Citrus fruits are considered a superfood. But can they also help you sleep or avoid motion sickness?

You've probably come across a lot of claims about what citrus can supposedly do — like lightening your hair on the cheap, sniffing lemon juice to prevent motion sickness or upgrading your health when you drink a morning mocktail of lemon juice and (welp) olive oil. More recently, a mom on TikTok, Jess Lynne, has been credited with creating the viral "lime sleep hack," which involves slicing a lime in half, placing it in a bowl and setting that next to a child's bed to keep them snoozing through the night.

While there's no question that fruits like lemon, lime, orange and grapefruit have many health benefits, not all of the claims associated with citrus actually hold up. Here's what it can and cannot do.

Can limes help with sleep?

Speaking to Yahoo Life over email, Lynne, a psychic medium, says she was inspired by various cultures' use of the fruit throughout history “to rid negative, fear-based energies and dark entities in their surroundings” and “promote peaceful sleep."

However, Dr. Luis Ortiz, a sleep medicine physician from Johns Hopkins All Children’s Hospital, tells Yahoo Life there is only limited clinical evidence to support claims that the smell of limes helps people sleep; most of that is preliminary research that hasn’t undergone rigorous study yet, he says.

Ortiz says it is possible that the aroma of citrus may help people calm down and relax before bed, and there is limited clinical evidence to support the benefits of aromatherapy in sleep. But while “there is more literature out there that suggests aromatherapy can help with anxiety,” there are also papers that “report citrus essential oils actually improve alertness and reduce drowsiness,” Ortiz notes. That would, in theory, not be conducive to sleeping.

While smelling cut limes isn’t likely to harm a child or anyone else trying to get a better night's rest, Ortiz cautions parents to be careful with essential oils, whether they're lime-based or not. “You never want to ingest it, and you don't want to use a water-based diffuser as it can last in the room for extended periods," he says. "Overexposure to essential oils has been found to irritate the lungs and interfere with mucus clearance."

Can smelling a lemon prevent motion sickness?

Possibly, says Krutika Nanavati, a registered dietitian and nutritionist. Citric acid, a main compound in lemon, can have a “calming effect” on the stomach and a “distracting effect that can shift one’s attention away from the feeling of nausea,” Nanavati tells Yahoo Life. However, these benefits aren’t exclusive to citrus. Peppermint and ginger may also provide relief from nausea and motion sickness, she notes.

Can citrus help prevent cancer?

For the most part, yes. “There is data that shows consuming citrus fruit reduces risks for [some] types of cancer, particularly oral cancers, pharynx, esophagus, lung cancer and cancers of the kidney and the bladder,” Heidi Silver, a research professor at Vanderbilt University Medical Center, tells Yahoo Life.

However, researchers have also found a link between consuming citrus (such as oranges and orange juice) and an increased risk of melanoma. “Consuming citrus juice could actually increase the risk to certain types of skin cancer, and that’s because of an interaction between components in the citrus juice and ultraviolet rays,” Silver explains.

She adds that people who consume excessive citrus juice and expose themselves to excessive sun have an increased risk for all three types of skin cancers: basal, squamous cell and melanoma.

Can citrus help with weight loss?

Silver says it’s possible. She co-authored a study that found that people who ate half a grapefruit or drank half a cup of grapefruit juice before every meal lost more weight than people who drank a glass of water before eating as part of a reduced-calorie diet. Participants who ate the grapefruit also saw an increase in “good cholesterol" (HDL), a decrease in appetite and an increase in vitamin C, which is typically under-consumed in the U.S.

Can citrus help prevent kidney stones?

Yes, particularly lemon and lime. As Silver explains, "Increased intake of citrus can increase the amount of citrate in the urine, and urinary citrate binds to excess calcium,” which is one of the more common causes of kidney stones. "So ingesting citrus can help prevent [kidney stones] or a reoccurrence," she says. Lemon water, anyone?

Can citrus prevent cardiovascular disease?

Maybe. A 2011 study in Japan found that frequently consuming citrus fruits could reduce the incidence of cardiovascular disease, including stroke and cerebral infarction. The flavonoids in citrus may also help reduce inflammation, which increases a person’s risk of heart disease. According to Dr. Michael Ayers, an assistant professor in cardiology at UVA Health, “Anything you do to mitigate inflammation likely reduces the progression of heart disease." But he adds that “overall, the body of evidence supporting individual food groups having a large effect size on cardiovascular outcome is minimal at best and speculative at worst.”

Still, Ayers believes there is little harm to people adding citrus to their diet to see if it helps. But the type of citrus matters. “You should eat the whole fruit and not [just] drink the juice," says Dr. Ana Baylin, an associate professor of nutritional sciences at the University of Michigan School of Public Health. "Even though the juice has vitamin C, it doesn’t have the fiber,” she explains, so it’s not “as beneficial."

Are there any people who should avoid citrus?

Because citrus is very acidic, Baylin says that people with gastritis and ulcers may want to avoid it. Consuming too much citric acid can also cause dental erosion, Silver says, so people with dental concerns may want to be more cautious when eating citrus fruits.

Baylin adds that it's also best to consider grapefruit and grapefruit juice carefully, as they can "interfere with some medications." Specifically, Silver says, people taking statins or those with chronic diseases who are on immunosuppressant drugs may be advised to avoid citrus, especially grapefruit.

And while there are many good reasons, in general, for most people to enjoy some citrus, it's possible to overdo it. If you're experiencing “gastrointestinal symptoms like diarrhea or bloating" after eating, say, your fourth orange of the day, you might be eating too much, Silver says.