There’s strong evidence tying nutrition with mental health. But the exact reason why people with low omega-3s often suffer from depression remains up for debate. 06/19/2020
We are what we eat, science shows. Across decades of research, studies have found that proper nutrition is vital for our physical and mental health. Food is so fundamental that changes in diet can even alter an organism’s DNA (Seward and Kelly 2016).
But as modern diets have shifted toward processed foods, our health has suffered. In particular, most modern humans now eat far less fish than our ancestors did.
That’s important because seafood is rich in a variety of vital vitamins and nutrients, including omega-3s. These healthy, essential fats from seafood help to lower the risk of heart disease, fight inflammation, let our brains develop properly, help our skin and may reduce the symptoms of many health conditions such as asthma. The body can’t make them on its own, so we have to get omega-3s from our food. In particular, fish like wild-caught salmon, mackerel and sardines are all rich in omega-3s.
But while many people now think of seafood as important for a healthy body, it contains compounds important for our mental health as well. In particular, scientists have found evidence that a lack of omega-3s in the diet could play a role in depression, though the link is still debated. But new studies might begin to clear things up.
Omega-3s and Mental Health
Omega-3 fatty acids are widely considered to be crucial for human health. Few nutrients have been studied more than omega-3s. And for years, studies have shown that deficiencies of omega-3 fatty acids are associated with dementia, bipolar disorder, ADHD, schizophrenia, autism and various psychiatric disorders (Lange et al. 2020). In particular, a lack of two specific omega-3s abundant in seafood, EPA and DHA, is commonly correlated with mental disorders.
Many studies suggest omega-3s can help fight depression and anxiety. In some studies, patients saw symptoms improve after simply taking omega-3 supplements (Ginty and Conklin et al. 2015). And one team of mental health researchers even found that EPA omega-3 supplements were as effective at treating depression as a common antidepressant (Jazayeri et al. 2008).
Omega-3s don’t seem to help only the mental health of people suffering from depression, either.
In research published in 2011, a team of scientists took 68 healthy, young medical school students and gave one group omega-3 supplements and the rest a placebo (Kiecolt-Glaser et al. 2011). After 12 weeks, the double-blind study showed that the students who got additional fatty acids saw their anxiety levels drop by 20 percent. There was no notable difference in depression levels. The results suggest that these seafood supplements can even help people without a diagnosed disorder, and fish could be a good food for those with anxiety concerns.
Omega-3s: A Natural Treatment for Depression?
Why might omega-3s help mental health? Studies have suggested these essential fats may increase serotonin, reduce inflammation, alter heart rates and even change the activity of certain messenger molecules in the brain connected to anxiety and depression (Lake 2018). Their effects are potent enough that some scientists think they could play a role similar to a commonly-prescribed class of antidepressant medications called SSRIs.
This connection between omega-3s and health could also potentially help explain rising levels of health disorders in Western society over the past century, which has coincided with stark changes in lifestyle and diet (Häberling et al. 2019). The processed food common in modern diets lacks omega-3s but is rich in omega-6s. These omega-6 fats are also important for health but can be harmful if not eaten in moderation. Scientists think it’s important to consume a well-balanced ratio of omega-3 to omega-6 fatty acids, which few people today achieve.
“Nowadays, there are hardly any processed foods without an excess of omega-6 fatty acids due to the widespread industrial use of vegetable oils,” wrote the authors of a recent study published in the journal Frontiers in Psychiatry (Häberling et al. 2019). “Furthermore, the intake of fish and other sources of omega-3 long chained polyunsaturated fatty acids have decreased, in particular in urban areas.”
Nutrition and Mental Health Debate Lingers
However, despite dozens of studies suggesting a connection between omega-3s and depression, scientists have yet to definitively prove that the two are directly linked. And in the past several years, a vigorous debate has erupted. While there’s very strong evidence that those suffering from depression often have low omega-3 levels, not everyone agrees that the deficiency itself is to blame. And the question has taken on new relevance as teen suicide levels have spiked in the United States in recent years.
“The prevalence of depression in a society is inversely related to that society's consumption of fish: the more that people eat fish, the healthier the population, both physically and mentally,” the non-profit Mental Health America writes in its summary of omega-3s. “But studies are split when it comes to proving a link between an individual's consumption of omega-3s and lowered depression.”
A recent study published in the Journal of Psychiatric Research added to the complexity. In a six-year study of thousands of participants, the authors confirmed that people with lower omega-3 levels were more likely to suffer from depression (Thesing et al. 2020). At the start of the study, researchers tested omega-3 levels in participants and asked about their mental health. People with signs of depression were more likely to be lacking omega-3s. But six years later, when they tested people again, they found that people whose omega-3 levels dropped hadn’t seen a corresponding increase in depression. Their results suggest the situation may not be as simple as fewer omega-3s equal more symptoms of depression.
New Studies, New Hope
Skeptics might suggest that the fact the pharmaceutical industry makes roughly $14 billion annually from patentable antidepressants is a “headwind” that slows extensive, definitive research into omega-3s mental health benefits (Brandessence 2019).
But such research appears to be coming nonetheless. Recent work from a large, international group of scientists calling themselves the Omega-3 Study Team suggests the results so far have been simply inconclusive and that more research is needed. The team suspects that differences in study methods, participant selection, drug composition and more could be to blame for the varying outcomes between studies (Häberling et al. 2019).
Thanks to their efforts, there could be some hope for resolution on the horizon. An outline of their clinical trial study published last November shows how they hope to finally answer the question one way or the other. The study will give omega-3s to hundreds of adolescent patients suffering from moderate depression and then monitor remission and recovery rates.
So, we may have to wait a while for the scientific community to agree on prescribing omega-3s as a treatment for depression. In the meantime, there’s plenty of other reasons why your brain and body will thank you for consuming seafood and omega-3 supplements.
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