Aderenţa la dieta mediteraneeană şi impactul său asupra greutăţii corporale şi a ciclului menstrual la femeile cu sindromul ovarelor polichistice

Introduction

The Mediterranean diet (MD) is recognized worldwide as one of the healthiest dietary patterns, with beneficial effects on people facing the pathologies associated with excess weight. The MD pattern is characterized by a predominant intake of vegetables, legumes, fruits, oil seeds and cereals, with the addition of olive oil as the main source of fat, a moderate intake of fish, eggs, dairy and poultry, a reduced intake of red meat and meat products, and also regular but moderate consumption of wine during meals^(1,2). Through a high consumption of natural antioxidants and a low fat intake, MD improves health and reduces the risk of diabetes^(3,4) and of becoming overweight^(5,6). Obesity affects worldwide women of reproductive age, increasing the risk of infertility⁽⁷⁾.

Polycystic ovary syndrome (PCOS) is the most common complex endocrine disorder that affects 4-8% of women of reproductive age⁽⁸⁾. In 2012, the World Health Organization (WHO) estimated that PCOS affected 116 million women (3.4%)⁽⁹⁾. The pathology has a significant impact on quality of life, the main signs for a diagnosis of polycystic ovaries including irregular menstruation, sporadic ovulation, hyperandrogenism, with or without hirsutism⁽¹⁰⁾, metabolic diseases (hepatic steatosis, type 2 diabetes), and cardiovascular disease. Also, an increased risk of endometrial cancer may occur in the long term if the condition is not addressed medically and in the absence of appropriate lifestyle changes⁽¹¹⁾. In association with obesity, the symptoms are amplified, further delaying pregnancy⁽¹²⁾. A weight loss of only 5% improves the endocrine profile, increasing the chances of regular ovulation and pregnancy, being recommended only for people with a Body Mass Index (BMI) greater than 25-27 kg/m². For lifestyle changes through diet and physical activity to become effective, these should be implemented before planning to conceive⁽¹³⁾.

In view of the above, we set three objectives for our study: (1) to assess the adherence to the Mediterranean diet of patients with PCOS, (2) to study the effects of this diet on the body weight, and (3) regulation of the menstrual cycle.

Materials and method

The study group consisted of 30 women in the fertile period, from Suceava County, Romania, who were diagnosed with polycystic ovary syndrome by a specialist in outpatient facility and were undergoing drug treatment. The study was conducted between December 2020 and April 2021, and followed the principles outlined in the Helsinki Declaration. The criteria for exclusion from the study were age under 18 and the presence of menopause. After obtaining the agreement of the hospital outpatient department, the women who signed the informed consent to participate in the study completed a validated food frequency questionnaire, to which we added additional items related to demographic and anthropometric data, alcohol consumption, smoking, perception of the importance of food in the management of PCOS symptoms, and whether they noticed positive changes in the regulation of the menstrual cycle after changing the eating habits.

Patients’ adherence to MD was assessed using the 14 items of the PREDIMED questionnaire (PREvención con DIetaMEDiterránea). Six items refer to the daily consumption of olive oil (>4 tablespoons), vegetables (≥2 servings), fruits (≥3 servings), processed red meat (<1 serving), butter, margarine (<1 serving) and carbonated drinks (<1 serving). Six items refer to the frequency of weekly consumption of wine (≥7 glasses), legumes (≥3 servings), fish (≥3 servings), sweets (≤2 servings), oilseeds (≥3 servings) and Mediterranean sauces (≥2 servings). Two items relate to the use of olive oil as the main source of fat for cooking, and the preference for the consumption of poultry meat instead of red meat and meat dishes.

Each item of the PREDIMED questionnaire receives one point if the answer meets the condition of the number of portions indicated. Adherence to MD was divided into three categories, depending on the score obtained: a score ≤5 means a low adherence, a score of 6-9 means a moderate adherence, and a score ≥10 means a high adherence⁽¹⁴⁾.

Anthropometric measurements like height, weight and Body Mass Index (BMI) were done. In reference to WHO BMI standards⁽¹⁵⁾, the nutritional status of ­women with PCOS was defined as underweight (BMI<18.5), normal (18.5≤BMI<25), overweight (BMI≥25), or obese (BMI≥30).

Data analysis was performed using MedCalc software version 20.106. To characterize the patient groups according to MD adherence, we used the mean, standard deviation, minimum values and maximum values recorded in the study. The associations between the detailed variables were analyzed using the t test for independent samples. We used the chi-square test to assess the significance of the mean values of the frequencies in categories. The limit for statistical significance was set at 0.05.
 

Results

The 30 patients diagnosed with PCOS were between 20 and 51 years old (mean age 37 years old; SD±7.7), and 76.7% (n=23) were residents in urban areas. The body weight of the patients varied between 49 and 89 kg (mean weight 66.3 kg; SD±10.4), and the height was between 155 and 189 cm (mean height 167 cm; SD±0.06). A percentage of 60% (n=18) were normal weight, 30% (n=9) were overweight, 6.7% (n=2) were obese, and 3.3% (n=1) were underweight.

Given that no patient with PCOS had high adherence to MD (score ≥10), we took into account the scores that indicated low adherence (score ≤5; 43.3%) and moderate adherence (score 6-9; 56.7%) for the presentation of the basic characteristics of the women participating in the study (Table 1).

No differences were found in terms of average age, residence, alcohol consumption, smoking, and the tendency to regulate menstruation between the categories of adherence to MD.

Mean body weight was lower in patients who showed greater adherence to MD.

Adherence to MD had an influence on the BMI value and, consequently, on the weight status.

For obesity indices, we found an apparent inverse association with the MD adherence score (r=-0.4; p=0.0255; 95% CI; -0.6 to -0.05). The mean BMI was 24.7, at the upper limit of normal weight, in women with low adherence to MD, compared to 21.9 in women who showed moderate adherence to this type of diet.

Given that patients scored from 0 to 8, Figure 1 presents the inverse association between the score showing MD adherence and BMI.

Of all women surveyed, a percentage of 56.7% (n=17) consumed alcohol daily or occasionally, and 33.3% (n=10) reported tobacco usage. Alcohol consumption did not influence the menstrual cycle (mean -0.2; 95% CI; -0.8 to 0.3; t=-0.7; df=28; p=0.4528). Instead, we noted the presence of a medium negative correlation between alcohol consumption and body weight (r=-0.36; p=0.0447; 95% CI; -0.64 to -0.01), and BMI (r=-0.37; p=0.0395; 95% CI; -0.64 to -0.02), respectively, which means that daily or occasional alcohol consumption among overweight women was higher than for overweight women.

Patients who reported that they used to drink alcohol were smokers rather than non-smokers (mean 0.9; 95% CI; 0.4 to 1.4; t=3.9; df=28; p=0.0006). Women who smoked also preferred wine (mean 0.5; 95% CI; 0.08 to 0.9; t=2.4; df=28; p=0.0210), but it was not found that smoking had an influence on the menstrual cycle (mean -0.1; 95% CI; -0.5 to 0.1; t=-1.05; df=28; p=0.3001).

In addition to the efficient therapeutic effect of MD combined with the low-carbohydrate diet in weight management in overweight patients with PCOS, the authors of a recent study⁽¹⁵⁾ suggested that this diet model is a good treatment for overweight patients with PCOS, restoring menstrual cycle significantly. However, unlike the limited period of our study, the data were collected when the normal menstrual cycles returned, over two years. Instead, we examined whether certain components of MD had an effect on the tendency to regulate the menstrual cycle in patients included in the study.

Table 2 presents the 14 items of the PREDIMED questionnaire in relation to the absence (36.7%), respectively the presence (69.3%) of the tendency to regulate the menstrual cycle in patients with PCOS.

Our results showed that there were no correlations between the components of MD adherence and the regulation of menstruation in patients with PCOS, except for the relatively statistically significant differences in the use of olive oil in the diet (Table 2). Thus, women who used olive oil as the main source of fat for cooking did not notice any visible changes in menstrual regulation (r=-0.38; p=0.0325; 95% CI; -0.73 to -0.03). Also, the daily consumption of at least four tablespoons of olive oil was negatively correlated with the tendency to regulate the menstrual cycle in patients with PCOS (r=-0.56; p=0.0013; 95% CI; -0.76 to -0.25).

Figure 2 illustrates comparatively the association of items to which patients responded with the effect of food on menstruation.

Although the results of our study did not show a direct connection between most MD-specific nutritional factors and the tendency to restore the menstrual cycle in patients with PCOS, we highlighted a number of correlations between different variables. For example, we found that the perception of the importance of nutrition in the management of PCOS symptoms increases with age (r=0.40; p=0.0257; 95% CI; 0.05 to 0.66). This perception positively influences the adherence to MD, because women who considered that food choices are important in preventing the accentuation of clinical manifestations of PCOS rarely consumed soft drinks (r=-0.42; p=0.0181; 95% CI; -0.68 to -0.08) and more often consumed vegetables, pasta, rice or other foods in combination with Mediterranean sauces of tomatoes, garlic or onions, sautéed in olive oil (r=0.44; p=0.0142; 95% CI; 0.09 to 0.69).

As we have shown that adherence to MD positively influences weight status, we checked the nutritional factors that contributed to this result, and we found an inverse correlation between BMI and vegetable consumption (r=-0.37; p=0.0426; 95% CI; -0.64 to -0.01), fish (r=-0.42; p=0.0191; 95% CI; -0.68 to -0.07), poultry (r=-0.37; p=0.0395; 95% CI; -0.76 to -0.25), and Mediterranean sauces (r=-0.56; p=0.0011; 95% CI; -0.76 to -0.25). These components of MD were more common in the diet of normal weight women than in overweight women.

We noticed the presence of a high positive correlation between legume consumption and the preference for daily olive oil, the correlation coefficient being 0.55 (p=0.0013; 95% CI; 0.24 to 0.76), and a high positive correlation between legumes consumption and the option for Mediterranean sauces (p=0.0001; r=0.64; 95% CI; 0.37 to 0.81).

Discussion

The Mediterranean diet is a food model with positive effects on health. Given this aspect, we assumed that this type of diet could be an optimal nutritional strategy for PCOS management. Therefore, in this cross-sectional study, we investigated the adherence to MD of women diagnosed with PCOS, by recording the answers to the PREDIMED questionnaire, to see if this diet could have a positive effect on body weight and menstrual cycle regulation. From the three adherence categories corresponding to the 14 items of the questionnaire (≤5 scores, 6-9 scores, and ≥10 scores), our results showed that women with PCOS obtained scores from 0 to 8, falling into the first two categories – low adherence and moderate adherence.

Even though none of the patients obtained a PREDIMED≥10 score, showing a high adherence to MD, the average of body weight was lower in the group of patients who showed adherence closer to the score 8, which influenced the weight status. Despite methodological differences, our findings are consistent with the results of previous studies which have shown that adherence to MD can be associated with an optimal body weight and a decreased body fat level in the general population^(16,17), in women of reproductive age⁽¹⁸⁾, and in patients with PCOS⁽¹⁹⁾. It is clear that unhealthy diets, in addition to proinflammatory effects, could adversely affect body composition, with excess adipose tissue being in turn responsible for worsening the clinical severity of PCOS. The increased level of adiposity is of interest, given its relationship with the inflammatory status, as a factor involved in the pathogenesis of PCOS.

Although studies have shown that daily alcohol consumption is a risk factor for obesity in young adults⁽²⁰⁾, our study revealed a weak negative relationship between alcohol consumption and overweight in patients with PCOS. We believe that this subject still needs to be supported by further studies to verify whether alcohol consumption is associated with an increase of body weight in patients with PCOS.

Alcohol consumption affects ovulation associated with the risk of infertility. This risk is almost 50% higher in women who drink more than 10 g of alcohol per day than in women who do not drink alcohol⁽²¹⁾. Our study showed that both alcohol and smoking did not affect the menstrual cycle, probably because of our study’s methodological weaknesses. In fact, there are studies that have not reported any effect of smoking on menstrual disorders⁽²²⁾.

The investigation of the frequency of consumption of specific foods revealed the absence of correlation of the 14 items of MD adherence with the tendency to regulate menstruation in patients with PCOS. Paradoxically, women who noticed a tendency to regulate their menstrual cycle did not use olive oil as their main source of fat in their diet, and consumed less of this type of oil than those who did not notice significant changes in their menstrual cycle. This result has a particular interest regarding the potential long-term anti-inflammatory effect of olive oil as part of MD, as it may help to slow the progression of the inflammatory condition⁽²³⁾ in patients with PCOS.

Even though the consumption of vegetables, fish, poultry and Mediterranean sauces was a relevant prognosis factor for maintaining optimal weight status in patients with PCOS, we believe that the nutritional approach to this condition should be based on a meticulous dietary assessment, along with an analysis quantitative and qualitative supply of nutrients, enabling the identification of an optimal dietary pattern for women with PCOS to obtain regular menstruation over time⁽²⁴⁾.

One of our biases was the small sample evaluated, but it was a pilot study towards this topic; secondly, as the patients were not required to take a Mediterranean diet (it was not an intervention), the effects of the nutritional characteristics of this diet on body weight and menstruation could be only partially assessed.

Conclusions

Although the target group of the study does not live in the Mediterranean area, we estimated that the Romanian food model can match the Mediterranean diet model, as the local cuisine includes a wide variety of foods, from vegetables, legumes, cereals, nuts and hazelnuts, up to fish, poultry and eggs, except olive oil.

In these circumstances, we have shown that this type of diet adherence scores (up to 8 score for the 14 items of the PREDIMED questionnaire) can be assigned to a group of women with PCOS, because we noticed positive effects on body weight, but not on the menstrual cycle. Our study showed that alcohol and smoking did not affect the menstrual cycle either. On the other hand, the tendency to regulate the menstrual cycle was observed by women who did not use olive oil as the main source of fat in their diet.

Therefore, further investigations are needed on the amount and use in food of the types of oil consumed in Romania.

In the future, the study may be performed to demonstrate the effectiveness of MD over a longer period of time. As the pathology is complex, groups of patients can be assigned according to comorbidities (obesity, diabetes, hirsutism etc.), to analyze the effects and clinical and biochemical, endocrine and metabolic effects, after a monitored nutritional therapeutic intervention, in order to provide optimal dietary recommendations to patients with PCOS.   

Acknowledgement

The authors thank all the women who participated in the study, as well as the authorities from the Outpatient Department of the “Sfântul Ioan cel Nou” County Emergency Hospital, Suceava, Romania, for their cooperation in research.


 

Conflict de interese: niciunul declarat.

suport financiar: niciunul declarat.

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