Biological factors of ARFID
Characterized by an extremely finicky diet, ARFID is often confused with picky eating. But the disorder is so much more. If left unchecked it can lead to a number of physiological issues, including nutritional deficiencies and delayed growth in children.
Some ARFID causes are also physiological. While research on the disorder is nearly as new as its entrant in the Diagnostic and Statistical Manual of Mental Disorders (DSM), scientists are beginning to connect some important dots, leading to a greater understanding of what causes ARFID.
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Like all disorders, ARFID can impact anyone of any age and start at any time. Though the majority of people develop the first signs of ARFID during early childhood or even infancy. (1)
This aspect of the disorder can be especially insidious, as many young children will undergo spells of legitimate picky eating behavior that aren’t related to ARFID. In fact, one study estimated between 14-50% of preschool-aged children and 7-27% of older children will exhibit some form of “picky eating” behavior. (2)
Comparatively, signs of ARFID—when picky eating doesn’t subside after several months—have been confirmed in children as young as 14 months. (2) And several studies on the subject have continually found ARFID patients to be younger than those with other eating disorders, typically anywhere from 5-13 years old at onset. (2)
A primary part of ARFID is the "avoidant" aspect of the disorder, when certain foods or even whole categories of foods will be routinely rejected. Traditionally, this type of behavior has been connected to more cognitive responses, with people refusing to eat foods they're less familiar with and increased exposure to the foods leading to less resistance.
This isn’t the case with ARFID, however. And many scientists believe the reason their preferences don’t wax and wane like other forms of picky eating has to do with sensory sensitivity.
Some evidence has pointed to both adults and children who identify as “picky eaters” having a hypersensitivity to both sweet and bitter flavors, or certain textures, making the experience of tasting them intense and unpleasant. Scientists believe this may also play a role in what causes ARFID or maintains the disorder. (1)
Many people who struggle with ARFID report simply not feeling hungry or interested in food and say they'll just not remember to eat at mealtimes. And once again, research is increasingly backing up this symptom with biological evidence.
Previous studies have shown that women with certain restrictive eating disorders have decreased activity in the hypothalamus—the part of the brain responsible for sending out hunger signals. (1) Others show these women have less activity in an area of the brain called the anterior insula, which is involved with detecting taste and other certain sensory aspects of eating. (1)
While no studies have yet drawn these same conclusions for people struggling with ARFID, scientists have hypothesized that there may be a similar connection, resulting in those people having a naturally less active appetite. (1)
One of the newest studies on avoidant restrictive food intake disorder has found a significant link between people struggling with ARFID and a number of comorbid—or, concurrent—conditions.
The largest overlap fell between people struggling with avoidant restrictive intake disorder and people with autism, which has a comorbidity rate as high as 13%. (3) Scientists conducting these studies hypothesized that the connection may also help inform the sensory sensitivity many people with ARFID experience, as a strong response to certain textures is also a common sign of autism. (3) Aspects of autism could also contribute to the very rigid dietary boundaries of ARFID. (3)
A lesser, but still significant, commonality was found between people struggling with ARFID and people with a history of gastrointestinal issues. (3) This finding was backed up by several similar findings that reported a link between gastroesophageal reflux disease (GERD) and avoidant restrictive food intake disorder. (4) The thought, generally, is that eating is less pleasant, overall, for people with gastrointestinal issues, which could potentially contribute to the development of ARFID. (4)
Environmental factors of ARFID
Like all eating disorders, ARFID causes can stem from the person’s environment, as well as their genes. Unlike many eating disorders, however, there’s still limited information on what, exactly, these causes are.
Still, a number of related studies have been examined to bring to light certain commonalities in people struggling with avoidant restrictive food intake disorder, including critical details about their backgrounds and reactions to the world around them.
One of the biggest common links for people struggling with ARFID is a traumatic experience with food in their background. (1) This could include an incident such as choking, vomiting, or experiencing severe abdominal cramps after eating, which can lead to another cardinal symptom of ARFID: neophobia, or the fear of trying new things.
Still, the literature notes that, while many people have experiences like this in their lives, relatively few go on to develop ARFID. So the prevailing theory is that people with these types of traumatic triggers may have certain gene expressions that make them especially susceptible to developing ARFID after these incidents. (1)
That finding dovetails with another common experience for people struggling with avoidant restrictive food intake disorder: anxiety. One study actually found that as many as 50% of participating patients with ARFID also had a generalized anxiety disorder. (1)
It’s possible that anxiety can act as an appetite suppressant through its activation of fight-or-flight hormones, which could also reinforce someone with ARFID’s low interest in eating. (4) Much more research has to be done to solidify these links, however.
Social/peer pressure and competition
Avoidant restrictive food intake disorder is rare in the realm of eating disorders in that it doesn’t have anything to do with a person’s perception of body image. In fact, the lack of concern or fear over thinness or weight gain is one of the primary markers that separate ARFID from anorexia nervosa. (1,2)
Many cases of ARFID are thought to begin long before a child would be consciously aware enough of cultural norms or societal pressure to present as thin. (4) And, though some studies have made connections between the disorder and certain parenting responses, these are mostly thought to draw out or reinforce the issue, rather than to be what causes ARFID. (4)
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Treatment for ARFID
Since avoidant restrictive food intake disorder is both so newly recognized and highly specified, there aren’t currently any evidence-based treatment recommendations or strategies specifically for the disorder.
Unfortunately, this has led to some complications for people struggling with ARFID. One study found those patients were more likely to be admitted to the hospital at lower weights than those struggling with anorexia, struggled more to put on weight at the hospital, required the use of feeding tubes more frequently, and had higher readmission rates within one year of discharge. (2)
Still, people with ARFID were found to have similar recovery rates to those of people with anorexia nervosa, proving recovery is possible. (2) And a number of strategies have been examined and designed helpful on a case-by-case basis.
And since ARFID causes malnutrition in a number of patients, and childhood malnutrition has been studied for many years, there’s a larger amount of research on potential treatments for some of the adverse effects of avoidant restrictive food intake disorder.
In many cases, therapists have borrowed aspects of cognitive behavioral therapy (CBT) for treatment. While CBT is a broad approach with many different facets, therapists have found its elements of "exposure therapy" especially helpful. (4) In these cases, patients are slowly and steadily exposed to foods they fear in order to dislodge the concept that they're worthy of fear.
Another aspect of CBT that’s been heralded for use with ARFID is its focus on teaching relaxation techniques. These have been found to be especially helpful with the many ARFID patients simultaneously struggling with anxiety disorders, which has helped lead to a sustained recovery from the disorder. (4)
Scientists seem to agree that there’s much more investigation into this disorder—and the best treatments for it—that needs to be done. But seeking treatment for any eating disorder, including ARFID, is still very important.
If you or someone you know is showing signs of struggling with ARFID—including appearing underweight or not eating frequently—you should seek help immediately.