If someone were to ask you what causes depression, what would you say?
Many people may include genetics and family history, personality, trauma or loss, and chemical imbalances in their answers, but nutritional factors are probably not the first thing that come to mind. Although it may be too strong of a statement to say that poor nutrition causes depression, research has shown that there is a strong and definite link between the two that may change the way that we think about treating depression.
Depression and other mental health conditions can be affected by a variety of factors, and as much as some people may dismiss these conditions with statements like “It’s all in your head” or “Just think positive thoughts,” understanding and treating them is a bit more complex than that. In fact, research has identified some significant links between depression and certain elements of nutrition that could change and improve the way that we think about and treat depression. Let’s consider how blood sugar, protein, and fat appear to impact the development of depression and related symptoms.
For some time now, it has been known that people who have diabetes are more likely to be depressed, as rates of depression tend to be higher in this population. It was originally thought that this was due to additional stress that comes with having to manage diabetes symptoms, but it may actually have something to do with higher blood sugar levels. Research has shown that consistently high blood sugar levels “increase the risk of developing depression” because it negatively affects some of the neurotransmitters in the brain. One study even found that consuming foods with higher scores on the glycemic index was associated with an increased risk of developing depression in menopausal women, while eating more fiber, whole grains, and vegetables “was associated with a decreased risk” of developing depression. However, having high blood sugar is not the only concern when it comes to risk of developing depression. Existing studies that show that low carb diets may also lead to increased depression risk indicate that low blood sugar levels could also be detrimental. With that being said, the research has concluded that when “blood sugar levels are too high or too low [they] have a negative impact on mood.”
Protein consumption also appears to have some impact on depressive symptoms, especially sleep-related issues. One study found that eating a high protein diet can improve sleep quality, which is linked to “improved memory and cognitive performance, improved immunity and resistance to stress, increased life expectancy and certainly improved mood.” Of course, the benefits of sleeping well are not surprising, but many people who struggle with depression have difficulty getting good quality sleep and eating more protein may have a positive effect on this. Furthermore, consistently eating lots of protein early in the day is shown to be helpful with increasing dopamine, which is closely associated with pleasure.
The last significant aspect of nutrition that is worth considering in relation to depression is fat. Not all fats are the same, and it is important to distinguish between “good” fats and “bad” fats when looking at fat’s impact on depression. Research has shown that regularly consuming omega 3 fatty acids, one of the “good” fats, is linked to an improved mood, in addition to other benefits such as improved memory and improved learning. There are many different kinds of omega 3s, two of which are EPA and DHA. Low levels of EPA have been found to be associated with higher rates of depression. On the other hand, EPA and DHA both slowed the onset of depression in one research study and EPA actually “decreased the incidence of depression” in that study. With that being said, it appears that omega 3s appear to act in a preventative way too, meaning that they have the potential to stop a person from ever developing depression in the first place. However, not all fats are created equal, and the “bad’ fats seem to have a negative effect. In fact, it has been found that “diets high in trans-fats and saturated fats adversely affect cognition, brain synapses, and several molecules related to learning and memory are adversely affected by unhealthy diets.”
Research is becoming increasingly interested in understanding depression, how it develops, what impacts it, and effective ways for treating it. The fact that there is so much evidence for nutrition’s impact on depression is quite exciting and it means that there may be unexplored treatments for this complex issue. It may even be possible to prevent depression in some cases by making simple changes to a person's diet and eating habits. Even though nutrition is clearly not the only factor that affects the development and severity of depression, it may be a powerful tool for supplementing other treatments for depression.
**Information in this article was found in a training put together by Claire Dorotik-Nana, LMFT and Gina Gunderson, MS, RD, LD/N called “Nutrition and Depression: Advanced Clinical Concepts.”
Claira Hart is a therapist who enjoys working with children, families, and couples to help them overcome depression, anxiety, behavioral problems, and family conflict. She is passionate about using a strengths-based approach in her work. received her Master of Arts in Marriage and Family Therapy from Northcentral University and her bachelor’s degree in Family Studies and Psychology from the University of New Mexico.