выделения завтрака как независимого фактора. Для подтверждения этих ассоциаций и выяснения причинно-следственной связи необходимы дальнейшие исследования с подобранными когортами или рандомизированные контролируемые исследования. Тем не менее полученные результаты подтверждают потенциальные метаболические риски нерегулярного питания и важность информации в сфере общественного здравоохранения, пропагандирующей регулярное сбалансированное питание.

Ключевые слова: инсулинорезистентность; сывороточный инсулин; уровень глюкозы в крови натощак; HOMA-IR; антропометрические параметры

Human cells utilize glucose as the primary substrate, and cellular uptake requires insulin. Insulin signaling is therefore so important for these tissues. Any decrease in insulin sensitivity due to the disruption of various molecular pathways causes insulin resistance [1]. Insulin resistance is identified as the disruption of the target tissues’ or cells’ function under insulin stimulation [2]. All tissues with insulin receptors have ability to show this resistance, however the liver, skeletal muscles, and adipose tissues are the main tissues that drive insulin resistance. It lead to glucose disposal, causing in a compensatory raise in the rate of hyperinsulinemia and production of β-cell insulin [3]. Some authors mentioned that hyperinsulinemia preceded insulin resistance. They suggested that hyperinsulinemia due to excessing calorie intake provoke metabolic dysfunction related to insulin resistance. These include hyperglycemia, dyslipidemia, hypertension, raised inflammatory markers, hyperuricemia, endothelial dysfunction, and a prothrombotic state. Insulin resistance progression can drive to metabolic syndromes, type 2 diabetes mellitus, non-alcoholic fatty liver disease [4-6]. Although the etiology of insulin resistance can be acquired, hereditary, or mixed, most individuals have its acquired causes [7].

Breakfast is often referred to as the most important meal of the day and in recent years has been implicated in weight control, cardio-metabolic risk factors, and cognitive performance [8]. Eating breakfast is a healthy dietary habit that should be encouraged since childhood. The consumption of dairy products, cereals, and fruits at breakfast is associated with healthier dietary patterns, with a beneficial impact on the overall quality of the diet [9].

The main aim of the study was to examine the association between breakfast eaters’ habits versus breakfast skippers and insulin resistance, regardless of dietary composition. Through this investigation, we seek to contribute to the scientific understanding of how breakfast behaviors may influence metabolic health and highlight the importance of regular breakfast eating. Finally, the overall goal was to support public health efforts by raising awareness within the community about the potential risks associated with breakfast skipping and its link to insulin resistance.

Material and methods

The cross-sectional study was performed on 40 healthy Iraqi participants (both females and males) aged range (20-50 years), with a body mass index (BMI) of 21-35 kg/ m² recruited into this study, divided into two groups, the first group (20 participants) that take normal breakfast, the second one that skips the meal. Subjects with the following conditions were excluded from the study: Diabetic Patients (type 1 and type 2), who had acute or chronic inflammatory or infective diseases.

Participants were recruited through voluntary enrollment in response to advertisements posted at a local university and a community health center. All participants provided written informed consent before participation.

Based on their self-reported breakfast habits, participants were divided into two equal groups:

- Breakfast eaters (n=20): individuals who regularly consumed breakfast (≥5 days per week).

- Breakfast skippers (n=20): individuals who habitually skipped breakfast (≤2 days per week).

Participants with a history of diabetes, or any acute or chronic illness, were not included into the study.

It was important to note that the selection process was non-random, and no matching was performed between groups based on BMI, age, or sex. This lack of matching is acknowledged as a limitation of the study.

Laboratory measurements

Blood samples were collected after a 12-hour fasting. The serum was separated and frozen at -20 ºC until analysis. Fasting blood glucose (FBG) was measured using the Abbott ARCHITECT plus c4000 device. The serum insulin level was assayed using an immune radiometric method (Demeditec/Germany). The insulin sensitivity was determined using the Homeostasis Model Assessment Index of insulin resistance (HOMA-IR) according to the following formula:

HOMA-IR = fasting insulin (μU/ml) × fasting glucose concentration (mmol/l) / 22.5 [10].

Statistical analysis was conducted using SPSS software version 26 (IBM, USA). The normality of data distribution for each variable was assessed using the Shapiro-Wilk test due to the small sample size.

- For variables that followed a normal distribution, comparisons between the two groups (breakfast consumers vs. skippers) were performed using the independent samples t-test.

- For non-normally distributed variables, the Mann-Whitney U test was used.

Correlation analysis was performed using Spearman’s rank correlation coefficient to assess the association between FBG, serum insulin levels, and BMI. A p-value <0.05 was considered statistically significant.

Results

The results presented in this article are based on the analysis of 40 healthy participants (both male and female) aged between 20-50 years divided into two main groups depending on breakfast skipping in the morning as shown in table 1. The BMI was significantly (p<0.01) higher in the Breakfast eaters (table 1).

The result presented in (table 2) indicates highly significant (p<0.01) differences in FBG, Insulin, and HOMA-IR between the studied groups. All these parameters of the persons eating in the morning were reliably lower in comparison to the breakfast skippers.

As shown in figure FBG showed a significant (p<0.05) positive correlation with insulin level, BMI, and HOMA-IR in those from the breakfast skipper group.

Discussion

We observed an improved body weight regulation among individuals who consumed breakfast regularly, suggesting a potential beneficial role of morning food intake in weight management. Presently, some Iraqi people skip breakfast due to influencers on social media, who say breakfast that causes weight gain.

The effect of breakfast skippers on health, especially in adults, remains a controversial topic. An analysis of the data was conducted to examine associations between breakfast eating patterns and weight loss, level of HOMA-IR, and breakfast skippers may reflect dieting patterns in overweight persons who are trying to control their weight [11].

BMI showed a dramatic difference (p<0.01) between persons in those Eating in the Morning and those breakfast skipping group, that reflects the beneficial role of regular breakfast for healthier BMI. Similar finding was observed with J. Wicherski et al., who “showed significant differences of BMI between studied groups” [12].

The level of serum FBG, Insulin, and HOMA-IR in persons who ate at morning indicated a better carbohydrate metabolism (p<0.01) in comparison to breakfast skippers, a similar finding was observed with H.S. Kim et al., who showed that breakfast has positive effects on fasting insulin levels and HOMA-IR in Korean adolescents who were breakfast skippers [13], likewise M.D. Salas-Gonzálezand, et al, who conclude: "A higher-quality breakfast was associated with better overall diet quality and a lower risk of insulin resistance” [14]. Unlike D. Duan et al., a study that suggested that the addition of breakfast might not be a good strategy for weight loss, regardless of established breakfast habits [15]. Moreover, recent meta-analyses and randomized controlled trials have suggested that regular breakfast eaters may improve appetite regulation, reduce snacking, and enhance energy metabolism, thereby contributing to better weight management [16]. Other studies have highlighted the important role of breakfast in regulating glucose metabolism and improving insulin sensitivity, which supports our findings of the metabolic benefits of regular breakfast eaters [17].

Study limitations

- Non-randomized sampling may have introduced selection bias.

- The dietary composition of breakfast was not assessed.

- Small sample size limits generalizability and statistical power.

Future studies should use matched cohorts or randomized controlled designs, and include dietary records to strengthen causal interpretations.

Conclusion

The study supports the hypothesis that breakfast eaters is associated with lower markers of insulin resistance and better glucose metabolism. However, the use of non-randomized sampling and the presence of significant BMI differences between groups limit the ability to attribute these effects solely to diet habits. To confirm these associations and clarify causality, future research should employ matched cohorts or randomized controlled trial designs. Nonetheless, the findings highlight the potential metabolic risks associated with irregular eating patterns and support public health messages that encourage regular, balanced meals.

Литература/References

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