How Diet Can Cause or Cure Depression

By Dr. Mercola | Waking Times

Foods have an immense impact on your body and your brain, and eating whole foods as described in my nutrition plan is a good way to simultaneously support your mental and physical health. Avoiding sugar and artificial sweeteners is in my view, based on the evidence, a crucial aspect of preventing and/or treating depression.

Both contribute to chronic inflammation and can wreak havoc with your brain function. Recent research also shows how swapping processed junk food for a healthier diet can significantly improve depression symptoms, which really shouldn’t come as a great surprise.

The Sugar Trap

Research^1,2 published in 2014 linked sweetened beverages — both sugar- and artificially-sweetened beverages — with an increased risk of depression. Those who drank more than four cans or glasses of soda had a 30% higher risk of depression compared to those who did not consume sweetened beverages of any kind.

Interestingly, fruit juices were even more hazardous. The same amount of sweetened fruit drinks (four glasses) was associated with a 38% higher risk of depression.

Overall, artificially sweetened so-called “diet” drinks were associated with the highest risks of depression, compared to beverages sweetened with sugar or high-fructose corn syrup. More specifically, compared to those who did not drink sweetened beverages:

• Those who drank primarily diet soda were 31% more likely to suffer with depression, whereas regular soda was associated with a 22% increased risk
• Those who drank primarily diet fruit drinks had a 51% higher risk for depression, while consuming regular fruit drinks was associated with a more modest 8% increased risk
• Drinking primarily diet iced tea was associated with a 25% increased risk for depression, whereas those who drank regular sweetened iced tea actually had a 6% reduced risk

Similarly, recent research³ detailed in “The Link Between Fast Food and Teenage Depression” found adolescents who had elevated levels of sodium and low levels of potassium in their urine — two factors indicative of a diet high in junk food and processed food — had more frequent symptoms of depression.

According to the authors,⁴ “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.”

Why Sugar Takes a Toll on Mental Health

There are at least four potential mechanisms through which refined sugar intake could exert a toxic effect on mental health:

1. Sugar (particularly fructose) and grains contribute to insulin and leptin resistance and impaired signaling, which play a significant role in your mental health
2. Sugar suppresses activity of a key growth hormone called brain derived neurotrophic factor (BDNF), which promotes healthy brain neurons. BDNF levels are critically low in both depression and schizophrenia, which animal models suggest might actually be causative
3. Sugar consumption also triggers a cascade of chemical reactions in your body that promote chronic inflammation. In the long term, inflammation disrupts the normal functioning of your immune system, which is linked to a greater risk of depression⁵
4. Sugar impairs the microbiome and its influence on the modulation of stress response, immune function, neurotransmission and neurogenesis

In 2004, British psychiatric researcher Malcolm Peet published a provocative cross-cultural analysis⁶ of the relationship between diet and mental illness. His primary finding was a strong link between high sugar consumption and the risk of both depression and schizophrenia. According to Peet:

“A higher national dietary intake of refined sugar and dairy products predicted a worse 2-year outcome of schizophrenia. A high national prevalence of depression was predicted by a low dietary intake of fish and seafood.

The dietary predictors of … prevalence of depression are similar to those that predict illnesses such as coronary heart disease and diabetes, which are more common in people with mental health problems and in which nutritional approaches are widely recommended.”

One of the key predictors of heart disease and diabetes is in fact chronic inflammation which, as Peet mentions, is also associated with poor mental health. Sugar is a primary driver of chronic inflammation in your body, so consuming excessive amounts of sugar can truly set off an avalanche of negative health events — both mental and physical.

Three-Week Dietary Intervention Lifts Depression

Most recently, a study^7,8,9 published in the October 2019 issue of PLOS ONE said to be the first of its kind, found dietary intervention can effectively treat depression in young adults. The researchers enrolled 101 individuals aged 17 to 35, whose stress and depression scores indicated moderate to high levels of depression.

Participants were divided into two groups. One received dietary intervention while the other (controls) received no intervention. Dietary instructions were provided to the treatment group by a registered dietician via a 13-minute video, which could be revisited at will.

The dietary recommendations were based on the 2003 Australian Guide to Healthy Eating protocol “with additional recommendations to increase concordance with Mediterranean-style diets … and diet components (e.g., omega-3 fatty acids, cinnamon, turmeric) that have beneficial effects on neurological function.”¹⁰ More specifically, the treatment group was instructed to eat:

Refined carbohydrates, sugar, processed meats and soft drinks were to be avoided as much as possible. According to the authors:¹¹

“There is strong epidemiological evidence that poor diet is associated with depression. The reverse has also been shown, namely that eating a healthy diet rich in fruit, vegetables, fish and lean meat, is associated with reduced risk of depression …

 

There was good compliance with the diet intervention recommendations assessed using self-report and spectrophotometry. The Diet group had significantly lower self-reported depression symptoms than the Control Group …Reduced DASS-21 depression subscale scores were maintained on follow up phone call 3 months later.

 

These results are the first to show that young adults with elevated depression symptoms can engage in and adhere to a diet intervention, and that this can reduce symptoms of depression.”

Dietary Intervention Significantly Lowers Depression Scores

The first graph below illustrates the difference in primary depression scores (based on Centre for Epidemiological Studies Depression Scale or CESD-R) between the two groups. The second graph illustrates the difference between the two groups based on DASS-21 depression subscale scores.

The researchers also report that the dietary intervention resulted in lower levels of anger. In the Discussion section of the paper, the authors make the following observations:¹⁴

“The results of this RCT provide support for improving diet as a useful adjunct treatment to reduce depressive symptoms … One of the most interesting findings is the fact that diet change was feasible in this population.

 

As the participants were young adults and university undergraduate students, we anticipated several potential barriers such as the perceived cost of the diet, the time demands of preparing food and/or reliance on others for food preparation (particularly if they lived at home).

 

Additionally, the participants were recruited based on self-reported symptoms of depression. We anticipated that the symptoms of depression, including low energy, reduced motivation and apathy, would present as barriers to eating well.

 

Despite these factors, there was a significant increase in the recommended foods and decrease in processed foods for the diet change group but not the habitual diet group.

 

Furthermore, within the diet change group, increase in recommended foods was associated with spectrophotometer readings. This provides objective evidence to support the participants’ self-reported compliance with the diet …

 

Even in the general population, adherence to diet advice is typically very poor, with over 80% of Australians reporting that they do not comply with dietary recommendations.

 

As a result, there is substantial nihilism regarding the ability to change people’s diets. The current study simply provided a brief 13-minute video, paper resources and minimal phone support.

 

The fact that this relatively low-cost intervention can result in a population of young adults adhering to diet recommendations is very promising. Furthermore, it is important to consider that participants in the current study did not need to adhere strictly to the diet recommendations to derive benefit.”

READ THE REST OF THIS ARTICLE…….