Can we eat our way to happiness (and out of depression)? New research (and May event) says so


The French lawyer (and writer, epicuregastronome, often considered 'the father of low-carbohydrate diet') Jean Anthelme Brillat-Savarin once said:

Tell me what you eat, and I will tell you what you are.

Although poetic in character, it may not be far from the truth. New research is showing a closer connection between our diet and mental health.

An article in The Atlantic (by Olga Khazan) talks of a recently released study in which researchers found that, out of 964 elderly participants, those who followed 'the dash diet' had lower rates of depression.

An excerpt:

“I think we need to view food as medicine,” Laurel J. Cherian, an assistant professor of vascular neurology at Rush University Medical Center in Chicago and the study’s lead author, told me. “Medications to treat depression are wonderful, but for many people, it’s going to be a combination of things.”

The research will be presented at the upcoming meeting of the American Academy of Neurology. The study has not been published yet in a peer-reviewed journal, but other researchers have found similar antidepression benefits from 'the dash diet', which was developed by the U.S. National Heart, Lung, and Blood Institute.

The dash diet itself is nothing revolutionary—a typical dinner consists of a lean meat, baked potato, and lots of vegetables. Researchers are still figuring out why it’s so beneficial, but a major pathway might be through the gut-brain connection.

When people eat a plant-heavy diet, the fiber from the plant matter ferments in the gut and creates short-chain fatty acids, which, in turn, regulate the immune system and influence gene expression in the brain and elsewhere. People who eat fiber have more diverse gut bacteria, and these bacteria make various chemicals that influence our mood.

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Inflammatory molecules, called cytokines, that are produced by body fat can spark inflammation elsewhere in the body. Inflammation increases the risk of depression and other diseases by harming the lining of the blood vessels.

Meanwhile, healthy fats increase the production of proteins called neurotrophins, which “act like manure to the brain as they promote the growth of new brain cells in the hippocampus,” Jacka says. “There is a strong link between the quality of people’s diets and the size of their hippocampus.”

Cryan (John Cryan, an expert in the gut-brain connection at University College Cork in Ireland) says these studies point to the growing recognition of the importance of diet—along with the other old standbys, exercise and sleep—in regulating mood. In fact, despite feeling cautious about the early nature of this line of research, he says he would recommend depressed people try eating better to see if it helps.

Another study proclaims a shift to a “modified Mediterranean diet” can improve depression:

This year, finally, we have the SMILES trial, the very first dietary trial to look specifically at a dietary treatment in a depressed population in a mental health setting. Participants met criteria for depression and many were already being treated with standard therapy, meds, or both.

The designers of this trial... decided to train people using dietary advice, nutritional counseling, and motivational interviewing. This was directed towards them eating a “modified Mediterranean diet” that combined the Australian Dietary Guidelines and the Dietary Guidelines for Adults in Greece.

They recommended eating whole grains, vegetables, fruit, legumes, unsweetened dairy, raw nuts, fish, chicken, eggs, red meat (up to three servings per week), and olive oil. Everyone in the study met criteria for a depressive disorder. 

[The subject of the diet experiments] were instructed to reduce their intake of sweets, refined cereals, fried food, fast food, processed meat, sugary drinks, and any alcohol beyond 1-2 glasses of wine with meals. There were seven hour long nutritional counseling sessions and a sample “food hamper” with some food and recipes.

The control group [non-participants in the experiment, running in parallel] had the same number of sessions in “social support". This is a type of supportive therapy that is meant to mimic the time and interpersonal engagement received by the experimental group, without utilizing psychotherapeutic techniques.

A few more interesting tidbits about the design and the study… they randomized a group of people found to be depressed and to eat more like the average Australian (meaning fast food, refined carbohydrates, etc) and excluded people who already ate very healthfully.

The researchers also looked at the cost, as many folks have concerns that eating healthy is more expensive and out of reach of many people, and found that the average experimental participant spent $138 on food per week before the trial and $112 per week during the trial. 

Despite the small size, the results were still statistically significant and better than anticipated. The dietary group had bigger reductions in depression scores at the end of 12 weeks. Remission of depression symptoms occurred in 32.3 percent of the diet group as opposed to 8 percent of the control group. That means that the “NNT” (or number needed to treat) for this study was 4.1, which is similar to and even better than many trials of chemical antidepressants.

The takeaway? Switching from a western style diet to a whole-foods based diet in a Mediterranean pattern can, in fact, treat depression. Given the evidence for this diet in other health conditions, you can also improve many aspects of health along the way while saving money and feeling better.

Of course it would be nice to see more studies, but it’s hard to imagine how reasonable healthful dietary instruction could hurt. The major issue with such a therapy is probably related to the trouble recruiting for this study: depression causes a lack of motivation, and it’s hard to take on changing diet (or other lifestyle change) when one is significantly depressed.

With such a strong treatment effect seen in this study, it may well be worth the time for the therapist or psychiatrist to talk about eating well with their patients.

Want to explore these possibilities with others? A London event on the 16th of May - put on by Action for Happiness - will investigate how we can transform our mood with food. 

Here's the event blurb:

What foods make us happy? Join us for an inspiring evening to explore the relationship between food and mental health - and discover new ways to boost your mood with food.

Author Rachel Kelly, who has a history of depression, will share her personal experience of how food helps her stay calm and well. She's teamed up with nutritional therapist Alice Mackintosh to find out how nutrition affects our wellbeing and what we can do about it.

Together Rachel and Alice will provide lots of research-based tips, including which foods boost energy, relieve low mood, comfort a troubled mind, support hormone balance and help you sleep better..


About The Speakers

Rachel Kelly is an author, journalist and mental health campaigner. Her first book Black Rainbow is an award-winning and moving memoir about her experience with depression. Her other books include Walking on Sunshine and most recently The Happy Kitchen. She is an ambassador for Rethink Mental Illness, Young Minds, Sane and The Counselling Foundation.

Alice Mackintosh is a highly-experienced nutritional therapist with a background in biomedical sciences. She has a passion for applying the latest research and helping people use nutrition to support good mental and physical health. As well as working directly with clients, Alice is a regular spokesperson on nutrition on the BBC and in magazines.

The event is a part of Mental Health Awareness Week (14-20 May). Find out what else is happing across the UK for Mental Heath Awareness Week here.

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