How Dopamine Genes May Be Influencing Your Eating Behavior (DRD2)

The DRD2 Gene in Dopamine Function 

Dopamine is a crucial neurotransmitter in the brain, where it controls [R, R]:

• Motivation and reward
• Creativity and cognition
• Movement
• Social and parental bonding

The DRD2 gene encodes the D2 dopamine receptor — one of several vital types of dopamine receptors that regulate the activity of this neurotransmitter [R, R].

Unlike other major types of dopamine receptors, D2 receptors are inhibitory. This means that having more of these receptors generally results in lower overall dopamine activity in the brain, and vice-versa [R, R, R].

However, the situation is not always that straightforward: D2 receptor activity also enables dopamine-dependent reward pathways that make certain experiences pleasurable. DRD2 variants can impair the function of D2 receptors and correlate with addictive or reward-dependent behaviors [R, R].

Dopamine is a neurotransmitter crucial for emotional and mental health. The DRD2 gene codes for the D2 receptor found mostly in our brain’s reward pathways.

D2 Receptor Function & Eating Behavior

Dietary habits depend heavily on the “anticipatory” and “rewarding” effects of food. Hence, it is no surprise that dopamine plays a key role in food intake and eating behavior via D2 receptors [R].

Along with substance abuse and other addictive behaviors, impairments in D2 receptor signaling can contribute to different eating disorders and influence food preferences [R, R, R, R, R].

Some scientists argue that addiction to tasty, energy-dense food may trigger some of the same mechanisms involved in drug addiction (albeit to a lesser extent). These highly “rewarding” foods may cause the brain to release large amounts of dopamine, which could “over-stimulate” the brain’s reward pathways. Eventually, this strong, long-term dopamine stimulation could result in the reduction (“down-regulation“) of the total number of D2 receptors in the brain [R, R].

D2 dopamine receptors enable the reward pathways that influence our eating behavior and food preferences. Eating disorders and addictive behaviors have been associated with impaired D2 signaling.

When it comes to the genetic influences of D2 receptor function, most research has focused on one SNP: rs1800497.

Studies often also mention other SNPs — such as rs2283265, rs1076560, rs6275, rs6277, rs6279, and rs2514218 — but these variants are often all inherited together with the variant you carry for rs1800497, so they usually don’t represent truly “independent” genetic factors [R, R, R, R].

Food Preferences

According to five clinical trials with over 1,300 participants, the ‘A’ (also known as the “A1”) allele correlates with a higher preference for [R, R, R, R, R]:

• Carbohydrates (especially sugar)
• Fast food
• High-fat, fried foods

Interestingly, these effects also seem to be independent of age, gender, and ethnicity.

One study of 26 volunteers used brain imaging to measure how the brain responded to tasty food, depending on the rs1800497 variant each participant carried. When given a delicious milkshake, all participants rated its tastiness similarly — but those carrying the ‘A’ allele showed a blunted (weaker) response in the reward system [R].

People with rs1800497-A crave tasty, energy-dense foods — but the feelings of “reward” they experience upon consumption may be relatively weaker.

Eating Behavior

Among 394 Malaysian adults, those with the ‘A’ allele were more prone to uncontrolled eating [R]. Similarly, in a trial of 279 Dutch adolescents, this variant correlated with emotional eating in response to high psychological control from parents [R].

In two smaller studies, rs1800497-A correlated with high food reinforcement, which means people with this allele were willing to work harder to obtain food they liked. Consequently, they ultimately consumed significantly more calories than people with other alleles [R, R].

This same genetic variant has been associated with other dopamine-related issues, such as eating disorders, substance abuse, and impulsive behavior [R, R, R, R]. 

rs1800497-A has been associated with increased food cravings, emotional eating, and sometimes even the development of eating disorders.

Obesity & Weight Maintenance

The link between rs1800497 and obesity has been a topic of intense research, although some of this work has produced conflicting results.

According to a large meta-analysis of 33 trials, there was no strong or consistent correlation between this variant and body mass index (BMI). However, people with the ‘A’ allele may not respond well to (or comply with) weight-loss interventions, possibly due to increased impulsivity making it harder for them to make healthy food choices [R].

In one study, rs1800497-A showed a much stronger correlation with obesity among people with substance use disorders [R].

The link between rs1800497 and obesity is not straightforward and likely depends on other factors, such as impulsive behavior and/or predispositions toward substance abuse and other dopamine-related issues.

How It Works: The Two Faces of Dopamine

rs1800497 is found in the gene ANKK1, which controls the activity of DRD2 gene. The ‘A’ (“A1”) allele correlates with a 30% lower number (“density”) of D2 receptors [R, R, R].

According to the primary suggested mechanism, reduced D2 density may hinder the reward system. This could cause people with rs1800497-A to overeat, and/or choose high-fat and high-sugar foods to compensate for the relative lack of pleasure they experience when eating other, healthier foods [R, R, R].

However, the D2 dopamine receptors are inhibitory, so their lower density implies higher overall dopamine levels [R, R, R]. While this might seem counter-intuitive, some authors have suggested that — contrary to popular belief — dopamine might not be responsible for making us feel “pleasure” from rewards per se — instead, dopamine makes us “want” the reward. Thus, excessive dopamine activity could actually cause a vicious cycle of food-craving, due to increased motivation for tasty food [R].

The rs1800497 variant significantly reduces D2 dopamine receptor density in the brain. This may impair the reward system, and could pave the way for “addictive” behavior by contributing to greatly increased motivation for eating unhealthy foods.

Food for Thought: Research of dopamine-dependent reward mechanisms has led some scientists to ask a fundamental question: Is modern society turning us into “mindless pleasure junkies”? In support of this idea, these authors have pointed to the fact that people may becoming more and more addicted to short-term dopamine-boosting experiences, while neglecting “longer-term” concerns such as overall prosperity, health, and well-being [R].

We’ll return back to this intruiging idea later on, so keep reading for a potential solution these authors are offering!

SNP Summary

Primary SNP:

rs1800497

• ‘G’ (“A2”) allele = not associated with eating behavior
• ‘A’ (“A1”) allele = associated with overeating, emotional eating, and unhealthy food choices

Population Frequency: Around 33% of European descendants carry the ‘A’ allele. However, this variant is up to twice as common among East Asian and African populations (64-65%).