Every once in awhile, a research study comes along that boosts integrative medicine’s credibility as a real treatment modality for mental health. By real, I mean one that can’t be ignored by conventional medicine.

The study I am talking about is the first to show that diet can be used as a TREATMENT for depressed adults.

If you have been following integrative medicine for a while, you are probably surprised and thinking to yourself, “Hasn’t that been done already?”

Well in fact it hasn’t.

What has been done are case studies and survey studiesIn a case study, a clinician tells the story of one of her patients (i.e. Sara was depressed, stopped eating grains and her depression went away). While very effective at conveying how well an intervention may work, these studies are regarded as being “one-offs” by researchers and are not taken very seriously.

Survey studies use questionnaires to assess the relationship between two variables. From this data, researchers can assert a relationship between these variables but can’t conclude that the a diet change “caused” the lessening of depression. When they find a relationship, they use language like “there seems to be an association between dietary choices and a person’s experience of depression”.

While these studies can be helpful, what we have been looking for is a study that demonstrates that a poor diet CAUSES depression and that a better diet could be used to TREAT depression. For this, we needed a “randomized blind controlled” study and that’s what we got!

The SMILES Trial

The SMILES Trial (Supporting the Modification of Lifestyle in Lowered Emotional States) was carried out in Australia and led by Dr. Felice Jacka, who is the director of the International Society for Nutritional Psychiatry Research (ISNPR).

Professor Jacka and her team followed 67 men and women with documented moderate-to-severe depression who were found to be eating an unhealthy diet (similar to the Standard American Diet) which included low intake of: dietary fiber, lean protein, fruit, and vegetables as well as a high intake of: sweets, processed meats, and salty snacks.

Half of the depressed recruits were put on a Modified Mediterranean Diet (described below) and required to attend seven individual nutrition sessions with a clinical dietician.

The other half continued to eat the way they had been eating at the beginning of the study and went to seven support sessions, which was used as a control.

Before the study began and again after 12-weeks, symptoms were rated using the Montgomery-Asberg Depression Rating Scale (MADRS) which rates mood on a scale of 0 to 60, with 60 being most severely depressed.

Results after 12 weeks

The subjects on the Modified Mediterranean Diet had MADRS scores that improved an average of 11 points and 32 percent (10 out of 31 people who completed the 12 week study) had MADRS scores that were so low they no longer met the criteria for depression.

The control group (the people who did not change their diet) improved by 4 points on the MADRS with only 8 percent (2 of 25) achieving remission of their depressive symptoms.

The results of the study were “statistically significant.” Here’s a link to the actual study for more details.

So what is the Modified Mediterranean Diet?

It’s a diet that focuses on consuming:

Whole Grains (5-8 servings a day)

Fruits (3 servings per day)

Vegetables (6 servings per day)

Legumes (3-4 week)

Unsweetened dairy products (2-3 servings per day)

Raw nuts (1 serving per day)

Fish (at least 2 servings per week)

Lean red meats (3-4 servings per week)

Eggs (up to 6 per week)

Olive oil (3 tablespoon per day)

2 sugary drinks/ week (optional)

2 alcoholic beverages/ day (optional, preferably red wine)

And restricting:


Refined Cereals

Fried Foods

-Fast Food

-Processed Meats

So what’s the takeaway?

Clearly this is a small study, and the first of its kind, so it will need to be replicated. It will be interesting to see if researchers in the United States can achieve the same results, as our food supply is much more compromised (in the US we have fewer sources of grass fed and pastured animals, more GMO crops and a wider use of pesticides to state a few differences).

That said, this is a huge step forward in showing that changing your diet can affect mood and should be part of every depression treatment.

The sad truth is that very few conventionally trained mental health professionals ever really consider diet as a significant contributor to mental health symptoms. My hope is that as more studies are published in mainstream psychiatric and psychological journals, it will bring acceptance of the power of diet as a treatment modality. It is clear to me that the time has come!

How do these results compare to medication treatment of depression?

About a third of the people in the treatment group in the SMILES study got so much better they were no longer considered depressed.

Compare that to the use of SSRI antidepressant medications in which 50 percent of people get better with 50 percent of their symptoms. This was the finding of the STAR*D study about 10 years back which was conducted by the US government to assess how well psychiatric medications worked.

Another consideration when comparing the outcome of this dietary study to antidepressant effectiveness is how many people have side effects when taking medications and how few people have any negative effects at all with diet change.

According to one study38 percent of antidepressant users have side effects. It’s important to remember that a small percentage of people taking antidepressants have dangerous and life-threatening reactions like becoming suicidal or homicidal. See the powerful website SSRIStories.com for more information about these severe reactions.

Questions raised (but not answered) by this study?

Why did a third of the people who got better get better?

Though not addressed directly, it likely had to do with the fact that the Modified Mediterranean Diet focuses on real whole foods that provide the vitamins, minerals and essential fats that are needed for optimal brain function and restricts most of the high sugar processed foods that are known to cause the physiological issues that lead to mental health symptoms (including hypoglycemia, protein malnutrition, and vitamin and mineral deficiency).

Why didn’t the other ⅔ in the treatment group see benefits?

Since this study only looked at the effects of one diet, it’s impossible to know if more (or less) people would have seen improvements in their depression if another diet had been used for the treatment group. For instance, this diet contains gluten, dairy and grains, which are three foods that have been linked to depression and other mental health symptoms in some people. See my previous blog for a more info on this.

So future studies will need to compare the effects of many different diets to see which one is most beneficial (i.e. Paleo, Vegan, Mediterranean etc.) I have a hunch that because we are all biochemically different, the most effective diet will take into consideration our unique biochemistry and genetic make-up.

So, the diet that is determined to be “best” overall may not be the diet best for you. It will likely take personal experimentation to figure out what’s optimal for each of us.

Furthermore, some people may not have responded because diet was not the main cause of their depression (so a diet change would not have been the solution). There are many psychological and biochemical issues that would not respond much to diet change and would require more targeted nutritional or psychological interventions (i.e. childhood trauma, pyroluria or under/over methylation).

Are you depressed and ready for a diet experiment?

What this small study proves is that diet is an effective treatment for depression for some people.

If you haven’t done a diet experiment, why not? What do you have to lose?

Here’s the diet that most of my patients follow. Many have amazing results! I could not imagine practicing in the mental health field without addressing diet first.

It’s called the Whole30. It’s an easy-to-implement 30 day Paleo diet experiment that restricts many foods that are known to cause a systemic inflammatory response (one of the main causes of depression), and focuses on real whole foods that provide what’s essential for stable and balanced moods.

If you go to the  Whole30 website and it doesn’t  seem right for you, work with another diet like the Mediterranean diet or the Ornish Diet. See what happens to your depression and report back to us in the comments section of this blog!

If you like this post and want to hear more information about the “root causes” of depression, sign up for my email list. As a bonus, you’ll get my FREE “Nutrition For Mental Health Guidebook”.

In good (mental) health,

Dr. Josh


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