Can Food Affect Mood?


In a measurable, even clinically relevant way, food absolutely can affect mood.

It doesn’t take a team of scientists to figure out that the prospect of a delicious meal has a way of perking up one’s mood.

But can food affect mood on a deeper, longer lasting level?

Can the food we eat actually affect whether or not we experience mood disturbances and/or mental illnesses?

The answer is yes; diet can influence mental health, says the research.

We’ve already explored a few connections between diet and mental health in our nutrition psychiatry post, but the research has plenty more to say.

Key Diet-Mood Connections

Though they are a little harder to conceptualize than purely physical, macro-level structures like bones and muscles, the chemical messengers (neurotransmitters) known to influence mood disorders like depression, anxiety, and others are still made out of nutrients we derive from food.

Moreover, some food items can influence how these chemical messengers are received and transmitted in the brain, and unfortunately, most of the pro-inflammatory foods in the Western diet have a negative effect on uptake.

Both of these concepts—food influencing neurotransmitter production as well as function—are often highly evident in the case of depression.

Food, Neurotransmitters, and Depression

Describing depression as serotonin or dopamine imbalance/shortage is woefully oversimplifying things, but nonetheless, this frequently parroted explanation does highlight one important mechanism involved in the disorder.

As this academic article from the University of Toronto explains, “production of monoamine neurotransmitters such as serotonin, norepinephrine, and dopamine…depends on adequate building blocks of amino acids, and mineral dependent co-factors.”

In other words, the set of chemical messengers that influence mood disorders like depression depend upon several nutrients not synthesized by the body (aka, those that need to be consumed through food) for their creation.

Also included in this list of nutrients are omega-3 fatty acids, which can be found in oily fish, some nuts, flaxseed, soybeans, and others.

Conversely, what you don’t eat is also very important, since the Toronto researchers found that participants who followed a “diet consistent with the inflammatory dietary pattern” were much more likely to develop depression than those who did not.

Common examples of these pro-inflammatory foods include sweetened soft drinks, refined grains, red meat (especially processed), and margarine.

The Carbohydrate Connection

Both quality and quantity are heavily influential in the case of carbohydrates and their impact on mood disorders.

What we mean by “quality” in this case is the rate at which a carbohydrate is broken down (glycemic index) and the extent to which it increases blood sugar irrespective of time (glycemic load).

For example, two carbohydrate-rich foods containing the same amount of carbs can have drastically different effects on the resulting blood sugar spike and insulin response because of a large difference in glycemic index, or how quickly they cause blood glucose levels to surge.

These concepts are not only essential for diabetics and people too busy for food comas, but for those trying to address or prevent mood disorders as well.

According to this study from the University of Manchester’s Division of Psychology and Mental Health, there is a positive association between “progressively higher dietary glycemic index and the incidence of depressive symptoms.”

It seems contradictory, but it’s actually the body’s hormonal response to the downswing of the sugar spike—aka, the crash—that is more confidently connected to increased depression and anxiety incidence by a growing pool of researchers in this area. 

Let’s ground this in real-world context; here’s a list of carbohydrates with high glycemic index and/or load that should be consumed sparingly (or not at all) for reasons of mental health and many others:

  • Pre-packaged cookies, cakes, and other pastries
  • Breakfast cereal
  • White bread
  • White rice (especially short grain)
  • White potatoes
  • Chips
  • Fries
  • Many more processed, sugary foods

It’s important to make a few key distinctions here that will help you sift apart the good from the not so good.

First, remember that fiber is your friend in this department; fiber slows down glucose uptakewhen consumed with carbohydrates, effectively flattening blood sugar spikes.

This is the main reason why most fruits, which are naturally high in sugar, are reasonably safe as far as blood glucose is concerned.

Also, more nutritious permutations of the above foods like sweet potatoes and long-grain brown rice are always a better choice.

Finally, remember that glycemic index, which is expressed on a scale of 0 to 100, is not the whole picture.

For example, watermelon has a very high glycemic index of around 75, but its glycemic load is very low, meaning this food will cause a sudden, but very low-amplitude spike in blood glucose.

A smaller spike means a smaller crash, which means less impact on mood disorder incidence.

Brain, Gut Microbiome, and Mood

The same University of Manchester study goes on to cite several instances in research where alteration of the “gut microbiome” caused significant and consistent changes in mood, including anxiety and depression onset.

The gut microbiome is a community of roughly 100 trillion bacteria (both benevolent and malevolent) that live in the human intestinal tract.

These bacteria have many functions, from gobbling up substances that we otherwise could not to immune support.

Included in these functions is a direct line of communication with the brain, which is maintained via “neural, inflammatory, and hormonal signalling pathways.”

As has been proven in dozens of cases, when illness, infection, or drastic dietary changes cause significant alterations to this sprawling “community” of bacteria, mood disorders can result.

To keep your gut microbiome healthy, it’s important to feed or replace the bacteria with prebiotic (feed) and probiotic (replace) foods like yogurt, kombucha, tempeh, sauerkraut, and other fermented foods.

Transitioning to a Mood-Friendly Diet

Keeping in mind these three pivotal connections between diet and mood—general nutrition, carbohydrates, and the gut microbiome—here’s a simple roadmap for the “mental health diet”: 

Reduce intake of processed snacks, sweetened beverages, refined carbs, and artificial preservatives/additives.

Increase intake of plant-based foods, omega-3 fatty acids, anti-inflammatory and antioxidant phytochemicals, and pro- and prebiotic foods.

These two steps alone will go far beyond improving your mood; they will improve your overall quality of life.

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