Doctor's Note

For more on the health hazards of arachidonic acid, check out:
When Meat Can Be a Lifesaver
Titanium Dioxide & Inflammatory Bowel Disease
Fighting the Blues With Greens?

For information on the role that plant-based diets can play in improving mood, check out: Plant-Based Diet & Mood

Also, be sure to check out my associated blog posts: Harvard’s Meat and Mortality StudiesInflammation, Diet, and “Vitamin S”The Most Anti-Inflammatory MushroomHow To Boost Serotonin NaturallyTreating Crohn’s Disease With DietTop 10 Most Popular Videos of the YearSaffron vs. Prozac for DepressionThe Science on Açaí BerriesRaspberries Reverse Precancerous Lesions; and How Probiotics Affect Mental Health.

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  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. For information on the role that plant-based diets can play in improving mood, check out my other video Plant-Based Diet & Mood. Also, there are 1,449 subjects covered in my other videos–please feel free to explore them!

  • Karen LaVine

    I wonder about meat intake and the higher rate of depression for people with diabetes… Yet another reason to try the PCRM plant-based diet for people with diabetes? Cool it only takes 2 weeks to affect the mood – that’s LOTS faster than SSRI’s.

  • Jordanelizabeth

    This video has perfect timing, I have suffered from depression and have been trying to stay off medication. This is week 2 of my vegan diet, for other reasons completely, but I have not felt any sadness or anxiety despite working full time and going to school full time! And I had three exams this week!

    • Happy to hear. I see your post was written a year ago. How are you now, still well?

  • Eric Needs

    this is amazing as usual

  • I suspect there are other studies that would evidence psychiatric metrics improving with statistical significance with higher consumption of n3 long-chain fatty acids (from fish). Dietary lipids seem to present many paradoxes.

  • VegeMarian

    I’m so glad to see this study. I have direct of experience of seeing someone who went vegan and, after 4 years, has not had any bouts of depression which had been frequent for her previous to going vegan. It wasn’t something she was expecting but a fantastic side benefit!

  • I went on a rawfood/vegan diet 2 yrs old, and many health issues went away. But the nice thing was my mood/depression that went away. If I added bad foods back on in my diet, I quickly started to feel depressed. Now, this video explains it. I’m NOT crazy after all! Woo-hoo! I’ll stay on raw foods/vegan for life. Oh, my thyroid med was dropped from a high 180 mcg (amour) to 40! Yay!

    • Wow Allison, great to hear — especially about the thyroid!

  • Is Golden algae oil free of Arachidonic acid? Let us know… and maybe that could be one advantage over fish oil.

    • Toxins

      Hello Lance,

      Although consuming excess arachadonic acid is harmful, there is significantly more harm in fish oil compared with algae oil. Please check out the following videos.

      I am not an advocate of consuming any oil since oil is essentially liquid fat with no nutrition. According to Dr. McDougall, “a condition of ‘essential fatty acid deficiency’ is essentially unknown in free-living populations….true essential fatty acid deficiency would result in: loss of hair, scaly dermatitis, capillary fragility, poor wound healing, increased susceptibility to infection, fatty liver, and growth retardation in infants and children.” Here is the full article Although the algae oil may have the DHA, oil is still oil and not a whole plant food. I respect Dr. Greger’s statement of avoiding fish oil for its many contaminants and using algae oil as a substitute but is it really necessary to ingest any pure DHA in the form of an oil? After weighing it out, to me, it doesn’t seem necessary.

      • elsie blanche

        Toxins, do you consider the oil in corn chips (they fry the chips with sunflower, safflower, and or canola oil) to constitute as a “free oil”, no longer a whole plant food once the oil has been extracted from the, say, sunflower seed? Or would the cooking of the sunflower oil into the corn flour make it somehow OK now? I am not an advocate of corn chips and the like, but the idea of extracted oils from plants and then re-combining them/cooking them into other plants, has me curious what your personal stance is on these sort of foods. Do you ever consume corn chips, taco shells, other products that have free oils cooked into them? Thanks for any insight, Toxins. And I do wonder if there is any “science” on this topic.

  • wickedchicken

    That is so interesting, and impressive. I wish I had been at that conference to hear the reaction of the medical attendees. I wonder… would giving up meat etc lead to decreased guilt over eating animals, and increased moral contentment [subconscious or not] and this be a mechanism for the improved mental health, rather than just physical and chemical body changes. I suspect it might be ..both!

  • GabrielG

    Interesting but it seems biased. You can read many reports on the web of people eating a paleo diet (which includes meat and animal fat) and better health and mood.

    • Toxins

      Hello Gabriel,
      You can read all about the harms of the paleo diet here on Micheal Greger’s free E book, “Atkins’s Exposed”. It has over a thousand references from studies and more.

      • GabrielG

        Thanks Toxins but paleo is not low carb like Atkin´s AFAIK

        • Toxins

          The paleo diet advocates high meat intake as well as vegetables and rejects complex carbohydrates such as beans and grains. Perhaps you have hybridized it. Nonetheless, high meat intake is by no credible standard healthy.

          • Ivy

            The paleo diet diet does NOT advocate high meat intake. People following a paleo diet should be consuming the same amount of meat as other omnivores, substituting vegetables and fruits for grains and legumes. It is not a high protein, or low carb, diet.

          • Ivy

            Also, it has been recommended by numerous doctors (a couple links:, that omega 3 is beneficial for mood disorders such as depression and bipolar.

          • Thea

            Ivy: Your post was actually pretty helpful to me. It helped to highlight for me where the problem is when communicating with proponents of the paleo diet. I believe that this is the key part is in defining what “high” means. Ie: “… NOT advocate high meat intake. … consuming the same amount of meat as other omnivores…”

            What we have learned on this site and from the many other experts in nutrition is that what “other omnivores” eat is very much high meat intake. It may not seem that way because you see lots of other people in your culture consuming such high amounts. But if you compare to what the science says is healthy, you can see that pushing such levels of meat intake is indeed a very high meat intake. So, if the paleo diet is pushing people to eat the same amount of meat as their peers, that is actually high meat intake.

            What I take from this is: the communication issue can be in understanding what “high” means. We once had someone post on NutritionFacts that he ate 50% of his diet from meat. And that seemed like a ballanced diet to him. Ie, it didn’t seem like high meat intake. Yikes.

            If you want to learn more about why meat is so unhealthy and why grains and legumes are so very healthy, this site is a great place to start.

    • Michael Greger M.D.

      I think you’ll find you can find just about anything online. That’s why controlled studies like this, and the field of scientific inquiry in general, are so important.

  • GabrielG

    It would help if you put links to the studies.

    If fish eaters also improved, it is not the meat but maybe the fat that is a problem. If I understood correctly there is a mention of saturated fat increasing arachidonic acid. So the problem is not sure to be animal protein.

    Also, how is “flesh food” defined? Lean cuts, pastured animals, cow, poultry, free range, sausages, hamburgers with french fries, fast food, fried food using corn or other high omega 6 oils?

    I want to know more this issue of inflammation is very important. Thanks for pointing it out

    • Toxins

      Gabriel Check out the sources cited section, all the studies are hyperlinked.

      Also, omega 6 gets converted to Arachadonic acid so perhaps the higher omega 3 content of fish balances this out.

  • BES

    Is it important for vegetarians to have omega 3 EPA supplements? My son’s doctor has recommended he take an EPA supplement to help with mood, but the studies cited in this video seem to imply that EPA is important mainly to counteract the arachodonic acid. If this is the case, would EPA be critical to the mood of someone who is vegetarian?

    Thank you so much for all the information you provide on this website!

  • Barbarasavedoff

    My 12-year-old son’s doctor has recommended that he take a supplement with EPA (and DHA) to help with mood issues. I have found an expensive supplement derived from yeast that provides the suggested amount of EPA, but I was wondering if it is likely to help my son.   Your video on mood shows that EPA is important to counteract arachidonic acid in meat-eaters, but is it likely to affect mood in vegans or vegetarians as well?  Would high dose EPA supplements be unnecessary for vegans and vegetarians since they do not have the same build-up of arachidonic acid?

  • Michael Greger M.D.

    For some context, please check out my associated blog post Harvard’s Meat and Mortality Studies!

  • How do I click on the stars to rate your videos? I appreciate the content but don’t know how to rate!

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  • albert

    those guys who switched to vegan diet were just high from knowing they are real vegans now. adventists are high all the time from being adventists (only half joke here).

  • Liz

    Hmm, I eat plant based, but still have ocassional meat and eggs. I will try complete vegetarian for 2 weeks, see how I feel. Hope my teeth don’t suffer, since eating fats and animal foods help avoid carb rich foods like rice, tubers, bread and corn. This will mean upping my fruit intake, as well as my rice and tuber intake. I dont get full on green vegetables alone.

  • Gisèle

    Hi,I suffer of Fibromialgia and am always in pain…. any suggestions? Thanks Gisèle

  • Appel

    I am one of the most stressed people I know and suffering from depression all my life , and I have been a vegetarian all my life and since five years a vegan. So I don’t know if this is true. I have been thinking to start eating fish again for the omega 3

  • Cheryl Lee

    Extracted from Wikipedia:

    Arachidonic acid is one of the most abundant fatty acids in the brain, and is present in similar quantities to docosahexaenoic acid (DHA). The two account for approximately 20% of its fatty acid content.[12] Like DHA, neurological health is reliant upon sufficient levels of arachidonic acid. Among other things, arachidonic acid helps to maintain hippocampal cell membrane fluidity.[13] It also helps protect the brain from oxidative stress by activating peroxisome proliferator-activated receptor gamma.[14] ARA also activates syntaxin-3 (STX-3), a protein involved in the growth and repair of neurons.[15]

    Arachidonic acid is also involved in early neurological development. In one study funded by the U.S. National Institute of Child Health and Human Development, infants (18 months) given supplemental arachidonic acid for 17 weeks demonstrated significant improvements in intelligence, as measured by the Mental Development Index.[16] This effect is further enhanced by the simultaneous supplementation of ARA with DHA.

    In adults, the disturbed metabolism of ARA contributes to neurological disorders such as Alzheimer’s disease and Bipolar disorder.[17] This involves significant alterations in the conversion of arachidonic acid to other bioactive molecules (overexpression or disturbances in the ARA enzyme cascade).

    Alzheimer’s disease
    Studies on arachidonic acid and the pathogenesis of Alzheimer’s disease is mixed with one study of AA and its metabolites suggests they are associated with the onset of Alzheimer’s disease,[18] whereas another study suggests that the supplementation of arachidonic acid during the early stages of this disease may actually be effective in reducing symptoms and slowing the disease progress.[19] Additional studies on arachidonic acid supplementation for Alzheimer’s patients are needed.

    Dr. Greger, it seems like some arachidonic acid is necessary for the brain to function optimally. Please share your thoughts on this.

  • DanielFaster

    Thanks for this. Are there any similar studies on OCD influencing foods/nutrients/diets?

  • Vic Werlhof

    Typically, I avoid meat. Occasionally, I eat animal products. If I eat only complex carbs for a week or so, I feel sacked. No energy, hard to get motivated. It is common for me to eat 85% chocolate. When down, a bag of Oreos or a plate of white spaghetti seems to rally me. What is wrong? Why don’t I get more energized when consuming complex carbs? Thanks.

    • Toxins

      What complex carbs are you consuming and how are they prepared? I find it rather interesting that whole wheat pasta makes you feel ill while white pasta does not.

      • Ivy

        Whole wheat pasta=gluten. From Wikipedia: Symptoms (of gluten intolerance) include bloating, abdominal discomfort or pain, diarrhea, constipation, muscular disturbances, headaches, migraines, severe acne, fatigue, and bone or joint pain.

        • Toxins

          White pasta has plenty of gluten too. White pasta is stripped of the bran but the endosperm still contains plenty of protein, thats what makes my question of interest.

    • Thea

      Vic Werlhof: Toxins asks a good question and makes an excellent point. I have another idea for you: Perhaps you are not getting enough calories? I had a friend who switched to a vegan diet, but she was eating a lot of veggies. Those filled her up and she wasn’t getting enough calories. Her symptoms were that she got weak and shaky. I suggested that she add some nuts and seeds to her diet, plus some avocado, and that has completely fixed her problem. She feels great now.

      This idea of adding more calorie-dense foods (but cutting out the junk!) might work for you since you say that eating chocolate and oreos helps. Those would be calorie-packed – but of course, not healthy. I imagine your plate of white spaghetti “rallies you” because it is a simple carb that goes straight to your blood and you feel that at least temporarily.

      I’m not an expert, but I hope that idea gives you something to work with. Good luck.

  • Leanna Lunde

    It needs to be made clear that this study was done on people with diabetes 2.

    It is interesting that typically in Arctic populations their diet is heavily meat based, especially during the dark season, and it is common to have a high amount of people with depression in the Arctic. But the depression is thought to be from the darkness, not the high consumption of meat. Meat, in fact, is thought to give energy and vitality. Reindeer meat is extremely high in saturated fat but is said to be as good as eating fish.

    I do find that a lot of studies on food do not consider the environmental factors on humans when examining diet.


  • Mitch Earleywine

    Two of 11 dependent variables related to mood improved significantly more in the vegan group. I’m all for a vegan diet, but let’s not make too much of this. Behavioral treatments for depression and anxiety are safe and effective.

  • I have to say the my plant based diet has super increased my energy. Why is this important. With super increased energy it is very difficult for me to have a bad mood. It is just not happening.

    • harriet v

      What kind of B12 do you use, if I might ask? What form, and how often? You seem to have some good insights and revelations on this website. Sublingual or swallowed with food?

      • When I do supplement, which may be 3-4 out of a month, I use a vegan sublingual B12supplement by DEVA. I eat a lot of raw food and I think some B12 has to remain on them because supplementing so little my B12 are 3/4 of the max recommended. Thank you very much for the complement. I am humbled. I just came from the boxing gym and I am outworking 25 year old kids, and I am 47. They can’t believe how old I am, and that does make me feel good. All praise to the Creator of Life for my enlightenment.

  • Alicia Griffin

    I have suffered from depression on and off since I was 14. I switched to a plant based diet over 2 years ago. I have since had a episode of major depression during a very stressful period (watching my father die being the main stressor) and had people try to tell me that my vegan diet might be partly responsible for my mood. So it is reassuring to know that if anything it is doing the opposite and helping to keep me mentally healthy. And that if I continue to eat this way and do all the other things I know I should such as regular exercise and changing the thought patterns/habits that can lead me down that black hole I have chance to beat depression permanently.

    • Thea

      Alicia: It sounds like you are doing absolutely everything you can to help yourself. I agree, from everything I have seen, your diet is only helping you. Best of luck. I hope it is only uphill from here.

  • DS

    I have type 2 diabetes. For the past 10 years, I have been able to control it with just diet, exercise and wine. The diet was a low carb diet with lots of chicken, eggs and fish. Several months ago, I started a whole foods vegan diet which I feel has had a very positive effect on my mood and emotionality. My glucose readings, however, have now become wildly erratic. I want to stick with a vegan diet so I started 1,000 mg of metformin per day, which I have now upped to 1,500. I’m still getting some very high readings, especially in the mornings. Would it be better to stick with a vegan diet and try to control the glucose spikes with drugs or to try to control the spikes by adding more protein to my diet in the form of egg whites and organic grass fed beef?

    • Thea

      DS: Good for you for taking your health into your own hands.

      Concerning controlling Type 2 diabetes, I highly recommend that you get the book, “Dr. Neal Barnard’s Program for Reversing Diabetes: The scientifically proven system for reversing diabetes without drugs”. That book will help you understand the details of what a whole plant food vegan diet should look like in order to stabilize and reverse your T2 diabetes. The back of the book even includes recipes. So, you can know exactly what the diet should consist of.

      Bottom line: You should not need any animal products at all. According to Dr. Barnard’s clinical trials, people did best without them.

      Hope that helps!

  • Jan Carrie Steven

    My understanding is that peanut butter has a lot of arachidonic acid. I am wondering if it should be on the “use sparingly” list?

    • Joseph Gonzales R.D.

      Hi Jan. I think it depends. Typically I would say sparingly is a good idea. You may find more info here, Is peanut butter good for you?. Thanks for your question, Joseph

  • Nalani

    What do you make of all the articles that keep getting written about ‘vegetarians having more anxiety and depression’, then? among several alarming anecdotal articles (which I know not to take seriously as they are individual cases) a couple of observational studies are being thrown around that imply vegetarians and vegans are more likely to have mental illness and too many people are taking them seriously as fact and I find it worrisome.

    This is the main study I see a lot

    I recognize though that surveys like this are not as indicative of anything as an actual controlled study (not do they address causes), but I would like some opinions. Arguing with some hardheaded people had become troublesome.

    • Thea

      Nalani: Some thoughts:

      1) There is at least one facility treating people with severe depression using a plant based diet. Consider the bio of this speaker from a talk I heard last year: “Neil Nedley, MD, directs the world’s most comprehensive program for depression and anxiety recovery, utilizing nutrition and lifestyle modalities to alleviate these mental illnesses. His program also greatly enhances general intelligence and emotional intelligence. Dr. Nedley is the author of three books, including Proof Positive: How to Reliably Combat Disease and Achieve Optimal Health Through Nutrition and Lifestyle, and also an 8-part DVD Workbook Series that is used extensively in mental health education programs throughout the U.S. and other countries.”

      2) People who switch to vegan diets often do so *because* they have a problem of some kind that they either consciously or subconsciously wish would help them. For example, it is not at all uncommon for someone to switch to a vegan diet after getting a cancer diagnosis. A survey of people and their diets might show that more people who eat vegan have cancer. But that kind of survey, as you seem to know, tells us nothing about cause and effect. I could totally see a person who has a mental health problem (either a known or unknown problem) giving a vegetarian diet a try. That doesn’t mean that the vegetarian diet caused the mental health problem.

      3) Many vegetarian diets are not healthy. Such diets contain lots of dairy and eggs (animal protein and fat) as well as processed plant foods. It would not surprise me if such unhealthy diets had a mental health impact. However, eating a whole plant food based (WPFB) diet is a healthy diet and as Dr. Greger shows here on NutritionFacts, has some good science to back up its positive impact on mental health.

      4) Anecdotes to counteract anecdotes: People on this site report great feeling of well being when being on a whole plant food based diet. As you seem to know from your comment, anecdotes are not science.

      Does this help?

      • Nalani

        Yes, thank you. I have a lot of opinions and knowledge but no one to discuss it with and a lot of self doubt. When I see people say things with conviction, even if I can point out flaws, I tend to worry about my stance and it makes me a lousy debater but I’m trying to work on it. I still feel the need for second opinions a lot though, especially with so many differing studies and articles out there. I’m still learning to be able to tell what makes a good study a good study.

        • Thea

          Nalani: re: “I’m still learning to be able to tell what makes a good study a good study.”
          That’s a tough one! Most people (including myself by and large) never get that far.
          There is a whole lot of ignorance out there. And as you say, it is flouted with conviction. My 2 cents is that sometimes it is worth while to “fight the good fight” as it might sow a seed of growth in someone, even if just a by-stander. But that kind of thing can sap your energy. I prefer to spend most of my time helping people who actually want to be helped. This site is a great place to do that. Feel free to stick around. ;-)