Monthly Archives: April 2017

Artificial sweeteners won’t help you lose weight

If you’re gonna call something “diet,” it should have to actually help you lose weight. But like dieting itself, diet foods don’t work as well in practice as they do in theory.

So put down that Coke Zero and listen up. Maybe you think the jury is still out on artificial sweeteners. Someone once told you they cause cancer. Someone else said they could help you kick your sugar habit. Yet another person claimed that only natural sweeteners are healthy, so you considered switching to stevia. Well, there’s good news and bad news.

The good news is that the scientific verdict on this stuff is actually pretty clear. The bad news is that none of those artificial sweeteners will help you lose weight. Oops.

This may be a revelation to you and that sanctimonious stevia sipper in your yoga class, but it’s not news to the medical community. Years of research has shown little benefit to switching from the real deal to a sugar-imitator. It’s just in the news now because of a meta-analysis published on Monday in the Canadian Medical Association Journal. A meta-analysis is basically when a group of researchers search for all the studies done on a certain topic and gather them to see whether there’s some overarching consensus. In this case, they searched for all the research about whether zero-calorie sweeteners helped people lose weight.

The vast majority of the studies they found were observational, so the quality of evidence isn’t great. Not to mention the few long-term, randomized controlled trials were sponsored by industry, which means they’re liable to be biased. But even with those issues, the preponderance of evidence says clearly and loudly that artificial sweeteners do not help you lose weight. Note: they also don’t give you cancer. So there’s that.

Some of the studies showed that those who ate non-nutritive sweeteners had higher BMIs and elevated risk for cardiometabolic problems. There are two ways to interpret that. One is through the lens of a relatively new idea that artificial sweeteners can change the way your body metabolizes sugars. There’s some evidence that if your body starts to learn that “sugary” things don’t contain calories, it could screw up your response to the real thing. But it’s also possible that people who eat artificial sweeteners tend to already have health problems. If you’re overweight or at risk of getting type 2 diabetes, you might switch to the supposedly healthier zero-calorie sweetener option. In a study that only observes the differences between sweetener eaters and non-eaters, it would seem that people eating the zero-cal option are contracting problems from the sweetener itself. But let’s all say it together: correlation doesn’t imply causation.

In a surprise third option, it’s also possible that people who eat non-nutritive sweeteners over compensate by eating more calories overall. If I drink a diet soda, surely I can have another scoop of ice cream. But surely you can’t. We see this phenomenon in exercising too: People who start to exercise to lose weight often overeat because they now have an excuse to eat more. If you do SoulCycle before brunch, you might feel like you earned an extra margarita—but that cocktail probably has twice as many calories as you actually burned listening to a peppy man on a bike tell you to pump it harder.

This news shouldn’t be your excuse for switching to regular Coke: you should just try to get out of the sweet game altogether. Sugar, especially refined sugar, boosts your insulin levels and makes you an addict in much the same way that hard drugs can (though the effect is significantly counter-acted by other ingredients in many natural sources, like fruit). One soda a day quickly turns into one soda per meal, and soon anything that’s not sugary just tastes bad. Artificial sweeteners are no better. When given a choice between a hit of coke (no, not the soda) and some saccharin (you know it as Sweet-n-Low), cocaine-addicted lab rats chose the saccharin. The researchers literally could not give the rats enough cocaine to get them to choose it over the sweetener.

Humans probably can’t get addicted to sugar to quite the same extent. An addiction diagnosis in humans, whether it be to illicit drugs or food or sex, is a serious thing. It’s not just craving, it’s an inability to function without the thing you’re addicted to. Sugar and drugs both play into positive reward loops in your brain, but so does caffeine. You experience some “withdrawal” symptoms with all of them, but if you can get through the day without sugar you’re not actually addicted.

But don’t let the fact that you’re not a true sugar addict lull you into complacency. Sugar is not good for you and it does give you cravings. Kick the habit now and your body will thank you later.

Vaccines could help the immune system fight cancer

The two teams of researchers conducted independent Phase I trials of personalized vaccines designed to prime the patients’ immune systems against melanomas, a category of skin cancers. In a scientific double whammy, both studies found that their vaccines—sometimes in combination with other immunotherapies—were able to prevent recurrence of the cancers in nearly all their subjects.

“We can safely and feasibly create a vaccine that is personalized to an individual’s tumor,” says Catherine Wu, senior author of one of the studies and associate professor at Dana-Farber Cancer Institute in Boston. “It’s not one-size-fits-all—rather, it’s tailored to the genetic composition of the patient’s tumor.”

Wu carried out her study with colleagues in Boston at Dana-Farber Cancer Institute and the Broad Institute. The other study was conducted in parallel by researchers in Germany, led by study first author Ugur Sahin, the co-founder and CEO of BioNTech, a biotechnology company that focuses on personalized immunotherapy treatments.

Both studies targeted the same type of cancer: melanoma. These skin cancers (best known for their link to UV radiation from tanning) are a good first target, Wu says, because scientists have a good understanding of the mutations that cause them. These mutations are the key, says Mathias Vormehr, a co-author on Sahin’s study and a scientist at BioNTech.

“In principle, you can target any tumor that has mutations,” Vormehr says. “And mutations are a main feature of tumors.”

The goal of a cancer vaccine is to turn the patient’s own immune system against the cancer by teaching it to fight the tumor cells. This is similar to other vaccines like the flu vaccine which contains dead or weakened flu viruses that can’t actually do harm but can model what the the immune system should be prepared to fight.

Past attempts to create cancer vaccines have used gene-carrying viruses to reprogram immune cells to recognize cancerous cells. Others removed some immune cells from the patient’s blood, taught them to recognize the cancer cells outside the body, then re-injected the trained immune cells into the patient to go to work.

The recent studies in Nature used neoantigen vaccines. Antigens are small proteins that decorate the outside of cells, and “neoantigens” refer to ones that are found only on cancer cells. Because they aren’t found on any healthy cells, neoantigens make a perfect target for the immune system—after all, you wouldn’t want the immune system to start attacking its own healthy cells. Normally, cancer cells evade the immune system by weakening its effects and by feigning the appearance of normal cells. But, if the immune system learns to recognize the neoantigens delivered by the vaccine as harmful, it could then recognize and fight the cancer cells, too. Delivering mass amounts of neoantigens at once, which is what the vaccine would do, could trigger this recognition and the immune system might see neoantigens as harmful from then on.

Since all tumors are different, the vaccine had to be personalized. To figure out which neoantigens were unique to a patient’s tumor, the researchers sequenced the tumor’s DNA and each group of researchers developed their own computer algorithm to identify the unique segments of DNA that encoded the instructions to assemble these neoantigens.

This is the point where Wu and Sahin’s studies diverged. The goal was to get the neoantigens into the patient to prime their immune system. Wu’s team loaded up the vaccine with the neoantigens themselves, while Sahin’s vaccines delivered the corresponding RNA — a cellular intermediary between DNA and proteins—so that the patient’s own cells could create the neoantigen. Sahin’s team chose to use RNA because RNA serves a two-in-one role in the vaccine, Vormehr says. Vaccines normally have an added component that boosts the immune response, and RNA can accomplish that on its own.

(Remember that these cancer vaccines aren’t preventative, like the ones that you take for the flu. They are “therapeutic vaccines,” designed after the onset of cancer to target each individual’s tumor specifically.)

Both studies found that vaccination resulted in suppression of the cancer in many of their subjects. In the cases where the cancer was not successfully eliminated, Wu and Sahin both tried adding another treatment called checkpoint therapy, which keeps the cancerous cells from avoiding detection by the immune system. And two was, in fact, better than one: They found that the combination of the two methods improved vaccine response.

Of the six subjects in Wu’s study, four had stage III cancer and 25 months after vaccination, there was no sign of tumors. In the other two subjects, who had stage IV melanomas, they saw improvement with additional checkpoint therapy. Likewise, in Sahin’s study, eight out of 13 initially tumor-free subjects remained tumor-free 23 months later; normally half of them would be expected to relapse, Vormehr says. Of five subjects who relapsed, two responded positively to the vaccine, and a third responded when the vaccine was combined with checkpoint blockade therapy. Looking more closely, both sets of researchers found that their subjects’ immune systems were learning to react to the neoantigens.

sleep problems

If you’re having trouble falling asleep, maybe you can rest easy knowing that if you just had a sense of purpose in life, you’d already be dreaming. But probably not. In all likelihood, that anxiety-inducing thought is actually going to make it harder for you to get enough sleep. That’s not stopping some neurologists from recommending “purpose” as a solution to your insomnia.

That may sound ridiculous to you. Good! You’re appropriately skeptical. You may have recently seen some far-fetched headlines about drifting into dreamland more quickly once you find your purpose in life, and you may have even read some of the attached articles. So let’s talk about the actual study behind all this coverage.

These findings found their way into trending Google News headlines by way of Northwestern’s School of Medicine, where three neurologists decided to take a look at whether a sense of purpose correlated with better sleep quality. Their results were published in Sleep Science and Practice on Monday. The study involved a lot of statistical analysis, but it basically relies on two things: a survey that attempts to quantify whether a person has a purpose in life, and a survey that attempts to quantify sleep quality. Both rely on self-reporting, meaning that study subjects assessed themselves, and are therefore subject to bias. Do you always remember how many hours you’ve slept, and are you sure you’d be honest on a survey designed to quantify your sense of fulfillment? But hey, maybe everyone in this study accurately reported everything about themselves. There’s still the small issue that the researchers found almost nothing of statistical significance.

Yes, the team did find that people who reported having a sense of purpose also reported better sleep. And yes, technically they found that a year later, people who gained some sense of purpose also gained some sleep quality points. But they failed to find any effect two or three years out from the baseline study, which seems a little suspect. If achieving a sense of purpose makes you sleep better, surely that effect should last, no? Apparently not.

But there’s also another layer to this. If having a purpose in life made you a better sleeper, you’d expect that even within one group, those with more purpose would have higher sleep quality. In scientific terms, we’d call that accounting for variance. If you measure sleep quality and “sense of purpose” accounts for a large percentage of the variance in sleep quality between people, that’s a fairly good indicator that sense of purpose (or lack thereof) significantly impacts sleep.

So guess how much variance a sense of purpose accounted for in sleep quality in this study? 4.3 percent. To their credit, the authors note this in the final paragraph of their paper, where they discuss potential limitations of their findings. Also listed? The fact that most of the study group was highly educated and therefore likely had access to good health care and the information and resources required to make healthy choices. They probably had pretty high quality sleep to begin with. All those things are especially true of older Americans, as high educational level and socioeconomic status (which already go hand-in-hand) are highly predictive of healthy diets and good exercise regimens, which tend to help you sleep better. This is where I should mention that the study focused only on older Americans, by the way, so even if the results were iron-clad and universally applicable, you’d still only be able to say the findings held true for an older cohort. You young rebels can carry on without a cause.

But when you look at all of the study’s limitations, it’s clear that having a sense of purpose in life isn’t a driving factor in getting you to sleep—it’s more of a marker. If you’re the sort of person who has had the time and resources to really investigate what’s important to you and what would make you happy in the grand scheme of things, you’re probably also a person who is wealthier and healthier.

If you’re struggling financially—working long hours, or even multiple jobs—you’re probably not spending a lot of time considering what your deeper purpose is. You’re also less likely to sleep well. The same goes for dealing with family troubles, or facing daily racism, or trying to climb a social ladder that’s stacked against you. Heck, if you’re too poor to afford a comfortable bed or proper heating and air conditioning, you probably aren’t getting great sleep, either. Really, the results of the study should be framed as “people who sleep better are more likely to have a sense of purpose in life.” Better yet, “people who sleep better generally live easier lives.”

Mac-n-cheese isn’t more toxic than other foods

There’s one meal guaranteed to meet the needs of picky toddlers, harried parents, and broke college students alike, it’s mac-n-cheese. Whether you prefer the classic stuff in the blue box or the organic brand famous for its pasta bunnies, you probably realize that mac-n-cheese isn’t healthy, exactly. But given the fast food alternatives, we tell ourselves, it’s isn’t that bad. And yet, because everything we love is secretly conspiring to kill us, a recent report suggests that each serving of America’s favorite processed cheese food also serves up a hefty dose of phthalates, a class of chemicals increasingly thought to interfere with the body’s hormones. But does this mean that you should give up eating that orange goo?

Phthalates, which includes chemicals such as di(2-ethylhexyl) phthalate (DEHP) and Diethyl phthalate (DEP), help make rigid plastics more flexible and less breakable. In cosmetics, phthalates help chemical components better bind to each other. Unfortunately, a growing body of research links them to genital birth defects, the disruption of some hormones, learning disabilities, and behavioral problems.

Thanks to a 2008 bill, phthalates are now banned in the production of children’s products (like toys). But they’re still abundant. You’ll find phthalates in vinyl flooring, aftershave, nail polish, and increasingly in food, although their presence there isn’t completely understood. It’s thought that some foods packaged in materials containing phthalates (including cellophane, paperboard, and plastics) pick the chemicals up as they sit on your shelves. Tasty.

Before delving into the mac-n-cheese report that is currently making the rounds, it’s important to note that unless you’re raising cows yourself with a feed you’re making yourself (and hand-milking said cow into glass containers), almost all dairy products you consume contain phthalates. In fact, you might do all of the aforementioned dairy farming and still find that your milk contains the chemicals. A 2013 study in the journal Environment International tracked the progression of eight different phthalates through the food chain and determined that basically every step of the milk production process helps introduce phthalates into the end result.

If you’re feeling smug because you don’t consume meat or animal products, you may be discouraged to discover that phthalates are also found in fruits and vegetables (albeit at lower concentrations). This is not a question of a single product being bad, but rather a symptom of an unhealthy food production system.

Which brings us to the mac-n-cheese report, which is not a peer reviewed study. This means that outside scientists haven’t been able to weigh in on the study methods, design, or conclusions. While it was conducted by an independent lab, it was done so at the behest of a host of environmental groups—including the National Resources Defense Council, Earth Justice, Center for Science in the Public Interest and others—under the not-exactly-subtle consortium name “Klean Up Kraft”. Additionally, the report is heavily redacted: the specific brands they tested aren’t referenced, and there are some discrepancies between the report and the summary sheet released to the media. The report, for example, says that they tested 51 samples, while the summary sheet reports that they tested 30. For simplicity’s sake, I’m referencing data from the summary sheet.

The summary sheet says that phthalates were detected in nearly every cheese product tested—29 out of 30—and that average phthalate levels were four times higher in the powdered stuff than in hard blocks and other cheeses. It also reports that the most commonly detected phthalates were Bis(2-ethylhexyl) phthalate (DEHP), which is used to make plastic more flexible, and Diethyl phthalate(DEP), which is most commonly used to bind cosmetics and fragrances. All of which suggests that you should give up mac-n-cheese, right?