How blood sugar affects your mood and memory

You may understand that a meal that raises blood sugar fast and furiously can leave you dragging like a willow in a windstorm. Not surprisingly, it doesn't do much for your mood, either. Read on to learn more about how blood sugar can affect your mood and even your memory.

Our moods are intimately affected by the levels of hormones in our systems, including the hormone insulin. These hormones in turn affect neurotransmitters, chemical messengers in the brain. The different types of nutrients we eat, including carbohydrates and protein, affect these transmitters differently, triggering drowsiness or alertness. But the brain may be most sensitive to one simple compound: blood sugar.

Unlike muscles, the brain can't store sugar. It needs just the right amount of it at all times to function best, so it's not surprising that it's very sensitive to even very small differences in the amount of blood sugar available. A steady supply is by far the best.

People with diabetes who control their blood sugar well report better moods, less depression and less fatigue than those who don't. Both low and high levels of blood sugar can cause trouble when it comes to your mood and memory. People report feeling more symptoms of depression when their blood sugar is low.

Memory is also affected by blood sugar. In one study, people with diabetes had more trouble processing information, remembering things and paying attention — besides being in a bad mood — when their blood sugar was low. In people with type 2 diabetes, blood sugar swings are linked not only with poor memory but also, over time, with cognitive decline and dementia.

High blood sugar levels spell trouble, too. Long before they cause diabetes, they can impair the brain, shrinking a part that stores memories and increasing the risk of Alzheimer's disease. In one study at New York University, researchers found that in people who tended to have high blood sugar levels after meals, a part of the brain called the hippocampus, which is most associated with long-term memory, was smaller than in people whose postmeal blood sugar levels were lower. On the positive side, keeping your blood sugar on an even keel can help you feel better and stay mentally sharp.

Careful studies have found that the better they control their blood sugar, the better they are able to recall a paragraph after reading it and to remember words from a list.

In general, eating a good breakfast is the best way for anyone to improve mental functioning later in the day. Studies regularly show that eating breakfast improves mood, mental alertness, concentration and memory. Eating the right breakfast, one that keeps blood sugar on an even keel until lunch, is likely to work even better.

Keeping your blood sugar at healthy levels can keep you feeling better overall.