How nutrition affects depression and mental health
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. www.pubmed.gov. 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 www.geneticpotentialnutrition.com.
Christopher Williams (a.k.a. Squatchy) is a paleo aficionado, educator, personal trainer, wellness coach, and hobbyist chef. He also works as part of the Robb Wolf team.