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Controlled Trial Study Shows Healthy Foods Reduce Depression

Analysis by Dr. Joseph Mercola Fact Checked

antidepressant foods

Story at-a-glance -

  • Accumulating evidence is highlighting the strong link between what you eat and how you feel, both mentally and physically
  • Researchers from Macquarie University, Australia, studied 76 students between the ages of 17 and 35 who followed a poor diet and had moderate to high levels of depression symptoms
  • One group of participants was asked to improve their diets by cutting back on refined carbohydrates, sugar, processed meats and soft drinks, while eating more vegetables, fruits, dairy products, nuts, seeds, healthy fats and anti-inflammatory spices such as turmeric and cinnamon
  • After only three weeks of healthier eating, those in the healthy diet group had significant improvements in mood and their depression scores even went into the normal range
  • Anxiety scores also reduced significantly, while the control group, which didn’t change their diet, experienced no changes in depressive symptoms or anxiety

What you eat affects your mood and, beyond that, is powerful enough to influence symptoms of depression for better or for worse. Globally, healthy diets have shifted to diets that favor processed foods and refined sugars, and the burden of depression has also risen worldwide, with 300 million people affected.1

Depression among adolescents is also on the rise, increasing by 30% in the last 10 years,2 but research suggests that changing eating habits, even for a short period of time, can lead to lasting improvements in symptoms among young adults, making dietary changes a key factor in relieving depression.3

Healthy Diet Reduces Symptoms of Depression

Researchers from Macquarie University, Australia, studied 76 students between the ages of 17 and 35 who followed a poor diet and had moderate to high levels of depression symptoms.4

One group of the participants was asked to improve their diets by cutting back on refined carbohydrates, sugar, processed meats and soft drinks, while eating more vegetables, fruits, dairy products, nuts seeds, healthy fats and anti-inflammatory spices such as turmeric and cinnamon.5

After only three weeks of healthier eating, those in the healthy diet group had significant improvements in mood and their depression scores even went into the normal range. Anxiety scores also reduced significantly, while the control group, which didn’t change their diet, experienced no changes in depressive symptoms or anxiety.

Among the 21% of participants who continued to eat a healthy diet for three additional months, improvements in mood were maintained.6 The study’s lead author, Heather Francis, said in a news release:7

"Modifying diet to reduce processed food intake and increase consumption of fruit, vegetables, fish and olive oil improved depression symptoms in young adults. These findings add to a growing literature showing a modest change to diet is a useful adjunct therapy to reduce symptoms of depression."

Past research, including a systematic review of studies involving youth aged 4.5 to 18 years, linked unhealthy diet with poorer mental health, while healthy diet led to better mental health.8

Likewise, the researchers noted, “Several systematic reviews and meta-analyses show a relationship between diet quality and depression. A meta-analysis showed that healthy diet regardless of pattern (e.g. Mediterranean, vegetarian, Tuscan) was linearly associated with reduced incidence of depression.”9

The featured study is particularly noteworthy because it shows improvements in mental health can be achieved just weeks after making healthier dietary choices, and those improvements continue as long as the healthy eating is maintained.

Processed Foods Linked to Depression in Teenagers

Accumulating evidence is highlighting the strong link between what you eat and how you feel, both mentally and physically. Researchers at the University of Alabama at Birmingham analyzed the excretion of sodium and potassium in the urine in 84 urban, low‐income adolescents, a group that may be at an increased risk of both unhealthy diet and depression.

Higher levels of sodium in the urine can be an indication of a diet high in sodium, such as processed foods and salty snacks. A low level of potassium, meanwhile, is indicative of a diet lacking in fruits, vegetables and other healthy potassium-rich foods, providing objective measures of dietary intake.

Higher sodium and lower potassium excretion rates, indicative of a fast food or processed food diet, were associated with more frequent symptoms of depression at follow up 1.5 years later.

“This study was the first to demonstrate relationships between objective indicators of unhealthy diet and subsequent changes in depressive symptoms in youth,” the study noted, with researchers adding, “Given the substantial brain development that occurs during adolescence, individuals in this developmental period may be particularly vulnerable to the effects of diet on the neural mechanisms underlying emotion regulation and depression.”10

Why Does Food Affect Your Mood?

The relationship between your diet and mental health is complex and tied to multiple biological mechanisms. Sugar, in particular, is a known detriment to mental health and has been linked to depression specifically.11 It’s a known inflammatory food, and depression is increasingly recognized as a problem rooted in chronic inflammation.

Cytokines and inflammatory messengers such as CRP, IL-1, IL-6 and TNF-alpha are predictive of12 and correlate to depression,13 and consuming sugar may increase circulating inflammatory markers, which could lead to depressed mood.14 Aside from sugar, many processed foods are inflammatory, and an inflammatory diet, overall, is associated with recurrence of depressive symptoms in women.15

Further, for the featured study, the researchers also measured biological markers of inflammation, although the data have not yet been analyzed to reveal its outcome.16 If you suffer from depression, it may be well worth your effort to take steps to reduce the level of inflammation in your body, starting by following an anti-inflammatory diet.

There are other links as well. Poor diet could influence depression by disturbing the gut microbiome, which could further influence brain function,17 for instance. It can also lead to obesity, which further affects inflammation and also presents psychosocial factors linked to depression.18 Poor diet, particularly one high in sugar, could also contribute to depression by:19

  • Decreasing levels of brain derived neurotrophic factor (BDNF), leading to hippocampal atrophy in depression
  • Causing an exaggerated insulin response, influencing hormone levels and mood
  • Triggering addiction-like effects, which could influence dopamine and mood

Omega-3 Fats for Depression

If you’re feeling depressed, be sure to increase y our intake of the animal-based omega-3 fats EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which are important for brain health and mental health.

The 2001 book, "The Omega-3 Connection," written by Harvard psychiatrist Dr. Andrew Stoll, was among the first works to bring attention to, and support the use of, omega-3 fats for depression, and they’ve been shown to lead to improvements in major depressive disorder.20

Small cold-water fish that are rich in animal-based omega-3 fats, but have a low risk of contamination, are among your best choices for a dietary source of omega-3s. This includes anchovies, sardines, mackerel, herring and wild-caught Alaskan salmon.

The omega-3s they contain are vital to your brain, helping to fight inflammation and depression alike. Supplementing with high-quality krill oil is also recommended, especially if omega-3-rich foods are not consumed on a regular basis.

In a set of five practical dietary recommendations for the prevention of depression, based on the best available current evidence, researchers writing in the journal Nutritional Neuroscience also highlighted “a high consumption of foods rich in omega-3 polyunsaturated fatty acids” as one of the key strategies.21

Whether you eat fatty fish or take a daily krill oil supplement, you'll want to track your omega-3 level. The best way to know whether you’re consuming adequate quantities of omega-3 is via a blood test. For optimal health, you'll want an omega-3 index of 8% or higher.

What Are the Best Antidepressant Foods?

Certain foods are nutrient-dense sources of nutrients known to help prevent depression as well as help recover from it. Twelve such antidepressant nutrients include:22

Folate

Iron

Long-chain omega-3 fatty acids (EPA and DHA)

Magnesium

Potassium

Selenium

Thiamine

Vitamin A

Vitamin B6

Vitamin B12

Vitamin C

Zinc

When researchers looked for the foods that would provide the most concentrated sources of these antidepressant nutrients, they came up with the following seven highest-scoring foods:

Oysters and mussels, but avoid those from contaminated waters

Seafood, particularly wild-caught Alaskan salmon, herring, sardines and anchovies

Organ meats, but only those from grass fed animals (not CAFO animals)

Leafy greens

Lettuces

Peppers

Cruciferous vegetables

Other foods that are good for your mood include dark chocolate, bananas, turmeric and even organic black coffee.

Focusing on real food and incorporating some of these superfoods for mental health into your daily diet is one strategy that may help fight depression in all ages. As the researchers noted, many people are lacking the nutrients found in these healthy foods:23

“Interestingly, many foods with a high AFS [Antidepressant Food Score] are not commonly eaten as part of the Western dietary pattern … The evidence linking dietary patterns and depressive disorders supports the consumption of a whole-foods based traditional diet as opposed to a Western dietary pattern to prevent and promote recovery from depression.”

Limiting Processed Foods for Mental Health

By following traditional dietary patterns — those that avoid or limit processed foods in favor of wholesome, nutritious foods — you can better your mental health, whether you’re an adolescent or an adult.

In still more research supporting this link, 32% of participants with depression who followed a diet rich in nuts, seeds, eggs, fruits and vegetables, fatty fish, olive oil and grass fed beef were no longer depressed at the end of three months. In contrast, only 8% of those who did not change their diets had such an improvement.24,25

While teens and young adults aren’t always known for their healthy food choices, this is a crucial period in which lifelong healthy eating patterns are established. In addition to modeling a healthy diet for youth, letting teenagers know they’re being manipulated by food marketers is a simple trick for getting teens to eat better.26

Students who read an exposé that revealed the manipulative practices used by marketing companies chose to eat less junk food and drank more water instead of soda, likely because it tapped into teens’ natural desire to rebel against authority. The healthier your diet becomes, the healthier your mental health is likely to be.

However, if you’re in the midst of a crisis and are finding it difficult to make healthy lifestyle changes, consult with a holistic health care provider who can help you along this healing journey.