Two studies link diets high in processed foods, sugar, and omega-6 fats to depression in women and ties whole-food diets to a reduced risk
By Craig Weatherby
Earlier this year, British researchers reported that people who ate “junky” diets—such as the average American diet—were more likely to suffer from depression.
The UK team analyzed diet and health data collected from 3,486 men and women (average age 55.6 years).
Based on how often the participants had eaten specific amounts of various foods during the previous year, researchers categorized them as falling into one of two dietary patterns.
- Women who ate a junky “Western” diet were 52 percent more likely to develop depression and 76 percent more likely to develop anxiety.
- The risk of depression or anxiety disorders was about 34 percent lower among women eating a “Traditional” Australian diet.
- Surprisingly, the risk of depression was 29 percent higher in women who ate a Modern (“spa” style) diet.
- Compared with the Traditional Australian diet, the Western and Modern style diets were likely higher in omega-6 fats, excessive intake of which has been associated with depression.
A “whole food” diet was defined as one dominated by vegetables, fruits and fish, while a “processed food” diet was marked by high intake of sweets, fried foods, processed meats, refined grains, and high-fat dairy products.
Five years later, the volunteers completed a questionnaire designed to measure depression symptoms.
The researchers’ analysis indicated that diets dominated by processed foods produced a greater risk of being diagnosed with depression after five years.
Conversely, the recruits whose self-reported diets were highest in whole foods were the least likely to develop signs of depression by the end of the half-decade study (Akbaraly TN et al. 2009).
Now the results of another study—this one involving only women—confirm those findings and strengthen the diet-depression connection in females.
Aussie study examines food-mood links in women
Researchers from the University of Melbourne conducted an epidemiological (diet-health) study in 1,046 female volunteers aged 20 to 93 (Jacka FN et al. 2010).
The women were followed for 10 years and answered a diet survey every other year.
Based on their responses to the surveys, the women were categorized as belonging to one of three diet groups:
The “Traditional Australian” diet resembles the tradtional diet of rural Americans in the 19th century, which is enjoying a comeback in the "slow food" movement, the "locavore" (local food) movement, and among folks aware of Weston A. Price, DDS, whose pioneering diet-health research was the first to link diverse traditional diets to better overall health.
- “Traditional Australian” Diet—Dominated by vegetables, fruit, beef, lamb, fish, and whole-grain foods.
- “Western” Diet—Dominated by meat pies, processed meats, pizza, chips, hamburgers, white bread, sugar, flavored milk drinks, and beer.
- “Modern” Diet—Dominated by fruits and salads plus fish, tofu, beans, nuts, yogurt, and red wine.
The term “Western” diet is another name for what nutrition researchers have long called the “Standard American Diet”… an eating pattern whose acronym (SAD) says it all.
Likewise, the diet pattern the Aussie team called “Modern” is one most people would recognize as a typical “spa” or “South Beach” style diet.
New findings support traditional Aussie/American diets full of diverse whole foods
The Aussie team’s analysis showed that the women who ate a Western diet were 52 percent more likely than average to develop signs of a depression disorder… and they were 76 percent more likely to develop signs of an anxiety disorder.
In contrast, the risk of depression/anxiety disorders was about 34 percent lower than average among women who ate a Traditional Australian diet.
That finding supports the view of Weston A. Price, and it supports his view—now backed by substantial evidence and accepted by many biomedical researchers—that saturated fat from whole foods like lamb and beef is not unhealthful.
Surprisingly, the risk of depression was 29 percent higher than average in women who ate the "Modern", spa-style diet characterized by fruits and salads plus fish, tofu, beans, nuts, yogurt, and red wine. However, their risk of anxiety was seven percent lower than average.
Importantly, the associations between the three diet styles and risk of depression/anxiety disorders persisted after the research team adjusted the results to account for a variety of factors known to influence the with risk of mood disorders: age, weight, socio-economic status, education, physical activity, smoking, and alcohol consumption.
Do omega-6 fats explain the depressing effects that "modern" diets seem to share?
The researchers posed two explanations for why women eating a “Modern”, spa-style diet had a higher risk of depression, compared to women who fell into the Traditional diet category.
First, they thought it could be a consequence of “reverse causality,” wherein the younger, more educated women that dominated the Modern diet group were more likely to have mild depression and had turned to the diet in an attempt to improve their mood.
And the Aussies posed a second possible explanation for the mood advantage of the Traditional diet versus the Modern diet:
“[It could be that the key] components of the traditional dietary pattern, such as vegetables, red meat, whole-grain foods, and high-fat dairy products, are particularly pertinent to the outcomes in question.”
In other words, they think that there may something about that particular mix of whole foods that does more do deter depression, compared to the mix of foods in the Modern, “spa” style diet.
However, they failed to address another likely explanation—excessive intake of omega-6 fats—for the higher depression risks seen in women eating the Western or Modern diets.
Judging from the limited lists of foods provided in their descriptions of the Western and Modern diet patterns, it seems safe to presume that those diets also included vegetable oils and packaged/frozen foods that are high in omega-6 fats.
So, compared with the Traditional Australian diet, the mix of foods in the Western and Modern style diets would probably deliver more omega-6 fats, excessive intake of which has been strongly associated with depression risk.
The association between excessive intake of omega-6 fats and greater depression risk holds true even when a diet contain reasonable amounts of omega-3s, as the Modern diet would, given that it included fish.
The bottom line seems clear: diets high in non-nutritious, processed foods put women (and men) at greater risk of developing anxiety or depression disorders.
- Akbaraly TN, Brunner EJ, Ferrie JE, Marmot MG, Kivimaki M, Singh-Manoux A. Dietary pattern and depressive symptoms in middle age. Br J Psychiatry. 2009 Nov;195(5):408-13.
- Jacka FN, Pasco JA, Mykletun A, Williams LJ, Hodge AM, O'Reilly SL, Nicholson GC, Kotowicz MA, Berk M. Association of Western and traditional diets with depression and anxiety in women. Am J Psychiatry. 2010 Mar;167(3):305-11. Epub 2010 Jan 4.