Tag: dietary intake

Are You What Your Gut-Microbiome Wants You To Eat?

Posted on by CNP Staff

We’ve all heard the saying “you are what you eat,” but new microbiome research is shedding light on this old adage, with a more modern-day update being “you are what your gut-microbiome wants you to eat.” Let’s look at why this is the case. 

First, we know that our food choices significantly impact our physical and mental health. As far back as the 1800s and 1900s, scientists hypothesized an apparent correlation between our food intake and the subsequent effects on appetite, body image, and brain function (Tzameli, 2013). Though biomedical research has already established the endocrine responses that regulate hunger and satiety in the gut-brain axis signaling, little attention has been paid to the mechanisms that influence an individual’s choice of food and nutrition.

 

Microorganisms that live in our gut may influence what we eat!

 

A growing body of evidence indicates that our gut microbiome may be one of the factors influencing our food choices. From Nutritional Psychology conceptualization, we are beginning to understand that eating behavior and food preferences are dependent on many aspects of the diet-mental health relationship (DMHR), such as our psychosocial environment, interoceptive experiences, sensory perception, cognitive processes, and psychological state. However, emerging research in the Microbiota-Gut Brain Axis (MGBA) suggests that the microorganisms residing within our gut may also influence what we eat. Therefore, the classic expression, “you are what you eat,” may soon be reframed as “you are [also] what your microbiome wants you to eat.”  

 

A feedback loop between our gut microbiome, brain, and food choices.

 

To explore the influence of the gut microbiome on diet selection behavior, Trevelline and Kohl conducted an experiment in 2022 to study the influence of gut microbes on the diet selection behaviors in mice. 

 

The classic expression, “you are what you eat,” may soon be reframed as “you are [also] what your microbiome wants you to eat.”  

 

To achieve this, intestinal microbiota from three “donor” mouse species, each with distinct foraging behavior, were transplanted into germ-free “host” mice to colonize their intestinal tracts.  

Following that, the donor germ-free mice were randomly divided into three treatment groups, each based on the donor species:

  • Carnivore (i.e., predatory-based)
  • Herbivore (i.e., plant-based)
  • Omnivore (i.e., inclusive-based)

The mice were then given a choice between a low protein-carbohydrate (LPC) diet and a high protein-carbohydrate (HPC) diet, and their diet preferences were tracked for 11 days. To assess the impact of the donor microbiome on host diet selection behavior, the researchers compared the microbiomes of mice in three treatment groups: predatory (carnivores), inclusive (omnivores), and plant-based (herbivores) (Fig 1A).

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Figure 1A. Experimental design to assess host diet selection behaviors across different microbiomes. From Trevelline and Kohl, Proceedings of the National Academy of Sciences, 2022.

 

Strikingly, the authors discovered that when mice have given a choice of selected diets varying in macronutrient composition, each microbiome had a distinct effect on food choice behavior (Fig 1B). For example, host mice that received microbiota from herbivorous donors voluntarily ate fewer carbohydrates, evidenced by a higher protein:carbohydrate (P:C) ratio diet intake. On the other hand, omnivore and carnivore treatment groups chose a lower P:C ratio diet intake.

Given that these host mice had no microbiome prior to transplantation, the change in diet selection behavior is evidence of the microbiome influencing food choice (Alcock, 2014). Moreover, through an in-depth analysis of blood and fecal samples, the authors discovered the microbial release of essential amino acids (EAAs) from the gut microbiome of host mice, including tryptophan. Tryptophan is an important food choice driver because it is a precursor to serotonin, the happiness hormone that has been shown to regulate feeding behavior, metabolism, and diet selection (Harrold, 2012; Cryan, 2019; Kaur & Bose, 2019; Yabut, 2019; Gao, 2020; Trevelline & Kohl, 2022). Together, these findings show that the gut microbiome can influence host diet selection behavior by mediating the availability of essential amino acids (EAAs).

 

The gut microbiome can influence host diet selection behavior by mediating the availability of Essential Amino Acids (EAAs).

 

Finally, the findings discussed here are of great interest to Nutritional Psychology. Together with other studies, they show us that what we eat can be influenced by our microbiota’s ‘bottom up’ connection. And in turn, this connection affects our food choices and dietary intake, which cycles back to influence our microbiota.

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Figure 1B. Gut microbiome of donor mice altering feeding choices in host mice.

 

This reciprocal feedback loop is partly caused by the gut microbiome’s ability to synthesize essential amino acids (EAAs), which interact with the gut-brain axis and, in turn, influence dietary habits. Depending on the food choices made, the body’s response to those choices can be beneficial or detrimental. Therefore, increasing awareness of the factors influencing dietary intake may help us to impact both our physical and mental health positively.

 

References 

Alcock, J., Maley, C. C., & Aktipis, C. A. (2014). Is eating behavior manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms. BioEssays : news and reviews in molecular, cellular and developmental biology, 36(10), 940–949. https://doi.org/10.1002/bies.201400071 

Cryan, J. F., O’Riordan, K. J., Cowan, C., Sandhu, K. V., Bastiaanssen, T., Boehme, M., Codagnone, M. G., Cussotto, S., Fulling, C., Golubeva, A. V., Guzzetta, K. E., Jaggar, M., Long-Smith, C. M., Lyte, J. M., Martin, J. A., Molinero-Perez, A., Moloney, G., Morelli, E., Morillas, E., O’Connor, R., … Dinan, T. G. (2019). The microbiota-gut-brain axis. Physiological reviews, 99(4), 1877–2013. https://doi.org/10.1152/physrev.00018.2018 

Gao, K., Mu, C. L., Farzi, A., & Zhu, W. Y. (2020). Tryptophan metabolism: A link between the gut microbiota and brain. Advances in nutrition (Bethesda, Md.), 11(3), 709–723. https://doi.org/10.1093/advances/nmz127 

Harrold, J. A., Dovey, T. M., Blundell, J. E., & Halford, J. C. (2012). CNS regulation of appetite. Neuropharmacology, 63(1), 3–17. https://doi.org/10.1016/j.neuropharm.2012.01.007 

Kaur, H., Bose, C., & Mande, S. S. (2019). Tryptophan metabolism by gut microbiome and gut-brain-axis: An in silico analysis. Frontiers in Neuroscience, 13, 1365. https://doi.org/10.3389/fnins.2019.01365 

Trevelline, B. K., & Kohl, K. D. (2022). The gut microbiome influences host diet selection behavior. Proceedings of the National Academy of Sciences of the United States of America, 119(17), e2117537119. https://doi.org/10.1073/pnas.2117537119 

Tzameli I. (2013). Appetite and the brain: You are what you eat. Trends in Endocrinology and Metabolism: TEM, 24(2), 59–60. https://doi.org/10.1016/j.tem.2012.12.001 

Yabut, J. M., Crane, J. D., Green, A. E., Keating, D. J., Khan, W. I., & Steinberg, G. R. (2019). Emerging roles for serotonin in regulating metabolism: New implications for an ancient molecule. Endocrine reviews, 40(4), 1092–1107. https://doi.org/10.1210/er.2018-00283 

 

Does Perception of Body Weight During Adolescence Influence Dietary Intake?

Posted on by CNP Staff

Adolescents seem to be vulnerable to feeling dissatisfied with their weight and body shape (Clay et al., 2005). Their perception of their body image (i.e., their Diet-Perceptual Relationship) may be shaped by the opinions of their family and friends; what they see in television, movies, and magazines (Silva et al. 2021); and all forms of social media (i.e., their Diet-Psychosocial Relationship). At the same time, it’s crucial that adolescents develop a healthy body image since it can affect mental and physical health — especially if their perception differs from their actual weight and nutritional status.

 

There is emerging evidence of a connection between body perception and diet.

 

There is emerging evidence of a connection between body perception and diet. For instance, researchers have found that Greek adolescents were less likely to be overweight or obese if they accurately guessed their weight status and adhered closely to a “healthy foods” dietary pattern, compared to those who followed a diet consisting of unhealthy/high-fat or starchy, protein-rich foods (Kanellopoulou et al., 2021). Unsurprisingly, many research papers have suggested that certain dietary patterns (typically those labeled “healthy” and/or “traditional”) can protect people against being obese/overweight. 

Based on such findings, it’s purported that an accurate perception of one’s weight in conjunction with healthy dietary intake habits may play into obesity prevention strategies. Let’s take a closer look at a cross-sectional research study on this topic by Silva et al. (2021), which examined the relationship between weight misperception and dietary patterns among Brazilian adolescents. 

 

Accurate weight perception in conjunction with healthy dietary habits could help prevent obesity.

 

For this study, the researchers recruited Brazilian teenagers from urban and rural schools in cities with populations larger than 100,000 across Brazil. Only adolescents deemed to be of normal weight were included. Their height and weight were measured and used to calculate their body mass index (BMI), and in turn their nutritional status (BMI relative to age). 

Next, the researchers assessed the participants’ perception of their own weight. The students were asked questions such as “Are you satisfied with your weight?” and “In your opinion, at what level is your current weight?” If they indicated feeling “not satisfied” and “below the ideal” regarding their weight, they were placed in the underestimation group. Those who answered “not satisfied” and “above the ideal” or “far above the ideal” were assigned to the overestimation group. The participants in these groups were considered to experience weight misperception. To understand the subject further, their dietary intake patterns were examined using 24-hour dietary recalls.

       

34% of the study sample (over 52,000 normal-weight adolescents) misjudged their own weight.

 

The data showed that 34% of the 52,038 normal-weight adolescents in Brazil misjudged their own weight, with higher incidence rates reported in girls (42.6%) than boys (25.6%). In addition, a higher proportion of girls perceived themselves as heavier than they actually were (weight overestimation) compared to boys (25.7% vs. 8.2%). The authors theorized that this higher prevalence of weight overestimation in girls could be attributed to gendered social constructs — in this case, perhaps the expectation of achieving a “perfect” body. While girls tend to overestimate their weight, boys are more likely to describe themselves as too thin (Park, 2011). Nowadays many young people are concerned about their body shape and size due to social pressures to conform to a thin, ideal body (Yan et al., 2018).

 

The higher incidence of weight overestimation in girls may be connected to the idea of a “perfect” body.

 

In this study, the female students showing weight overestimation were less likely to follow the “processed meat, sandwiches, and coffee,” “ultra-processed and sweet foods,” and “traditional Brazilian” dietary patterns (the latter is characterized by rice, beans, vegetables, and meat). This suggests a sense of apprehension towards eating — of restriction. A different study in South Korea demonstrated that girls with weight overestimation tend to have poor eating habits and employ unhealthy dieting methods to lose weight (Lim et al. 2014). In short, normal-weight adolescents who perceive themselves as overweight seem to put effort into losing weight — intentions that do not exactly translate into healthy weight loss behaviors. 

Similar to the girls, the normal-weight boys with weight overestimation were less inclined to adhere to a “traditional Brazilian” dietary pattern. As noted above, this “traditional” diet consists of several unprocessed or minimally processed foods, which are recommended by the Food Guide for the Brazilian Population. Worth mentioning is that this dietary guide does not recommend the intake of ultra-processed foods, warning Brazilians to avoid several of these food items found in the “ultra-processed and sweet foods” dietary pattern.  

For girls who underestimated their weight, the “ultra-processed and sweet foods” and the “traditional Brazilian” dietary patterns were more likely to be adopted. In boys, weight underestimation was directly associated with greater adherence to the “processed meat, sandwiches, and coffee” and “ultra-processed and sweet foods” dietary patterns. 

 

Weight underestimation showed correlations with the “ultra-processed and sweet foods” dietary pattern in both sexes.

 

Weight underestimation showed correlations with the “ultra-processed and sweet foods” dietary pattern in both sexes. Coupled with the association between weight overestimation and lower adherence to the “traditional Brazilian” dietary pattern, these results highlight that weight misperception is related to unhealthy eating habits among adolescents. 

Awareness of the adolescent Diet-Perceptual Relationship in children and adolescents can be an important element for policymakers in developing and implementing intervention programs to support accurate self-perceptions of body weight. Successful efforts on this front could contribute to the adoption of better eating habits and enhanced overall general health in youth. 

 

References

Clay, D., Vignoles, V.L. and Dittmar, H. (2005), Body image and self-esteem among adolescent girls: testing the influence of sociocultural factors. Journal of Research on Adolescence, 15: 451-477. https://doi.org/10.1111/j.1532-7795.2005.00107.x

Cuypers, K., Kvaløy, K., Bratberg, G., Midthjell, K., Holmen, J., & Holmen, T. L. (2012). Being normal weight but feeling overweight in adolescence may affect weight development into young adulthood-an 11-year followup: the HUNT Study, Norway. Journal of obesity, 2012, 601872. https://doi.org/10.1155/2012/601872

Lim, H., Lee, H. J., Park, S., Kim, C. I., Joh, H. K., & Oh, S. W. (2014). Weight misperception and its association with dieting methods and eating behaviors in South Korean adolescents. Nutrition research and practice, 8(2), 213–219. https://doi.org/10.4162/nrp.2014.8.2.213

Park, E. (2011). Overestimation and underestimation: adolescents’ weight perception in comparison to BMI-based weight status and how it varies across socio-demographic factors. The Journal of school health. 81. 57-64. 10.1111/j.1746-1561.2010.00561.x.

Silva, S., Alves, M. A., Vasconcelos, F., Gonçalves, V., Barufaldi, L. A., & Carvalho, K. (2021). Association between body weight misperception and dietary patterns in Brazilian adolescents: A cross-sectional study using ERICA data. PloS one, 16(9), e0257603. https://doi.org/10.1371/journal.pone.0257603

Yan, H., Wu, Y., Oniffrey, T., Brinkley, J., Zhang, R., Zhang, X., Wang, Y., Chen, G., Li, R., & Moore, J. B. (2018). Body Weight Misperception and Its Association with Unhealthy Eating Behaviors among Adolescents in China. International journal of environmental research and public health, 15(5), 936. https://doi.org/10.3390/ijerph15050936

 

 

Do Taste Perception, Preference, Personality, Mood, and Dietary Intake Behavior Interconnect?

Posted on by CNP Staff

For hundreds of years, scientists have suspected a connection between our personality traits and taste preferences. Anton Brillat-Savarin, the famous French gastronome, is quoted saying, “Tell me what you eat, and I will tell you who you are.” 

 

Tell me what you eat, and I will tell you who you are.

 

But what influences what we eat? It turns out that a symphony of elements influences our dietary intake patterns. These elements include (but are not limited to) our psychological traits (and mood states), cognitive and perceptual processes, behavioral attributes, psychosocial (including cultural) environment, and interoceptive experience. Each of these elements, in turn, is driven by physiological, biological, neuropsychological, and environmental states that are constantly at play within us (figure 1) (see the Nutritional Psychology Research Library).

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Figure 1. Elements of the diet-mental health relationship (DMHR) informing nutritional psychology (NP)

 

Understanding the diet-mental health relationship (DMHR) involves a wealth of conceptual complexity. The burgeoning field of nutritional psychology is attempting to integrate this conceptual complexity into a singular infrastructure by which the conceptualization of the DMHR can grow (figure 1). Nutritional psychology involves understanding the myriad factors interconnecting our dietary intake with our psychological processes, functioning, and experience. A plethora of research exists (and is growing) to improve our understanding of these interconnections and is contained in the CNP Research Libraries. 

What is Guiding What We Eat?

On the surface, many of us believe that what we eat is guided by what we like and want to eat (or in the current dietary intake landscape additionally, what we crave to eat and what is available to eat). In fact, what we eat goes far deeper than simply wanting and liking certain foods. A host of involuntary factors, of which we are mostly unaware, influence our daily dietary intake including our perceptions and preferences, personality, mood, behavioral attributes, and even genetics (Neuroscientist News, 2022). Let’s begin by looking at taste perception, preference, and their connection with personality traits.

Genetic Basis for Taste Perception and its Connection with Personality Traits

Perceiving taste involves complex pathways that interface with multiple cranial nerves and areas in our brain. The five taste sensations (bitter, sweet, umami, sour, and salt) arise because of the activation of specific taste receptor cells on the lingual papillae on the tongue. Specific genes encode the different taste receptors. Varieties in these genes lead to the expression of different proteins associated with different tasting abilities, preferences, and personality traits. This serves as the genetic basis for taste and the perception of taste. 

Interestingly, sensory science divides people into supertasters, medium-tasters, and non-tasters. The TAS2R38 gene, located on chromosome 7, provides the genetic basis for taster status (Figure 2).  

Supertasters are defined as individuals with uncommonly low gustatory thresholds and strong responses to moderate concentrations of taste stimuli (Supertaster – APA Dictionary of Psychology, n.d.). Supertasters have an unusually high number of taste buds. This gene in supertasters increases their perception of bitter flavors in foods. 

 

Varieties in genes lead to the expression of different proteins associated with different tasting abilities, preferences, and personality traits.

 

For example, supertasters tend to find the taste of coffee to be very bitter. In relation to personality characteristics, studies have found that supertasters and medium-tasters tend to be more tense, apprehensive, and imaginative than non-tasters, while non-tasters are inclined to be more relaxed, placid, and practical (Mascie-Taylor et al., 1983).

Science also reveals a genetic basis for sweet liking, identified by a locus on chromosome 16 (Figure 2). Researchers divide the population into three categories related to the liking for sweetness: sweet-likers, sweet-neutral, and sweet dislikers. Regarding differences in the preferences for sweetness, studies have shown that these differences predicted intentions, prosocial personalities, and behaviors (Meier et al., 2012). 

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Figure 2. The five taste sensations. The genetic basis for sweet liking is identified by chromosome 16, while chromosome 7 provides the genetic basis for taster status

 

It is important to note that in addition to our genes, our biochemical makeup also plays a role in our food perception and preference. For example, one study showed that salivary testosterone levels correlated with the amount of spice (Tabasco in this case) that participants chose to add to their food (Bègue et al., 2015). 

Now that we’re aware of the genetic (and biochemical) basis for taste perception and preference, and learned how our genes can influence personality, let’s look at how personality can influence food preference. 

Personality and Food Preference

Regarding food preferences, key factors of a person’s personality, including openness to experience (i.e., curiosity vs. caution), have been found to correlate with various aspects of food preference. For example, in a study by Conner et al. (2017), people with personality attributes like openness scored above average on preference for new food experiences. The controversy associated with such research, however, is that it has largely been conducted using self-rated food preferences, not in settings with actual food choices.

 

Key factors of a person’s personality have been found to correlate with aspects of food preference.

 

Many studies have addressed this issue. For example, a 2016 study analyzed participants’ willingness to try new foods. In this study, bite-sized pieces of twelve food items were placed in front of each participant (these included: octopus, hearts of palm, seaweed, soya bean milk, blood sausage, Chinese sweet rice cake, pickled watermelon rind, raw fish, quail egg, star fruit, sheep milk cheese, and black beans). Findings showed that the most anxious participants were the least willing to try new foods (Otis, 2016). This has been supported by other publications showing that anxious patients exhibit greater food aversions (Spence, 2021).

 

The most anxious participants were the least willing to try new foods.

 

Taste Perception and its Influence on Mood and Behavior

Now that we’ve explored some interconnections between genes, taste perception, and personality, let’s see how taste perception can influence our mood and behaviors. An example study by Vi and Obrist (2018) showed that those experiencing a sour taste were more likely engage in risk-taking. This was measured using the standardized Balloon Analogue Risk-Taking (BART) task, a computerized gambling task. Participants were asked to virtually pump up a balloon on a computer screen, with an accumulated monetary reward at stake. After each pump, the balloon either explodes or increases in size based on a randomized algorithm, yielding greater reward. Participants who had tasted something sour (as compared to a neutral water stimulus) were more likely to keep inflating the virtual balloon, risking the loss of the reward. 

A study exploring the interrelation between taste perception and mood (Chan et al., 2013) showed that tasting something sweet made people feel temporarily more romantic. And that by having people remember an episode of romantic love, they would report some foods as being sweeter than did those who were asked to recall a jealous memory. 

In another study by Ren et al., (2014), researchers exposed a group of participants to the sweet taste of Oreo cookies. This exposure resulted in a greater interest in initiating relationships with a potential partner. 

A study by Greimel et al., (2006) found that prompting people to remember being mistreated at work resulted in bitter tastes being rated as more intense, while watching a joyful film clip (compared to a sad movie clip) resulted in participants rating a sweet drink as more pleasant.

Taste Perception and Clinical Disorders

Some research on taste perception in the context of mental health shows that depressed patients have differences in perception of taste. While some studies have reported no difference in taste perception in depressed patients (Arrando, 2015; Nagai, et al., 2015), researchers Hur et al. (2018) found that the prevalence of altered smell and taste among patients with major depressive disorder was 39.8% and 23.7% respectively.

These changes in taste perception are hypothesized to be due to several mechanisms, but one mechanism seems to involve neurochemical changes that happen in our brain due to either emotional or pathological processes (e.g., depression leads to elevation of inflammatory cytokines like interleukin 6). These changes can result in actual changes in the gustatory system. 

It is hypothesized that changed taste thresholds could be attributed to reduced serotonin and noradrenaline levels in depressed patients, as suggested by Heath et al. (2006) (Figure 3). This proposed mechanism was supported by another study (Kim et al., 2017), which found reduced expression of 5‐HT1A receptors for serotonin in the taste cells of rats that developed anhedonia — a common symptom of depression. Case reports demonstrate that a change in taste is a neglected symptom in depressed patients that is worthy of further investigation (Miller & Naylor, 1989; Mizoguchi et al., 2012). 

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Figure 3. Human gustatory pathway. Variations in serotonin levels are associated with different thresholds for certain tastes like bitter and sweet (Heath, 2006).

 

Research also shows that patients with panic disorders can have exhibited reduced sensitivity to bitterness (DeMet et al., 1989), while anxiety levels are positively correlated with the taste thresholds for bitterness and saltiness (Heath et al., 2006). 

According to Hur et al. (2018), it may be advisable for primary care providers to screen their patients for depression or other psychiatric conditions when they report changes in taste or smell.

Conclusion

In this article, we’ve had a little ‘taste’ of how our genes influence our taste perception and preferences. The DMHR plot thickens when we begin to be aware of how these perceptions and preferences can interplay with our personality, mood, and behaviors (figure 4).

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Figure 4. Interconnections between genes, taste perception, and preference, behaviors, personality, and mood.

 

For example, we learned how anxious individuals can prefer a narrower range of food while people with personality attributes like openness typically score above average on preferences for new food experiences. Intriguingly, differences in food behavior and taste perception have been linked with circulating levels of certain neurotransmitters like serotonin and can affect taste perception in clinical disorders. 

While not lending to a conclusive understanding of the factors involved in dietary intake, our goal with this article is to provide you with a new awareness of the interconnection that occurs between your genes, personality, emotions, and food-related behaviors and preferences.  

To learn more, visit the CNP Diet and Personality and Diet and Sensory-Perception research categories in the NPRL. 

 

References

Arrondo, G., Murray, G. K., Hill, E., Szalma, B., Yathiraj, K., Denman, C., & Dudas, R. B. (2015). Hedonic and disgust taste perception in borderline personality disorder and depression. The British journal of psychiatry: the journal of mental science, 207(1), 79–80. https://doi.org/10.1192/bjp.bp.114.150433

Bègue, L., Bricout, V., Boudesseul, J., Shankland, R., & Duke, A. A. (2015). Some like it hot: Testosterone predicts laboratory eating behavior of spicy food. Physiology & Behavior, 139, 375–377. https://doi.org/10.1016/J.PHYSBEH.2014.11.061

Chan, K. Q., Tong, E. M. W., Tan, D. H., & Koh, A. H. Q. (2013). What do love and jealousy taste like? Emotion (Washington, D.C.), 13(6), 1142–1149. https://doi.org/10.1037/A0033758

Conner, T. S., Thompson, L. M., Knight, R. L., Flett, J. A. M., Richardson, A. C., & Brookie, K. L. (2017). The role of personality traits in young adult fruit and vegetable consumption. Frontiers in Psychology, 8(FEB). https://doi.org/10.3389/FPSYG.2017.00119

DeMet, E., Stein, M. K., Tran, C., Chicz-DeMet, A., Sangdahl, C., & Nelson, J. (1989). Caffeine taste test for panic disorder: Adenosine receptor supersensitivity. Psychiatry Research, 30(3), 231–242. https://doi.org/10.1016/0165-1781(89)90014-0

Greimel, E., Macht, M., Krumhuber, E., & Ellgring, H. (2006). Facial and affective reactions to tastes and their modulation by sadness and joy. Physiology & Behavior, 89(2), 261–269. https://doi.org/10.1016/J.PHYSBEH.2006.06.002

Heath, T. P., Melichar, J. K., Nutt, D. J., & Donaldson, L. F. (2006). Human taste thresholds are modulated by serotonin and noradrenaline. The Journal of Neuroscience, 26(49), 12664–12671. https://doi.org/10.1523/JNEUROSCI.3459-06.2006

Hur, K., Choi, J. S., Zheng, M., Shen, J., & Wrobel, B. (2018). Association of alterations in smell and taste with depression in older adults. Laryngoscope Investigative Otolaryngology, 3(2), 94–99. https://doi.org/10.1002/LIO2.142

Kim, D., Chung, S., Lee, S. H., Koo, J. H., Lee, J. H., & Jahng, J. W. (2017). Decreased expression of 5-HT1A in the circumvallate taste cells in an animal model of depression. Archives of Oral Biology, 76, 42–47. https://doi.org/10.1016/J.ARCHORALBIO.2017.01.005

Mascie-Taylor, C. G. N., McManus, I. C., MacLarnon, A. M., & Lanigan, P. M. (1983). The association between phenylthiocarbamide (PTC) tasting ability and psychometric variables. Behavior Genetics, 13(2), 191–196. https://doi.org/10.1007/BF01065667 

Meier, B. P., Moeller, S. K., Riemer-Peltz, M., & Robinson, M. D. (2012). Sweet taste preferences and experiences predict prosocial inferences, personalities, and behaviors. Journal of Personality and Social Psychology, 102(1), 163–174. https://doi.org/10.1037/A0025253

Mizoguchi, Y., Monji, A., & Yamada, S. (2012). Dysgeusia successfully treated with sertraline. The Journal of Neuropsychiatry and Clinical Neurosciences, 24(2). https://doi.org/10.1176/APPI.NEUROPSYCH.11040095

Nagai, M., Matsumoto, S., Endo, J., Sakamoto, R., & Wada, M. (2015). Sweet taste threshold for sucrose inversely 

Neuroscientist News. (2022, June 14). Do our genes determine what we eat? https://neurosciencenews.com/genetics-taste-perception-20833/

correlates with depression symptoms in female college students in the luteal phase. Physiology & behavior, 141, 92–96. https://doi.org/10.1016/j.physbeh.2015.01.003

Otis, L. P. (1984). Factors influencing the willingness to taste unusual foods. Psychological Reports, 54, 739–745.

Ren, D., Tan, K., Arriaga, X. B., & Chan, K. Q. (2014). Sweet love: The effects of sweet taste experience on romantic perceptions. Http://Dx.Doi.Org/10.1177/0265407514554512, 32(7), 905–921. https://doi.org/10.1177/0265407514554512

Smith, W., Powell, E. K., & Ross, S. (1955). Manifest anxiety and food aversions. Journal of Abnormal and Social Psychology, 50(1), 101–104. https://doi.org/10.1037/H0049253

Supertaster – APA dictionary of psychology. (n.d.). Retrieved January 28, 2022, from https://dictionary.apa.org/supertaster

Spence C. (2021). What is the link between personality and food behavior?. Current research in food science, 5, 19–27. https://doi.org/10.1016/j.crfs.2021.12.001

Vi, C. T., & Obrist, M. (2018). Sour promotes risk-taking: An investigation into the effect of taste on risk-taking behaviour in humans. Scientific Reports, 8(1). https://doi.org/10.1038/S41598-018-26164-3

 

Exploring Dietary Intake Behaviors Related To The Covid-19 Lockdown

Posted on by CNP Staff

In 2019, the Coronavirus disease (COVID-19) evolved into a worldwide pandemic requiring us to quarantine and isolate ourselves to protect ourselves from catching and spreading the virus. As the world went into isolation for extended periods, many secondary aspects of our lives were impacted, including interrupted schedules and routines, significant changes in our social activities and experiences, and changes in our dietary intake patterns. The list of physical and mental health implications of these impacts is varied and significant and has resulted in both positive and negative effects on our health.

A recent scoping review by Bennett et al. in 2021 reviewed studies that explored the impact of people’s dietary intake changes within the first wave of the COVID-19 lockdown. Findings were divided into four themes: 1) dietary patterns, 2) favorable dietary habits, 3) unfavorable dietary habits, and 4) others (physical health factors). 

Findings showed that two prominent dietary intake patterns changed during the pandemic, including an increase in snacking and meal numbers. 

The researchers in the study categorized the increase in snacking as an unfavorable dietary habit. Most of the snacks consumed during the pandemic involved empty-calorie foods, which were associated with the need for comfort and reducing momentary anxiety levels from the pandemic. This unfavorable dietary habit suspends interest in making healthful food choices because it redirects an individual’s focus on nurturing their emotions (Shen et al., 2020). 

 

Most of the snacks consumed during the pandemic involved empty-calorie foods, which was associated with the need for comfort food.

 

The authors state that although there is much evidence mentioned about the adverse effects of the pandemic, there is some information that shows favorable dietary intake habits arising from being in isolation. Studies have shown that lockdown has decreased the amount of fast-food consumption. Instead, many people have been obliged to make food at home. Isolation has also reduced the consumption of alcohol for those who often drink while socializing. The reduced access to unhealthy foods and drinks has created favorable dietary habits for some individuals as cooking at home increased. However, even if positive dietary intake patterns and habit outcomes have arisen from being in lockdown, this review identifies more undesirable effects on peoples’ health during the COVID-19 pandemic.

 

Isolation has also reduced the consumption of alcohol for those who often drink while socializing.

 

To see more studies examining the influence of Covid-19 and dietary intake, visit the CNP Research Library Diet and COVID-19 Research Category. Thank you to CNP Intern Hashmin Sajjan for contributing to this blog post!

 

References

Al-Musharaf S. (2020). Prevalence and Predictors of Emotional Eating among Healthy Young Saudi Women during the COVID-19 Pandemic. Nutrients, 12(10), 2923. https://doi.org/10.3390/nu12102923

Bennett, G., Young, E., Butler, I., & Coe, S. (2021). The Impact of Lockdown During the COVID-19 Outbreak on Dietary Habits in Various Population Groups: A Scoping Review. Frontiers in Nutrition, 8, 626432–626432. https://doi.org/10.3389/fnut.2021.626432

Shen, W., Long, L. M., Shih, C. H., & Ludy, M. J. (2020). A Humanities-Based Explanation for the Effects of Emotional Eating and Perceived Stress on Food Choice Motives during the COVID-19 Pandemic. Nutrients, 12(9), 2712. https://doi.org/10.3390/nu12092712

 

Neuroplasticity, Behavior, and Dietary Intake — Rewiring the Brain for Better or Worse

Posted on by CNP Staff

What we think, do, say, and eat has the ability to change our brain processes and structures — a process called neuroadaptation (see Diet and Brain and Diet and Cognition in the CNP Research Libraries). These adaptations can influence the long-term rewiring of our brain circuitry. In this post, we explore two different actions that many of us engage in that can influence the development of neuroadaptations in our brain. Becoming aware of these actions can support us in influencing these adaptations to work in our favor. 

Within psychology and neuroscience, the term “neuroplasticity” is used to describe how the brain changes and adapts in response to experience. Dr. Micheal Merzenich, a neuroscientist at The University of California in San Francisco explains it like this: “Your experiences, behaviors, thinking habits, thought patterns, and ways of reacting to the world are inseparable from how your brain wires itself.” (Science explains what happens to someone’s brain from complaining every day, 2020).

 

Your experiences, behaviors, thinking habits, thought patterns, and ways of reacting to the world are inseparable from how your brain wires itself.

 

Let’s explore an example of how what we say and do can result in changes to our brain — take, for example, the act of verbally complaining. Although everyone complains now and then, when we express dissatisfaction or annoyance about something frequently, we can fall into a habitual pattern that results in neuroadaptations in our brain and the rewiring of our brain circuitry.

A study from Stanford University found that just 30 minutes of complaining or even just hearing someone complain, could result in changes to the brain’s structure and function (Pisano, n.d.). As Donald Hebb, a Canadian psychologist known for his work in neuropsychology, states, “Neurons that fire together, wire together.” This means that the more you complain, or think negatively, the more you strengthen those synapses between neurons, creating a vicious cycle that can be hard to break (Pisano, n.d.).

 

Neurons that fire together, wire together.

 

Given that our brain reinforces pathways that are often used (whether supportive or not), do we have any influence in encouraging more positive neuroadaptations and making neuroplasticity work in our favor?  In 2017, Dr. Barbara Fredrickson and her colleagues at the University of North Carolina showed that people who meditate daily tend to have more positive emotions than those who do not. Interestingly enough, meditation has also been shown to strengthen the insula — the part of the brain responsible for Interoception (Sharp et al., 2018). Within Nutritional Psychology, interoceptive awareness plays a key role in developing our ability to monitor our internal states in relation to the foods we eat (more about this can be found in Introduction to Nutritional Psychology Methods (NP 110). 

Just like evidence reveals the impact of frequent complaining on our brain, evidence shows that eating a Western-style dietary intake pattern influences changes to both brain structures (Jacka et al., 2015) and functions (Stevenson et al., 2020). One such area is the hippocampus (Attuquayefio et al., 2017) which is the part of the brain responsible for learning and memory. 

 

The western-style dietary pattern results in changes to brain processes and structures in numerous areas of the brain.

 

While consuming highly palatable foods (those high in salt, sugar, and/or processed oils) can result in neuroadaptations that negatively influence brain function and structure, consuming unprocessed nutrient-dense and diverse foods daily, like fresh (or even canned or frozen) vegetables, fruits, high-quality proteins and healthy fats (the kinds found in olive oil, avocados, and nuts), can result in the opposite — a processed called neurogenesis* which involves the proliferate of new neurons and other resident brain cells (Poulose et al., 2017) (Otsuka, et al., 2021).

As we can see, both psychological and dietary factors can influence our brain structure and function, and the resulting neuroadaptations can influence our functioning positively, or negatively. At the end of the day, it is up to us as individuals to steer them in a favorable direction, whether that be through consciously choosing a nutrient-dense diet, maintaining a positive mindset when life events don’t go our way, or engaging in mindfulness techniques.

*Dietary components such as curcumin, resveratrol, blueberry polyphenols, sulforaphane, polyunsaturated fatty acids (PUFAs), and diets enriched with polyphenols, have been shown to induce neurogenesis in adult brains (Poulose et al., 2017)

 

References

Attuquayefio, T., Stevenson, R. J., Oaten, M. J., & Francis, H. M. (2017). A four-day Western-style dietary intervention causes reductions in hippocampal-dependent learning and memory and interoceptive sensitivity. PloS one, 12(2), e0172645. https://doi.org/10.1371/journal.pone.0172645Fredrickson, B. L., Boulton, A. J., Firestine, A. M., Van Cappellen, P., Algoe, S. B., Brantley, M. M., Kim, S. L., Brantley, J., & Salzberg, S. (2017). Positive Emotion Correlates of Meditation Practice: A Comparison of Mindfulness Meditation and Loving-kindness Meditation. Mindfulness, 8(6), 1623–1633. https://doi.org/10.1007/s12671-017-0735-9

Jacka, F. N., Cherbuin, N., Anstey, K. J., Sachdev, P., & Butterworth, P. (2015). Western diet is associated with a smaller hippocampus: a longitudinal investigation. BMC Medicine, 13, 215. https://doi.org/10.1186/s12916-015-0461-x 

Otsuka, R., Nishita, Y., Nakamura, A., Kato, T., Iwata, K., Tange, C., Tomida, M., Kinoshita, K., Nakagawa, T., Ando, F., Shimokata, H., & Arai, H. (2021). Dietary diversity is associated with longitudinal changes in hippocampal volume among Japanese community dwellers. European journal of clinical nutrition, 75(6), 946–953. https://doi.org/10.1038/s41430-020-00734-zPisano, T. (n.d.). Complaining is Bad for your Brain! M1 Psychology. https://m1psychology.com/complaining-is-bad-for-your-brain/

Poulose, S. M., Miller, M. G., Scott, T., & Shukitt-Hale, B. (2017). Nutritional Factors Affecting Adult Neurogenesis and Cognitive Function. Advances in Nutrition (Bethesda, Md.), 8(6), 804–811. https://doi.org/10.3945/an.117.016261

Science explains what happens to someone’s brain from complaining every day. (2020, July 8). Power of Positivity: Positive Thinking & Attitude. https://www.powerofpositivity.com/complaining-changes-brain-anxious-depressed-research/?fbclid=IwAR0fXxg_NqwWZQAz_d3SkPO3EeE8hTdHnOgdOdFS5WW2o7toZpuwTN55x_k

Sharp, P.B., Sutton, B.P., Paul, E.J. et al. Mindfulness training induces structural connectome changes in insula networks. Sci Rep 8, 7929 (2018). https://doi.org/10.1038/s41598-018-26268-w

Stevenson, R., Francis, H., Attuquayefio, T., Gupta, D., Yeomans, M., Oaten, M., & Davidson, T. (2020) Hippocampal-dependent appetitive control is impaired by experimental exposure to a Western-style diet. Royal Society Open Science, 7(2).

Dietary Intake and Resilience: Is There a Connection Across the Lifespan?

Posted on by CNP Staff

Dietary Intake and Resilience: Is There a Connection Across the Lifespan?

Psychologists define resilience as the process of adapting well in the face of adversity, trauma, tragedy, threats, or significant sources of stress (APA, 2012). These can include family, relationship, and social problems, physical or psychological health issues, employment or financial stressors, and world pandemics. By some estimates, most people will experience one or more potentially life-threatening traumatic experiences that can influence their mental health and even result in post-traumatic stress disorder (Karam et al., 2014). 

The latest viewpoint on the construct of resilience is that it is complex, and comprises biological, genetic, epigenetic, developmental, psychological, social, economic, and cultural factors that interact to determine one’s responses to stressful stimuli and experiences (Southwick et al., 2014).

Within Nutritional Psychology, we seek to determine the connections between dietary intake and resilience, and the mechanisms by which these connections occur. Studies demonstrating a relationship between diet and resilience are included in a growing repository of links within the “Diet and Resilience” and “Diet and Quality of Life” research categories in the NPRL and Parent Research Libraries. In these libraries, you will find research to support the connection between dietary intake and resilience across the lifespan. Let’s take a look at a few of these publications.

 

The Diet-Resilience Connection in Youth

Nutritional quality and breakfast intake are two dietary factors among young people that are shown to positively mediate psychological distress and improve resilience. In 2019, Whatnall et al. examined this connection by using diet questionnaires to record 2,710 Australian students’ consumption of fruits, vegetables, soft drinks, and takeaway food, as well as how frequently they ate breakfast. The Kessler Scale and Brief Resilience Scale (BRS) were used to assess psychological distress and resilience, with adjustments made for socio-demographic factors, undergraduate/postgraduate status, and health characteristics. Findings showed that higher fruit and vegetable consumption per day (analyzed separately), more consistently having breakfast, and less frequent intake of soft drinks and takeaway foods were all significantly associated with both lower psychological distress and higher resilience. 

 

The Diet-Resilience Connection in Adults

Within the more general population, diet quality is also an important link when it comes to managing stress and adapting in the face of adversity. This is evident in a 2018 study by Bonaccio et al., where adherence to a Mediterranean-type diet (categorized by a high intake of vegetables and olive oil) proved to have a positive connection in terms of resilience. Food intake was measured among 10,812 participants using a Food Frequency Questionnaire, psychological resilience using a Psychological Resilience Score, and adherence to the Mediterranean diet using both a Mediterranean Diet Score and an Italian Mediterranean Index. Increased polyphenol or antioxidants in the diet and greater diversity in fruit and vegetable consumption, as opposed to a nutrient-depleted Western diet, were linked with enhanced psychological resilience. The findings give us insight into the positive associations between adherence to a nutrient-dense Mediterranean-type diet and psychological resilience and suggest that by adopting a similar diet, we too can better handle psychological distress and improve resilience.

 

The Diet-Resilience Connection in Elderly Individuals

Another factor that is shown to positively correlate with increased resilience is dietary diversity. Dietary diversity, defined as the number of different food groups consumed within a given reference period, is a key element of high-quality, nutrient-dense diets. A 2019 study by Yin et al. took a closer look at diet diversity within an elderly Chinese population consisting of 8,571 participants. From this sample, the frequency of consuming different food groups was reported, with the consumption of vegetables, fruits, and nuts contributing the most to dietary diversity. Psychological resilience was assessed using a simplified resilience score (SRS). Analyses showed a significant association between lower dietary diversity and poorer resilience, as compared to those with good dietary diversity and higher resilience. The findings show that greater diet diversity is crucial in maintaining and improving cognitive function as it relates to resilience in older populations.

 

Resilience: The Other Side of Stress

While it is important to examine the mechanisms and outcomes associated with our experience of stress, it is also important to investigate the mechanisms and outcomes associated with our experience of resilience. These and other studies in the CNP Research Libraries show that an association between stress, resilience, and diet in fact exists.  Nutritional Psychology encompasses the examination of this and other connections between dietary intake and psychological functioning.

 

References

Building your Resilience. American Psychological Association. https://www.apa.org/topics/resilience

Karam E. G., Friedman M. J., Hill E. D., Kessler R. C., McLaughlin K. A., Petukhova M. (2014). Cumulative traumas and risk thresholds: 12-month PTSD in the world mental health (WMH) surveys. Depression and Anxiety, 31, 130–142. 

Denckla, C. A., Cicchetti, D., Kubzansky, L. D., Seedat, S., Teicher, M. H., Williams, D. R., & Koenen, K. C. (2020). Psychological resilience: an update on definitions, a critical appraisal, and research recommendations. European Journal of Psychotraumatology, 11(1), 1822064. https://doi.org/10.1080/20008198.2020.1822064

Southwick, S. M., Bonanno, G. A., Masten, A. S., Panter-Brick, C., & Yehuda, R. (2014). Resilience definitions, theory, and challenges: interdisciplinary perspectives. European Journal of Psychotraumatology, 5, 10.3402/ejpt.v5.25338. https://doi.org/10.3402/ejpt.v5.25338

Whatnall, M. C., Patterson, A. J., Siew, Y. Y., Kay-Lambkin, F., & Hutchesson, M. J. (2019). Are psychological distress and resilience associated with dietary intake among Australian university students?. International Journal of Environmental Research and Public Health, 16(21), 4099.

Bonaccio, M., Di Castelnuovo, A., Costanzo, S., Pounis, G., Persichillo, M., Cerletti, C., Donati, M. B., de Gaetano, G., & Iacoviello, L. (2018). Mediterranean-type diet is associated with higher psychological resilience in a general adult population: findings from the Moli-sani study. European Journal of Clinical Nutrition, 72(1), 154–160.

Yin, Z., Brasher, M. S., Kraus, V. B., Lv, Y., Shi, X., & Zeng, Y. (2019). Dietary diversity was positively associated with psychological resilience among elders: A population-based study. Nutrients, 11(3), 650.

 

Does Exposure to Food Advertisements Influence Dietary Intake?

Posted on by CNP Staff

The diet-sensory-perceptual relationship (DSPR) is a central component of the diet-mental health relationship (DMHR) — and one of the six major elements defining the field of nutritional psychology (NP). The DSPR examines the interconnected relationship between our sensory-perceptual experience and how it connects with our dietary choices and intake behaviors.Food advertising (viewing food advertisements on television or the internet) influences our dietary intake via the DSPR. While we discuss this at length in the Diet Sensory-Perceptual Module within NP 110, let’s review a study exploring the relationship between advertisements and dietary intake by Zimmerman and Shimoga (2014).

In this study, the authors assessed the impact of TV advertisements on participants’ food choices. Participants were exposed to: 1) food advertising + a cognitively demanding task; 2) food advertising + a non–cognitively demanding task; 3) non-food related advertisement while performing a cognitively demanding task; or 4) non-food advertising task before performing a non-cognitively demanding task. The outcomes measured were the number and calorie contents of the unhealthy snacks selected by the participants.

The data revealed that those participants exposed to food advertising chose 28% more unhealthy snacks than those who encountered the non-food advertising (leading to a 65 kcal increase in dietary intake).

While the different advertisements did not significantly affect the individuals assigned to the less cognitively demanding task, there was a large and significant influence of advertising in the participants completing the cognitively demanding task. Those in the cognitively demanding task exposed to food-related advertisements ate 43% more unhealthy snacks, taking in 94 more total calories, compared to the participants who saw non-food advertisements.

This study demonstrated that televised food advertising strongly influences people’s food choices, particularly when these individuals are challenged cognitively. Other findings demonstrate that advertisements (through both the internet and television) influence dietary intake choices in both the adult and child/adolescent population.

While findings like these are instrumental for increasing our understanding of the intimate relationship between dietary intake and psychological health, it is necessary to build a conceptual framework within which we can house these findings. Nutritional Psychology is the field of science dedicated to building this structure.

You can learn more about the DSPR, as well as the other five key elements informing the DMHR, in NP 110: Introduction to Nutritional Psychology Methods.

 

References

Zimmerman, F., & Shimoga, S.V. (2014). The effects of food advertising and cognitive load on food choices. BMC Public Health, 14, 342-342. https://doi.org/10.1186/1471-2458-14-342

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