Published on June 7, 2021

Analysis of NHANES 2011-2012 data shows a significantly reduced risk of more severe depression with higher levels of omega-3 fatty acids

Depression is a common mental disorder that affects more than 300 million people worldwide and is the leading cause of disability. In fact, depressive symptoms can affect just about anyone at any time with varying degrees of interruptions to daily life. A recent analysis of the 2011-2012 National Health and Nutrition Examination Survey (NHANES) data set showed that, of 1186 adults surveyed in the United States, 14.3% reported mild depressive symptoms, 5.06% moderate, and 2.75% moderately severe to severe depressive symptoms.

In past blogs, we have discussed the association between depression and magnesium, vitamin D, and omega-3s. Our last post featured a video by Dr. Bill Harris on omega-3s and anxiety and depression. Today, we are reviewing one of the latest studies on omega-3 fatty acids and depression.

Previous Study Shows Strongest Evidence for Omega-3s and Depression

The world’s largest review (called a meta-synthesis) of nutrient supplements and mental disorders published by Firth et al. examined 33 meta analyses of randomized controlled trials on dietary supplements and mental health. The analysis included data from 10,951 individuals with diagnoses such as depression, stress and anxiety, bipolar, personality disorder, schizophrenia, and attention-deficit/hyperactivity disorder (ADHD). The strongest evidence from this review showed the effect of omega-3s (with an average dose of 1422 mg/day of EPA) on reducing symptoms of major depressive disorder, which produced benefits beyond those of taking antidepressants alone. The strongest effect was seen with omega-3 supplements that contained at least 50% EPA.

New Analysis Compares Blood Levels of EPA and DHA to Depression Scores

A study by Murphy et al. looked at the NHANES 2011–2012 data set to determine the association between concentrations of EPA, DHA, and total long chain omega-3 fatty acids in the blood and the severity of depression symptoms. Depression was categorized as minimal, mild, moderate, and moderately severe to severe, with an additional assessment of the impact of depressive symptoms on daily life.

Overall, there was an inverse relationship between long chain fatty acid concentration in the blood and depression scores, such that the risk of moderately severe to severe depression decreased with higher levels of omega-3 fatty acids in the blood, and the association remained significant after adjustments were made for sex, age, race/ethnicity, education, marital status, poverty to income ratio, and smoking status.

Click to Enlarge & Print

The charts above show the reduced risk of moderately severe to severe depression versus minimal depression among individuals with higher blood concentrations of EPA and DHA. EPA specifically was found to have a significant relationship to depressive symptoms, with a 70% decreased risk of moderately severe to severe depression versus minimal depression for those with higher EPA levels (p=0.005), and a 61% decreased risk of very or extreme difficulty with daily tasks due to depressive symptoms (p=0.05).

Higher levels of DHA were also significantly associated with a lower risk of moderately severe to severe depression relative to minimal depression, with a 59% reduced risk (p=0.03), suggesting that both DHA and EPA omega-3 fatty acids are important for mental-emotional wellness.

What Level of Omega-3s Should You Aim For?

In studies using a measurement called the Omega-3 Index test, individuals with a low Omega-3 Index were shown to have a 10-fold higher risk of death compared to those with a high index. The Omega-3 Index records the percentage concentration of omega-3s EPA and DHA in red blood cells. An Omega-3 Index between 8% and 12% was associated with lower risk for death from cardiovascular disease, versus an index less than 4%.

Higher omega-3 levels, with an Omega-3 Index of at least 8%, have also been associated with heart health, a longer life, brain health, breast cancer, reduced inflammation, and even an improved immune response to viral infection. Unfortunately, due to the Western diet, a majority of the population has omega-3 levels that are below what is recommended for health; in fact, 82% of GrassrootsHealth participants have an Omega-3 Index level below the recommended 8%.

What can you do to make sure you are getting enough?

Check Your Omega-3 Index and Your Vitamin D Level Today!

By enrolling in the GrassrootsHealth D*action+Omega-3 Project, you can measure your Omega-3 Index and your level of vitamin D. Vitamin D is also very important for mental-emotional wellbeing, as is magnesium among others. Ensuring you are getting enough of each of these essential nutrients by testing your levels could be your first step towards improving your mood and easing depression and anxiety.

Vitamin D is also very important for mental-emotional wellbeing, as is magnesium and several other essential nutrients. Ensuring you are getting enough of each of these essential nutrients by testing your levels could be your first step towards improving your mood and easing depression and anxiety.

When it comes to vitamin D especially, correcting a deficiency at any age and any time of life can decrease potential disease severity and improve outcomes. With almost 90% of the general population having vitamin D levels below the recommended 40-60 ng/ml (100-150 nmol/L), it is obvious that most people need more vitamin D. While most of us cannot achieve a vitamin D level of 40-60 ng/ml from sun alone, either due to our lifestyle, where we live, or other circumstances, we can certainly reach those levels with the right amount of supplementation.

Below is a guide for how much you might need, and who may need more. Your levels can be tested safely at home – order your home test kit today.

Click to Enlarge & Print

By joining the GrassrootsHealth projects, you are not only contributing valuable information to our study, but you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it. Do you know what your status of vitamin D, omega-3s, and other essential nutrients is? Could your levels be improved? Test now to find out!

We now have a NEW GIFTING SERVICE that allows you to quickly send ‘Gift Cards’ to friends, family and coworkers who you consider might need immediate access to testing, and to Claim the Joy of Your Health TODAY. Give the gift today!

What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

STEP 1 - Do you know what your vitamin D level is? If not, be sure to test today to find out.

STEP 2 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L).

STEP 3 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 4 – Optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 5 – Re-Test! This is an important step to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-4 months is recommended.

STEP 6 – Adjust, Repeat…

Give your immune system the nutrients it needs to support a healthy you and protect yourself from unnecessary diseases, especially COVID-19.


The first Randomized Controlled Trial on vitamin D and COVID-19 has shown a 96% lower risk of ICU admission for those receiving vitamin D (as 25(OH)D to quickly boost vitamin D blood levels) along with the standard treatment, compared to those receiving standard treatment alone.

These results support many previous observational studies showing a relationship between vitamin D levels and intake and COVID-19 severity.

Review the Latest Nutrient Research for COVID-19

GrassrootsHealth Nutrient Research Institute has launched the new Immune Boost project with the use of our myData-myAnswers nutrient health system that nearly 15,000 people are already using for their health. Specific markers that influence immune health are suggested for testing as part of this project including:

  • Vitamin D
  • Omega-3 Index
  • Essential elements magnesium, selenium, and zinc
  • hsCRP

Our goal is to demonstrate how one can use the Nutrient Research Model established by Dr. Robert Heaney to show the effect of vitamin D serum levels of at least 40 ng/ml (100 nmol/L) on risk reduction for all ethnicities in the population. Status and intake of other nutrients will also be analyzed for any type of relationship to immune status and symptom severity. Join the project today!

Please let us know if you're interested in helping sponsor this project.

CLICK HERE for updates and new information about the project.

Through GrassrootsHealth Nutrient Research Institute, you can also test your essential elements magnesium, copper, zinc and selenium, toxins such as lead, mercury and cadmium, as well as your omega-3 levels, inflammation levels and thyroid stimulating hormone (TSH) level. Find out your levels today! Log on to the test selection page (click the link below) to get your tests and see for yourself if your levels can be improved.

Make sure you track your results before and after, about every 6 months!

Click Here to Access the Test Page

How can I track my nutrient intake and levels over time?

To help you track your supplement use and nutrient levels, GrassrootsHealth has created the Personal Health Nutrient Decision System called

For each specific supplement, you can track what days you take it, how much, and many other details.  This will help you know your true supplemental intake and what patterns of use work for you to reach and maintain optimum nutrient levels. Check it out today!