To our best knowledge, this is the first case-control study determining the association between food security status and dietary patterns with PCOS. The results demonstrated that FI especially with moderate to severe hunger was significantly higher among PCOS women than healthy non-PCOS women. Moreover, the risk of PCOS was positively associated with FI, quasi-western dietary pattern, low economic level, waist circumference, and menstrual age and negatively associated with physical activity and healthy dietary pattern even after controlling the potential confounders.
According to our result, almost 60% of women with PCOS and 30% of non-PCOS women had FI. Around the world, FI especially in women is one of the most challenging can exert several adverse effects such as obesity [30, 31, 53–55] and altering physical activity [56]. Furthermore, obesity itself which can be manifested as high waist circumference can amplify the severity of kinds of metabolic disorders such as PCOS [57–59]. Also, it is reported that physical activity is inversely associated with and PCOS [8, 60]. Therefore, it can be concluded that FI has a potential role to indirectly affect PCOS risk. Our results demonstrated that the risk of PCOS was positively associated with waist circumference and menstrual age and negatively associated with physical activity. However, some other studies have failed to find any significant association between PCOS with waist circumference, menstrual age [61], and physical activity [36, 61, 62] in comparison to non-PCOS women.
Several studies demonstrated a positive association between low economic levels with FI [63, 64] and PCOS [8, 32] in line with the present study. FI can induce persons to pay less cost for purchasing foods, consume smaller amounts of foods, change their dietary patterns [65–67], reduce the variety of dietary intakes, and increase the consumption of high-calorie foods [68]. A high-calorie diet itself can lead to hyperlipidemia, obesity, and T2DM [69–71].
According to the results of the current study, the quasi-western dietary pattern and healthy dietary pattern were associated with the increased and decreased risk of PCOS, respectively. This positive effect of quasi-western dietary pattern on the risk of PCOS can be due to the low rate of healthy foods including fruits and vegetables, and the high rate of unhealthy food items e.g. meats, industrial juice, French fries, and sweets [39] and excessive amounts of fats and sugar in this type of diet [72].
Saturated fatty acid as an undeniable component of the quasi-Western diet, is directly related to increased IR [73, 74] unlike omega-3 unsaturated fatty acid as a component of a healthy diet [2, 22]. The results of the current study identified higher consumption of saturated fats and MUFAs and lower consumption of cholesterols and docosahexaenoic acid in women with PCOS. Numerous studies have shown that high dietary fat intake, particularly trans and saturated fats is associated with a higher risk of T2DM and CVD [75, 76] that can exert an adverse effect on the PCOS with increasing the inflammatory factors [77]. No significant differences were seen between the intake of calories, trans fats, PUFAs, linoleic acid, linolenic acid, and eicosapentaenoic acid in women with and without PCOS in our study. In a cohort study, Douglas et al. indicated that total, trans, and saturated fat, MUFAs, PUFAs, and cholesterol were not significantly different between the two groups [78]. However, other studies reported a higher intake of saturated fatty acids in PCOS women [79, 80]. Moreover, meats have been related to obesity and inflammation due to their high-fat content [81]. But, they are suggested to be considered as healthy dishes of PCOS subjects due to their high content of iron [60]. Our result demonstrated that adult women with PCOS were more adhere to meat consumption. In contrast, Hajivandi et al. reported a low intake of meats in young PCOS women [60].
There are contradictory results on the association between high intake of protein with insulin and glucose responses [82, 83]. In the current study, the protein intake of PCOS women was lower; while, the proportion of unhealthy protein such as meats to healthy protein sources such as fish, poultry, legumes, and soy were higher in the women with PCOS than non-PCOS women. However, other studies did not report any differences among women with and without PCOS [62, 78]. Based on a possible mechanism, animal proteins compared to vegetable proteins may increase the serum levels of insulin-like growth factor I (IGF-I) which can be involved in increasing the risk of PCOS [8].
It was found that high intake of fats and low intake of carbohydrates can be positively associated with weight, insulin and androgen concentrations, and the prevalence of PCOS [84]. The results of this study indicated that the total mean of carbohydrates was lower in women with PCOS compared to non-PCOS women. However, other studies failed to find any significant differences [62, 78]. On the other hand, our results demonstrated that the proportion intake of simple carbohydrates such as sugar and soft drinks to complex carbohydrates such as legumes was higher in the PCOS subjects. In line with our results, it was reported that PCOS women were more likely to have high GI foods and there is a positive association between this diet and IR [85]. In contrast, low GI foods appeared to have beneficial effects on IR improvement [86].
Several studies have demonstrated the inverse relationship between the healthy dietary intake which is rich in fruits and vegetables with visceral fat, weight, and the risk of T2DM and also the intake of dairy products with IR and dyslipidemia [87–89]. This study showed that the consumption of vegetables, fruits, and dairy products was lower in PCOS women. Fruits and vegetables are a major source of fiber, vitamins, and minerals that are associated with a lower prevalence of metabolic diseases [90]. It has been shown that fiber intake has been associated with a reduction of PCOS risk [80]. Moreover, dietary intake of dairy products exerts its beneficial effects on infertility and BMI by reducing the IR [91–93]. However, the effects of high-fat over low-fat dairies on PCOS are not clear [7]. Similar to the previous study [36, 61], PCOS women in the present study had lower consumption of dairy products than non-PCOS women. However, Shishehgar et al. found no significant differences between the dietary intake of dairies and fruits among the two groups [94].
The results of the present study reported that PCOS women had a lower intake of several kinds of vitamins such as A, B5, B6, B12, C, and D, potassium, iron, zinc, thiamine, niacin, magnesium, phosphorus, and total fiber compared to non-PCOS women. It has been reported that adult women with FI were less likely to intake magnesium, vitamins B6 and E, thiamine, and niacin [95]. Consistent with our finding, Moran et al. demonstrated a higher intake of magnesium, vitamins A and E, phosphorus, and iron in PCOS women [96]. Moreover, Douglas et al. found no significant association in the magnesium intake of women with and without PCOS [78]. Epidemiological studies have shown that magnesium intake might decrease the risk of T2DM in PCOS women [97, 98] and dietary intake of sodium can exert an adverse effect on their blood pressure [99]. Calcium as one of the key minerals is suggested to be consumed by PCOS women due to its beneficial effects on IR, follicular maturation, and menstrual regulation [100]. Most studies have indicated the role of vitamin D and calcium in IR and insulin secretion [101, 102]. However, the exact molecular mechanisms of the effects of vitamin D on the improvement of IR and PCOS are not yet clear [103]. The possible role for folate and vitamin B12 is decreasing the serum levels of homocysteine among PCOS women with IR [104, 105] and also for zinc is modifying the clinical and inflammatory biomarkers of PCOS women [11]. In our study, there were no differences between the rate of trans fats, PUFAs, eicosapentaenoic acid, sodium, vitamin E, alpha-tocopherol, manganese, selenium, and chromium among PCOS and non-PCOS women. However, Eslamian et al. positively demonstrated the association between fat, animal protein, carbohydrate, cholesterol, saturated fatty acid, sodium, biotin, iron, copper, fluoride, zinc, and calcium with the risk of PCOS [19].
Several major strengths are in the present study. First, this study investigated the association between FI and PCOS for the first time in Iran. Second, we compared characteristics of both PCOS and non-PCOS women due to the case-control design of our study. Third, we considered the non-smoking women and excluded those who had any current history of cardiovascular, liver, and/or kidney diseases which might affect the results. Last but not least, this study also assessed the association between PCOS with dietary patterns and food intakes. However, our study had some limitations. The sample was limited to overweight and obese women with specific ranges of age and BMI, who were referred to the infertility clinic of one hospital which makes it difficult to generalize the results to other women with other ages and BMI.