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Antioxidant- and Folate-Rich Foods for Depression

According to the Centers for Disease Control and Prevention, the rates of all of our top 10 killers have fallen or stabilized except for one, suicide. As shown in my video, Antioxidants & Depression, accumulating evidence indicates that free radicals may play important roles in the development of various neuropsychiatric disorders including major depression, a common cause of suicide.

In a study of nearly 300,000 Canadians, for example, greater fruit and vegetable consumption was associated with lower odds of depression, psychological distress, self-reported mood and anxiety disorders, and poor perceived mental health. They conclude that since a healthy diet comprised of a high intake of fruits and vegetables is rich in anti-oxidants, it may consequently dampen the detrimental effects of oxidative stress on mental health.

But, that study was based on asking how many fruits and veggies people ate. Maybe people were just telling the researchers what they thought they wanted to hear. What if you actually measure the levels of carotenoid phytonutrients in people’s bloodstreams? The same relationship is found. Testing nearly 2000 people across the United States, researchers found that a higher total blood carotenoid level was indeed associated with a lower likelihood of elevated depressive symptoms, and there appeared to be a dose-response relationship, meaning the higher the levels, the better people felt.

Lycopene, the red pigment predominantly found in tomatoes (but also present in watermelon, pink grapefruit, guava and papaya) is the most powerful carotenoid antioxidant. In a test tube, it’s about 100 times more effective at quenching free radicals than a more familiar antioxidant like vitamin E.  

Do people who eat more tomatoes have less depression, then? Apparently so. A study of about a thousand older men and women found that those who ate the most tomato products had only about half the odds of depression. The researchers conclude that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.

Higher consumption of fruits and vegetables has been found to lead to a lower risk of developing depression, but if it’s the antioxidants, can’t we just take an antioxidant pill? No.

Only food sources of antioxidants were protectively associated with depression. Not antioxidants from dietary supplements. Although plant foods and food-derived phytochemicals have been associated with health benefits, antioxidants from dietary supplements appear to be less beneficial and may, in fact, be detrimental to health. This may indicate that the form and delivery of the antioxidants are important. Alternatively, the observed associations may be due not to antioxidants but rather to other dietary factors, such as folate, that also occur in plant-rich diets.

In a study of thousands of middle-aged office workers, eating lots of processed food was found to be a risk factor for at least mild to moderate depression five years later, whereas a whole food pattern was found to be protective. Yes, it could be because of the high content of antioxidants in fruits and vegetables but could also be the folate in greens and beans, as some studies have suggested an increased risk of depression in folks who may not have been eating enough.

Low folate levels in the blood are associated with depression, but since most of the early studies were cross-sectional, meaning a snapshot in time, we didn’t know if the low folate led to depression or the depression led to low folate. Maybe when you have the blues you don’t want to eat the greens.

But since then, a number of cohort studies were published, following people over time. They show that a low dietary intake of folate may indeed be a risk factor for severe depression, as much as a threefold higher risk. Note this is for dietary folate intake, not folic acid supplements; those with higher levels were actually eating healthy foods. If you give people folic acid pills they don’t seem to work. This may be because folate is found in dark green leafy vegetables like spinach, whereas folic acid is the oxidized synthetic compound used in food fortification and dietary supplements because it’s more shelf-stable. It may have different effects on the body as I previously explored in Can Folic Acid Be Harmful?

These kinds of findings point to the importance of antioxidant food sources rather than dietary supplements. But there was an interesting study giving people high dose vitamin C. In contrast to the placebo group, those given vitamin C experienced a decrease in depression scores and also greater FSI. What is FSI? Frequency of Sexual Intercourse.

Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don’t live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one—some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency; so, it does not appear that the depression scores improved just because of the improved FSI.

For more mental health video, see:

Anything else we can do to enhance our sexual health and attractiveness? See:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

13 responses to “Antioxidant- and Folate-Rich Foods for Depression

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  1. I’ve heard about the importance of the EPA/AA ratio in blood as a possible predictor of heart attacks, strokes and CV death. I’ve not seen you reference this and follow your communications daily. Can you educate on this?

    BTW, I loved the book and have given it as gifts.

    1. Thanks for your question Chris.

      That is a very interesting point you make.

      According to a 2014 publication (see full text here):

      EPA improves the arterial stiffness in association with an increase in the EPA/AA ratio and a decrease in inflammation in obese patients with dyslipidemia.

      Last year (2016), another publication has found that:

      several studies have reported that low eicosapentaenoic acid (EPA) and EPA/arachidonic acid (AA) ratio are related to plaque vulnera- bility, and that EPA treatment contributes to plaque stabilization in patients receiving statins


      The present study revealed that EPA/AA ratio was an indepen- dent associated factor of High Risk Plaque in patients without Coronary Artery Disease (CAD). Coronary computed tomography angiography (CCTA) might help risk stratification in patients with conventional coronary risk factors. Patients with conventional coronary risk factors and low EPA/AA ratio would be candidates for CCTA to evaluate plaque characteristics for the primary prevention of CAD. Low EPA/AA ratio would be useful to identify high risk patients for CAD in patients without previous CAD, and patients with EPA/AA of <0.3 should be treated with EPA for primary prevention of CAD.

      This study also confirmed that EPA/AA was an independent predictor of cardiovascular events in patients without previous CAD, and HRP was an independent predictor of the events including early revascularization.

      Hope this answer helps.

  2. If you have all this descriping above in your diet you can still get depressed very quickly… if you have patients they are sick but don’t like to change anything of there food habit. If you have relatives, parents, sisters and brothers they struggle with high blood presure, diabetes II, obesity and novardays with dementia and they are not willing to listen to your advise…because there physicans say they have to take there drugs it is the only chance…then you can go depressed very quick.

  3. Why was it necessary to include the bit about Vitamin C and intercourse? That had nothing to do with the subject of the article. Which started off with excellent information.

    1. Thanks for your question Kathy.

      I believe the last paragraph explains:

      Evidently, high dose vitamin C improves mood and intercourse frequency, but only in sexual partners that don’t live with one another. In the placebo group, those not living together had sex about once a week, and those living together a little higher, once every five days, with no big change on vitamin C. But for those not living together, on vitamin C? Every other day! The differential effect for non-cohabitants suggests that the mechanism is not a peripheral one, meaning outside the brain, but a central one—some psychological change which motivates the person to venture forth to have intercourse. The mild antidepressant effect they found was unrelated to cohabitation or frequency, so it does not appear that the depression scores improved just because of the improved FSI.

      Hope this answer helps.

      1. I agree with Kathy. The flip to FSI makes no sense to me. Seems completely out of context and so convoluted it’s very hard to interpret in and of itself at all.

  4. In this article, the corresponding video is linked It’s well worth checking out, and the comments section especially. One poster “Kim” comments on the complexity of issues surrounding depression – very interesting post.

    I think an interventional study might tell us more on what impact high fruit and vegie consumption might have on depressive states and moods. To me , its no surprise that studies of depressed folks show lower consumption of fruit and veg. It takes a lot of resources to plan, comparitively shop for, store, and prepare fresh foods. Resources being time, energy, money (fruit and veg very expensive in parts of canada) , transportation . For the depressed person, these factors may be mutually exclusive to their state of mind, and lack of any resources mentioned simply cause further impediment.

  5. I did not review the linked studies so maybe the answer is there, but I wonder if the eat-vegetables-reduce-depression path is true, or if people who are not depressed tend towards better self-care and as part of that eat more vegetables? Same thing with the processed (junk) food study. Seems like these food and self-care pathways can be circular–hard to tell which comes first. Even more complicated when we mix in the theory, again circular, that the food we eat determines what bugs populate our gut, and those bugs attempt to determine what food we eat to ensure their own survival, and that those bugs can have other chemical effects on the brain. Also on the pill-vs-whole food nutrient, we know now how complex the relationships are between whole foods and the gut ‘biome’–the pill won’t have any fiber or other stuff that the whole-food nutrient comes with, and that other stuff may affect depression.
    p.s. I LOVE NutritionFaces.ORG!

    1. Interesting ideas. I can only speak for myself, but I suffered from frequent depression most of my life, and going WFPB has been a blessing! The icing on the cake though was adding fermented foods to my diet. I hate to sound corny but I found joy in these soured foods, it took my mood to the next level and now I crave them! So I am in total agreement with the idea that our microbiome plays a huge role in total AND mental health, and glaringly obvious when appropriate changes are made! It took almost 3 years however, to get off the stinking antidepressants because the withdrawal symptoms were brutal! They are a short term patch for a selected few at best, proven to be not very effective besides the placebo effect, and a nightmare otherwise!

  6. It is indeed the folate! It is estimated that 30-40% of the population has a genetic mutation/variation of the MTHFR genes (there are 2) which deal with methylation & folate availability. Those who have this mutation (like my husband and several family members) have an impaired ability to transform folic acid into the bio-available form of folate. And since most people aren’t eating very many fruits and veggies as it is, their folate levels can be quite deficient leading to many dis-eases in the body, including depression.

    Of course eating more fruits/veggies is important, but for those suffering from depression or the other associated dis-eases, there is also a bio-available form of folate on the market, called methyl-folate that people can take. I have seen many people come out of depression/anxiety within 1-2 days of taking methyl-folate. My own husband had a similar profound response. The trick is finding the right dose to take because it is different for each individual. Also, methyl folate must be taken with methyl-B12 to get the full benefit.

    There are many resources on the web to understand this–Dr Ben Lynch is one. If you are suffering from depression/anxiety, you can just try taking the methyl folate and methyl B12 and see if it works for you–remembering that you will have to experiment and “dial into” the right dose. You can also get your genome mapped by 23andme and see if you have the mutated MTHFR genes if you want scientific confirmation. Since it is gene related, it runs in families, so this can really help generations.

  7. I’m sure that eating antioxidants and a healthy diet in general are sure to help with low mood symptoms, however I have concerns that reducing this down to a single cause risks continuing along the lines of a medical model which has been very unhelpful to a lot of people. I work as a psychological therapist and having spoken to hundreds of people about their past experiences, it appears unlikely that physiological influences such as this would have more influence than, for example, trauma, bullying or abusive relationships or significant loss, not to mention the influence of our society.
    Yes, it’s important for us to be in good physical condition and to look after ourselves, and hopefully that can prevent milder forms of depression, but often people have gone through really difficult times, and we need to acknowledge that too.

  8. I had read somewhere about the miracles of antioxidant, I would like to share how antioxidant woks. While oxygen is one of the most vital components for the living, it is also could be negative. Oxygen is a highly reactive atom that is capable of becoming part of possibly damaging molecules commonly called ‘free radicals’. These free radicals are accomplished of attacking the healthy cells of the body. This may lead to impairment, disease and severe illnesses. Since free radicals contain an unpaired electron they are unstable and reach out and capture electrons from other substances in order to defuse themselves. Normally free radical formation is controlled naturally by various beneficial compounds known as antioxidants. When there is a deficit of these antioxidants damage due to free radicals can become increasing and devastating.Antioxidants are capable of stabilizing, or deactivating, free radicals before they attack cells.

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