TIME heart

This New FDA-Approved Cholesterol Drug Is a Game Changer

The FDA approved the first of a new class of drugs for treating high cholesterol. Here’s the story of how researchers went from a DNA mutation to a drug in 10 years

On Friday, the U.S. Food and Drug Administration (FDA) approved the first new class of cholesterol-lowering drugs since the statins flooded the market beginning in the 1980s. Similar to the way statins work, by binding up cholesterol made in the liver so less of it circulates in the blood, this new class, called PCSK-9 inhibitors, takes advantage of genetic mutations that regulate the level of LDL receptors in the liver. Less PCSK9 leads to more LDL receptors that can soak up LDL and therefore leave less cholesterol in the blood.

The FDA approved alirocumab (Praluent), an injectable drug made by Sanofi and Regeneron, in people with familial hypercholesterolemia, a genetic condition in which cholesterol levels are high, or those with a history of heart disease who can’t reduce their LDL levels enough with existing statin drugs. (Another PCSK9 inhibitor, evolocumab (Repatha) developed by Amgen, received approval in Europe but won’t be evaluated by the U.S. FDA until the end of August.)

MORE: The Next Big Drug to Treat Heart Disease

While PCSK9 drugs help to lower cholesterol, the story of how these medications developed began in a French family with the opposite problem. Their members had exceptionally high levels of LDL and greater than average rates of heart disease. But unlike others with similar cholesterol problems, this family did not have the usual mutations in cholesterol-regulating genes. Instead, French researchers studying them in 2003 found they had aberrations in PCSK9, a gene that produces a protein found primarily in the liver, kidneys and intestines.

An ocean and half a continent away, Jonathan Cohen and Dr. Helen Hobbs at the University of Texas, Southwestern Medical Center in Dallas (coincidentally the same institute where scientists discovered LDL, or the heart-disease contributing cholesterol and earned the Nobel Prize for their work), read the description of PSCK9 and wondered whether those with lower levels of PCSK9 would show the opposite effect of the French family and actually enjoy decreases in levels of LDL in the blood.

MORE: New Class of Cholesterol Drugs Shows Promise For Heart Disease

Cohen and Hobbs were involved in a large heart disease study involving nearly 15,000 participants, and decided to look for the PCSK9 mutations among their participants. They homed in on those with the highest and lowest levels of LDL cholesterol, and sequenced their genomes to see if any patterns emerged. Sure enough, they found 33 people whose LDL levels were about 40% lower than average and who shared mutations that effectively silenced PCSK9. Essentially, their LDL amounts were about the same as those who relied on statins to drop their cholesterol.

These PCSK9 mutations associated with the lowest LDL appeared predominantly in African-American participants. Those with one copy of the mutation in this gene showed an 88% lower risk of heart disease. Another mutation in the same PCSK9 gene that appeared more commonly in whites had the same effect, but to a lesser extent, dropping LDL by 15% and the risk of heart events by 47%.

“The results were quite compelling,” says Cohen, who published the findings along with his colleagues in the New England Journal of Medicine (NEJM) in 2006. “They told us that PCSK9 was likely an attractive therapeutic target.” Even more encouraging, in all of the people with the mutations and lower LDL levels, there didn’t seem to be any significant side effects. For all intents and purposes, these participants were healthy and had the added advantage of being at very low risk of heart disease.

To confirm this, Cohen searched for anyone in the study with two copies of the mutation, to see if having double the effect would trigger any adverse events. He found one woman, a 32 year old daughter of one of the participants, who had two different mutations in each of the PCSK9 copies she inherited from her mother and father. The result? An LDL of 14 and no other health problems. “If you measure the amount of PCSK9 in her blood, it’s basically absent, you can’t see any,” says Cohen. That contributed to an unprecedented low level of LDL cholesterol as well.

So far, he says, only one other individual has been described with two mutant copies of PCSK9, a 21 year old woman living in south Africa with an LDL of 20.

Those descriptions piqued the interest of researchers at Regeneron, a biotech company that specializes in turning genetic discoveries like this one into drugs. To confirm and better understand the effects of PCSK9, researchers there studied the effect of human versions of PCSK9 in mice, and then began trials of antibodies they developed that inhibit the function of this gene, much like the mutations do, in several thousand people.

Those results, published in the NEJM last April, showed that PCSK9 inhibitors can lower LDL cholesterol by an additional 60% on average beyond that achieved by statins. Those findings formed the basis of the companies’ application to the FDA for approval of these first-in-class drugs.

For now, the agency says the drugs should only be prescribed to people with familial hypercholesterolemia, or those who have failed to reduce their LDL levels sufficiently using statins. For many, the new drugs will be taken in combination with statins and a heart-healthy diet. But doctors say they anticipate many patients outside of these groups, who have family histories of heart disease or other risk factors, such as hypertension or diabetes, may start asking about the medications. For them, doctors will have to weigh how well they are doing on statins before considering adding a PCSK9 inhibitor.

TIME medicine

The First-Ever Malaria Vaccine Just Got a Big Break

Drugmakers received a thumbs up from European regulators, moving the vaccine closer to human use

After nearly 30 years of development and testing, the world’s first malaria vaccine got a major push forward on Friday morning.

Drug maker GlaxoSmithKline announced that a European Medicines Agency (EMA) committee has given a positive recommendation for the company’s vaccine for malaria called Mosquirix (scientifically known as RTS,S). The drug is intended for children ages six weeks to 17 months living in Sub-Saharan Africa. Because the vaccine is not intended for countries outside of Africa, the European regulatory agency is not “approving” the vaccine, but offering a positive opinion that the World Health Organization (WHO) will use to create its own recommendation for the vaccine’s use. Countries in Africa will then approve the vaccine through their own regulatory agencies.

Mosquirix is the first vaccine to prevent malaria in humans and was first created in 1987.

The data assessed by the EMA was primarily from a phase III clinical trial of the vaccine in about 16,000 kids in multiple African countries. After 18 months, GSK reported that the vaccine had about 46% efficacy against clinical malaria and 36% efficacy against severe malaria in kids ages five to 17 months. In babies ages six to 12 weeks, the drug had a 27% efficacy against clinical malaria and 15% against severe malaria.

The efficacy rates may seem low, but the researchers tell TIME that the vaccine is the only one available thus far and will save a significant number of lives that would be lost to the mosquito-borne disease. The vaccine also shows efficacy for a few years after initial vaccination. “Is there room for improvement? Yes. We can improve a lot,” says Moncef Slaoui, co-inventor of the vaccine and the Chairman of GSK Vaccines, in an interview with TIME. At the end of the study period, the researchers found that more than 6,000 cases of clinical malaria were prevented for every 1,000 children who were vaccinated in areas of high transmission. The efficacy of the vaccine was also assessed in a safe study context in which children slept with bed nets treated with insecticide, a measure not always taken.

According to data provided by GSK, there were 584,000 deaths worldwide from malaria in 2013, and 90% of those deaths took place in Sub-Saharan Africa. More than 80% of the deaths occurred in kids under age five.

Currently, the vaccine Mosquirix requires four doses. The first three happen a month apart from each other, and the fourth happens about 18 months later. Ensuring that parents get their children the full dosage can be challenging, but Slaoui notes that most infant vaccines require multiple doses, and while not ideal, there’s still a significant benefit with just three doses.

Slaoui says GSK also has a second generation version of the vaccine in the works—one that may have even better efficacy rates. “It’s a tweak of the current vaccine,” he says. “We know the next generation is close by.”

TIME medicine

Doctors Say Cancer Drug Costs Are Out Of Control

488635643
JUAN GARTNER—Getty Images/Science Photo Library RF Illustration of cancer cells in middle of dividing

Prescription drug prices rose 12% in 2014

A group of 118 oncologists put their foot down on the rising costs of cancer medication in an editorial in the Mayo Clinic medical journal, the Mayo Clinic Proceedings, on Thursday. The editorial threw its support behind a grassroots patient effort to push for fairer prices from drug companies.

According to the editorial, many cancer patients are bankrupted by the high cost of care. Even for insured patients, a treatment that costs $120,000 a year might only be reduced to $30,000 in out-of-pocket expenses–more than half the average U.S. household income. The cost of drugs is so high that as many as 20% of oncology patients don’t take their medication as prescribed.

Cancer drugs were not always so expensive. Over the past 15 years, according to one study in the Journal of Economic Perspectives, the cost of cancer drugs rose by 10% (or about $8,500) every year. In 2014 alone, prescription drug prices rose 12%.

“High cancer drug prices are affecting the care of patients with cancer and our health care system,” the lead author, Dr. Ayalew Tefferi, who is a hematologist at Mayo, said. The doctors designed a list of ideas that would make cancer drugs more affordable for the people they treat.

The group’s solutions included a proposal to allow individuals to import cancer drugs from other countries, where the medicine is far cheaper. In Canada, for example, oncology drugs are half the price of American ones.

Other solutions included creating a regulatory body that would propose fair pricing after a drug gains F.D.A. approval, allowing Medicare to negotiate drug prices, and preventing pharmaceutical companies from delaying access to generics.

“It’s time for patients and their physicians to call for change,” Dr. Tefferi said.

TIME Exercise/Fitness

How Exercise Helps Curb Alzheimer’s Symptoms

79366412
Pamplemousse—Getty Images/OJO Images RF

Most studies so far have focused on the importance of physical activity before you develop Alzheimer’s. But can it treat the disease once you are diagnosed? Two studies hint that may be the case

At the annual Alzheimer’s Association International Conference in July 2015, scientists report some encouraging news about the benefits of exercise. In the first studies to look at physical activity among people already diagnosed with the early stages of Alzheimer’s, moderate to high intensity workouts may not only slow down the biological symptoms of Alzheimer’s—but may lead to improvements in cognitive functions as well.

In one study involving 200 people with mild or moderate disease, Dr. Steen Hasselbalch from the University of Copenhagen and his colleagues randomly assigned some participants to an hour of exercise three times a week for 16 weeks, while allowing the remainder to continue without a regular activity regimen. After a phase-in period, the exercisers were working at a moderate to intense level, achieving 70% to 80% of their maximum heart rate for at least half of each session.

MORE: Your School Grades Affect Your Risk of Dementia

That level of intensity is important, says Hasselbalch, to achieve results. Compared to the control group, the exercisers showed fewer symptoms such as anxiety, changes in mood and depression that are common among Alzheimer’s patients. Overall, those who were more active did not show any changes in cognitive functions, but when Hasselbalch looked at the results more carefully, he found that participants with milder disease who exercised actually did perform better on intellectual skills after the 16 weeks. They were tested on memory, language, mental speed and other executive functions.

“It’s been shown with other diseases that exercise can have beneficial effects,” he says. “Now we have shown it’s also important for dementia. So if you now have this alternative treatment, it sends a message that you can do something even after diagnosis to treat dementia.”

MORE: Two New Alzheimer’s Drugs Offer Hope—With Caveats

Because the people exercised in a group setting, he says that simply being part of that social situation and getting out of the house and interacting with others appears to reduce the mood-related symptoms of Alzheimer’s. “But if you really want an effect on cognition, then you have to exercise hard.”

He admits that his study did not delve into how the exercise might be contributing to the improved cognitive changes, but he will be analyzing the blood and cerebral spinal fluid collected from the participants to study that further.

MORE: Alzheimer’s May Show Up in Saliva

Such changes are what Laura Baker, from Wake Forest School of Medicine, and her team did with another group of early stage Alzheimer’s patients. They wanted to see what biological changes exercise might have on the Alzheimer’s process, and focused on 70 patients with mild cognitive impairment and diabetes, both of which significantly increase the risk for Alzheimer’s. Some were randomly assigned to simple stretching exercises, while others were told to exercise four times a week and, like those in Hasselbalch’s study, had to work hard enough to raise their heart rate to 70% to 80% of its maximum for 30 of the 45 minutes of each session. Baker then studied their cognitive function tests, brain imaging and levels of Alzheimer’s proteins in their cerebral spinal fluid.

She found that those who exercise rigorously increased the blood flow in the areas of the brain responsible for memory and higher level processing. The result was a dramatically increased score, by 80%, on average on the cognitive tests than those who just stretched, even after accounting for age-related changes in thinking. More intriguing, the exercisers also showed on average a 14% lower level of the protein tau, which is a good indicator that brain neurons are dying and Alzheimer’s processes are well underway, at the end of the study compared to before they began the exercise regimen.

“What’s encouraging to us is that we don’t have treatments now; there’s nothing for Alzheimer’s patients,” says Baker. “The possibility that a non-medicine intervention could actually change the disease — we’re just very encouraged by these results,.”

While the exercise regimen wasn’t an easy one — it qualifies as moderately intense physical activity, which for a group of older adults who are likely sedentary to begin with is certainly a challenge, both Hasselbalch and Baker say that with the right execution — by working with participants and by gradually increasing their exercise level — achieving the amounts of activity needed to help their brains is possible. Baker also points out that it’s time to start studying the combined effects of new medications that are being tested for Alzheimer’s and increased physical activity. Together, she says, they may hold the key to actually slowing down and possibly even reversing progression of the disease.

TIME Cancer

When Chemotherapy Does More Harm than Good

146155759
Photo by Selina Boertlein c/o SBPhotography—Getty Images/Flickr RF

Chemotherapy has saved countless lives and is a mainstay of cancer care. But the latest data suggests that it can also do more harm than good for some patients

A cancer diagnosis is a life-altering event, and the news—let alone making decisions about how to manage treatment—is already challenging enough. But with a terminal diagnosis, those choices become even more fraught. At some point, say ethicists, doctors and patient advocates, enough is enough. Meaning the potential for benefit has to be weighed against the quality of what life is likely to be left. But where is that line? And how does each patient find it?

A study published in JAMA Oncology highlights just how agonizing those choices can get. Holly Prigerson, director of the Center for Research on End of Life Care at Weill Cornell Medical College and her colleagues studied the use of chemotherapy among a group of 312 terminal cancer patients. All had been given no more than six months by their doctors, and had failed at least one if not multiple rounds of chemotherapy, seeing their tumors spread to other parts of their body. About half were on chemotherapy, regardless of its ineffectiveness, at the time of the study.

Read more No More Chemo: Doctors Say It’s Not So Far-Fetched

Despite the intuitive sense that any treatment is better than none, there is not much evidence that chemotherapy is the right choice in these cases—and it may very well be the wrong one. Prigerson’s analysis showed that these patients experience a drop in their quality of life if they get chemo, and that they are therefore worse off than if they hadn’t opted for the treatment. On measures of things like whether they could continue to walk on their own and take care of themselves and keep up with their daily activities, those on chemotherapy reported marked declines compared to patients who opted not to receive more chemo.

“The results were counterintuitive to some extent,” says Prigerson. “The finding that the quality of life was impaired with receipt of the toxic chemotherapy was not surprising. The surprising part was that people who were feeling the best at the start of the therapy ended up feeling the worst. They are the ones most harmed and who had the most to lose.”

In other words, the chemo made the patients feel worse without providing any significant benefit for their cancer.

Previous studies have showed that chemotherapy in terminal patients is essentially ineffective; among those with non-small cell lung cancer, for example, third rounds of chemo were associated with a 2% response rate in tumor shrinkage, while fourth rounds showed 0% response. And whatever tumor shrinkage occurred wasn’t linked to a longer life.

Read more How Fish Oil Makes Chemo Less Effective

Groups like the American Society of Clinical Oncologists (ASCO) recently advised doctors to be more judicious with their chemotherapy use in terminal patients. The group’s guidelines recommend limiting it to relatively healthy patients who can withstand the toxic treatment and potentially overcome side effects.

The decision about how long to continue care, including chemotherapy, is up to each cancer patient, but Prigerson hopes that her results help to better inform those choices in coming years. Recent studies showed, for example, that despite explanations from their doctors, many cancer patients still believe that more rounds of chemo will provide some benefit to them, and are therefore—and understandably—reluctant to stop receiving therapy. But at some point, the data shows, more treatment is not better.

That may be especially true of patients with end-stage cancer who are still relatively healthy and not feeling sick. For them, additional chemotherapy will likely make them weaker, not to mention eat up more of the precious time they have left traveling to and from infusion centers. Prigerson plans to continue the study to better understand the dynamics of how decisions about treatments are made toward the end of life, but in the meantime hopes the latest findings at least convince doctors to reconsider how they advise their terminal patients about end-stage chemotherapy.

Read next: Why Breast-Cancer Survivors Gain More Weight

Download TIME’s mobile app for iOS to have your world explained wherever you go

TIME medicine

There’s Yet Another Downside To Overusing Antibiotics

502865411
BSIP/UIG—Getty Images/Universal Images Group

Scientists have found yet another reason not to overuse the drugs—they’re turning bacteria into better infectious agents

Scientists have been warning for decades that we use too many antibiotics, both in people to treat relatively mild infections and in agriculture to bulk up farm animals and keep them free of disease. The consequences, they caution, are dire—and already emerging in hospitals with bacteria that can’t be treated with any of our existing antibiotic medications.

But the thinking went that to become resistant to the drugs we use on them, bacteria have to pay a price. They may be able to survive the pharmaceutical onslaught, but they’re less fit and therefore less able to reproduce, less likely to remain for long in their host of choice and otherwise sapped of the energy needed to really wreak havoc on human or animal immune systems.

MORE: Study Links Widely Used Pesticides to Antibiotic Resistance

At least, that was the theory (and perhaps the hope) until now. In a study published in Science Translational Medicine, however, researchers show how misguided that belief is. Delving into the genetic code of certain common bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii — both of which are resistant to multiple antibiotics— and Vibrio cholerae, the researchers identified genes that change in the presence of these drugs. In animal models, they observed how these changes affected the different bacteria’s ability to infect and populate in hosts.

To their surprise, rather than being compromised, the antibiotic-resistant bacterial strains seemed to be stronger, more robust and better able to infect cells than less resistant strains.

MORE: Why Reducing Antibiotic Resistance Is Harder Than It Seems

“With all the possible mutations in the bacteria, there is a battle royale, a competition among all the mutants, and we see that the most fit, the most virulent were the ones that were resistant to the antibiotics,” says Dr. David Skurnik, senior author of the paper and assistant professor of medicine at Brigham and Women’s Hospital and Harvard Medical School. In the case of P. aeruginosa, he says, “the acquisition of antibiotic resistance was associated with the most increased fitness in all the possible mutations in P. aeruginosa.”

That means that the problem of antibiotic-resistant bugs just got more complicated. Overuse of antibiotics increases the number of bacterial strains that have mutations which make them better able to withstand the drugs, and this latest research shows that these strains may also be more adept at infecting hosts and causing disease. “We’ve gotten a double whammy with the acquisition of antibiotic resistance,” says Gerald Pier, a co-author of the paper and professor of medicine, microbiology and immunobiology at Brigham and Harvard Medical School. “Not only does antibiotic resistance make it more difficult to treat infections because we have fewer drugs they will respond to, but it makes the organism better able to cause infection.”

While still important, the conventional solution of cutting back on antibiotic use may not be enough, he says. Using antibiotics more appropriately will certainly reduce the appearance of new drug-resistant strains, but it won’t be enough to tamp down the emergence of these fitter, more virulent bacteria that also happen to be adept at evading the effects of antibiotics. For that, he says, other infection-fighting strategies, including boosting the immune system with vaccines or antibody treatments, may be needed.

That’s what Pier and Skurnik are working on currently, and so far, they’ve developed encouraging options for treating infections that may keep the more robust bacteria at bay. They’re targeting parts of bacteria that many strains have in common and developing new says to recognize these targets and neutralize the bacteria so they can’t cause serious infections and disease. “These results show that, yes, the problem of multi-drug resistant bacteria is more complex than we thought, but there are solutions,” says Skurnik.

TIME Innovation

How Damaged Brains Can Learn From Healthy Ones

The Aspen Institute is an educational and policy studies organization based in Washington, D.C.

These are today's best ideas

1. Could damaged brains learn to heal from healthy ones?

By Brian Handwerk at Smithsonian Magazine

2. From VOA to Radio Free Europe, the U.S. needs a single news voice abroad.

By Al Pessin at Defense One

3. Here’s how the dwindling teacher supply is complicating education reform.

By Paul Bruno in the Brown Center Chalkboard at the Brookings Institution

4. The mobile web sucks.

By Nilay Patel in the Verge

5. What’s better than a clinical trial for understanding drug side effects?

By Aviva Rutkin in New Scientist

The Aspen Institute is an educational and policy studies organization based in Washington, D.C.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME medicine

Dad Bod Is Explained By Science In a New Study

A first-of-its kind study to follow men for up to 20 years from adolescence shows that dads do get a little squishier after the kids

According to Clemson student Mackenzie Pearson, who wrote a viral essay essay on the appeal of the dad bod, it’s a physique that’s a “nice balance between a beer gut and working out,” the result of going to gym but indulging in a few pizzas once in a while and being okay with that. (Think John Hamm, and Chris Pratt before he went Jurassic.)

And according to scientists, Pearson and her demographic have pretty much nailed it. The source of that “more human, natural and attractive” body is unique to fathers and can be traced to simply having kids.

In a study published in the American Journal of Men’s Health, Dr. Craig Garfield, a pediatrician at Northwestern University Feinberg School of Medicine and his colleagues dove into a database of 10,263 men beginning when they were 12 years old and followed them for up to 20 years. They looked specifically at how body mass index (BMI), a combination of height and weight, changed over time as the men either became fathers or did not, and for those who did, whether they were what the researchers called resident fathers who lived with their children, or non-residents who lived separately.

Read more Why We Accept ‘Dad Bod’ on Rich Men

Whether or not they lived with their kids, becoming a father was linked to around a four pound increase in weight over the study period, while remaining child-free was associated with a 1.4 pound weight loss for a six-foot-tall man.

“It’s a unique look at the influence that a social phenomenon, becoming a father, has on a biological marker, namely BMI,” says Garfield. “It really plants fatherhood as a potential social determinant of health for men.”

That’s a critical finding, especially since men, and in particular young men, are typically less proactive about taking care of their health. Garfield notes that while many men will quit smoking and drink less and otherwise try to become healthier when they become fathers, there may be other factors associated with caring for kids that counteract those good intentions, such as being surrounded by more kid-friendly, high calorie foods and snacks, as well as their leftovers.

“From my own point of view, we wouldn’t have as many pizzas in the house if the kids weren’t around, and we wouldn’t have the brownies my wife makes if the kids weren’t around,” says Garfield. “Having kids around changes not only the food in the house and what is available to you for meal, but also for snacks. It also changes whether you are able to find time to get out and exercise and get enough sleep and take care of yourself.”

Read more Dadbod, Mombod and Our Pretty Bad Bod Prob

Dads, of course, are not alone in experiencing these effects of parenthood. But this is the first study to tease out specifically the effects of fatherhood on weight gain over time. Since men are less likely to be seeing doctors regularly, if they are joining their partners during prenatal visits or pediatric visits, says Garfield, those are good opportunities to talk to them about their own eating, exercise and sleep habits to make them aware of the sneaky way that pounds can creep up on dads and potentially affect their health (even if the look seems to have its own kind of physical appeal).

Read next: For the Dad Who Is Confident About How He Looks in Swim Trunks

Listen to the most important stories of the day

TIME HIV/AIDS

A Woman Born HIV-Positive Is in Remission Despite Stopping Treatment Years Ago

475180273
Science Stills/Visuals Unlimited, Inc./Getty Images

Doctors believe early rather than continuous treatment with antiretrovirals is key

The first case of a woman in long-term HIV remission despite not receiving treatment for many years has been documented in France.

The 18-year-old was HIV-positive at birth and given antiretroviral drugs as a child, but her family decided to cease the treatment when she reached the age of 6. Twelve years have passed and today her viral load is too low to be measured. Doctors can’t figure out why the women’s HIV has stalled.

“With this first, highly documented case of this young woman, we provide the proof of concept that long-term remission is possible in children, as in adults,” Dr. Asier Sáez-Cirión, from the Institute Pasteur in Paris, told the BBC.

“However, these cases are still very rare,” he said.

Some experts believe that early treatment is the key to future remission, but large-scale studies still need to be conducted to nail down this theory.

Although there is still much to learn, predicting HIV remission has been the subject of studies in the past. Sáez-Cirión previously led a research group of 14 patients who had no sign of the virus re-emerging after coming off antiretroviral drugs. Thirteen years passed and the patients’ viral loads remained low.

[BBC]

TIME medicine

What You Should Know About Leaky Gut Syndrome

woman-stomach-cramp-pain
Getty Images

What’s a leaky gut, and how do I know if I have one?

“Leaky gut syndrome,” on its own, is a diagnosis that’s not recognized across the board by conventional medicine. The theory is that having a poor diet or ingesting too many antibiotics or painkillers can damage the mucosal barrier, the layer of cells lining your intestine. Normally, this barrier lets nutrients through but blocks larger molecules and germs from getting into your bloodstream. It’s thought that a porous, or “leaky,” intestinal lining can allow food particles or germs to pass into the blood, causing inflammation throughout your body.

Symptoms of a leaky gut are said to include everything from bloating, gas and abdominal pain to recurrent vaginal infections, asthma and mood swings. Some experts even claim that leaky gut can put you at risk of serious conditions such as migraines, rheumatoid arthritis and food allergies.

Is it for real? There is evidence that having high “intestinal permeability” is involved in the development of certain autoimmune diseases, like Crohn’s and type 1 diabetes, in people who are already predisposed to these conditions. But it remains unclear whether intestinal permeability causes issues such as irritable bowel syndrome, food allergies or asthma—or if it’s just a symptom of them. In my experience, having a “leaky gut” is mostly a symptom of a disease, not a disease on its own.

There are tests your doctor can perform to measure how well your intestines are absorbing nutrients and blocking the bad stuff. The most common one involves drinking a mixture of mannitol (a small sugar molecule) and lactulose (a large one) and then testing your urine for each over six hours. But these tests are time-consuming and expensive, and they don’t reveal anything that your doctor can use to recommend treatment. So, honestly, there is no point in getting them.

Some alternative medicine practitioners recommend supplements or home tests (which they conveniently sell on their websites), but ignore these. The best advice for keeping your gut and its lining healthy is to eat plenty of fiber and fermented foods like kefir, or take a probiotic supplement, and stay hydrated.

This article originally appeared on Health.com

More from Health.com:

Your browser is out of date. Please update your browser at http://update.microsoft.com