Food for Thought: How Food Is Linked to Mood

A Whole9 guest post by Emily Deans M.D., a board certified psychiatrist with a practice in Massachusetts and a clinical instructor in psychiatry at Harvard Medical School.

It’s obvious that mental problems such as depression or anxiety are directly linked to stress. All of us encounter stress in our daily lives, sometimes far more than we think we can handle, but the key to moving on and bouncing back is stress management. Usually when we think of managing stress, we think about yoga classes, other exercise, or squeezing stress balls. However, eating real, whole foods is also a big part of stress management and resiliency. What we eat has a huge impact on our moods.

How could that be? Your meals, after all, seem to be in an entirely different realm than family history of depression, or a tragedy in the family, or a fight with a coworker, or a traumatic experience. All these things can have a big impact on mental health, leading to symptoms such as a pervasive low mood, shortness of breath, headaches, worrying, panic attacks, insomnia or oversleeping, and all sorts of other signs of a mental health problem. Repeated, overwhelming stressors can cause your body’s natural “fight or flight” reaction system to go haywire and more or less break down, leading to mental health issues. Genetics make some people more vulnerable to this breakdown than others.

How the Brain Works

Where food enters the picture is how the brain works. Our brains are enormously complicated, energy-gobbling masses of cells made mostly of fat and with the consistency of a fine custard. Brains make up 2-5% of our body’s mass, but the process of thinking and all the unconscious tasks the brain does, like managing appetite, coordinating breathing, digestion, etc. takes up 20% of the energy we use every day. This high energy usage and the way the brain works means it needs a ton of raw materials all the time.

Certain amino acids, minerals, vitamins, cholesterol, and, in particular, long chain omega 3 fatty acids are vital to the structure and function of the brain. Without all the right components, the ability of the brain to keep up its high energy output and clean up metabolic byproducts breaks down, leading to inflammation and toxins that can build up and even destroy neurons. The brain is hungry, and needs just the right sort of nutrient-rich fuel.


Another important aspect of brain health is neuroplasticity. That is the ability of neurons in the brain to adapt to new requirements and tasks. Both chronic stress and lack of raw materials can lead to decreased neuroplasticity. One of the cardinal features of depression is problems with memory and concentration, in part caused by poor neuroplasticity and inflammation leading to an inability to respond to normal daily mental tasks, such as listening to your boss in a meeting, or paying bills online without making errors. Add poor nutrition to general life stress, and all the sudden you have a recipe for poor resiliency leading to mood and anxiety problems. On the other hand, good nutrition will help your brain cope much better via neuroplasticity, efficient energy usage and cleanup, and enhanced cellular repair mechanisms.

Our brains evolved to work with the raw materials provided by whole, minimally processed foods. Processed foods will interact poorly with the brain in two basic ways:

  1. Unbalanced, micronutrient-poor but calorie rich food leads to overabundant energy without sufficient cellular repair machinery to deal with it, leading to inflammation and damage. It would be like putting purified alcohol in the car in lieu of the gasoline the spark plugs are designed to work with.
  2. Processed foods will introduce novel chemicals, particularly from grains and food dyes that will cause inflammatory reactions in certain people.

Whole, Unprocessed Foods

While a number of factors work together in keeping our brains healthy and happy, providing the noggin with whole, unprocessed foods is absolutely vital for good mental health. Grain heavy processed diets will tend to be low on some of the most important brain nutrients, such as zinc, vitamin B12, and the long chain omega3 fatty acids. Lack of these specific nutrients will, in a relatively short period, lead to neuron death and serious mental health issues. However, each of these nutrients works with others (other B vitamins, other minerals and fatty acids and cholesterol), so, in general getting nutrients from whole foods is better than supplementing just one vitamin unless you know you are acutely deficient.

In the future, I’ll discuss exactly how some of these nutrients affect mental health, and how specific disorders seem to relate to deficiencies, but for now, know that every time you eat a meal of whole, mostly unprocessed food, you are supplying your brain with a lot of goodies it needs, without the toxic byproducts and overabundance of energy of modern processed foods. The Whole30 meal planning template (a palm size of good quality protein surrounded by vegetables cooked or dressed with healthy fats, along with a bit of good starchy tubers and fruit) will take you a long way to making a firm, strong base for good mental health.