Mind & Mood Archive

Here's what the research says about diet and depression.

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If you've ever found yourself in front of the TV after a bad day, mindlessly digging ice cream out of the container with a spoon, you know that mood and food are sometimes linked. But while stress eating is a verified phenomenon, the relationship between food and actual mood disorders, such as depression, is less clear. Or, to put it another way: can the things you eat influence your risk for depression — and can dietary changes potentially improve your mental health?

"The research regarding dietary factors and depression is still inconclusive," says Patricia Chocano-Bedoya, a visiting scientist in the Department of Nutrition at the Harvard T.H. Chan School of Public Health. But there have been hints that food may play a role in depression.

Stress management may reduce health problems linked to stress, which include cognitive problems and a higher risk for Alzheimer's disease and dementia.

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It's not uncommon to feel disorganized and forgetful when you're under a lot of stress. But over the long term, stress may actually change your brain in ways that affect your memory.

Studies in both animals and people show pretty clearly that stress can affect how the brain functions, says Dr. Kerry Ressler, chief scientific officer at McLean Hospital and professor of psychiatry at Harvard Medical School. Scientists have seen changes in how the brain processes information when people experience either real-life stress or stress manufactured in a research setting. (For the latter, researchers might challenge subjects to perform a difficult task, such as counting backward from the number 1,073 by 13s while being graded.) Either type of stress seems to interfere with cognition, attention, and memory, he says.

So how do you keep your brain healthy, stay cognitively fit, and build your cognitive reserve? It's easier for some people than for others. And though genetics set the stage for your brain health, you can do something to improve your brain health and cognitive fitness.

First it is important to remember that you need a healthy body to have a healthy brain. Therefore, ensuring your brain health depends upon regularly seeing your doctor, following her or his recommendations, and managing any health conditions you have.

A regular practice can help your brain better manage stress and anxiety that can trigger depression.

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Depression continues to be a major health issue for older adults. It affects about 20% of adults ages 65 and older, and regular depression can lead to higher risks for heart disease and death from illnesses. It also affects people's daily lives by making them more socially isolated and affecting cognitive function, especially memory.

In fact, a study of 1,111 people (average age 71), published online May 9, 2018, by Neurology, found that those who had greater symptoms of depression also had worse episodic memory — the ability to recall specific experiences and events.

A study shows that moving in reverse may help with short-term memory.

Lost your car keys? Instead of retracing your steps, you might want to try walking backward to jog your memory.

A study published in the January issue of Cognition found that people who walked backward, imagined they were walking backward, or even watched a video simulating backward motion had better recall of past events than those who walked forward or sat still.

The REACH method teaches how to overcome lingering bad feelings toward someone who did you wrong.

Almost everyone has experienced being wronged by someone. It could be a former co-worker, friend, or family member. But hanging on to those negative feelings can do great harm to your health.

"Forgiving a person who has wronged you is never easy, but dwelling on those events and reliving them over and over can fill your mind with negative thoughts and suppressed anger," says Dr. Tyler VanderWeele, co-director of the Initiative on Health, Religion, and Spirituality at the Harvard T.H. Chan School of Public Health. "Yet, when you learn to forgive, you are no longer trapped by the past actions of others and can finally feel free."

Forgetting things? Memory problems are more common than you think

It's normal to forget things from time to time, and it's normal to become somewhat more forgetful as you age. But how much forgetfulness is too much? How can you tell whether your memory lapses are normal forgetfulness and within the scope of normal aging or are a symptom of something more serious?

Healthy people can experience memory loss or memory distortion at any age. Some of these memory flaws become more pronounced with age, but — unless they are extreme and persistent — they are not considered indicators of Alzheimer's or other memory-impairing illnesses.

Exercise is as effective as antidepressants in some cases.

One in 10 adults in the United States struggles with depression, and antidepressant medications are a common way to treat the condition. However, pills aren't the only solution. Research shows that exercise is also an effective treatment. "For some people it works as well as antidepressants, although exercise alone isn't enough for someone with severe depression," says Dr. Michael Craig Miller, assistant professor of psychiatry at Harvard Medical School.

The exercise effect

Exercising starts a biological cascade of events that results in many health benefits, such as protecting against heart disease and diabetes, improving sleep, and lowering blood pressure. High-intensity exercise releases the body's feel-good chemicals called endorphins, resulting in the "runner's high" that joggers report. But for most of us, the real value is in low-intensity exercise sustained over time. That kind of activity spurs the release of proteins called neurotrophic or growth factors, which cause nerve cells to grow and make new connections. The improvement in brain function makes you feel better. "In people who are depressed, neuroscientists have noticed that the hippocampus in the brain—the region that helps regulate mood—is smaller. Exercise supports nerve cell growth in the hippocampus, improving nerve cell connections, which helps relieve depression," explains Dr. Miller.

Research we're watching

People who sleep too much or too little may be at higher risk for cognitive decline, according to a study published Sept. 21, 2020, by JAMA Network Open. Researchers looked at self-reported sleep duration from 20,065 people in two large studies, one in the United Kingdom and one in China. The participants from the United Kingdom were ages 50 and older and those living in China were 45 and older and were followed by researchers for up to 15 years. Researchers asked participants questions about their sleep patterns and performed a cognitive assessment. The process was repeated at two year intervals during the various study periods. Researchers found that people who slept too little (four or fewer hours a night) or too much (10 or more hours a night) were more likely than more typical sleepers to experience cognitive decline.

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While looking at the sunny side of life offers a lot of light moments, there may be a better path to well-being.

Optimism feels good. The expectation that positive things will happen is associated with happiness and better health, including fewer heart attacks and a lower risk for premature death. Pessimism, on the other hand, feels bad; it makes you depressed or anxious and keeps the fight-or-flight system activated, triggering chronic inflammation (which is linked to many diseases).

You might think the best way to improve your well-being is to cultivate an optimistic outlook. Think again. "Better than cultivating an artificial optimism is to see the situation and the world realistically," says Ronald Siegel, an assistant professor of psychology, part-time, at Harvard Medical School and medical editor of the Harvard Special Health Report Positive Psychology.