Prior research studies had shown that a healthy diet could be effective in the treatment and prevention of depression. Sanchez et al. (2011) produced the evidence findings to the link between fatty acids and depression through the development of a randomised study of 12,059 university graduates from 1999- 2010. The study used food frequency questionnaires (FFQ) to gather the data needed. The data collected estimated the intake of saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA), trans unsaturated fatty acids (TFA) and monounsaturated fatty acids (MUFA) as well culinary fats such as olive oil, seed oils, butter and margarine. The incidence of depression was accessed every two years through reports of new clinical diagnosis of depression by a physician and the use of antidepressant drugs. The result findings showed a weak inverse association in MUFA, PUFA and olive oil, whereas a detrimental relationship was found between the intake of TFA and depression risk. When analysing the evidence findings Sanchez et al. (2011) suggest the need for dietary interventions to be implemented by health care professionals for the preventions or treatment of depressive disorders. Although the study showed evidence that a diet consisting of TFA could be linked to the development of depression Sanchez et al. ( 2011) believe that evidence findings need to be confirmed by further prospective studies and trails to increase the reliability of the research findings.
Comparatively, although a detrimental relationship was found between the intake of TFA and depression in the study by Sanchez et al., (2011) variables such as sociodemographic status, age and gender were not considered. In previous research carried out by Akbaraly et al., ( 2009) that analysed the diet patterns and depressive symptoms of 3486 office-based civil servants also examined factors such as age, gender, marital status, education, and income. These factors can play an essential role in the variability in the prevalence of depression (Freeman et al., (2016). In previous research, age was found to be one of the demographic characteristics that can account for some of the variances in the prevalence of depression (Freeman et al., 2016). A survey carried out on the Canadian National population (2000/2007) showed men aged over 65 to have low symptoms of depression whereas males aged between 12-24 to be as high as 5.2%. The survey also should that depression in women aged 65 and over ranged from 3.1%, whereas women aged between 12-24 was 9.6%. of depression in females over 65 to 9.6% in the 12 to 24 age group. The prevalence of depression has can also be found to vary based on gender (Jaksby, 2016). Research has shown that women have nearly double to triple the prevalence rates for 12-month depression to men (Jaksby, 2016). Research has also indicated that the likelihood of depression in the lowest SES group is as much as twice that found in the highest SES group. With people in the lowest class far more likely to suffer from psychiatric disorders than those in the highest class (Jaksby, 2016). Once all the data was analysed Akaraly et al., ( 2009) identified two dietary patterns: ‘ whole food ‘ which consists of large intakes of vegetables fruit and fish and ‘ processed food, which consisted of high in sugar desserts, fried food, processed meat, and high-fat dairy products. Through the use of the centre for Epidemiologic Studies-Depression ( CES-D) scale, self-reported symptoms of depression were also assessed five years later. The study showed evidence on the robust association between the two-dietary pattern and depressive symptoms with Akbaraly et al. (2009) suggesting that the findings offer a need for consideration to a potential target for the prevention of depressive disorders within health services. Although on reviewing the participants who consented to be involved in the study, it became restricted to only white European members of staff. Meaning this cannot fully represent the British population therefore the evidence findings can be seen as unreliable