Thursday, March 12, 2015

Food Addiction

            You open a bag of chips and plan on only eating a few from the bag.  Before you know it, the entire bag is gone.  Perhaps you decide to eat a scoop of ice cream, but somehow, you ended up finishing the entire tub instead.  Everyone has encountered situations like these before.  However, there are some people who have a lack of self-control, and it leads to them compulsively overeating, which poses a threat on their health and put them at a high risk for obesity.  

http://www.yalescientific.org/wp-content/uploads/2011/05/features-brainfood-1.jpg

There are neural pathways in the brain with regards to these types of reward and motivational behaviors.  Foods that are particularly high in fat and sugar are highly associated activating these systems in the brain.  Obesity is becoming a growing problem in the United States recently; in the “past three decades the average prevalence of obesity in the US adult population has risen from below 20% to 35.7%” (Stice et al. 2013, 2).  The fight against obesity in the United States is not a simple one.  The problem of obesity can be looked at similar to that of drug addiction.  Telling a drug addict to “just say no” to drugs is not very effective.  Likewise, telling people to simply eat less or to “just say no” to foods high in fat and sugar is not that easy either.  People tend to generally place the blame on the individual for overeating, but that may not simply be the case.  There are neurochemicals reward pathways in the brain that are strong enough to override the normal willpower in controlling people’s hunger, resulting people eating more than they want and placing them at a higher risk for obesity.  Recent research has shown that there are many parallels between the behaviors of overeating and drug use in the brain.  Analyzing obesity with this perspective and by showing how compulsive overeating can have the same effects of drug use on the neural pathways in the brain can help researchers to further understand the underlying pathology of obesity as not just a metabolic disorder, but as a brain disorder as well.

The main pathway that is involved in the reinforcing and addictive behaviors in drug abuse is the mesolimbic dopaminergic pathway. Research has shown that the signals that inform the metabolic and nutritional status act on the same pathway of the brain as well, as these signals travel to the mesolimbic dopamine neurons that has projections to the ventral tegmental area (VTA) to the nucleus accumbens. The VTA, nucleus accumbens, and other striatal regions of the brain are activated when either a drug or a certain palatable food activates the reward pathway. Overlapping signals of the same regions of the brain in both drug use and particular foods show that both behaviors are engaged in the same reward pathway in the brain.

Food and drug intake are also similar in their effects on dopamine signaling and can affect the neural plasticity of the reward pathway. Consumption of foods high in fat and sugar enhances the release of dopamine in the striatum, resulting in the increased feeling of pleasantness after eating a meal high in fats and sugar. Over time, due to the increased levels of dopamine in the brain, there is an alteration in the neural pathway, resulting in the decrease of D2 receptor binding and availability in the striatum and other brain regions involved in the pathway. By altering the sensitivity of these regions, the down regulation of receptors cause an increase in the behavior, such as overeating or increased drug intake, in order to release more dopamine to maintain or increase the same pleasurable effect due to the behavior. This tolerance to a drug or food has detrimental effects on a person as it results in a person consuming more of the food or drug, leading to dire consequences in their health.

It can be said that foods highly processed in fat and sugar is biologically addictive, as these types of foods can overstimulate this reward pathway. A study has shown that even though the rats were trained to fear the shock, the rats would disregard the warning signal before the shock and continue to eat the high-calorie foods high in fat and sugars. Their uncontrollable desire to devour these types of food regardless of their trained fear of the shock shows how powerful the motivational reward pathway in the brain can be. Because this behavior physically alters and rewires the neurochemicals pathways in the brain, it becomes difficult for people to break the habit of overeating.

There are slight differences, of course, between overeating and addicted drug use. Even though both food and drugs serve as strong reinforcing attributes to this neural reward pathway, food is considered necessary for survival while drugs are not. Overall, similar neural pathways are being used in the brain from addicted drug use and uncontrollable eating and how these behaviors are physically altering and rewiring the reward pathways in the brain. This lack of self-control can lead to many people in becoming obese, which is why it is currently becoming a growing problem, as obesity is shown to be more than just the problem of the individual at the surface. Seeing parallels between the two behaviors of overeating and addicted drug use can provide valuable insight and a new perspective into further research toward designing new treatment approaches for obesity.

References:

Hyman, Mark. "Food Addiction: Could It Explain Why 70 Percent of America Is Fat? - Dr. Mark Hyman." Dr. Mark Hyman. Np.p., 18 Oct. 2014, Web. 03 Mar. 2015.<http://drhyman.com/blog/2011/02/04/food-addiction-could-it-explain-why-70-percent-of-america-is-fat/#close>

Kenny, Paul J. "Is Obesity and Addiction?" Scientific American. N.p., 20 Aug. 2013. Web. 10 Mar. 2015. <http://www.scientificamerican.com/article/is-obesity-an-addiction/?page=1>.

Stice, Eric, Dianne P. Figlewicz, Blake A. Gosnell, Allen S. Leine, and Wayne E. Pratt. “The Contribution of Brain Reward Circuits to the Obesity Epidemic.” Neuroscience Behavior Review 37 (2013): 1-24. Web.

13 comments:

  1. I read an article recently that indicated that the US has added sugars in food products that have been considered healthy. I would think that this hidden sugar content in so-called "healthy food" is causing a food addiction from a very young age. Even in products such as bread there is extra sugar and if parents are unaware of how much sugar is added in the foods they are giving to their kids, they could be creating this food addiction as the child develops, making it even more difficult to break the habit in adulthood.

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  3. I learned in my endocrinology class last year that obesity is also associated with certain hormones, i.e. leptin, ghrelin, etc which help control satiety. Perhaps, there is an interaction between these hormones, whether lack there of or the opposite (too much), and the neural pathways. This could be an interesting topic for research in future studies.

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  4. This blog post is relevant to a psychopharamacology class I took at Colgate, which focused not only on how drugs affected the brain, but also on how other common substances, such as processed sugars, could alter reward circuits and influence addiction. One study we focused on prepped rats with sugar supplements before exposing them to methamphetamines. Brain activity revealed that the rats were primed for addiction to the drug as their reward circuitry had already been altered by sugar exposure. In contrast, control rats did not immediately become addicted to the drugs and instead took longer for brain circuitry to be impacted. This post reinforces the idea that obesity may not be all about self-control, but instead relies upon complex pathways in the brain and perhaps hormone interactions there-in, which are comparable to altered states of the brain as seen in cases of drug addiction.

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  5. I think it's really interesting to look at obesity/over-eating from the context of addiction. It gives me hope that someday we will be able to actually create treatments that will be able to help people overcome obesity and return to a healthy body weight. I would be curious to learn more about what mechanism allows some people to only binge eat occasionally while others feel the need to do it day-after-day, resulting in their condition.

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  6. I find it very interesting how eating certain foods can be associated with a drug addiction. It is true that obesity is a huge problem in the United States due to the very large portions served and the surplus of fast food restaurants. To me, it is crazy to think that some foods can actually be considered addictive because of the effect they have on a person's body. Self control is something that obese people lack, but also what about those who are anorexic and bulimic. Could it be said that they have a lack of self control because they do not have the power to eat what they want and keep it in their system? I think that the way diseases like those effect the body would be an interesting topic to go along with this post.

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  7. I think it is very interesting that people with obesity can show D2 receptor abnormalities that are similar to drug addicts. This shows why, just like it is hard to kick an addiction, it is hard to lose weight. It demonstrates why usually people who get liposuction to lose weight end up gaining that weight back within a year. It also makes me wonder, do underweight people have GREATER D2 receptor density? Or is their density the same as a normal weight person.

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  8. The comparison between food addiction and drug addiction, and I think the comparison of these two could help society the true impact of a food addiction. Dopamine receptors are affected in both cases, and the struggle that both addictions cause is very similar. However, in the case of drugs, society has developed rehabilitation clinics, hotlines, and other ways to help hedge addiction. For food however, society tends to place the blame more on the individual, and is reluctant to help. This is something that has to change if we as a society are to correct the rising obesity problem.

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  9. While some people who previously commented might not see the connection between a food addiction and drug addiction shown in the D2 receptor abnormailties, I can clearly see a link. Sugar, salt, and fat are addicting. Theyre good and they satisfy someones needs for that short amount of time of consumption, and then they go into a low again, and return to food like a drug addict would do with the same cause and effect food has. It'll be interestin in the future what will be done about food addictions and obesity in America and the world.

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  10. I thought this article was very interesting because we typically think about overeating as a meter of self control but when thought of in terms of an addiction your brain truly is making you eat. I don't know if anyone has seen the documentary "Fed Up" but it is a really interesting take on the obesity epidemic and is definitely worth watching. I think restructuring the way we think about waiting and obesity can help solve the problem rather than blaming it on a lack of self control.

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  11. As a visitor to the US I find it incredible how much packaged, processed, sugary and fatty foods are on offer in US supermarkets (compared to my home at least). I think the goal of making food easier and more convenient is the ultimate downfall. I'm not saying obesity would be cured if there were no more rolls of cookie dough or fast food restaurants but the opportunities for overeating and poor food choices are everywhere! The culture needs to shift

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  12. I 100% agree that overeating is a neurological condition and its similarities to addiction is almost alarming. I've personally experienced instances like this and it always seems to occur with fatty/sweet foods. If only people could get addicted to vegetables! I'd be interested to see if any treatments for addiction can also lead to treatment options for overeaters as well.

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  13. I feel like part of the reason people aren't as likely to take food addiction seriously or to see it in parallel with drug addiction is that everyone can relate to eating too much or not wanting to stop eating, but they can control themselves a majority of the time, so they view it as a matter of self control. On the other hand, most of us have never been addicted to or even tried hard drugs like heroin or crack and only know from what we have been told that it is very dangerous and addictive, so who are we to say that it is not.

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