Newsletter #178: Omega-3s for Mental Health 🐟🧠
Hello there, humanOS friends! This week, we are continuing to look at the subject of brain performance (hey, brains are pretty important). However, this time, we are looking at omega-3s, and specifically their potential benefits for psychological health.
Depression is a profoundly underappreciated problem. An analysis of US healthcare spending found that depressive disorders are the sixth most costly health condition, costing $71 billion, and an estimated 11 million American adults have had at least one major depressive episode with severe impairment. So this is a pretty big deal!
The causes of depression are complex. But it is plausible that aspects of nutrition might influence mental health, and there is particular interest in omega-3 fatty acids - specifically in the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids are absolutely essential for normal brain function, and in fact make up a significant portion of the brain itself. However, research into omega-3s and depression have inconsistent findings, with some studies showing significant improvement, but systematic reviews suggest minimal improvement in response to omega-3 supplements.
I decided to dig into the research a bit. Scroll down to learn more 👇🏼
This Week’s Research Highlights
🐟 The vast majority of Americans do not consume enough omega-3s, based on circulating levels in the blood.
Researchers analyzed data on long-chain fatty acid concentrations (EPA and DHA) measured in serum in a representative sample of 945 children and 1316 adults. They then compared these values to fatty acid concentrations that had previously been identified as roughly equivalent to the current dietary recommendations of 250 mg per day of DHA and EPA. The results were pretty bleak: 95.5% of children and 68.3% of adults had LC omega-3 concentrations below the level corresponding to the intake recommended by dietary guidelines. This is a particularly robust study since it relies on measured objective biomarkers, rather than self-reported dietary intake, which obviously has some major problems.
🐠 Higher blood levels of omega-3 fatty acids are associated with lower risk of depression.
The same research team from the study described above analyzed data on serum long chain omega-3 fatty acids from 1186 adults, and then examined how blood levels of these fatty acids associated with incidence of depression in this population sample. They found that higher serum EPA, DHA, and sum of long chain fatty acids were associated with lower relative risk of moderately severe to severe depression, and serum EPA specifically was associated with ability to perform daily life tasks. This is supported by prior research which showed that higher fish consumption was linked to a 17% lower risk of depression.
🔥 Clinical depression is linked to greater inflammation in the brain.
Researchers performed PET scans on twenty patients with depression (but who were otherwise healthy) and twenty control participants. When they examined the brain imaging, they specifically looked at levels of translocator proteins. Translocator protein levels go up when immune cells in the brain are activated, which in turn increases secretion of chemical messengers that boost inflammation, so this is a useful way to identify inflammation in the brain. Sure enough, levels of brain inflammation were ~30% higher in the subjects with depression, compared to healthy controls.
🔮 Levels of inflammation predict whether patients with depression will respond to omega-3 fatty acid supplementation.
Researchers assessed levels of various biomarkers of inflammation in a group of outpatients with depression, and then randomly assigned the participants to either take 1) placebo, 2) 1060 mg of EPA, or 3) 900 mg of DHA daily for two months. At the end of the study period, participants with at least four biomarkers of high inflammation were significantly more likely to experience remission from depression if they took EPA. Specifically, among the highly inflamed patients, remission rates were 40% for EPA, 14% for DHA and 25% for placebo, while remission rates for subjects without any markers of high inflammation were 19% for EPA, 43% for DHA and 44% for placebo. This might explain why the research is so mixed on omega-3s and mood disorders, if the benefits are mainly confined to people with higher brain inflammation.
🔥 Omega-3s protect against brain inflammation and in turn may alleviate depressive symptoms.
Researchers treated human brain cells, in vitro, to EPA or DHA before then exposing them to inflammatory cytokines. Typically, cytokines cause these brain cells to stop growing or die, but the EPA and DHA seemed to shield the cells from these consequences. When the researchers probed more deeply, they found that EPA and DHA formed several metabolites which seemed to be playing an active role in protecting the brain cells from inflammatory damage. Then, the researchers took a sample of 22 patients who had been diagnosed with depression, and randomly assigned them to treatment with either EPA (3 grams per day) or DHA (1.4 grams per day) for 12 weeks. In both groups of patients, treatment of EPA and DHA were associated with an increase in the aforementioned metabolites, as well as a significant improvement in depressive symptoms, with an average reduction in symptom scores of 64% for EPA and 71% for DHA. Furthermore, subjects with higher levels of the metabolites found in the in vitro experiments tended to have lower scores of depressive symptoms. This suggests that a subgroup of depressed individuals with higher levels of inflammation may benefit from long-chain omega-3 supplements, which is pretty awesome since a huge percentage of people with depression are unresponsive to antidepressant drugs, and treatment-resistant individuals are more likely to have high levels of inflammation.
Random Trivia Question of the Week
🤔 What creature has the strongest teeth? (Also the strongest known natural material on Earth!)
🦷 ANSWER
Podcasts We Loved This Week
• Marion Hetherington: Psychology and development of food preference and eating behavior. Via Sigma Nutrition Radio.
• Arthur Allen and Sarah Jane Tribble: Behind the booster battle. Via Science Friday.
Products We Are Enjoying
Opti3 algal oil
Most omega-3 supplements are derived from fish or other marine wildlife. However, some people are concerned about the sustainability of current fishing practices (or they’re not crazy about the taste of seafood products). If you share these reservations, algal oil might be a smart solution.
This oil is derived from microalgae grown in a closed environment, meaning that there is no risk of them absorbing toxic compounds from the ocean, and the process is fully sustainable. Each dose contains 916 mg of omega-3 (including 324 mg of EPA and 534 mg of DHA) plus 200 IU of vitamin D3.
humanOS Catalog Feature of the Week
Thank you so much, as always, for reading, and see y'all next week!