How Blood Sugar Affects Your Mood

Could the old saw "you are what you eat" have a bearing on your mood? Possibly. If you have mood swings, especially if you have diabetes, you may want to evaluate your food choices. They may be affecting your blood sugar levels.

Blood Sugar

When we digest carbohydrate foods, they break down into glucose, a simple sugar that easily converts to energy and reaches cells via the blood stream. This is called blood sugar, or blood glucose.

Normally, our body self regulates to maintain stable blood sugar levels by producing a hormone called insulin. Too much blood sugar, however, can contribute to health problems, including Type 2 diabetes.

Blood Sugar and the Brain

While it's far from the largest organ in the body, the human brain burns more than its share of glucose just to function normally. When you wait too long between meals, you may experience changes in your ability to concentrate, think clearly, and have a balanced mood.

Following digestion, glucose directly enters the blood stream, immediately affecting blood sugar levels. In the long term, however, elevated glucose levels can be dangerous. Persistently consuming high glycemic foods (typically white foods such as bread, rice, and potatoes), can decrease insulin sensitivity and increase risk of diabetes.

In one small study, researchers from Australia conducted MRIs of 249 participants, age 60 to 64, at four and eight years and found an association between blood glucose levels and reduced brain volume in the left and right hippocampus area and the amygdala. After evaluating the data using several types of analyses, they attributed higher plasma glucose levels to 6 to 10 percent of the atrophy. The researchers recommend further studies to confirm their findings and are currently analyzing another four-year wave of MRIs.

According to Rebecca K. Kirby, MD, MS, RD, poorly nourished brains may cause individuals to experience depression and mood swings. She cites a study from Great Britain in which 80 percent of people with mood disorders noticed that food choices affected how they felt.

Maintaining Blood Glucose Levels and Stable Mood

Dietitian Alison Massey offers a few eating tips to maintain healthy blood sugar levels.

  • Focus on small, frequent meals, preferably at least three modest meals and 1 to 2 healthy snacks daily.
  • Try to eat about the same amount of carbohydrates at each meal.
  • Incorporate complex carbohydrates (those high in fiber and nutrient value) with lean proteins, healthy fats, and nonstarchy vegetables to create a well-balanced meal.

Massey suggests monitoring blood glucose levels before and 2-hour after meals if you already have diabetes.

Alison Massey, RD reviewed this article.




McAuliffe, W. George, DC, CCN, Camo, Bonnie, MD, and Mullen, Dorothy, MA. "Are You on The Blood Sugar/Mood Chemistry Rollercoaster?" Web.

Pearson, Lindsey, MD. "Experiencing Mood Swings? It Could Be Blood Sugar." Blog posting. Web. 3 March 2012.\

Kirby, Rebecca K., M.D., M.S., R.D. "Mood Swings And Depression: Let's Get To The Bottom Of It." Web.

Anderson, Pauline. "Even High Normal Blood Glucose Linked to Brain Atrophy." Medscape Medical News. Web. 5 September 2012.