Nutrition and Depression

Written by: Kevin Cann

            Depression is one of the biggest problems our society faces today.  According to the National Institute of Health, one quarter of the population of the United States suffers from depression.  This trend is not expected to change anytime in the near future.  According to the Institute of Functional Medicine, depression is estimated to be the second leading cause of disability worldwide by 2020.  Antidepressants are widely prescribed by doctors, yet the figures for depression continue to rise.  Annual costs on antidepressants in 1985 were $240 million.  Today that number has jumped to $12 billion!  If antidepressants are not the answer then what is?  Hippocrates stated that “Food is our medicine, and medicine is our food.”  Believe it or not this may be the best medicine when battling depression.

Our gut and our brain are both in constant communication with one another via the vagus nerve.  In fact traumatic brain injury can actually cause gastrointestinal distress.  In one study the researchers actually found that stimulating the vagus nerve after a brain injury prevented intestinal permeability in the patients (Bansal, 2010).  This link between our brain and our gastrointestinal tract is essential in understanding the mechanisms of action involved in depression.

To further show the correlation between our gut and our brain, depression has been linked to obesity.  In a meta-analysis done in 2010 it was determined that obesity increases the risk for depression and depression is predictive of developing obesity (Floriana, 2010).  There are genetic and environmental factors that may contribute to both obesity and depression however; the strong correlation between the two cannot be ignored.  One major cause of both of these health problems is systemic inflammation.

Systemic inflammation can be caused from a number of factors.  Having excess adipose tissue is one factor.  Our fat cells are living tissue and studies have proven this.  The communication between our lymphocytes and adipocytes help with immune regulation.  Our adipose tissue releases a number of inflammatory and anti-inflammatory factors.  One major factor is the inflammatory cytokines.  These inflammatory factors have been proven to play a role in insulin resistance and increased risk for cardiovascular disease.  They also have been proven to cause inflammation within our brains when they are allowed to pass the gut-brain barrier.  These inflammatory cytokines can cross into our hypothalamus and other parts of the brain that control mood and cause some serious problems for us.  In his write up for Molecular Psychiatry, Licinio explained that inflammatory cytokines (especially the IL-1 family) have a role in major depression.  These cytokines can be formed from a number of factors such as; stress, body weight, sleep, food intake, and body temperature (Licinio, 1999).

Some of the problems associated with this inflammation of the brain are an increase in our insulin and leptin hormones.  In his study Xu concluded that insulin resistance is at least in part, a chronic inflammatory disease initiated in the adipose tissue (Xu, 2003).  This leads to sympathetic nervous system over arousal.  The sympathetic nervous system is our stress response controller.  This over arousal can lead to increased cortisol levels and can cause the body to lose magnesium (Takase, 2004).  Decreased magnesium can lead to migraines and poor sleep.  This is a reason why magnesium supplementation at bed time seems to be an effective strategy for promoting better sleep quality.  Increased intake of sugar can have a similar effect on our nervous system.  Excess glucose in the blood stream auto-oxidizes and forms advanced glycation end products.  These AGEs also degenerate brain function and cause an overproduction of cortisol.  They also have been linked to increased rate of aging.  Increases in cortisol levels have been linked to weight gain and insulin and leptin resistance.

Food intolerances are another cause of systemic inflammation.  Dairy products, legumes, and grains tend to be the most inflammatory out of all the foods in our diets.  A large number of the population does not possess the enzymes capable of breaking down the proline proteins in grains, especially gluten and gliadin.  The saponins in legumes and lactose and casein in dairy are also problematic for most people.  When undigested particles cross through our intestine into our bloodstream our body treats it like a foreign invader and sends an immune response.  This response causes inflammation.  The same inflammatory cytokines that were mentioned earlier are also released.  People with celiac’s disease report much higher rates of depression then the average person.  This shows a strong link between the two.

Also, fructose malabsorption and lactose intolerance have been linked to malabsorption of the essential amino acid L-tryptophan.  L-tryptophan deficiencies have been linked to serotonin deficiencies, clinical depression, anxiety, and ADD/ADHD.  Fructose can be found in a number of processed foods in the form of high fructose corn syrup.  In fructose intolerance the GLUT5 transporter in the small intestine does not pick up the fructose as well as it should.  The fructose then moves down into the large intestines and the colon and can cause gas and bloating as well as an increase in AGEs.  In lactose intolerance the lactase enzyme is inefficient or not present.  This leads to lactose being transported to the large intestine and colon which leads to gas, bloating, and diarrhea (Gedgaudas, 2009).

Now to address the problems through diet.  The first step is to cure the inflammation and restore gut health.  The first step is balancing out our ratio of essential fatty acids.  This can be done by eating more foods high in omega 3 fats (grass fed meats and wild caught fish), or by supplementation.  We should aim for 2g-4g of EPA/DHA per day whether by food sources or supplementation.  We also need to remove the foods that are causing the inflammation.  For most of us this will be grains, legumes, and dairy.  Other foods can cause problems for individuals as well, such as eggs.  If this is the case remove all foods that are causing a negative reaction to you.  We also want to remove foods high in processed sugars to decrease the AGEs and prevent obesity.

So then what can we eat?  We want to make sure we are eating plenty of vegetables to feed the good gut flora and help our digestive system heal from the inflammation.  Fruit and dark green vegetables are also high in folate which can also help with depression.  Low selenium levels can also play a role in poor mood.  Foods high in selenium are quality meats, seafood, nuts, and seeds.  Foods that are high in tryptophan that we want to include to help with a possible deficiency are beef, turkey, and bananas.  Vitamin D deficiency has also been linked to depression, especially seasonal affective disorder, so we want to make sure we get adequate sunlight.  Vitamin D supplementation may be necessary depending on where you live.

Supplementation is sometimes necessary in helping cure depression.  Vitamin D can be a bit tricky determining the right dosage.  Depending on the levels of vitamin D in your blood, supplementation may fall between 1,000iu’s and 10,000iu’s daily.  Cod liver oil should be taken to help counteract the vitamin A lost if you are getting adequate vitamin D from the outdoors.  A b-complex vitamin can be supplemented to help possible deficiencies.  Also, 600mg-800mg of magnesium, preferably magnesium glycinate because it is highly bioavailable.  If L-tryptophan supplementation seems right for you take 500mg daily and take it with vitamin c and a b-complex vitamin to better absorb the amino acid.  It is always best to consult with a licensed practitioner regarding these matters.

Handling stress becomes a large issue as well.  Like I said previously, our brain and digestive system are linked via the vagus nerve and they are constantly in communication with one another.  If the brain is not healthy neither is the gut and vice versa.  Taking a little time of every day to try meditation or another stress management technique can go a long way to helping relieve symptoms.  Also, take your time while eating.  Digesting starts with the cephalic phase of digestion.  This is the phase right before our food goes into our mouth.  Make sure you relax and try to take in the aroma and delight of your food before you begin to eat.  Take your time eating and enjoy every bite, and chew your food well.  There are practices called mindful eating that I highly recommend.

In conclusion, following a paleo diet can go a long way to helping heal depression.  With the proper nourishment we can heal systemic inflammation, regulate our hormones, and heal our digestive system.  We can take this even further by managing our stress as well as practicing mindful eating to fully heal both out gut and our brain.  It is just a few slight changes that can go a long way to improving quality of life.




Takase, Bonpei (2004).  Effect of chronic stress and sleep deprivation on both flow-mediated dilation in the brachial artery and the intracellular magnesium level in humans.  Clinical Cardiology.  Retrieved on March 15, 2012.

Xu, Haiyan (2003).  Chronic inflammation in fat plays a crucial role in the development of obesity-related insulin resistance.  The Journal of Clinical Investigation.  Retrieved on March 15, 2012.

Licinio, J (1999).  The role of inflammatory mediators in the biology of major depression: central nervous system cytokines modulate the biological substrate of depressive symptoms, regulate stress-responsive systems, and contribute to neurotoxicity and neuroprotection.  Molecular Psychiatry.  Retrieved on March 15, 2012.


Floriana, S (2010).  Overweight, obesity, and depression.  Archives of General Psychiatry.  Retrieved on March 15, 2012.


Bansal, V (2010).  Stimulating the central nervous system to prevent intestinal dysfunction after traumatic brain injury.  Retrieved on March 15, 2012.



Kevin is owner of Genetic Potential Nutrition. He is a holistic nutritionist, wellness coach, and strength coach. He works with people fighting illness, to competitive athletes. Check out his site at

Categories: Anti inflammatory diet, General


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  1. mark says

    “We also need to remove the foods that are causing the inflammation. For most of us this will be grains, legumes, and dairy.”

    What about the vegetable oils?

    Great article!

  2. Joshua Gilbreath says

    Hi Christopher!

    I enjoyed your article very much thank you for the post!

    I am curious about once factor that was not included in the section covering the supplements. I have read that L-tryptophan can be useful in the treatment of depression. Although I have read more over that the supplement 5-Hydroxytryptophan (HTP)is much more effective in positive mood enhancements than L-tryptophan taken alone.

    From my reading I have always seen L-tryptophan paired with HTP. This is because L-tryptophan makes HTP bioavailable by acting as a inhibitor.

    Has there been any Paleo research regarding this?

    Thanks I would love to hear your opinion on the subject.

    • Ann says

      Joshua – I found that I had little response in my neural function when taking 5HTP, but quite a lot of improvement when I switched to L-Tryptophan.

      I don’t have an explanation, but I have wondered if maybe my body just needed to make the conversion for it to work. In other words, somehow the process of conversion itself may have been the catalyst for the uptake of the 5HTP. That’s just a guess.

    • Josh Almanza says

      You NEVER want someone to supplement long term with only Serotonin precursors. The enzymes (AAAD, MAO) needed for synthesis and break down of Serotonin are the same for Dopamine. If you do not supply the precursor l-tyrosine you can end up depleting Dopamine and the person will start to go down hill again. The person will then think they need more 5HTP which will further deplete Dopamine. Other cofactors needed to make these conversions would be cysteine, calcium, folate, and selenium.

      Messing with the brain is not something someone should do without some help.

      • Ingrid says

        I am currently taking L Tryptophan and breastfeeding my one month old (just taking a small amount before bed). Should I be taking a typosine in the am as well? My doc doesn’t seem to know much about this stuff so I have been erring on the side of caution by not taking it.

  3. says

    Very well said Kevin! Nice connection of the vagus nerve between the gut and the brain (don’t forget about everything else the vagus nerve provides parasympathetic tone to). Another path from the gut (and other viscera) to the sympathetic nervous system is through the thoracic and lumbar splanchic nerves – inflammation of any area of the viscera will alter mechanical function of the nerves as well as nerve signalling through the sympathetic chain ganglia. When the sympathetic system is in overdrive our digestion becomes compromised as more of our function is on mounting an immune response. Removing the offending stimulus (inflammatory foods) is a great way to deal with altering the sympathetic nervous system activity.

  4. says

    Great summation of a complex topic, Kevin.
    Between your discussion on omega 3’s (and lack of them that most people get in their diet), pro-inflammatory foods, (among other factors), and the potential relationships they have with depression, you covered the bases very well.
    Thanks for a great post.

  5. says

    Great post!

    I’m prone to head injuries (yeah, I know) and have noticed they are usually followed, maybe a couple of weeks later, by depression, irritiability and overwhelming cravings for outright crap foods. Which, of course, makes me gain weight in my midsection, which doesn’t exactly help my mood, so then I’m craving…

  6. says

    Terrific article – lots and lots of helpful information here! I know I’ve not felt this good in a long time, and I attribute it pretty much entirely to my diet (and judicious supplementation), which has taken a 180 since my Hashimoto’s diagnosis, which led me first to wheat-free and then to Paleo/Primal. It’s also good to have the science to back me up when well-meaning family and friends insist that I’m not only depriving myself but my children as well. :-)

  7. says

    What!?! Depression is a medical illness and can only be treated with drugs from a pharmaceutical company. How dare you suggest anything otherwise! Some of us are just born with the depression gene.

    Sorry, just had to clear that out of my system. Thanks for your article!

    I can tell you firsthand that my mood significantly improved with dietary and lifestyle changes. A large part of that came when I realize I could do something about my depression that didn’t involve antidepressants.

    I hope more studies are carried to show this as it seems like a lot of the studies deal with correlations.

  8. says

    Great article! I’ve been eating Paleo for nearly three years and still have gut issues called Splenic Flexure Syndrome. It’s where the part of my descending colon is too long and it is bunched up under my diaphragm thus causing excruciating pain to the point where I pass out when gas gets trapped there. Thus, I have to try to avoid vegetables and or fruits that cause excess gas in the digestive tract. There are days that I don’t even notice it and then days that act up.

    I really found it very interested when you mentioned about the Vagus nerve connecting the brain and the digestive tract. I’m a massage therapist and knew about that connection but never put it in the terms that you did. When I read your article it was like a light bulb went off in my brain.

    I suffered a brain injury back in 2008 where I slipped down a set of stairs that were covered in ice. Since then I do not get the “hunger pains” that you would normally get if you are hungry, although I still can tell when I ate too much. I am also stuck with permanent vertigo and had to adjust my lifestyle accordingly. I’m sure that I was born with my splenic flexure being too long, but thinking back most of my digestive issues started after my head injury.

    Thank you for this light bulb moment!

    Dana M. Brandt
    Licensed Massage Therapist.

  9. TMS71 says

    I’m a big proponent of paleo dieting but I’ve found absolutely no effect on my mood from making the switch to meat and veg, omega-3 and vit D supplementing. I think for some, depression or low mood has more to do with personal history and genetics than diet.

  10. Rachel says

    TMS71 how long have you been eating Paleo? It’s a shame it doesn’t seem to be working for you. :(

    I had long resigned myself to been chronically sad, I just thought it was me, some past trauma or genetic quirk. It was quite the revelation to actually feel *normal*. Un-sad. Just in emotional balance, if you like. Definite success story here. Full disclosure- my current diet is a low carb high fat weightloss one. It’s free of processed foods, grains and legumes, but I do have full fat dairy. I supplement with Omega 3 and D3 too.

    Happier than I ever remember being. I hope it works out for you. x

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  12. Debbie B in MD says

    I have had my son eating gluten free for about a month or so. It has helped with depression greatly. He looked at me one night during dinner and had bread with his berbecue beef. I didn’t say a word. That is until the next morning when that darkness had returned in earnest. He was so mad that I brought up the gluten. By the end of the day things were better and he hasn’t had anymore gluten since. It is really miraculous as far as I am concerned. My daughter and I are gluten/grain free due to celiac. He has been tested but the results were negative. I He is frutrated by being gluten free, but at least he is smiling about it!!!! Of course, he heads to college in August. We shall see what he chooses.

  13. Peter says

    I am really interested in the link between diet and mental health. I am feeling significantly better after 6 weeks without sugar, grains, legumes and having just a little dairy.
    I am aiming to reduce my anti-depressants after i have laid down a good 3 months of paleo eating.
    It’s great to read this article and the encouraging experiences here.

  14. says

    Great article.

    “When undigested particles cross through our intestine into our bloodstream our body treats it like a foreign invader and sends an immune response. This response causes inflammation.”

    Its not only the food we eat, but how we eat it.

    One of the key reasons why digestive problems is becoming epidemic is because people have forgotten how to chew food properly. Get this part right and most digestive issues won’t be a problem.

    Fact is, you need to be chewing food until it becomes a paste like consistency, no lumps. Secondly, you should be mixing the food in with your saliva. Really mix it in. Your saliva contains enzymes that breakdown carbohydrates – the stomach doesn’t do this!

    This makes the job of your digestive system so much easier. You also put less strain on your body to produce more enzymes. These are vital for the absorption of nutrients and we lose these as we age!

    People underestimate this because it is so simple. They rather give up the responsibility of their own health to pharmaceutical companies and their pills. The answer to your own health is within you.

    Start by learning how to chew thoroughly and combining this with a Paleo diet can transform your health.

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