“No need to ponder – Sugar is harmful to your mental health.”
Sugar is Harmful: Summary
In the following article, we provide a small body of evidence indicating that sugar is harmful to mental health. The link between depressive symptoms in adults and children is clear. A wider body of literature targeting treatment approaches, designed to decrease sugar intake to decrease mood and anxiety symptoms, is called for in future research. In summary, the following five scientific findings are discussed below (annotated bibliography to follow):
- Standard diets low in fibre contribute to mood symptoms both during and after pregnancy.
- Sugar consumption is correlated with annual rates of depression, possibly related to metabolic impact of sugar.
- Excessive sugar consumption has similar patterns seen in other addictions (withdrawal, craving, etc.).
- Highly refined carbohydrate intake in children is associated with depressive symptoms.
- Suboptimal nutrition is a key contributor to increased mental health symptoms, particularly high sugar intake.
Depression: Conventional Scientific Literature
Our system is built on science, and that is a good thing! The rigorous requirements of the scientific method dictate that conclusions can only be made with a large body of quality peer-reviewed evidence. Moreover, it defends against quick assumptions based on individual personal experience(s). The plural of anecdote is not data.
There is a large body of peer-reviewed literature about both the ethology and treatment of clinical depression. This is convention in that we now know the heritability factor contributing to the complicated collection of depressive symptoms, and thus, the degree that environment (e.g. our diet) plays a role.
This convention guides our understanding and treatment decision making. The body of literature is overwhelming. However, the problem with convention, supported by a massive database of findings, is that we tend to ignore emerging perspectives, even holding emerging results to a higher standard. One such emerging body of evidence is the dietary impact on mood and anxiety. It should also be noted that industry is absolutely not interested in research supporting this connection.
Emerging Impact of Diet on Mental Health
Dr. Monique Tello, in her 2018 article on diet and depression in Harvard Health Publishing, indicates that, “What we eat, matters.” The emerging field of Nutritional Psychiatry supports the bidirectional relationship of the mind-body experience. To be specific, what we eat can put us at risk for depression. Meta-analysis by Ye Li, et al., indicates that:
- The Western diet is associated with increased risk of depression.
- A healthy diet is associated with decreased risk of depression.
- Dietary guidelines with scientific rationale should be considered.
Five Articles Showing that Sugar is Harmful (Annotated Bibliography)
The team at Finding My Psych did a quick scan of the peer-reviewed literature, specifically supporting the connection between sugar and mood. While the breadth of findings is lacking, it is clear that a line can be drawn.
In 2018, a cross-sectional study of 712 pregnant women, assessed the impact of diet on mental health. Findings indicate that the standard Brazilian diet was associated with a higher prevalence of depression, both during an after pregnancy. A diet high in fruits and beans (high fibre) were not associated.
In 2002, a preliminary investigation into the hypothesis that sugar consumption impacts the prevalence of major depressive symptoms, was conducted using a cross-national epidemiology database. Results indicated that sugar consumption was correlated with annual rates of major depression. While this does not necessarily impact ethology, it does point towards treatment considerations. Metabolic reasons (b-endorphins) and oxidative stress are discussed.
Researchers explored the model of addiction to sugar intake. Binging, withdrawal, craving, and cross sensitization are evaluated using an animal model (rats). Evidence supports the hypothesis of sugar dependance, and the behavioural implications therein. This view is particularly not supported by industry.
Researchers examined the relationship between nutritional intake and depressive symptoms in school children. 710 children between the ages of 6 and 9 years of age were selected for this study. Objective measures for mood and physiology were collected. Results demonstrate that high consumption of simple highly refined carbohydrates were associated with depressive symptoms.
Using a primary care model, Holford reviews the impact of nutrition on depressive symptoms. While not a peer-reviewed study, Holford draws several important conclusions about the impact of suboptimal nutrition and mental health. This includes blood sugar imbalances, low tryptophan and tyrosine amino acid levels, low vitamin B, and a lack of essential fats, such as Omega-3.
A Call For Future Research – Sugar Is Harmful (Is it?)
Is sugar harmful? I just might be! The impact of diet on mental health is difficult to deny. The above literature should be considered a starting point in the scientific understanding that sugar is a primary contributor depressive symptoms. While changes in diet should never be considered a singular treatment approach for decreasing depressive symptoms, it is one biopsychosocial element with strong augmenting impact.
If you have seen, “That Sugar Film,” you cannot help but be impacted by the anecdotal evidence pointing to the negative effects of a high sugar diet commonly seen in Western culture. Rigorous scientific methods should be applied in order to substantiate this connection. Moreover, we also believe that future research should focus on various impacts on mental health (depression and anxiety).
While there is no disagreement that diet is a critical treatment consideration in the field of Behavioural Medicine, supporting evidence has the power of broader impact and adoption in terms of treatment.