Literature Review on Impact of Diet on Depression
Mr. Rishu Mittal
Cordflex Electronics Pvt. Ltd.
The present work deals with reviewing the existing literature and come up with the useful insight about the impact of diet on depression. With the busy life, the problem of depression has become common among professionals. Many psychologists and dietician across the world are in the process of finding the factors responsible for depression and how to minimize the impact of such factors. Diet is one among such factors. The present work highlights the influence of the type of diet and the unhealthy dieting habits on the state of depression in the individuals. The study revealed the positive relation between them. Also, the study attempted to make connect between gender, diet and depression.
Keywords: Diet, Depression, Gender.
There are two ways to define the term "Diet". Diet may refers to the food we consume. For instance, the vegetarian diet, the non-vegetarian diet, the liquid diet and other allied forms. On the other hand, diet can also refer to the restriction on the intake of food, an individual imposes, in order to either lose weight or for any medical reasons.
Depression can be described as the feeling of severe sadness, despondency and desolation. It is a complex disease which might be the result of serious medical illness, may be due to any major life event which may be positive such as starting a new job, pregnancy, or may be negative such as death of a loved one, divorce, or may be due to family heredity, or no known reason of the patient. There is no clarity in terms of the underlying reasons behind the state of depression in human beings.
The purpose of this study is to determine the impact of diet on depression. Since the reasons for depression are many and are still under investigation, this study can be useful to gain insight about whether diet is one of the reasons behind the state of depression in human beings or not. For this, the study aims to present the review of the existing literature to verify the connect between these two terms, i.e., diet and depression and to state whether there is any significant impact of diet on depression. The findings of the study will be act as a useful input to the psychologists around the world in diagnosing whether diet might act as one of the reason behind the state of depression in their patients.
Literature review act a reservoir of crucial information for any research work as it helps the researcher in making useful comments about the topic under consideration
- The type of diet and its impact on the state of depression
In this part of the literature review, we will consider the first definition of the diet, i.e., diet may be referred to as the food we consume. For instance, the vegetarian diet, the non-vegetarian diet, the liquid diet and other allied forms and will try to investigate the connect between the type of diet and its impact on the state of depression in the human beings.
(Key, Davey and Appleby, 1999) conducted a study comparing the health benefits associated with the type of diet, vegetarian or non vegetarian, followed by an individual. The study revealed an interesting finding that the type of diet is associated with several health problems in human beings. The authors stressed on the finding that vegetarian diet, in any way, is better than a non-vegetarian diet as intake of the vegetarian diet significantly lower down the risk of various health related issues such as constipation, gallstones, appendicitis, and many more. The research proved that the vegetarian participants have lower mean BMI, lower mean cholesterol level, and lower down the death due to IHD.
In this context of the association of the type of diet and health effects, even the authors (Beezhold, Johnston and Daigle, 2010), in their study concluded that the vegetarian diet results in positive mood and vegetarian people exhibit less negative emotions as compared to non-vegetarians. In their study, the authors have also found that intake of vegetarian diet makes individual less prone to depression as compared to the intake of omnivorous diet. The researchers made use of Depression Anxiety Stress Scale (DASS) to measure the level of depression, anxiety and stress in the vegetarian and non-vegetarian people. However, only depression variable is of the interest of this study. The mean DASS-D value is found to be 1.67 + 0.28 in case of vegetarians while it is 4.81 + 0.69 in case of omnivorous diet. The test results clearly showcase that intake of the non-vegetarian diet can be one of the reason behind depression in human beings. Another test was conducted by the researchers, namely, Profile of Mood States (POMS) covered six mood domains. However, we will discuss the result of Depression-Dejection mood domain (POMS-D) for the purpose of the present study. The mean POMS-D value is found to be 4.36 + 4.10 in case of vegetarians while it is 8.99 + 0.80 in case of omnivorous diet. The test results is in line with the test result of DASS-D that the intake of the non-vegetarian diet can be one of the reason behind depression in human beings.
Hence, from these two studies conducted by (Key, Davey and Appleby, 1999) and (Beezhold, Johnston and Daigle, 2010), the type of diet has an impact on depression state in human beings and the intake of omnivorous diet makes an individual more prone to the problem of depression.
- Dieting and its impact on the state of depression
In this part of the literature review, we will consider the second definition of the diet, i.e., diet can be refer to as the restriction on the intake of food, an individual imposes, in order to either lose weight or for any medical reasons and will try to investigate the connect between the practice of dieting and its impact on the state of depression in the human beings.
The authors (Wolfe and Hewitt, 2016) conducted a research study on college students and found that self focus is a major reason behind the increasing temptation of the college students towards the practice of dieting. With self focus, authors refers to the state of mind of individual to control their dietary habit in order to look good. However, the study revealed that the increasing self focus leads to body dissatisfaction, further leading to eating disorders which in turn leads to the state of depression in the individuals. Another interesting revelation of this study is that the presence of body dissatisfaction in the mind of individual increases the chances of the state of depression by four times (4x times) as compared to individuals in which the level of body dissatisfaction is concerned.
In this context of the association of the dieting and depression, even the authors (Gillen, Markey, and Markey, 2012) in their study, tried to establish whether the dieting practices are associated with the state of depression in individuals or not. Here, the researchers established an interesting connect between the BMI of individuals and their involvement in the dieting practices. The researchers found that the individuals with higher BMI are more tempted toward dieting as compared to individuals with lower BMI. Here, we can connect the finding of this research with the finding of the research conducted by the (Key, Davey and Appleby, 1999) wherein the researchers indicate that vegetarian individuals have lower BMI. Thus, if we connect these two, we can establish that a vegetarian individual has a lower BMI and is less tempted towards unhealthy dieting practices. Discussing further the results of the study conducted by (Gillen, Markey, and Markey, 2012), the authors found that the unhealthy dieting practices lead to the higher level of depression symptoms in individuals as compared to individuals involved in the intake of healthy diet, or vegetarian diet as also commented by (Key, Davey and Appleby, 1999) and proved by (Beezhold, Johnston and Daigle, 2010). Here, the authors (Gillen, Markey, and Markey, 2012) added a new demographic dimension to their results by concluding that depression is not associated to dieting practices in males whereas the depression is associated to the dieting practices in females. The study revealed the inverse relationship between women' weight control practices and the state of depression.
- Impact of demographics on diet and depression
The review of the research conducted by (Gillen, Markey, and Markey, 2012), as discussed above, opens a new door for discussion in the present study. Now, we can try and find the impact of demographics on the person's urge to engage in the dieting practices and their corresponding association on the state of depression in individuals.
The authors (Davila, Kolodziejczyk, Norman, Calfas, Huang, Rock, Griswold, Fowler, Marshall, Gupta and Patrick, 2014) conducted a research on the students of three universities in South California to determine the relationship between gender, diet and depression. The study highlighted that 29% of participants were involved in unhealthy dieting practices in order to reduce weight and look good. This finding is in line with the results of the study conducted by the authors (Wolfe and Hewitt, 2016). Furthermore, the study conducted by (Davila, Kolodziejczyk, Norman, Calfas, Huang, Rock, Griswold, Fowler, Marshall, Gupta and Patrick, 2014) revealed that there is no connection between gender and the involvement in unhealthy dieting practices, such as fasting and purging. However, the authors are of the view that unhealthy dieting leads to the state of depression, but gender has no role to play in establishing a connect between the diet and depression.
Another research study was conducted by the researchers (Brown, Kola-Palmer and Dhingra, 2015) to determine the correlation between gender and unhealthy and extreme dieting practices followed by the US adolescents. The study also supported the findings of the study conducted by (Davila, Kolodziejczyk, Norman, Calfas, Huang, Rock, Griswold, Fowler, Marshall, Gupta and Patrick, 2014) as the study conducted by the researchers (Brown, Kola-Palmer and Dhingra, 2015) failed to find any evidence supporting the role of gender in establishing a connect between the diet and depression. However, the authors (Brown, Kola-Palmer and Dhingra, 2015) are of the view that other psychological factors, such as urge to look good, are the reasons behind the showcasing of extreme dieting practices by the US adolescents. According to researchers, this might not only lead to the state of depression but also in suicide attempts, marijuana use or development of chain smoking behaviour among individuals. However, the only link to gender is that these psychological factors are more prominent on males as compared to females.
To conclude, we can summarise the findings as recorded beneath:
- Definition of diet and depression: Diet may refers to the food we consume or can also refer to the restriction on the intake of food, an individual imposes, in order to either lose weight or for any medical reasons. However, depression can be described as the feeling of severe sadness, despondency and desolation.
- Impact of type of diet on the state of depression: The type of diet has a strong impact on depression state in human beings and the intake of omnivorous diet makes an individual more prone to the problem of depression as compared to the vegetarian individuals.
- Impact of unhealthy dieting on the state of depression: Self focus, body dissatisfaction, lower BMI are some of the reasons behind the people's urge to follow unhealthy dieting practices such as fasting or purging. This has a strong impact on depression state in human beings
- Relation between gender, diet and depression: There is no clarity in whether gender has a role to play in establishing connect between the diet and depression. Some researchers are supporting it while others are clearly denying it. Thus, we can leave this part for the future research work.
Key, T. J., Davey, G. K., & Appleby, P. N. (1999). Health benefits of a vegetarian diet. Proceedings of the Nutrition Society, 58(02), 271-275.
Beezhold, B. L., Johnston, C. S., & Daigle, D. R. (2010). Vegetarian diets are associated with healthy mood states: a cross-sectional study in seventh day adventist adults. Nutrition journal, 9(1), 1.
Wolfe, W. L., & Hewitt, K. (2016). Self-Focus Mediates the Relationship between Body Dissatisfaction, Depression and Disordered Eating Behaviors.North American Journal of Psychology, 18(1), 85.
Gillen, M. M., Markey, C. N., & Markey, P. M. (2012). An examination of dieting behaviors among adults: links with depression. Eating behaviors,13(2), 88-93.
Davila, E. P., Kolodziejczyk, J. K., Norman, G. J., Calfas, K., Huang, J. S., Rock, C. L., Griswold, W., Fowler, J.H., Marshall, S.J., Gupta, A. & Patrick, K. (2014). Relationships between depression, gender, and unhealthy weight loss practices among overweight or obese college students. Eating behaviors, 15(2), 271-274.
Brown, C. S., Kola-Palmer, S., & Dhingra, K. (2015). Gender differences and correlates of extreme dieting behaviours in US adolescents. Journal of health psychology, 20(5), 569-579.