Nurses are well aware of the physiologic benefits of consuming a healthy diet. Incidence of cardiovascular disease is lower in individuals who adhere to a diet rich in vegetables and fruits, whole grains, and low in saturated fats such as the Mediterranean Diet. Recent work by experts in nutrition and psychiatry indicates diet also may play a role in prevention of depression (Opie et al., 2015). Appreciating the potential magnitude of the problem, as well as the current evidence can alert healthcare providers to include a nutritional assessment when interacting with individuals whom they consider may be depressed.
What is the magnitude of the problem? Depression, whether chronic or episodic, "comprised the major contributor to global disability" (Opie et al., 2015, p. 1). Depression likely affects approximately 16 million adults in the United States, and more than 350 million persons globally. Thus, investigating whether diet exerts an influence on the occurrence of depression is important, given the overall global toll exerted by depression.
What do we know? Both what is eaten and the pattern of consumption seem to influence presence or absence of depression. Sanchez-Villegas et al. (2011) found increased consumption of transunsaturated fats (TFA) was associated with a higher risk of depression, assessed by means of a self-reported diagnosis. An inverse relationship was noted when the impact of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) were studied: increased consumption of these fatty acids resulted in decreased risk for depression. Similar findings were reported when diet pattern was examined (Sanchez-Villegas et al., 2015). Individuals who adhered to a moderate Mediterranean Diet, a Provegetarian Dietary Pattern, or an alternative healthy eating pattern were at decreased risk of depression compared to those with low adherence. However, their data suggested a threshold effect, with little further benefit with moderate-to-high or very high consumption adherence. This finding could have implications for how diet information is presented, as positive benefits may result without excessive patient commitment.
What is recommended? Many recommendations offered to prevent depression are similar to those offered to prevent cardiovascular issues. Opie et al. (2015) suggest:
* Encourage individuals to follow a traditional dietary pattern similar to the Mediterranean Diet, a Norwegian diet, or a Japanese diet. Predominant foods in these diets include whole grains and fish. The shared experience of eating with family or community is included.
* Encourage families to increase consumption of vegetables, fruits, nuts, seeds, and whole grain cereals. This recommendation is not new; however, current information makes its implementation more compelling.
* As with previous recommendations, increased consumption of foods high in omega-3 PUFAs such as fish should be encouraged.
* Consumption of unhealthy foods, such as fast foods, should be limited and replaced with more nutritional foods such as fruits and nuts.
* Limit consumption of red meats, and monitor vitamin D status. The latter's role in many brain processes could play a role in depression.
What does this mean for nurses? Although nurses are already familiar with these recommendations, the link between diet and the presence of depression may be new. Assessing the quality and pattern of dietary consumption can become part of a comprehensive assessment when nurses interact with persons experiencing either episodic or chronic depression.
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