The current cross-sectional study indicates a pioneering investigation aiming to establish an interaction of genetics risk score (GRS) and plant-based diet on factors atherogenic and body adiposity indexes among overweight and obese women. We showed that plant-based dietary patterns regarding genetic susceptibility can have effects on the predictable risk factors of cardiometabolic disease in our population. Our results emphasize the importance of following plant-based dietary patterns, individuals at higher or moderate genetic risk may benefit from the positive effects of these dietary patterns to modify cardiometabolic risk factors.
Our results unveil a significant negative interaction between tertile 2 of PDI and moderate risk allele and high-risk alleles with AIP, TGy, LAP, and VAI compared to low-risk allele. Additionally, we detected a negative significant interaction between tertile 2 of PDI and high-risk allele with CRI. II compare to low-risk allele participants. Furthermore, there was a negative significant interaction between tertile 2 of hPDI and moderate risk allele with ABSI compared to low-risk allele participants. There was a positive significant interaction between tertile 2 of uPDI and moderate risk allele with CRI. I and ABSI compare to low-risk allele participants. The present study found a significant mean difference between GRS and the participant's body weight, BMI, WC, WHR, BRI, ABSI, and LAP. Our results are in line with previous investigations regarding the genetic effects of GRS on BMI and waist circumference (66–68). A cross-sectional study illustrated the merged effect of some genetic variants on obesity in Pakistanis and showed by a GRS for obesity, the possibility of the prognosis of anthropometric traits (69), and several investigations indicate the positive relationship between obesity risk factors such as BMI, WC, and WHR with cardiometabolic diseases (70–72). CAV-1 as one of the considered genes in this study, has some functions such as the main regulator for fat distribution and genetic lipodystrophy in humans and it can be relatively higher in obese women compared to thin women (73–76). CAV-1 is also associated with oxidative stress, which can therefore play a role in many metabolic diseases. According to a study, following the PDI diet can reduce metabolic diseases among those who carry a risk allele in the CAV-1 gene (77). Other roles, such as abnormalities in the binding of cholesterol and fatty acids, disturbance in the path of differentiation of fat cells, dysfunction of fat droplets, and increase in insulin signaling, are attributed to this gene (73, 78). In addition, several studies showed the association of the MC4R gene and its role in energy balance, food intake regulation, total fat, total obesity, peripheral obesity, abdominal obesity, and higher BMI (79, 80).
The results of the PREDIMED trial, show that following plant-based dietary patterns can significantly reduce the risk of CVD (81), and the Adventist Health Study also showed that vegetarian diets reduce CVD mortality by exerting their protective effect (82). Comparing other diet indices (such as Alternate Healthy Eating Index, Dietary Approaches to Stop Hypertension [DASH], and Mediterranean diet scores), PDI dietary patterns are derived from some food items, including healthy and less healthy plant-derived foods, to capture the combined and varying intakes of different food items. Moreover, some components in the uPDI, such as coffee, sugar-sweetened beverages, and saturated fat, could be involved in genetic predisposition to obesity (83–88). Interactions between GRS and PDI food patterns can be due to less adherence to less healthy plant-based foods and animal foods, low energy density, the increased involvement of plant bioactives through the regulation of thermogenesis without energy consumption and shivering, as well as the improvement of the balance of intestinal microbiota due to the increase in dietary fiber consumption (88–91). According to a study conducted in 2023 by Fatemeh Gholami et al. on 377 obese and overweight women, significant interactions between GRS and h-PDI were observed on body fat mass index, body mass index (BMI), and waist circumference. In this study, the interaction between GRS and PDI was performed on some predictive factors of cardiovascular diseases such as C-reactive protein, plasminogen activator inhibitor 1, and insulin. According to the findings of this study, following a plant-based food pattern despite the genetic differences in people seems to be a protective factor against the risks of cardiometabolic abnormalities (92). Interestingly, according to past results, following more healthy plant-based diets in people who are at a higher genetic risk of obesity (regardless of the presence of basic obesity), causes more benefits in these people (93, 94). Our findings revealed a negative significant interaction between the second tertile of PDI and moderate risk allele and high-risk allele with AIP compared to the low-risk allele. In a cross-sectional study conducted in 2023 by Farnaz Shahdadian et al., it was found that participants with the highest quartile of PDI, as well as the third quartile of hPDI, were associated with reduced odds of having high-risk AIP compared to the first quartile (95). In this regard, other studies reported the relationship between PDI, especially hPDI, and their role in the management and prevention of high-risk AIP (96–98). One of the reasons for the effect of a PDI on reducing high-risk AIP can be attributed to its role in reducing TG because AIP is a logarithm of the ratio of triglycerides and HDL (95). Mahdieh Khodarahmi et al. in a cross-sectional study observed that the interactions between DASH score and MC4R rs17782313 genotypes on AIP among the female group were statistically significant (99). In an observational study, a significant interaction of GRS and hPDI on lipid factors was observed, and in this regard, other studies also reveal the beneficial effects of healthier plant-based diets in reducing TC levels and controlling HDL (93, 100–102). However, the results for TG have been controversial (101).
Findings indicate a positive significant interaction between tertile 2 of uPDI and moderate risk allele with CRI.I compare low-risk allele participants and positive significant interaction between tertile 2 of uPDI and moderate risk allele with CRI.II compared to low-risk allele participants. In a study conducted in 2019 on 96 participants, CRI.I was considered as an index to predict cardiovascular risk among people in two diet groups, vegetarians and omnivores. In this study, CRI-I was significantly greater in omnivores than in vegetarians, and people who have higher adherence to a vegetarian diet elevate by 17 times the probability of having a normal CRI-I (103, 104).
Earlier studies have found the potential role of diet in body composition; however, little attention has been paid to LAP and TyG, which are strong indicators of cardiovascular disease (105, 106). We found a negative significant interaction between the second tertile of PDI and moderate risk allele and high-risk allele with TGy compared to low-risk allele participants. Also, there was a negative significant interaction between the second tertile of PDI and moderate risk allele and high-risk allele with LAP compared to low-risk allele participants. In a cross-sectional study conducted in 2020 by Mahshid Shahavandi and his colleagues on 270 adults, the results indicated that more adherence to hPDI was associated with a decrease in BMI, WC, WHR, and LAP. However, in this study, there was no correlation between following PDIs and TyG (107). In another study conducted on Iranian adults in 2017, no significant relationship was found between healthy dietary patterns with the TyG index and visceral fat level (108). However, in a prospective cohort study conducted in 2020, a negative association between an anti-inflammatory diet and the TyG index was found (109).
In our findings, there was a negative significant interaction between tertile 2 of PDI and moderate risk allele and high-risk allele with VAI compared to low-risk allele participants. Results show a negative significant interaction between tertile 2 of hPDI and moderate risk allele with ABSI compared to low-risk allele participants. Moreover, a positive significant interaction between tertile 2 of uPDI and moderate risk allele with ABSI was shown. Also, there was a positive significant interaction between tertile 3 of uPDI and high-risk allele with ABSI compared to low-risk allele participants. Based on a cross-sectional study a significant positive association between fat intake and visceral adipose tissue (VAT) was observed among overweight young adults. In this investigation, participants who followed a diet rich in carbohydrates, sugar, and total fat, as well as saturated fat, showed an increased mean in VAI and LAP. However, following a diet rich in vitamins, and minerals, with a high amount of fiber was associated with reduced levels of VAI and LAP (108). In another study conducted in 2018 on older Americans, a negative association was indicated between the DASH diet index and VAI (110).
Strength and limitations:
Our investigation is a novel study to evaluate the interaction of genetics risk score (GRS) and Plant-based diet on atherogenic, visceral, and body adiposity, which examines certain factors that have not been considered in previous studies. The current study's major strengths include appropriate sample size and adjusting for potential confounders. However, there are some limitations such as the design of the study which cannot explain the causal relation between confounders. As our study was conducted on overweight women, our obtained findings cannot be generalized to other groups of society.