Food and Mood

Food also impacts mood, which in turn impacts behaviour.

Dog Knows : page 9, Chapter 1, Essay on Canine Nutrition

The other day my lunch consisted of tasty fresh veggies and rice and it made me feel so good, spring-in-my-step-and-a-boost-in-my-brain kind of good. This got me re-thinking about how what we eat can impact how we feel. And more importantly it re-confirmed to me that food is an important tool in our toolbox, when looking at the behaviour of dogs. But the connection between food – mood – behaviour is more layered than we might think.

Mixed feelings towards food

Food goes beyond provisioning of energy and nutrients necessary for physical health. Studies on both humans and animals show, that what we eat can impact how we feel and behave (Bosch, 2009). Studies on humans show that a mere mention or a picture of food can elicit positive or negative emotions (Cardello et al., 2012; Drobes et al., 2001; Hay and Katsikitis, 2014). People with an eating disorder had increased negative emotional response like fear and disgust and reduced positive response like happiness when looking at pictures of food (Hay and Katsikitis, 2014). Another study looked at how human participants who have been food deprived for 6 and 24 hours reacted to food pictures and cues, compared to non-food deprived participants. Food deprived participants had a greater startle response while viewing appetising pictures of food, they reported greater arousal, interest, and lack of control while viewing food cues, and showed an elevated heart rate response. On the other hand they rated food pictures as pleasant, and as significantly more interesting than did the non-deprived. These mixed results were explained by the researchers by the fact that participants were only looking at the pictures of the food and didn't get to eat it at any point. So the positive emotions were followed by the frustration of not being able to eat the food (Drobes et al., 2001). I couldn't find a similar studies done on dogs. But we should think about how the mere presence of food or an indication of its presence can impact the dog's behaviour. We should put greater consideration especially to situations where food is used as a training tool. Is it really as positive to the dogs as we have been led to believe? More attention should also be paid to the dogs who don't have the best relationship with food – how does the presence of it influence them and their behaviour? What about dogs who don't get to eat when they are hungry, but are rather fed on human's schedule?

Role of cravings in stress-response mitigation

It's not just the food that impacts how we feel, but how we feel also impacts what and how we eat. Many of us have experienced cravings for so-called comfort foods. These are usually foods high in fat, sugar and/or energy density in some form. These cravings usually appear when we feel low or are facing stressful times. We are often guilted for this, but it is a common human (Firth et al., 2020) and apparently also animal experience (McMillan, 2013). Being stressed can result in both overeating or eating less than usual (AlAmmar et al., 2020). Studies in rats showed that this depends on the severity of the stressor – severe or uncontrollable stress usually reduced food intake and moderate or low stress increased it. For example social isolation and deprivation of play increased food intake in rats. Similar to humans, emotional distress in laboratory settings resulted in an increased intake of comfort foods in rodents, even when they were not hungry or had no homeostatic need for calories. Because of the way these comfort foods are used to alleviate unpleasant emotions and stress some researchers started to look at them as a way of self-medication. The consumption of highly palatable foods stimulates hypothalamic release of opioids, which elevate mood and satisfaction. The secretion of glucocorticoids, which happens as a response to stress, is another avenue that's been studied in relation to stress-induced and emotional eating. Elevated levels of these chemicals have been shown to increase appetite (McMillan, 2013). This research provides us with an insight into the purpose of cravings. It's likely that stress-induced activation of the emotional brain is reduced in laboratory animals and people if they have access to palatable foods and plentiful energy stores. (Dallman et al. in McMillan, 2013). A few studies done on dogs add to our understanding of this topic. The first two (Hennessy et al. in McMillan, 2013) showed that certain foods can reduce the intensity of stress response. What's even more interesting and important is, that this stress-mitigating effect was enhanced when combined with positive human contact. The third study (Kato et al. in McMillan, 2013) found that a specific diet seemed to improve dogs' ability to cope with stress and reduce anxiety-related behaviours. As humans, we have the option to choose the preferred type of comfort food anytime we need. But this choice is often not available to our dogs. But an emotional eater, be it human or animal, will overeat whatever food is available in the absence of the preferred one. We have considerable evidence of this (McMillan, 2013).

Nutrition for stress-response mitigation

The impact of nutrition on mood is a relatively new field of research (Lee et al., 2023). But the findings thus far show that high-quality diets that are rich in nutritionally dense ingredients and low in refined, sugary, ultra-processed foods can beneficially influence our mood (Lee et al., 2023). Furthermore, a nutritious, well balanced diet can also have stress reducing benefits "that improve brain functioning, shore up immune function, lower blood pressure, improve the circulation, and reduce toxins from the body" (Singh, 2016). For example nutrients like complex carbohydrates, proteins like tryptophan, phenylalanine, tyrosine and theanine, Vitamins B and C, minerals like Magnesium, and Selenium play a very important role in reducing the levels of cortisol, adrenaline and other stress chemicals that are associated with stress response (Singh, 2016).

The mechanism

While we know that food impacts mood and consequently behaviour, we don't yet have clarity on how this happens. If we consider how complex the mechanisms behind this connection are, there probably isn't a simple explanation. The following are some possibilities:

• Diets with high glycemic index can impact mood negatively through repeated and rapid increases and decreases in blood glucose. High glycemic load and its compensatory responses could lower plasma glucose to the point that hormones like cortisol, adrenaline, growth hormone, and glucagon are triggered. This can cause changes in anxiety, irritability, and hunger. Furthermore mood disorders have been connected to repeatedly low blood sugar levels. Also the inflammatory response to foods with high glycemic index can negatively impact mood (Firth et al., 2020).

• Mental wellbeing can be connected to the gut microbiome (Firth et al., 2020). A complex bidirectional connection between gut and brain is "understood  to  act  as  pathways  for  potential  effects  on  mood,  cognitive  and  emotional  processes" (Zagon in Leeds et al., 2020). "Gut microbiota can metabolise food from the host into a variety of metabolites that then may enter host circulation and influence the central nervous system, while the brain may affect the gut microbiota by influencing gut motility, secretion, and permeability" (Ephraim et al., 2022). A majority of serotonin, whose function doesn't include just mood, but also cognition, reward, learning, memory, is also produced in the gut (Sandua 2023). Genetic factors, exposure to antibiotics and diet can influence the diversity, abundance and and functionality of the gut microbiome (Firth et al., 2020).

• To function properly, brain relies on a delicate balance of neurotransmitters. Their production and availability is strongly influenced by the foods we consume (Sandua, 2023). For example deficiency of nutrients such as vitamin B complex, vitamin C, vitamin D, zinc, omega-3 fatty acids, and antioxidants can drastically affect the mood, because they regulate and balance the neurotransmitters responsible for adjusting mood. (AlAmmar et al., 2020).

  
  

From complex carbohydrates to omega-3 fatty acids, there are multiple foods or nutrients that can have beneficial influence on the individual's mood. However when we try to find research that has been done on dogs, we run into 2 main problems – research on dogs and how food can impact their mood is limited and the findings can often be contradictory. But based on the overwhelming evidence that has been accumulated by studies on different mammals, we shouldn't disregard the promising results on connection between food and mood. What we feed our dogs should definitely be on our mind, since all current research shows that a nutritious, well-balanced diet has a positive impact on the individual's well-being. But we have to keep in mind that diet is just one piece of the puzzle. How an individual feels or behaves is influenced by multiple factors beyond nutrition, such as genetics, environment, psychological factors like stress and trauma and individual's physiology and metabolism can also play their part in response to different dietary intakes (Sandua, 2023).

Resources

AlAmmar, Welayah & Albeesh, Fatima & Khattab, Rabie. (2020). Food and Mood: the Corresponsive Effect. Current Nutrition Reports. 9. 10.1007/s13668-020-00331-3.

Armand V. Cardello, Herbert L. Meiselman, Howard G. Schutz, Caelli Craig, Zachary Given, Larry L. Lesher, Steven Eicher, Measuring emotional responses to foods and food names using questionnaires, Food Quality and Preference, Volume 24, Issue 2, 2012, Pages 243-250, ISSN 0950-3293, https://doi.org/10.1016/j.foodqual.2011.12.002.

Bosch, G. (2009) Can diet composition affect behaviour in dogs? Food for thought. Ph.D. thesis, Wageningen University, the Netherlands. With references – with summaries in English and Dutch. ISBN 978-90-8585-356-5

David J Drobes, Erica J Miller, Charles H Hillman, Margaret M Bradley, Bruce N Cuthbert, Peter J Lang, Food deprivation and emotional reactions to food cues: implications for eating disorders, Biological Psychology, Volume 57, Issues 1–3, 2001, Pages 153-177, ISSN 0301-0511, https://doi.org/10.1016/S0301-0511(01)00093-X.

Ephraim, Eden & Brockman, Jeffrey & Jewell, Dennis. (2022). A Diet Supplemented with Polyphenols, Prebiotics and Omega-3 Fatty Acids Modulates the Intestinal Microbiota and Improves the Profile of Metabolites Linked with Anxiety in Dogs. Biology. 11. 976. 10.3390/biology11070976.

Firth J, Gangwisch JE, Borisini A, Wootton RE, Mayer EA. Food and mood: how do diet and nutrition affect mental wellbeing? BMJ. 2020 Jun 29;369:m2382. doi: 10.1136/bmj.m2382. Erratum in: BMJ. 2020 Nov 9;371:m4269. doi: 10.1136/bmj.m4269. PMID: 32601102; PMCID: PMC7322666.

Hay P, Katsikitis M. Emotional responses to images of food in adults with an eating disorder: a comparative study with healthy and clinical controls. Eat Behav. 2014 Aug;15(3):371-4. doi: 10.1016/j.eatbeh.2014.04.016. Epub 2014 May 10. PMID: 25064283.

Lee MF, Angus D, Walsh H, Sargeant S. "Maybe it's Not Just the Food?" A Food and Mood Focus Group Study. Int J Environ Res Public Health. 2023 Jan 21;20(3):2011. doi: 10.3390/ijerph20032011. PMID: 36767376; PMCID: PMC9915006.

Leeds, Joanna & Keith, Regina & Woloshynowych, Maria. (2020). Food and Mood: Exploring the determinants of food choices and the effects of food consumption on mood among women in Inner London. World Nutrition. Vol 11. 68-96. 10.26596/wn.202011168-96.

Mcmillan, Franklin. (2013). Stress-induced and emotional eating in animals: A review of the experimental evidence and implications for companion animal obesity. Journal of Veterinary Behavior: Clinical Applications and Research. 8. 376–385. 10.1016/j.jveb.2012.11.001.

Singh, Karuna. (2016). Nutrient and Stress Management. Journal of Nutrition & Food Sciences. 6. 10.4172/2155-9600.1000528.

Sandua, David. (2023). The Happiness Diet: Food and Its Influence on Mood. Independently published.

About the author

Eva Pirnat Click to know more

Eva is a BACBED graduate from Slovenia. She is passionate about sharing her knowledge with dog guardians who want to deepen and strengthen the relationship with their dogs. She knows first hand how difficult it can be living and trying to built a relationship with a traumatized and reactive dog. Her adopted, ex-hunting dog was the first to experience the BHARCS way Eva was learning through the BACBED diploma. She advocates for a compassionate, dog-centered approach as she truly believes that dogs are the experts on dogs and they can give us all the knowledge we need if we are ready to listen and observe. She has a soft spot for the "difficult", misunderstood dogs and it's her mission to equipt the carers with necessary knowledge to look past the labels.