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Surprise! There’s Little Medical Evidence to Support Flossing Your Teeth

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Despite everything your dentist has ever told you, there’s not all that much scientific evidence that supports daily flossing, a major investigation by the Associated Press finds. 

“The AP looked at the most rigorous research conducted over the past decade, focusing on 25 studies that generally compared the use of a toothbrush with the combination of toothbrushes and floss. The findings? The evidence for flossing is ‘weak, very unreliable,’ of ‘very low’ quality, and carries ‘a moderate to large potential for bias,’” the news service reports. 

The American Dental Association and the American Academy of Periodontology have both asserted that flossing is an essential part of dental hygiene. But the studies they cite to back up this claim, the AP says, are marred by major design flaws, including outdated methods, small samples, or short time frames. (Some studies, for example, lasted just two weeks—which is not enough time for a cavity or dental disease to develop, the AP points out.) And many studies on flossing are designed and paid for by the companies that sell floss, like Procter & Gamble and Johnson & Johnson. Industry-funded research findings can be legitimate, but when a private company is designing and paying for studies, there are many opportunities to bias the results in favor of the corporation’s bottom line. 

This is a potential problem in many health-related industries, including pharmaceuticals, as The Washington Post argued in 2012:

“Company executives seeking to promote their drugs can design research that makes their products look better. They can select like-minded academics to perform the work. And they can run the statistics in ways that make their own drugs look better than they are. If troubling signs about a drug arise, they can steer clear of further exploration.”

Nutrition studies funded by the sugar industry, for instance, tend to gloss over the major health risks associated with sugar, and only last year, Coca-Cola and other beverage companies sponsored a study that found that drinking diet soda was more beneficial to weight loss than water. While Procter & Gamble may have a stake in finding the best ways to keep your teeth healthy, the company also benefits if you buy more of those little plastic floss picks it sells, regardless of whether you need them or not. 

This year the U.S. government dropped flossing from its dietary guidelines for the first time since it was included in 1979. The government told the AP that its effectiveness had not been researched, which is required by law for inclusion in the guidelines.  

Flossing is a relatively low-cost, low-risk activity for the average dental patient, so it’s not particularly surprising that more dentists haven’t come out against it. But that doesn’t necessarily mean it’s necessary.   

Read more about it from the AP.

Know of something you think we should cover? Email us at tips@mentalfloss.com.

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science
New Patient Test Could Suggest Whether Therapy or Meds Will Work Better for Anxiety
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Like many psychological disorders, there's no one-size-fits-all treatment for patients with anxiety. Some might benefit from taking antidepressants, which boost mood-affecting brain chemicals called neurotransmitters. Others might respond better to therapy, and particularly a form called cognitive behavioral therapy, or CBT.

Figuring out which form of treatment works best often requires months of trial and error. But experts may have developed a quick clinical test to expedite this process, suggests a new study published in the journal Neuropsychopharmacology.

Researchers at the University of Illinois at Chicago have noted that patients with higher levels of anxiety exhibit more electrical activity in their brains when they make a mistake. They call this phenomenon error-related negativity, or ERN, and measure it using electroencephalography (EEG), a test that records the brain's electric signals.

“People with anxiety disorders tend to show an exaggerated neural response to their own mistakes,” the paper’s lead author, UIC psychiatrist Stephanie Gorka, said in a news release. “This is a biological internal alarm that tells you that you've made a mistake and that you should modify your behavior to prevent making the same mistake again. It is useful in helping people adapt, but for those with anxiety, this alarm is much, much louder.”

Gorka and her colleagues wanted to know whether individual differences in ERN could predict treatment outcomes, so they recruited 60 adult volunteers with various types of anxiety disorders. Also involved was a control group of 26 participants with no history of psychological disorders.

Psychiatrists gauged subjects’ baseline ERN levels by having them wear an EEG cap while performing tricky computer tasks. Ultimately, they all made mistakes thanks to the game's challenging nature. Then, randomized subjects with anxiety disorders were instructed to take an SSRI antidepressant every day for three months, or receive weekly cognitive behavioral therapy for the same duration. (Cognitive behavioral therapy is a type of evidence-based talk therapy that forces patients to challenge maladaptive thoughts and develop coping mechanisms to modify their emotions and behavior.)

After three months, the study's patients took the same computer test while wearing EEG caps. Researchers found that those who'd exhibited higher ERN levels at the study's beginning had reduced anxiety levels if they'd been treated with CBT compared to those treated with medication. This might be because the structured form of therapy is all about changing behavior: Those with enhanced ERN might be more receptive to CBT than other patients, as they're already preoccupied with the way they act.

EEG equipment sounds high-tech, but it's relatively cheap and easy to access. Thanks to its availability, UIC psychiatrists think their anxiety test could easily be used in doctors’ offices to measure ERN before determining a course of treatment.

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Food
A Pitless Avocado Wants to Keep You Safe From the Dreaded 'Avocado Hand'
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The humble avocado is a deceptively dangerous fruit. Some emergency room doctors have recently reported an uptick in a certain kind of injury—“avocado hand,” a knife injury caused by clumsily trying to get the pit out of an avocado with a knife. There are ways to safely pit an avocado (including the ones likely taught in your local knife skills class, or simply using a spoon), but there’s also another option. You could just buy one that doesn’t have a pit at all, as The Telegraph reports.

British retailer Marks & Spencer has started selling cocktail avocados, a skinny, almost zucchini-like type of avocado that doesn’t have a seed inside. Grown in Spain, they’re hard to find in stores (Marks & Spencer seems to be the only place in the UK to have them), and are only available during the month of December.

The avocados aren’t genetically modified, according to The Independent. They grow naturally from an unpollinated avocado blossom, and their growth is stunted by the lack of seed. Though you may not be able to find them in your local grocery, these “avocaditos” can grow wherever regular-sized Fuerte avocados grow, including Mexico and California, and some specialty producers already sell them in the U.S. Despite the elongated shape, they taste pretty much like any other avocado. But you don’t really need a knife to eat them, since the skin is edible, too.

If you insist on taking your life in your hand and pitting your own full-sized avocado, click here to let us guide you through the process. No one wants to go to the ER over a salad topping, no matter how delicious. Safety first!

[h/t The Telegraph]

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