The Food Mood Connection: Examining the Link Between Diet & Depression
Updated: Jul 1, 2019
Does what you eat, impact how you feel?
Science says- YES. Several studies have found that people who regularly consume a poor-quality diet — one high in alcohol, caffeine, processed meats, sugar, fried food, refined grains and high-fat dairy foods, were more likely to report symptoms of depression. On the flipside, there is mounting evidence that one way to help ALLEVIATE symptoms of depression is to consume a diet rich in fruits, vegetables, and omega-3's.
It's estimated that over the next decade, depression will become the most common health problem in the world, with women being affected almost twice as much as men. As a coach who works a great deal with women, I have done a lot of reading and research on the role that nutrition can play in mitigating the symptoms of mental illness, including depression.
The purpose of this post, is to discuss some of the ways in which your food choices affect depression (both positively and negatively) and to lay out some key nutrients you may want to consider consuming more of if you struggle with depression.
**Please note, if you are struggling with depression it is imperative to seek assistance from a health practitioner or qualified counselor/therapist who can help you. Nutrition alone will NOT "treat" depression. The information in this post is not meant to "treat" your illness, only to educate you on how your food choices impact how you feel.
Sugar, Alcohol & Caffeine
It's important to keep in mind that depression involves the whole body and there are many nutritional factors that can trigger, or compound depression. Stimulants like sugar, alcohol, and caffeine can create problems within the body that worsen symptoms of depression. For example too much sugar can create blood sugar instability. Unstable blood sugar means you will have more dramatic rises and falls in the amount of glucose in your blood, resulting in symptoms like fatigue, irritability, dizziness, insomnia, poor concentration and forgetfulness, depression and crying spells, and digestive disturbances. Since the brain depends on an even supply of glucose it is no surprise to find that sugar has been implicated in anxiety, depression and fatigue.
In fact, there was a study of 3,456 participants, published in British Journal of Psychiatry that found those who had a diet which contained a lot of processed foods had a 58% increased risk for depression, whereas those whose diet could be described as containing more whole foods had a 26% reduced risk for depression.
Caffeine, when consumed in excess can deplete the body of vitamin B6, which is a crucial nutrient required for the production of serotonin, a neurotransmitter that helps regulate mood and social behavior, appetite and digestion, sleep, memory, and sexual desire and function. Low serotonin has been linked over and over again to depression. Furthermore, blood sugar imbalances also prevents the absorption of tryptophan in the intestine, which impedes the production of dopamine and serotonin.
As for alcohol, there have been links found between the neurophysiological and metabolic changes brought about by excessive drinking and symptoms of depression. Initially, when you drink it acts like a stimulant, making you feel better. This happens thanks to an increase in neurotransmitters such as dopamine, which trigger the brain’s “reward center", causing you to feel good. However, as blood alcohol content decreases, more of its suppressive qualities start to take hold. Alcohol dampens excitatory neurotransmitters that regulate energy levels such as glutamate. Alcohol also reaches the primary inhibitory neurotransmitter GABA, which slows down the system, resulting in the “downer” feeling that can follow drinking.
Allergies & Food Sensitivities
Allergies and food sensitivities can also play a role in depression. Food allergies promote inflammation, alter hormones and brain chemicals and can lead to feelings of depression. A study done by food allergy expert Dr William Philpott linked many common allergens (like wheat and milk/dairy) to symptoms of depression. It's really important, if you do struggle with mental illness or depression to avoid any foods that you are allergic to and if you DO chose to consume foods you are sensitive to, to do so in moderate amounts only.
Another factor that can lead to depression is nutrient deficiency. More than 75% of Americans are deficient in one or more KEY nutrients, which is a given when you consider how processed the standard American diet has become. Diet high in refined sugar, processed foods, pesticides, preservatives and additives have all been linked to depression. But when it comes to managing depression it's not just about NOT eating certain foods, it's about ensuring you eat enough of the right ones. Optimal mental health hinges on a richly varietized, nutrient dense diet.
Serotonin and Depression
Serotonin, your "feel good" neurotransmitter is produced in the brain (20%) and in the gut (80%) and helps regulate mood, sleep and appetite. Depression is largely associated with a deficiency in serotonin production. This is why what you eat is so important. As I mentioned 80% of your serotonin is produced in your GUT. This is why individuals with digestive disorders (such as IBS and IBD) are prone to depression or feelings of sadness. Imbalances in the digestive system are linked to mood.
It's important to know that antidepressants themselves do not manufacture serotonin. I'm not saying I'm against the use of them, I am saying that they only maintain what is already existent through the foods you eat. Only by changing your diet, and supplementing with something like 5HTP or Tryptophan (precursors to serotonin) can you actually INCREASE your body's production of serotonin.
Key Nutrients that Alleviate and Prevent Depression
1- OMEGA 3 FATTY ACIDS
60% of your brain is made up of fat. We need fat for our brains to function optimally. But the TYPE of fat is crucial. Just like trans fats are bad for your heart, the same is true of your mind. Therefore, it's really important to consume most of your fats from omega 3 sources like sardines, algae, nuts and seeds like flax, chia and sacha inchi, walnuts, hemp seeds, salmon, anchovies, and mackerel.
The optimal ratio of Omega 3 to Omega 6 fats is 2 parts Omega 6 to 1 part Omega 3 but most Americans get something like 20:1. This skewed ratio causes inflammation, allergies, cognitive issues and a whole host of other problems including being a contributory factor to depression.
A Harvard study indicated that Omega 3 fatty acids are an effective alternative to drug therapies in treating depression and that when complimented with traditional drug therapies can enhance their efficacy. A meta-analysis of 10 studies found that Omega 3's had significant effects in treating depression, bipolar depression and ADHD.
Omega 3's (particularly DHA) stabilize the brains cell membranes allowing the communication across the synapses to be more effective. Omega 3's also help increase your brain's neuronal connections and the number of feel-good serotonin receptor sites.
2- B VITAMINS
B vitamins are CRUCIAL for depression. B1, for example (which is thiamine) fuels the brain with glucose for energy and is required for nerve stimulation.
A deficiency in B3 (which is niacin) is linked to depression and anxiety. In fact B3 is used to treat schizophrenia.
And Vitamin B6 is required for the production of serotonin and other neurotransmitters and is essential in keeping your mood stable.
B12 is also required to produce serotonin and for proper nervous system function. There is a strong link between depression and B12 deficiency.
Foods rich in B1 (thiamine) are whole grains, lean meats like fish, poultry, and eggs, and nuts and seeds.
Foods rich in B3 are chicken breast, salmon, tuna, turkey, avocado, brown rice, mushrooms and potatoes.
Foods rich in B6 are salmon, tuna, eggs, carrots, spinach, sweet potatoes, avocado, bananas and chickpeas.
And foods rich in B12 are clams, sardines, beef, tuna, trout, salmon and eggs.
Folate deficiency has been linked to depression since the 1960's. It's another nutrient required for the production of serotonin. In addition to anemia and other health problems, folate deficiency can also lead to the development of major depressive disorder (MDD). Similarly, having either a folate deficiency or problem with malabsorption is associated with poor response to antidepressant medications. Good dietary sources of folate include broccoli, spinach, lentils, asparagus and bananas. But this is one instance where SUPPLEMENTING may help, particularly with L-Methylfolate, which is the only form of folic acid that crosses the blood-brain barrier and plays a role in neurotransmitter synthesis. It indirectly facilitates the synthesis of serotonin,dopamine and norepinephrine. L-methylfolate has been shown in several studies to enhance the efficacy of selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), two commonly prescribed classes of antidepressants.
Putting It All Together
Nutrition cannot in and of itself TREAT mental health issues, but what you chose to eat can be a powerful tool in helping you manage your anxiety or depression. If you struggle with mental health issues or other mood disorders, simply strive to consume a diet that is rich in:
- Antioxidants (mainly lots of nutrient rich fruits and vegetables)
- Low sugar/low processed carbs (fruits, starchy tubers, whole grains)
- Protein (turkey, tuna, chicken, salmon ,eggs etc)
- Omega 3's (nuts, seeds, avocado, olive, olive oil, fatty fish, dark leafy greens)
- B vitamins and folate (see lists above)
Be sure to also LIMIT your amounts or consumption of processed foods, refined sugars, alcohol and caffeine.