Dietary patterns and quality of life

Nutritional habits are major life-style related factors, playing major role in the pathogenesis of numerous chronic diseases. Recently, dietary patterns have attracted much attention because of the role of diet and nutrients in the human life and health. The role of nutrition in human health is a reflection of the complicated interactions between dietary nutrients or components exhibited by their inhibitory or even synergistic effects rather than their isolate action. The effect of an isolated nutrient could be too small as to be detected, whereas the cumulative effect of multiple nutrients included in an overall dietary pattern could be sufficiently large as to exhibit meaningful health effects. Dietary patterns are obtained via numerous statistical approaches and are closely related to quality of life. Health-related quality of life (HRQoL) is a multi-dimensional concept that includes domains related to physical, mental, emotional, and social functioning. It goes beyond direct measures of population health, life expectancy, and causes of death, and focuses on the impact of the health status on health related quality of life. In this regard, we could summarize the association between dietary patterns and quality of life into two major categories among healthy individuals and among unhealthy patients with chronic disease. It is strongly supported that healthy dietary patterns (e.g. Mediterranean dietary patterns, DASH dietary regimens and healthy dietary patterns obtained by principal component analysis) are closely associated with better scores of health related quality of life both among healthy and unhealthy individuals. Accordingly unhealthy dietary pattern mainly known as western dietary pattern is associated with lower scores of both physical and mental aspects of quality of life. The possible underlying mechanisms are improvement in mental status by increasing brain neurotransmitters, promote effective neurotransmission, reduced neuro-degeneration, reduced inflammatory status and reduced pro-inflammatory cytokines production in the brain, improved gut microbiota and improved glucose homeostasis. These healthy effects are attributed to the high content of different beneficial compounds in healthy patterns, including dietary antioxidants, largely present in leafy vegetables, fruits, olive oil, high monounsaturated (olive oil) or polyunsaturated fatty acids (mainly from fish and nuts), dietary fiber and low glycaemic index of its ingredients. Accordingly, western dietary pattern has a high content of saturated, trans-unsaturated fatty acids, and refined sugars usually present in the foods that characterize the Western diet as candidates in the etiology of numerous disease including CVD, diabetes, mental disorders and cancers.