The Reason Some People Crave Dirt, Lemons, And Even Toilet Paper

"Normal" or not?
We’ve all had a craving for salty, savory, or sweet (hello, chocolate!). But sometimes that urge to satisfy our taste buds can seemingly only be filled by the strangest substances. 
Weird cravings can include paint, lemons, dirt, ice, chalk, clay, pebbles, sand, hair, metal — and even toilet paper, according to a recent report of a British mom who can’t use the bathroom without noshing on this non-nutritive household item.
What’s going on here? Let’s take a closer look at why we crave — both the normal stuff and the strange stuff.
Cravings, explained
If you’ve ever wondered why you simply can’t move on until you’ve had a slice of pizza or a piece of German chocolate cake, you’re not alone: Scientists have been trying to figure out the mystery of cravings for some time. 
There are a few major theories behind garden-variety cravings, says Dana Hunnes, PhD, MPH, RD, a senior dietitian at Ronald Reagan-UCLA Medical Center. One theory is that low levels of the calming hormone serotonin trigger the desire for our favorite foods, in turn increasing levels of serotonin and endorphins, which then make us feel good. (If you’ve ever felt the instant gratification after a cup of gelato, this idea’s not hard to believe.)
Another theory, says Hunnes, is that our hypothalamic-pituitary-adrenal axis (HPA) needs to call timeout. Since this part of the brain’s neuroendocrine pathway controls reactions to stress when disrupted, the urge for a break may increase desire for certain substances, foods, or even activities. Cravings.
A third theory is that our brains are just pretty darn smart, and can signal when there’s an internal need. “If we are missing some nutrient in our body, or are deficient, our body will naturally seek out, or crave, foods or other items that contain that missing nutrient,” Hunnes tells Yahoo Health.          
Why you might crave the weird stuff
This final theory, about our bodies seeking out nutrients, is what most experts focus on when it comes to why we might have odd cravings.
If you’re deficient in an important vitamin or mineral, your body will begin to seek it out — somewhere, anywhere, even if it’s not a correct source. “Consuming non-food substances such as chalk, clay, coal, pebbles, dirt, or possibly even ice, has been associated with iron-deficiency anemia,” Hunnes says.
“There is a theory that, in addition to iron-deficiency, there may be other nutrient deficiencies that may be present, and eating these abnormal items may help to fill some of those nutrient gaps,” she says, indicating that’s at least what your body assumes.
Other weird cravings? According to Hunnes, craving lemons has been associated with vitamin C deficiency and iron-deficiency anemia. Chewing ice has been associated with iron-deficiency anemia, possibly to overcome the chronic fatigue associated with the condition, according to an October 2014 study.
The downside is that most of these cravings are non-nutritive, meaning if you’re lacking in a mineral — say, iron or zinc — and have a strange urge to taste chalk, it won’t provide you any nutritional support. In fact, in some cases, these substances that aren’t meant to be edible may leech nutrients from your system, or disrupt normal intake of mineral-rich foods.
Jessica Setnick, MS, RD, CEDRD, a senior fellow at Remuda Ranch Eating Disorder Treatment Center explains it like this: “There may be some kind of misfiring in the brain that confuses one thing with another,” she tells Yahoo Health. “Someone looks at chalk and thinks, ‘I would like to eat that.’ Even though there is another part of their brain that is aware that the chalk is not food, the compulsion is overwhelming to eat it.”
From a psychological perspective, Robert London, MD, a practicing psychiatrist for more than three decades and a National Columnist for Elsevier/Frontline, says he’s seen people obsessively crave weird substances for a variety of reasons. 
“Some simply desire a specific texture in their mouth,” London tells Yahoo Health. “This is more commonly seen in women and children, and in areas of low socioeconomic status. Particularly it is seen in pregnant women, small children, and those with developmental disabilities such as autism.”  
The link to pregnant women may provide another clue as to the source, explains Setnick. “The fact that this happens when women are pregnant is a clue to me that it is hormonally related,” she says. 
While cravings are fine, the moment you start to persistently obsess over paint or sand is the moment you should talk to your doc. “Ones that become compulsive and can cause permanent damage to your health, like eating indigestible objects like metal, dirt, hair, or inhaling toxic chemicals,” are concerning cravings, says London. “These are considered a medical condition.”
What makes people want to eat dirt
The medical condition London is referring to is pica, an eating disorder whereby men and women crave non-nutritive substances like paint, dirt, or clay. The condition doesn’t resolve itself quickly and on its own. “These actions must persist for more than one month, and at an age where eating these objects is considered developmentally or culturally inappropriate,” says Hunnes. “It is different from normal cravings, mostly related to the fact that it is for non-nutritive, non-food items.”
Pica cravings might be the result of that mineral deficiency, but like most eating disorders, many cases may result from the interplay of multiple issues — hormonal, behavioral, environmental, and so forth. “Biochemicals, stress, sleep, hormonal changes and exercise are all factors,” says London.
Experts aren’t entirely sure how many people currently live with pica, since estimates are based on only those who have sought treatment. “Doctors can only assess those who have developed stomach or other complications due to the volume of the non-food items they have eaten,” says Setnick, who has seen people with pica cravings ranging from packets of artificial sweetener, to cardboard and flour.
Hunnes says some estimates of pica sufferers suggest up to 50 percent of those with iron-deficiency anemia may have some kind of pica craving. And since, according to the World Health Organization, 30 percent of people worldwide are thought to have an iron deficiency, non-nutritive cravings could be more common than realized.
So, why do we think they’re “weird” if they’re so common? Like any eating disorder, people would rather not talk about it. “It’s the social and psychological stigma of consuming these non-food substances,” says Hunnes. “It is nearly impossible to accurately assess how many individuals have pica. Researchers estimate prevalence to be anywhere from 8 percent to 65 percent of individuals who have iron-deficiency anemia.” So, that could be a lot of weird cravings.
Those with pica sometimes have even greater mineral deficiencies as the condition progresses and cravings interfere with normal healthy eating. The disorder also puts people at risk for infections from excessive bacteria on non-food items, toxins within non-food items, and issues like constipation if items cannot be digested (think metal objects such as pennies, for instance).
Since pica can lead to a host of complications, it’s important to speak up if you (or your child, or someone close to you) experiences bizarre cravings.
When you should see a doc
Talk to your doc about pica if you have a persistent craving for anything that falls in the non-nutritive spectrum — ice, dirt, chalk, paint, toilet paper, you name it. Trust your gut (literally) if your urge feels off.
Not only could the substance be harmful to your health — ingesting metal might cause an intestinal blockage, or paint may give way to lead poisoning in children — but it may be the sign of an underlying condition.
“There is likely a physiological or psychological explanation for the consumption of these items that should be treated,” says Hunnes. “It might be iron-deficiency anemia, or other neurological or hormonal conditions.”
According to London, a doctor will do a full medical evaluation to assess for nutrient deficiencies, as well as the potential harm non-food substances may have caused in the body — especially if they’re known to contain toxins. 
Thankfully, many times, docs can identify the source of the issue — and it’s oftentimes that key mineral we’ve been talking about. “Worth noting, most of these non-food cravings appear to resolve, or at least significantly decrease, with the normalization of iron levels,” Hunnes says. Other signs of iron-deficiency anemia are fatigue, lightheadedness, weakness and shortness of breath, so talk to your doc about any other symptoms you have in addition to the craving.
In some cases, pica needs to be treated with therapy. After a physician checks for deficiencies, docs tend to use a multi-faceted approach including developmental, behavioral, and environmental therapy.
“A psychiatrist will evaluate if there is a background issue of anxiety, depression, or obsessive-compulsive disorder, and a dietitian can ensure that the individual knows what to eat for good nutrition and to strategize alternatives of what to eat when the cravings hit,” says Setnick. “A counselor can also address the behavioral aspects, and help the individual identify and manage any external elements that trigger the cravings, such as stress or emotions.”
Ultimately, the prognosis depends on the case. Pica may stop spontaneously in children and pregnant women (blame those hormones), but it can go on for years, especially in people with mental and developmental disabilities, unless treatment is sought.
“A number of cravings are simply built into our DNA, and are the reason why some people crave sugar over salt and vice versa,” says London. “But if you find yourself becoming obsessively compulsive about anything for an extended period of time, you should see a specialist about it.”