**4. Discussion**

This study was performed to test the hypothesis that the dietary patterns of Saudis may play a role in increasing the risk of CVD. To our knowledge, this is the first study that assesses the dietary intake using the adherence score to the Saudi dietary guidelines and its relationship to CVD in Saudi males living in Jeddah. As such, the data obtained from this study may be considered an important preliminary step in gaining an increased understanding of variables in the Saudi population that may affect their risk of CVD.

This study found a number of significant differences between the non-CVD and CVD patients that align with previously published studies. Firstly, the present study found that a family history of CVD was significantly higher in the CVD patients. This indicates the strong effect of genetics as a factor that could increase the risk of CVD. Studies showed that a family history is associated with an increase in CVD mortality across long-term follow-up [33].

Secondly, the evaluation of dietary habits using the adherence score to the Saudi dietary guidelines revealed that fruit, olive oil, and non-alcoholic beer were more highly consumed in the non-CVD patients than in the CVD patients. These food items are rich in polyphenols and dietary fiber, nutrients for which high levels of intake were previously associated with a decreased risk of developing CVD [34]. Moreover, we found that the consumption of non-refined cereals and breads was particularly low relative to recommendation. The high intake of refined carbohydrate is reported to increase the risk of type 2 diabetes and CVD [35]. The Saudi dietary guidelines are well publicized; however, more effort may be needed on education and promotion of the guidelines to reduce the risk of diseases including CVD.

Olive oil is the main source of fat in the Mediterranean diet and is linked with a lower mortality for CVD [18]. An olive-oil-rich diet is associated with enhanced lipoprotein metabolism and a reduction in oxidative damage, inflammation, blood pressure, endothelial dysfunction, and thrombosis [36]. A study by Guasch-Ferre et al, demonstrated that olive-oil intake, in particular the extra-virgin variety, decreased the risk of mortality and cardiovascular disease for individuals from Spain who were at high CVD risk [37]. Furthermore, a study by Carnevale et al. reported that olive oil advanced the post-prandial glucose and lipid profile in patients with impaired fasting glucose [38].

A study carried out by Woodside et al. found a strong correlation between the intake of fruits and vegetables and a reduction in the risk of developing coronary heart disease (CHD) [22]. Vegetables and fruits are a good source of nutrients, including vitamins, minerals, dietary fiber, and other biologically active compounds. These compounds have important mechanisms of action, including enhancing the immune system, reducing platelet aggregation, modulating cholesterol synthesis, reduction of blood pressure, and antioxidant, antibacterial, and antiviral effects [39].

The higher non-alcoholic beer consumption among the non-CVD patients may indicate that non-alcoholic beer could have a positive effect on heart health. It was reported that non-alcoholic beer can inhibit blood coagulation and platelet activation, which benefits the cardiovascular system without the negative effects of alcohol [32]. Despite the differences between non-CVD and CVD patients in their dietary habits, the lipid profile biomarkers, including total cholesterol, triglycerides, and LDL, were not significantly different. This is in contrast with the reported study by Rossouw, who showed that cholesterol levels are correlated with the risk of CHD, even at "normal" levels of cholesterol, in both men and women of all ages [40]. In addition, unpredictably, the levels of HDL were significantly higher in the CVD patients. The reason underlying this association is unknown, but one plausible explanation could be due to medications that were prescribed to CVD patients to control blood pressure, hyperlipidemia, and cardiac disease. These types of medications, such as niacin and atorvastatin, are known to enhance the lipid profile, and they were reported to increase HDL [41]. The current study also did not detect any significant differences between the non-CVD and CVD patients in the anthropometric measurements of weight, waist circumference, and BMI. This is in contrast with Alissa et al., who reported a strong significant relationship between BMI and the CVD risk in Saudi participants [29]. The inconsistency between these results could be due to differences in the sample size, which was smaller in this preliminary study. This study is the first to assess the adherence to the Saudi dietary guidelines among CVD male patients in Saudi Arabia. Currently, there is no validated food frequency questionnaire available specifically for the Saudi population; therefore, in this study, efforts were made to include food items that are more representative of the typical components of the Saudi diet. Furthermore, the analysis of adherence to the Saudi dietary guidelines was performed in parallel with the collection of blood biomarkers. As such, the data generated by this pilot study offer a unique insight into Saudi CVD populations, which may help in the planning and design of future studies to validate these findings. Further studies are now recommended to assess the association between the adherence to the Saudi dietary guidelines and the risk of CVD on a larger population sample. Moreover, as not all biomarker data of all for our patients were found in the patients' electronic system, the sample size calculation for future studies needs to consider the missing biomarker data of patients in the hospital electronic records when determining the power of their studies to allow for examining a more complete dataset of biomarkers.
