Is Your Mood Disorder a Symptom of Unstable Blood Sugar?

Isa Kay, MPH '18

October 21, 2019

Many people may be suffering from symptoms of common mood disorders, such as depression and anxiety, without realizing that variable blood sugar could be the culprit.

A growing body of evidence suggests a relationship between mood and blood-sugar, or glycemic, highs and lows. Symptoms of poor glycemic regulation have been shown to closely mirror mental health symptoms, such as irritability, anxiety, and worry. This should come as no surprise, as the brain runs primarily on glucose.

Depression currently affects about 25% of individuals with diabetes, a population more susceptible to pronounced blood sugar highs and lows.¹ The diabetic population provides valuable insight on the effects of blood sugar variability on both ends of the spectrum. 

One study found that inconsistent blood sugar levels among women with diabetes were associated with lower quality of life and negative moods.² Among diabetic, higher blood glucose, or hyperglycemia, has historically been associated with anger or sadness, while blood sugar dips, or hypoglycemia, has been associated with nervousness.³

Persons with diabetes are not the only ones vulnerable to mood disturbances as a result of blood sugar fluctuations. Otherwise healthy individuals consuming a diet high in refined carbohydrates and added sugars may experience a sudden surge in their blood sugar, followed by an exaggerated insulin response, leading to acute hypoglycemia.⁴ 

A 2017 prospective study found positive associations between high sugar consumption and common mental disorders, concluding that sugar intake from sweet foods and beverages has an adverse effect on long-term psychological health.⁵

Individuals with recurrent mental health symptoms may choose to rule out alternative causes before jumping into mental health treatment or interventions. Several lifestyle principles can help stabilize blood sugar: 

• Reduce and manage stress. Stress has been shown to negatively affect the regulation of blood glucose. Specifically, hormonal changes during acute and chronic stress can affect glucose balance.⁶
• Increase intake of protein and fiber. Protein has a low glycemic index (GI), which means they have a low impact on blood sugar levels. Fibrous foods are also shown to have a lower GI value when compared to their refined counterparts.⁷
• Reduce intake of sweet beverages and refined carbohydrates. A diet high in refined carbohydrates, including sweet beverages, has a high GI value and is associated with unstable blood sugar regulation.^4,7

Although more studies are warranted to solidify the relationship between mood and blood sugar, considering dietary and lifestyle implications on common mood disorders can rule out lesser known causes. 

References

1. Anderson RJ. Freedland KE. Clouse RE. Lustman PJ. The prevalence of comorbid depression in adults with diabetes: a meta-analysis. Diabetes Care. 2001;24:1069–1078. doi: 10.2337/diacare.24.6.1069
2. Penckofer S, Quinn L, Byrn M, Ferrans C, Miller M, Strange P. Does glycemic variability impact mood and quality of life?. Diabetes Technol Ther. 2012;14(4):303–310. doi: 10.1089/dia.2011.0191
3. Gonder-Frederick LA. Cox DJ. Bobbit SA. Pennebaker JW. Mood changes associated with blood glucose fluctuations in insulin-dependent diabetes mellitus. Health Psychol. 1989;8:45–59.
4. Schwartz NS, Clutter WE, Shah SD, Cryer PE. Glycemic thresholds for activation of glucose counterregulatory systems are higher than the threshold for symptoms. J Clin Invest. 1987;79(3):777–781. doi:10.1172/JCI112884
5. Knüppel A, Shipley MJ, Llewellyn CH, Brunner EJ. Sugar intake from sweet food and beverages, common mental disorder and depression: prospective findings from the Whitehall II study. Sci Rep. 2017;7(1):6287. Published 2017 Jul 27. doi:10.1038/s41598-017-05649-7
6. Marcovecchio, ML. Chiarelli, F. The effects of acute and chronic stress on diabetes control. Sci Signal 5. 2012; 10. doi: 10.1126/scisignal.2003508
7. Atkinson FS. Foster-Poell K. Brand-Miller JC. Glycemic index (GI) and glycemic load (GL) values determined in subjects with normal glucose tolerance: 2008. Diabetes Care. 2008;31(12):2281-3. doi: 10.2337/dc08-1239

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About the Author

Isa Kay, MPH, RDN is a Registered Dietitian Nutritionist and completed her Master’s of Public Health in Nutritional Sciences from the University of Michigan School of Public Health. She is also a Navy veteran, yogi, and integrative health coach. Treating the body as an interconnected whole, Isa links nutrition with brain health, mood, and mental wellbeing. Her continued interests include the emerging field of nutritional psychiatry, functional medicine, and the gut-brain axis. You can follow Isa on social media at @meanutrition.