Ask Dr. Kelly: Does the food I eat REALLY make a difference in how I feel?


When I talk to my clients about improving their mental and physical health, we often discuss the role that food plays in their life. Many of my clients feel overwhelmed by the amount of nutrition and diet information available at every turn. Should they try keto? What if they lost weight on low-fat back in the 80s? Is the HGH diet safe? They don’t know what to believe.

I’ve seen the big impact that food has on mood in my life and in the lives of my clients. To help my clients understand the scientific evidence connecting food and mood, I put together this mini-literature review to show what the science has found. I hope that this helps to answer your questions about food and mood.

Nutritional psychiatry is a growing field that utilizes food and targeted supplements as part of an integrated treatment approach to prevent and treat mental health disorders. Countless research studies have shown that adequate nutrition is essential for proper brain functioning and mental health (e.g., Bodnar & Wisner, 2005; Jacka & Berk, 2007; Jacka et al., 2011; Murakami & Sasaki, 2010; Psaltopoulou et al., 2013; Rossler et al., 2016). Poor nutrition has been specifically tied to psychotic symptoms, social withdrawal, mania, anxiety, dementia, memory impairment, lack of motivation, poor energy, depression, and isolation (Bottomley & McKeown, 2008). A diet rich in fruits, vegetables, and fish has been associated with a lower risk of developing depression (e.g., Popa & Ladea, 2012; Sanhueza et al., 2013; Volker & Ng, 2006). In a primary care clinic population, patients with depression and anxiety were less likely to consume fruits and vegetables and consumed more junk food. These patients were deficient in folate, magnesium, and calcium (Forsyth, Williams, & Deane, 2012). Diets containing junk food (i.e., processed foods) may be a risk factor for depression (Sanhueza et al, 2013; Sarris, 2014). The associations between nutrition and mental health have been found to be independent of income, education, physical activity, smoking, body weight, and culture.

Physical and mental health are in constant interaction with one other, each influencing the other in a positive correlation. Researchers have identified the gut-brain axis which means that digestion directly affects the brain and vice versa. The health of the microbiome (gut) directly affects mental health. 95% of your serotonin is produced in your GI tract (APA, 2012). If the intestinal microbiome isn’t functioning well, serotonin production will be disturbed. Serotonin is a vital neurotransmitter that helps to regulate mood, appetite, and pain. In addition, the GI tract contains approximately 100 million neurons. The health and functionality of these neurons is influenced by the levels of healthy bacteria in the intestinal microbiome. These good bacteria protect against bad bacteria, reduce inflammation, aid in the absorption of nutrients from food, and activate neural pathways between the gut and the brain.

Water is the most common nutritional deficiency in the American population. Increased water consumption was associated with better mood (less tension, less depression, and more mental clarity) (Munoz et al., 2015). Dehydration affects serotonin, tryptophan and essential amino acids in the body and brain. Dehydration can cause an increase in heart rate, dizziness, and light-headedness (symptoms mistaken for anxiety/panic). Because of this, even mild dehydration can cause feelings of anxiety and irritability (Armstrong et al., 2012). High amounts of caffeine are associated with depression and sleep disturbances in a military population. A survey of 586 military personnel found that 53% of the sample regularly consumed energy drinks (Stephens et al., 2014).

gluten bread

Gluten sensitivity affects 5-25% of population (Catassi et al, 2013) and is directly tied with anxiety and depression (Brottveit et al, 2012). You don’t have to have celiac disease in order to be negatively affected by gluten. In addition, there is often cross-reactivity between gluten and other non-glutenous grains which means that those who have sensitivity to gluten can also be sensitive from grains like quinoa, rice, and oats.

Research has moved from examining the relationship between specific nutrients and mental health to a focus on overall diet quality and mental health. Chronic inflammation related to stress, poor sleep, smoking, and diet is related to mental health conditions such as depression, bipolar disorder, and schizophrenia (Berk et al., 2013; Fernandez et al., 2016). Diets higher in vegetables, fruits, and healthy fats, such as the Mediterranean diet, have been linked to lower levels of inflammation (Schwingshackl & Hoffmann, 2014; Watzl, et al., 2005). The same factors that contribute to inflammation can also cause oxidative stress in the body. Oxidative stress is elevated in patients with depression.


Omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fish and commercial fish oils have antidepressant effects (Sarris, 2014) and anti-anxiety effects (Dean, 2011). Consumption of trans fats has been linked to depression (Sanchez-Villegas et al., 2011).

Blood sugar regulation is vital to most systems in the body. Anxiety, phobias, nervousness, irritability, depression, violent outbursts, obsessive compulsive behavior, forgetfulness, anti-social behaviors have all been associated with hypoglycemia (Brogan, 2016). Depression is related to inflammation, and blood sugar dysregulation increases levels of inflammation in the body (Berk et al., 2013). High blood sugar is one of the greatest risk factors for depression (Brogan, 2016). Women with diabetes are 30 percent more likely to develop depression than women without diabetes (Kim et al., 2015).

Vitamins and minerals cannot be manufactured in our body; therefore, we must obtain them from our food and supplements. Mitochondrial dysfunction has been associated with depression, bipolar, and schizophrenia. Mitochondrial function can be improved with dietary supplements including resveratrol, coenzyme Q10 and alpha-lipoic acid. Foods and supplements containing amino acids tryptophan and 5HTP help in the treatment of depression (Harbottle & Schonfelder, 2008). Depression has been linked to deficient levels of folate and vitamin B12 – both important for dopamine synthesis (Bottomley & McKeown, 2008; Harbottle & Schonfelder; 2008; Meyer et al., 2013; Sanhueza et al., 2013). Chromium (a mineral found in gluten-free grains, mushrooms, liver, broccoli, and potatoes) improved mood in people with atypical depression (Davidson et al., 2003). Low levels of zinc are associated with depression (Harbottle & Schonfelder, 2008; Sarris, 2014). Magnesium is associated with lower depression (Yary, 2016). Low magnesium was found to be even more of a contributor to depression in young adults (Tarlelton et al., 2015). In addition, a meta-analysis of 11 studies showed that people with the lowest intake of magnesium were 81% more likely to be depressed than those with the highest intake. People with the lowest Vitamin D levels are 10 times more likely to be depressed (Vitamin D Council, 2016). Multivitamins (mainly formulations high in B vitamins) may provide an acute mood enhancement and decreased perceived stress (Sarris, 2014).

There’s the science! I hope that this has helped you to see the solid, scientific backing linking nutrition to mood. Now that you have the knowledge, use it to your advantage. You make changes with each bite, with each meal, each day. In my best Julia Child voice, "Bon appetit!”


APA (2012). That gut feeling, 43, 50.

Armstrong et al. (2012). Mild dehydration affects mood in healthy young women. The Journal of Nutrition, 142, 382-388.

Berk, M., Williams, L.J., Jacka, F.N. et al. (2013). So depression is an inflammatory disease, but where does the inflammation come from? BMC Medicine, 11, 200.

Bodnar, L.M. & Wisner, K.L (2005). Nutrition and depression: Implications for improving mental health among childbearing-aged women. Biological Psychiatry, 58, 679-685.

Bottomley, A. & McKeown, J. (2008). Promoting nutrition for people with mental health problems. Nursing Standard, 22(49), 48-55.

Brogan, K. (2015). A mind of your own: The truth about depression and how women can health their bodies to reclaim their lives. New York: Harper Wave.

Brottveit et al. (2012). Absence of somatization in non-coeliac gluten sensitivity. Scandanavian Journal of Gastroenterology, 47, 770-777.

Catassi et al. (2007). A prospective, double-blind, placebo-controlled trial to establish a safe gluten threshold for patients with celiac disease. American Journal of Clinical Nutrition, 85, 160-166.

Davidson, J.R.T., Abraham, K., Connor, K.M., & McLeod, M.N. (2003). Effectiveness of chromium in atypical depression: a placebo-controlled trial. Biological Psychiatry, 53, 261-264.

Forsyth, A.K., Williams, P.G., & Deane, F.P. (2017). Nutrition status of primary care patients with depression and anxiety. Australian Journal of Primary Health, 18, 172.

Harbottle, L. & Schonfelder, N. (2008). Nutrition and depression: A review of the evidence. Journal of Mental Health, 17(6), 576-587.

Jacka, F. & Berk, M. (2007). Food for thought. Acta Neuropsychiatry,19, 321–323.

Kim, W.K., Shin, D., & Song, W.O. (2015). Depression and its comorbid conditions more serious in women than in men in the United States. Journal of Women’s Health, 24, 978-985.

Munoz et al. (2015). Habitual total water intake and dimensions of mood in healthy young women. Appetite, 92, 81-86.

Marriott, B.P., Yu, K., Majchrzak-Hong, S., Johnson, J. & Hibbeln, J.R. (2014). Understanding diet and modeling changes in the omega-3 and omega-6 fatty acid composition of US garrison foods for active duty personnel. Military Medicine, 179, 168-175.

Meyer, B. J., Kolanu, N., Griffiths, D. A., Grounds, B., Howe, P. C., & Kreis, I. A. (2013). Food groups and fatty acids associated with self-reported depression: An analysis from the Australian National Nutrition and Health Surveys. Nutrition, 29, 1042-1047.

Murakami, K. & Sasaki, S. (2010). Dietary intake and depressive symptoms: a systematic review of observational studies. Molecular Nutrition & Food Research, 54, 71–88.

Psaltopoulou, T., Sergentanis, T.B., Panagiotakos, D.B., Sergentanis, I.N., Kosti, R., Scarmeas, N. (2013). Mediterranean diet, stroke, cognitive impairment, and depression: A meta-analysis, Annals of Neurology, 74, 580-591.

Popa , T.A. & Ladea, M. (2012). Nutrition and depression at the forefront of progress. Journal of Medical Life, 5, 414-419.

Rossler, W. (2016). Nutrition, sleep, physical exercise: Impact on Mental Health. European Congress of Psychiatry, 33, S12.

Sanchez-Villegas, A. et al. (2011). Dietary fat intake and the risk of depression: The SUN project/ PLOS One.

Sanhueza, C., Ryan, L., & Foxcroft, D. R. (2013). Diet and the risk of unipolar depression in adults: systematic review of cohort studies. Journal Of Human Nutrition & Dietetics, 26, 56-70.

Sarris, J. (2014). Nutrients and herbal supplements for mental health. Australian Prescriber, 37, 90-93.

Schwingshackl, L. & Hoffman, G. (2014). Adherence to Mediterranean diet and risk of cancer: a systematic review and meta-analysis of observational studies. International Journal of Cancer, 135(8), 1884-1897.

Stephens, M.B., Attipoe, S. Jones, D., Ledford, C.J., & Deuster, P.A. (2014). Energy drink and energy shot use in the military. Nutrition Reviews, 7272-7277.

Tarleton, E.K. et al. (2015). Magnesium intake in depression in adults. Journal of the American Board of Family Medicine, 28, 249-56

Volker, D. & Ng, J. (2006). Depression: Does nutrition have an adjunctive treatment role? Nutrition & Dietetics, 63, 213-226.

Yary, T. et al. (2016). Dietary magnesium intake and the incidence of depression: A 20-year follow-up study. Journal of Affective Disorders, 193, 94-98.