Last week, the FDA was out for blood. The blood of the people out for the blood of young people, that is.
In a scathing statement, the administration slammed companies offering a treatment known as parabiosis—transplanting the blood of the young into the bodies of the old. The FDA wrote that it had “significant public health concerns” about the the sci fi-like practice with “no proven clinical benefit.”
While Silicon Valley wasn’t named directly in the FDA’s statement, the implication was obvious. In recent years, startups across Palo Alto have been fighting to plant their foot in the industry. Valley billionaire and venture capitalist Peter Thiel has repeatedly expressed his interest in the treatment—and is even rumored to have tried it. Blood transfusions even made it on an episode of the HBO’s satirical comedy Silicon Valley.
But parabiosis is far from the Valley’s only beloved “biohack” that isn’t backed by rigorous scientific evidence. Here are three of the Valley’s other offenders.
Polyphasic Sleep
The Claim: Tech CEOs are always trying to increase their productivity—and one of the simplest methods is to sleep less, and work more.
That’s where polyphasic sleep—sleeping in multiple phases, for fewer total hours—comes in. There are a few different common polyphasic sleep cycles, including the Uberman variety, which consists of only 6 20-minute naps spaced evenly throughout the day, and the Everyman cycle, a 3.5-hour nap supplemented by three 20-minute naps.
Proponents of the technique—Leonardo DaVinci and Nikola Tesla were reportedly polyphasic sleepers, too—say that they can be just as productive with a fraction of the shut-eye. WordPress cofounder Matt Mullenweg has credited a (slightly modified) Uberman cycle with helping him develop the landmark content management system.
“It was probably one of the most productive periods of my life,” Mullenweg told author Tim Ferris in 2015. “I wrote WordPress in that time.”
The Reality: While there may be a very small number of people who can function well on minimal sleep, the science is clear for the vast majority of us: seven consecutive hours of sleep is vital for mental and physical well-being.
This big problem is this: No matter when they’re sleeping, polyphasic sleepers just aren’t getting enough shut-eye, Emmanuel During, a sleep specialist at the Stanford Sleep Medicine Center, told The Daily Beast. The Uberman schedule, for example, prescribes just 2 total hours of sleep a night; the Everyman recommends 4.5 hours.
Less than seven hours of sleep a night, and especially less than six, can cause myriad short- and long-term health problems in adults aged 18-60, During said, including decreased cognitive function, increased anxiety, and a higher risk of weight gain, diabetes, and heart problems.
“The bottom line is, for most adults, more than 7 hours is needed,” he said. (Notorious Silicon Valley short-sleepers like Elon Musk, Tim Cook, and Marissa Meyer should take note.)
But there’s another problem with a fragmented sleep schedule, During said. Sleeping in phases cuts back on the amount of rapid-eye-movement (REM) sleep, a critical phase that helps with mood regulation, memory, and psychological well-being—and that only typically occurs after a period of slow-wave sleep.
Proponents of polyphasic sleep claim that their bodies eventually learn to fall into REM sleep faster. But During disagrees: “These people who go into short naps almost never get into REM sleep,” he said. And even if polyphasic sleepers could hack their bodies to get the requisite level of REM sleep, they’re still missing out on the benefits of other sleep phases.
There’s another problem: circadian rhythm. Sleeping in phases throughout the day, During said, inherently disrupts the 24-hour biological clock that regulates our natural sleep and wake cycle. Falling out of sync with that clock, he added, will exacerbate many of the problems associated with typical sleep deprivation.
“You’re in a suboptimal state where health is not maintained,” During said, adding that “it’s a breakdown of all these pathways—blood sugars, cortisol—and all of the cognitive functions.”
Intermittent Fasting
The Claim: One of the most ubiquitous Silicon Valley bio-hacking is intermittent fasting: indulging on some days, and severely restricting calorie intake—or not eating at all—on others.
The fasting strategies vary. Facebook executive Dan Zigmond only eats between 9:30 am and 5:30 pm each day. A cadre of Silicon Valley intermittent fasting enthusiasts called WeFast abstains from food for one 36-hour period each week. Others follow the 5:2 diet, eating normally for five days and severely limiting their calorie intake for two.
One of the most prominent supporters is Phil Libin, former CEO of Evernote and current CEO of the AI startup All Turtles. Libin, like other proponents, told The Guardian that intermittent fasting leads to “euphoria,” and improved mood, focus, and energy. There’s alleged weight loss benefits, too: in a Medium post on intermittent fasting that eventually received over 1.3 million views, entrepreneur Sumaya Kazi claimed that she lost 50 pounds in eight months.
The Reality: The evidence isn’t there yet. While some people may lose weight or feel better from intermittent fasting, most of the hard scientific research backing its efficacy comes from animal studies—which don’t translate reliably to humans.
There have been a few human studies showing weight loss potential. A 2017 paper published in JAMA Internal Medicine, for example, showed that intermittent fasting was about as effective as a more typical daily calorie restriction at promoting weight loss. But the dropout weight was higher for intermittent fasters (39 percent) than it was for daily restriction (29 percent) or the control group (26 percent).
The other purported benefits, like increased insulin sensitivity and lower blood pressure, have remained largely confined to animal studies—and researchers are still working to determine if they’re inherent to the fast or just a byproduct of the weight loss. One study showed that cardiometabolic health, including insulin sensitivity and blood pressure, improved even if patients didn’t lose weight—but that study only included eight people, which is a remarkably small sample size.
Raw Water
The Claim: The most vocal Silicon Valley supporter of raw water—water that is unfiltered and untreated—is Doug Evans, the CEO of the now-defunct and widely mocked juicer startup Juicero. After Bloomberg reported that the benefits of Evans’ $400 juice press could be replicated by simply squeezing the produce packs by hand (yikes), and the company went under, Evans reportedly embarked on a 10-day cleanse during which he drank nothing but raw water.
Why? Proponents claim that natural, untreated spring water has beneficial minerals that are filtered out of conventional tap water—and that fluoride treatments (which have been hailed by the CDC as one of the top 10 public health interventions in the last century) are unnecessary and harmful.
“Tap water? You’re drinking toilet water with birth control drugs in them,” the founder of one popular raw water brand told The New York Times. “Chloramine, and on top of that they’re putting in fluoride. Call me a conspiracy theorist, but it’s a mind-control drug that has no benefit to our dental health.” He’s not alone here—conservative provocateur and noted conspiracy theorist Alex Jones isn’t a fan of fluoride, either.
The Reality: Evans was wrong about the need for Juicero. And he’s recklessly, dangerously wrong about the need for raw water.
“On the whole, I don’t think it’s particularly safe,” Ameet Pinto, an assistant professor of civil and environmental engineering at Northeastern University, told The Daily Beast. Pinto explained that municipal drinking water—the kind that comes out of your tap—goes through “quite rigorous treatment processes” to remove particles, organic matter, and pathogenic microorganisms.
“When you drink from a natural water source that has not gone through any of these treatments,” he added, "there’s always the potential risk that there’s some contamination.”
That contamination could be human-generated, like chemical pollutants dumped in a river. But even water that hasn’t been tainted by humans could pose a risk, Pinto said. That’s because most water is contaminated by small particles of animal feces that can carry pathogens like giardia and cryptosporidium. Both of those pathogens can cause parasitic intestinal diseases that can lead to diarrhea, vomiting, and dehydration that last for 1-2 weeks.
He also contested the claim that there’s anything wrong with water fluoridation. At unreasonably high concentrations, he acknowledged, fluoride can pose risks. But at the “very very low” levels found in fluoridated drinking water, he said, the public has no reason for concern. In fact, he added, they should be concerned if fluoride isn’t in the water supply, due to its well-documented role in preventing tooth decay.
And while he acknowledged that municipal water has its failures—most notably, the contaminated water crisis in Flint, Michigan—“extensive” testing and regulatory requirements make it the best possible option.
“It just feels quite peculiar when people are buying into something like this—and especially paying crazy high prices,” Pinto said, “when they could just open their tap in their homes and get a safe and reliable water supply.”
When it comes to unfounded health fads, one thing is clear: Tech CEOs, they’re just like the rest of us!
