Our Moods, Our Foods

Have you ever wondered why you sometimes have good days and bad days, or are in good or bad mood? Can there be a connection between the food you eat and how you feel afterwards?

You don’t need a study to tell you the obvious: we see a lot of people all around us who just aren't feeling the love. Such people could be our coworkers, the impatient people in the supermarket, and aggressive and vindictive drivers. In the United States, it is estimated that nearly 21 million adults suffer from mood disorders and about 40 million people have anxiety disorders. Stop for a moment and reflect on how food affects your mood [1].
Do you sometimes feel fuzzy-headed and sleepy after lunch? This is due to the increase in blood sugar level which suppresses orexin; a neuropeptide linked to alertness [1]. On the contrary, when your blood sugar level is low due to hunger, more primitive brain regions take charge and you are more likely to be impatient and easily irritated [2].

Source:  http://bit.ly/1OvEDhe

Eating specific foods affects brain chemicals and eating patterns also affect blood sugar levels, both of which play a role in mood. However, the connection between food and mood not only depends on blood sugar fluctuations, but also on the quality and quantity of nutrients in the diet [1,3]. Our mood is just like our bodies: better enhanced with fresh, whole foods containing proteins, vitamins and minerals. Everything we eat affects the synthesis of neurotransmitters and hormones and the quality of our synaptic connections. These together go a long way to influence how we respond to stress and the demands of daily life [3].

Eating Yourself Happier
Making certain changes in one's diet may help to improve mood: Eating regular meals, especially breakfast and choosing positive mood foods containing tryptophan (essential for the synthesis of serotonin, a neurotransmitter important for a positive affect) can influence one’s mood positively. In addition to eating tryptophan-containing foods, the intake of carbohydrates, vitamins, and minerals which help the uptake of serotonin is also highly recommended. A late night snack can actually help you fall asleep!

WHAT YOU EAT DEFINES YOUR MOOD

 
A study conducted at the University of Otago, Dunedin, New Zealand, shows that fruit and vegetable consumption may contribute to a well-being state and hence positive affect. They reported that there is a correlation between eating more fruits and vegetables to the state of well-being, curiosity, and creativity [3]. One possible biological mechanism underlying the relation between the intake of fruits and vegetables to a greater positive affect and well-being is the fact that vitamins B and C are cofactors for the synthesis of dopamine; a neurotransmitter responsible for motivation and greater engagement. In addition, the antioxidants found in fruits and vegetables are known to lower inflammatory responses. A lower inflammation leads to lower levels of depression and promotes positive affect [4,5].

Happy Fats
Who said all fats are bad? Are you constantly getting rid of fat from your meal? Then stop and think again. Omega-3 fatty acids, although not technically neurotransmitters, are essential for normal brain function and mood regulation. The brain is composed of 70% fat and therefore needs fat for maintaining normal balanced moods throughout life and for moderating aggressive behavior. Omega-3 fatty acids improve the activity of neurotransmitters by assisting the communication between brain cells and thus enhancing plasticity and reducing inflammation which can damage brain cells [6]. By completely eliminating one thing from your diet, even fat, it can have negative consequences on your mood.

Bad Mood Foods
I guess we all want to be in a positive mood most of the time. There are various foods that put us in a bad mood. For example studies show that depression is a symptom of gluten intolerance. Individuals with gluten intolerance have lower levels of serotonin [7,8].
Other examples include soy because it contains proteins that the body finds difficult to digest. The stress on the digestive tract in digesting this protein can equally put us in a state of stress and discomfort. Refined white flour, sugars, vegetable oils can also affect our mood depending on their quantity [9]. Therefore go ahead, eliminate the sad mood foods and eat yourself happier.

[1] http://bit.ly/1U1JOth
[2] http://bit.ly/1DIut7g
[3] http://bit.ly/1IABMp9
[4] Wurtman et al, Am J Clin Nutr, 2003
[5] Girbe et al, Neuroreport, 1994
[6] Appleton et al, Am J Clin Nutr, 2006
[7] Coleman NS et al., Clin Gastroenterol Hepatol, 2006
[8]  http://bit.ly/1H1YizV
[9] http://bit.ly/1fz7OVa 

by Priscilla Koduah, PhD Student AG Meisel
This article originally appeared 2015 in CNS Volume 8, Issue 3, Food for Thought.

Can You Be Addicted to Food?

Clearly, food is something that most people really cannot go without. For some, it is the casual craving for carbohydrate-rich food after a long, frustrating day, while others just enjoy Schnitzel too much. But in recent years, a growing controversy has developed from the question of whether there is a darker, more sinister side to the pleasure of eating. As an old Jewish proverb has it, "worries go down better with soup". But can drowning your sorrows in soup become a problem someday?

The concept of “food addiction” has been around for significantly longer than current debates may make you believe (nearly 60 years, to be precise) [1]. Conceptually, its location on the etiological food chain ranks it somewhere between substance (e.g. alcohol) and behavioral addictions (e.g. gambling). One reason why food addiction offers such an intuitive appeal is its seamless correlation with the global rise in obesity levels. Additionally, it offers a psychological remedy (a sugar-coating, if you excuse the pun) that relieves the consumer from the responsibility to choose: who could be blamed for overeating if all those companies sell food that has been carefully developed to maximize palatability and reward? However, the story may not be that straightforward.

Source: Bay Hippisley

As always when in doubt, a look at animal models proves instructive. And indeed, there is a plethora of studies indicating that animals often fall prey to developing addiction-like behavioral phenotypes when offered access to food. However, not all foods are created equal. More specifically, it has been shown that highly palatable foodstuff (so, the goodies that you should be careful with... you know, the ones with health warnings on them) including a high proportion of processed sugar, fat or salt, are especially attractive.

While it is generally appreciated that eating highly toothsome food activates reward areas and neurochemical paths that are notorious for their implication in addiction, it has remained significantly less clear whether this follows the act of eating per se, or depends on food content (i.e. certain ingredients). For instance, while there is evidence to suggest that lab rodents may show withdrawal-like symptoms when going cold turkey on sugar [2], such behaviors have generally not been described in humans (except in a single case study) [3]. For fat and salt, results have even been less clear.

Fast food is equivalent to pornography

Besides, there are some semantic problems that the term “food addiction” has difficulties digesting. Essentially, while no one debates the existence of problematic eating behavior, for instance, during binge eating attacks, the concept of addiction implies that there is something in the food that gets people hooked. However, humans who overeat tend not to be picky about a particular nutrient, but rather binge on a wide range of available toothsome foodstuff. And normally, there is very little evidence to suggest that humans ingest specific food to satisfy their craving for specific ingredients, like sugar or fat, or that these chemicals are consumed in isolation [4].

Eating addiction may be more appropriate than food addiction

From this perspective, ”addictive eating behavior” may be a better term. What is more, at this point, it has become challenging to tell apart people with increased appetite/reduced satiety from people with real “eating addiction” [4]. Overeating may, therefore, be something that is the consequence of high and readily availability of food paired with a certain vulnerability, such as negative effect, emotion dysregulation, and stress susceptibility [5]. To satisfy criteria for an addiction, rather than a maladaptive, potentially harmful behavior per se, science still has to carry forward the necessary proof. In any case, medicalizing such behavior may have its benefits, as has been the case for smoking, which today receives undivided medical/therapeutic attention. 

And while “food addicts” have been able to exchange their experiences among peers in Food Addicts Anonymous since 1987, they might have been the victims of a simple misnomer. For all those in doubt, better try the quiz at http://www.foodaddicts.org/am-i-a-food-addict.


[1] Randolph, Q J Stud Alcohol, 1956
[2] Colantuoni et al, Obes Res, 2002
[3] Thornley and McRobbie, N Z Med J, 2009
[4] Hebebrand et al, Neurosci Biobehav Rev, 2014
[5] Gearhardt et al, J Law Med Ethics, 2013

By Helge Hasselmann, PhD Student AG Otte

This article originally appeared September 2015 in Volume 08 Issue 02 "Food for Thought"

Are Oreos the New Cocaine?

We have all found ourselves reaching for that second delicious, crunchy Oreo (or maybe the German variant, Neo) after we finished the first one all too soon. But just because we do not stop with one cookie, does this mean we are addicted to them? Can Oreos be compared to drugs of abuse? Maybe. At least in rats.  

Source

Researchers at the University of Connecticut made headlines with their discovery that rats spent as much time in a chamber where they got Oreos as in one where they got a shot of cocaine or morphine. In other words, when rats had to pick between two chambers – one with a boring, bland, rice cake and one with an Oreo cookie – they preferred the Oreo chamber. And when given the choice between a shot of saline and a shot of morphine, they picked the morphine chamber. The researchers also found that eating cookies activated more neurons in the brain's nucleus accumbens than exposure to drugs of abuse [1]. 

EATING AN OREO GIVES US PLEASURE

Can we conclude that Oreos are as addictive as drugs of abuse? No! Here is a fatal flaw in the experiment: the researchers never directly compared Oreos to cocaine. They performed two independent experiments in two different groups of animals comparing rice cakes to Oreos and cocaine to saline. What the study does show is that eating an Oreo produces pleasure. But this is nothing new! In order to really find out if Oreos are as addictive as cocaine, we have to compare how hard a rat will work (for example, how often they press a lever) to get either an Oreo or a dose of cocaine [2]. Junk foods can create addictive-like tendencies [4] – this idea is neither new nor wrong. But the conclusions of this particular study certainly are [3].

How addictive are high fat/high sugar foods? Read the upcoming article to find the answer before checking into the treatment center for your addiction just yet!

[1] http://bit.ly/1KrTRTG
[2] http://bit.ly/1er5Fdp
[3] http://bit.ly/1MuWaIS
[4] Avena et al., Method Mol Biol, 2012


by Apoorva Rajiv Madipakkam
This article originally appeared 2015 in CNS Volume 8, Issue 3, Food for Thought.

The Role of BDNF in the Regulation of Body Weight and Energy Homeostasis

Brain-derived neurotrophic factor (BDNF) has been shown to play a crucial role in the regulation of neuronal development including survival, differentiation, and growth of existing and new neurons [1]. However, BDNF has also been identified as a key component of the hypothalamic pathway that controls body weight and energy homeostasis [2]. 

In the hypothalamus, BDNF mRNA is found in most of its functional units, i.e. paraventricular, arcuate, ventromedial and dorsomedial nuclei as well as the lateral hypothalamic area and the median eminence. Together with the hippocampus, the hypothalamus is the brain structure that contains the highest BDNF mRNA and protein levels. BDNF is largely coexpressed with its tyrosine kinase receptor trkB, suggesting that autocrine or paracrine mechanisms account for the general modality of BDNF action in the CNS (reviewed in [3]).
It has been shown that BDNF levels are low in obese people [4]. Interestingly, on the contrary, it has been found that serum levels of BDNF are significantly increased in obese women and significantly reduced in female patients with anorexia nervosa or bulimia nervosa compared to age-matched normal control subjects. Since BDNF has been described to exert a satiating effect, this may represent a long-term adaptation to counteract decreased caloric ingestion in anorexic and bulimic individuals or the increased one in obese subjects [5-7]. In humans, obesity and obesity-related symptoms have been associated with functional loss of one copy of the BDNF gene [8] and with a de novo mutation in the BDNF receptor Ntrk2 gene [9].
In animal studies, obese phenotypes are found in Bdnf-heterzygous mice associated with hyperphagia, hyperactivity, hyperleptinemia, hyperinsulinemia, and hyperglycemia [10, 11]. Both central and peripheral administration of BDNF decreases food intake, increases energy expenditure, and leads to weight loss [12, 13]. A recent study suggests that gene transfer of BDNF has a therapeutic efficacy in a mouse model of obesity and diabetes, leading to marked weight loss and alleviation of obesity-associated insulin resistance [14]. Knowledge of the exact molecular mechanisms of how BDNF regulates body weight and energy homeostasis is sparse and must be further elucidated.
 
[1] Hofer and Barde, Nature, 1988
[2] Wisse and Schwartz, Nat Neurosci, 2003
[3] Tapia-Arancibia et al., Front Neuroendocrinol, 2004
[4] Krabbe et al., Diabetologia, 2007
[5] Nakazato et al., Biol Psychiatry, 2003
[6] Montelone et al., Psychosom Med, 2004
[7] Montelone et al., Psychol Med, 2005
[8] Gray et al., Diabetes, 2006
[9] Yeo et al., Nat Neurosci, 2004
[10] Kernie et al., EMBO J, 2000
[11] Rios et al., Mol Endocrinol, 2001
[12] Pelleymounter et al., Exp Neurol, 1995
[13] Bariohay et al., Endocrinology, 2005
[14] Cao et al., Nat Med, 2009

By Charlotte Klein, PhD Student Medical Neurosciences, AG Neural Regeneration and Plasticity  

This article originally appeared December 2012 in "Fat Gut or Fat Brain"

How Wearing a Fitness Tracker Can Change You

Lately, a big market for fitness trackers has emerged. Different wearables and apps can measure a number of fitness-related parameters, including heart rate, GPS tracking, steps, distance covered, pace, calories burned or even sleep quality. In many cases, you can also log your caloric intake to get an even better profile of your performance. But the psychological aspect of fitness trackers is just as important as the technology behind them because they do more than inform: they reinforce, motivate and reward.

The Advertised Effects
Fitness trackers and apps are advertised as beneficial for your health and lifestyle. They provide an objective measure of your activity so you can’t lie to yourself. Wearable trackers should get you to be more active, motivate you during exercise and provide information about your daily routine or workout without requiring manual calculations or notes. Furthermore, they should help you to reach your fitness goals.
These devices and apps are becoming increasingly popular in personal healthcare and promise easy lifestyle changes. These promising words fall on fertile soil. Most adults are aware of (or at least suspect) not meeting their recommended daily activity guidelines. However, there are no objective research results to bolster up their promise of improving physical activity levels.

Do They Work?
Fitness trackers are great for those who really have no idea how many calories they burn during an activity and can help those in need of a motivational tool to keep them going. However, one study found that using a pedometer did not significantly increase step count among overweight and obese adults [1]. Another study with overweight people showed that after 18 months, those who had used a device that tracked steps and calorie expenditure lost on average five pounds less than people without self-tracking [2]. Thus, devices that monitor and provide feedback on physical activity may not offer an advantage over standard behavioral weight-loss approaches after all.

A FITNESS TRACKER INITIALLY INCREASES MOTIVATION

 

From personal observations and a (non-representative) survey among colleagues, it became apparent that a fitness tracker motivated us to be more active initially . For nearly all it was fun to log and track our own health data and progress with colorful charts and badges for achievements. However, the excitement – as with all new toys – had died away at some point and most of us were back to our previous activity levels after a while. Until now, not a single long-term study has analyzed the effect of constantly wearing a fitness tracker on the average consumer.

The Author's Personal Records

What Else Do They Do?
However, many users also observed that they developed a guilty conscience if they had not moved enough. In some cases this led to abandoning the device altogether. Thus, wearing the device alone is not enough to lead a healthier life. Many devices and apps offer an online platform where users can compare themselves with others or even challenge a friend. This additionally increases the motivation, but also the pressure to perform and reach your goals as the wearer is held accountable by the device, app and group members. The motivation to be at the top of a ranking can also be amplified by the ability to broadcast your exercise statistics via social media.

USING A FITNESS TRACKER CAN WORSEN EATING DISORDERS

This can, for obvious reasons, also have negative consequences for some people. One study examined the relationship between use of calorie counting and fitness tracking devices with eating disorder-related behaviour in college students [3]. Participants using calorie and fitness trackers manifested higher levels of eating concern and dietary restraint. Interestingly, fitness tracking, but not calorie counting, emerged as a unique indicator of eating disorder symptomatology. These findings suggest that for some individuals, these devices do more harm than good.

Should I Track?
It is nice to know your daily step count, heart rate, caloric intake, and the like, but wouldn’t you also have an approximate idea about these parameters if you simply reflected on your daily routine? Depending on how important it is for you to know the exact parameters, it makes sense to wear such a device... or not. Many devices have a built-in alarm that goes off if you have not move for a certain time. This might come in handy, but can also be annoying if you are at work and just can’t go for a walk right now. In the end, it always depends on the individual who wears the device.
If you are not prone to being overly critical about your weight, tracking your workouts and food intake can be motivating. But tracking everything might become obsessive for some, as the numerical focus of the trackers is akin to the obsessive fixation characteristic for eating disorders and exercise addiction.
It's true that these devices make you be more aware of your health. However, this can also be achieved without fitness trackers but instead with good education about lifestyle and health.

[1] Takahashi et al, Clin Interv Aging. 2016
[2] Jakicic et al, JAMA. 2016 
[3] Simpson et al, Eat Behav. 2017

by Claudia Willmes, PhD Alumni AG Eickholt/Schmitz

this article originally appeared June 2017 in CNS Volume 10, Issue 2, Digital Health and Big Data