No, megadoses of vitamin C won't cure a coronavirus infection

The world is awash in treatments for COVID-19, the illness caused by coronavirus. Or at least that's what you might think if you just searched the internet.

The truth is, we don't yet have any effective treatments for COVID-19, although thousands of scientists are working furiously to try to create them.

Today we'll look at just one of the supposed treatments, which is being actively promoted on social media and many websites: vitamin C.

For those who don't want to read further, I'll start with the conclusion: vitamin C won't help to prevent or to treat coronavirus infection. I wish we had such a simple solution, but we don't.

Now let's back up a bit. Why would anyone think that vitamin C might be effective in treating this terrible virus? Vitamin C is an essential nutrient, and we all need it, but most people get plenty of vitamin C in their normal diet. As I've written before, taking vitamin C supplements is unnecessary, although probably harmless, although megadoses carry the risk of kidney stones.

The modern craze with vitamin C started with Linus Pauling, a brilliant chemist and a Nobel Prize winner. Late in his career, he wrote a book promoting vitamin C as a miracle cure for many illnesses, including the common cold (which is caused by a virus). He had very little good evidence for this belief, but his promotion of vitamin C led to hundreds of studies testing his hypothesis. The bottom line: vitamin C doesn't work at preventing or curing the common cold. (See Paul Offit's book if you want more details on this and many other "miracle" cures.)

But wait, someone might object: haven't some of those vitamin C studies (as in this review paper) shown a benefit against the common cold? Well yes, but when you run hundreds of studies of a treatment that doesn't work, this is what happens: negative studies are hard to get published, but positive studies are easier. Run enough studies, and a few of them, merely by chance, will show a small positive effect. That's what we've seen with vitamin C.

Today, though, everyone is looking for a cure for COVID-19, and not surprisingly, many people (even some doctors) are claiming vitamin C is the answer. I've seen Twitter users explain, very confidently, that you just need to take 12,000 mg of vitamin C and you'll get better. This wesite comes right out and states that high-dose vitamin C will cure coronavirus, based on a widely-shared video from a doctor in China. (I won't provide the link because it has already done enough damage.)

It's almost impossible to disprove a claim that a treatment works. For example, I could claim that ginger snap cookies helps to prevent coronavirus infection. That's right! Ginger snaps, made with real ginger, which seems to have magical curative properties. If you object, I could demand that you prove me wrong–but the onus is on me, as the one making the claim, to first provide some genuine evidence. We haven't seen anything like that for vitamin C.

We need well-controlled experiments to know with any confidence that a treatment works. Some doctors at Wuhan University have started a trial of vitamin C to see if it has any benefits for COVID-19, but results won't be available for many months. I'm skeptical, but at least they're approaching the question the right way.

Dozens of studies of new treatments for COVID19 are being launched right now, with remarkable speed due to the urgency of the pandemic.The WHO has just launched trials of the 4 most promising existing drugs (which don't include vitamin C, I should add). To obtain a believable, positive result, we need to see evidence that a carefully administered treatment provides a significant benefit over what we're doing now–which is little more than supportive care, unfortunately.

Meanwhile, we'll have to wait and hope that one of the plausible efforts currently under way will yield an effective treatment. We've been down this road too many times with vitamin C, though, and the chances that it will have any effect are, based on past experience, close to zero.

FDA to coronavirus scammers: watch out!

The coronavirus pandemic has the whole world's attention. For now, there's no treatment and definitely no cure for COVID-19, the disease caused by the virus.

That hasn't stopped charlatans and scammers to claim that they have treatments, and to offer them for sale. I often wonder (sometimes in this column) whether people selling bogus cures truly believe their own statements, or whether they are just liars who know they're selling nonsense. In the former case, they are merely misinformed or ignorant. In the latter case, they are con artists who deserve our scorn. In either case, though, we shouldn't be buying their products.

Let's look at a few marketers who have gotten the attention of regulators just this past week. In the U.S., the FTC and the FDA announced that they just took the following action:
"The FTC and FDA have jointly issued warning letters to seven sellers of unapproved and misbranded products, claiming they can treat or prevent the Coronavirus. The companies’ products include teas, essential oils, and colloidal silver."
That's right, scammers: you better clean up your acts, or else we're going to ... write you a letter!

To be fair, it's not the fault of the FTC or the FDA that their enforcement powers are so weak. Congress has severely limited the ability of the FDA to regulate businesses who sell supplements and other scams, as I've written before. The supplement industry is big business, and they've lobbied Congress–very successfully–to prevent any truly effective regulation.

So here are the seven scammers whose claims were so outrageous that the FDA and the FTC have already (in just a few weeks, record time for these agencies) notified them that they must stop their false advertising:


The products offered by these dishonest marketers include essential oils, teas, and colloidal silver. None of them work at all against coronavirus. The FTC warning letters point to their websites, Twitter, and Facebook.

I checked them out to see if the claims are still there, and here's what I found.

Twitter suspended the Quinessence account for violating its rules, but the N-ergetics Twitter account is still live, and it features a claim that "Colloidal Silver Benefits against Antibiotic resistant ZIKA, Viruses, Superbugs, Flu." (That claim is false.)

Vivify Holistic was using Facebook to promote false claims (according to the FDA letter), and Facebook has apparently shut down that page. GuruNanda's FB and Twitter accounts are both active, but they seem to have removed their claims about coronavirus.

Vital Silver's FB page has a posting from March 9, apparently prompted by the FDA letter, stating that "These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease." This is the standard disclaimer that all supplement makers use. But then they added this "The content of this page are based on my religious beliefs as protected by the First Amendment." That's a new one to me. Nonetheless, their product still can't cure coronavirus.

Herbal Amy promotes her products through Facebook and a website: the FDA told her to take down her "Coronavirus protocol" products (she had many of them), which she seems to have done. Her FB page is still active, and she explains there that "we have had a Coronavirus protocol for sale for the last 2.5 YEARS. This is not a new herbal formula or a new virus." Huh? So her argument is that she has been making a false claim for a long time now?

Jim Bakker is another story. For those too young to remember, Bakker was a popular televangelist in the 1970s and 1980s who was convicted of 24 counts of financial fraud. He served five years in prison and resumed his television preaching in 2003. One of the ways he makes money is selling colloidal silver (tiny silver particles suspended in liquid), which he recently claimed could cure coronavirus. This led the FDA, the FTC, and the NY Attorney General to order Bakker to stop his false advertising.

The state of Missouri has gone further than the feeble FDA: they are suing Jim Bakker to stop him from harming people. The Missouri attorney general charged that Bakker is
"falsely promising to consumers that Silver Solution can cure, eliminate, kill or deactivate coronavirus and/or boost elderly consumers' immune system and help keep them healthy when there is, in fact, no vaccine, pill, potion or other product available to treat or cure coronavirus disease 2019."
Good for the Missouri AG. Time will tell if all of these demands will change Bakker's behavior.

I should add that colloidal silver doesn't treat anything, and in fact it can be truly harmful. A JAMA Dermatology article a few years ago described it as "dangerous and readily available." Stay away from this stuff.

This article wouldn't be complete if I didn't add one more scam artist: the far-right conspiracy theorist Alex Jones has claimed, ridiculously, that he has a toothpaste that can “kills the whole SARS-corona family at point-blank range.” No such toothpaste exists, and the New York attorney general has ordered Jones to stop.

As I wrote at the beginning, I can't know for certain which of the people selling these products truly believe they have a treatment for COVID-19 and which of them are knowingly lying. But consumers should beware: false claims will continue to appear as long as there's money to be made.

No one has a treatment for coronavirus infection. The WHO has a site up now, which I recommend, that dispels many of the myths. I'll close with a quote from that site:
"To date, there is no specific medicine recommended to prevent or treat the new coronavirus (2019-nCoV)."

Coronavirus: time to panic?

The world is starting to panic over the 2019 coronavirus outbreak. Are we over-reacting?

Here are 3 reasons why we should panic, followed by 4 reasons why we shouldn't.
  1. The virus, 2019-nCoV, is completely new to humans, and we don't know exactly how bad it will get. As of 29 February, it has already killed nearly 3,000 people, over 2,700 of them in China. 
  2. It appears to be very infectious. Cases are now appearing in people who didn't travel to China, and who didn't have any contact with known cases. Coronavirus illness (newl named COVID-19) has now been reported in over 60 countries, on every continent except Antarctica. No matter where you are, it is probably coming your way.
  3. The mortality rate has been reported to be as high as 2%.  The Johns Hopkins University tracking site makes it appear even higher, with 2,933 deaths out of 85,688 cases, which is over 3%. By comparison, the 1918 Influenza pandemic had a mortality rate of around 2-3%, and in that epidemic, the worst in modern history, 30–50 million people died, which was 1.7% of the world's population at the time.  Extrapolating to today's population of 7.7 billion people, a virus that deadly would kill 130 million people.
This seems really bad. So perhaps we are not overreacting.

On the other hand, there are several very good reasons why we should stay calm.
  1. The mortality rate is probably much, much less than 2%. The rapid spread of COVID-19 suggests that many more people are infected than those who have confirmed cases. The number of people who have no symptoms or very mild symptoms is likely to be ten times as high as the number of reported cases. (This is only a guess.) That would mean the mortality rate might be only 0.2%, or even lower. We still don't know. (The cruise ship that was quarantined in the Japan had just over 700 cases, and 6 people have died, suggesting a mortality rate of 1%.)
  2. The reported mortality rate is dramatically lower in young people. If you are under 30, you can probably relax a bit. However, if you are over 70, the mortality rate is frighteningly high, 8-15%
  3. 2,933 deaths is a tragedy, but it's a tiny number compared to the annual deaths from the influenza virus, which we have learned to live with. In the U.S. alone, the CDC estimates that 12,000–61,000 people die each year from the flu (the number varies a lot because the virus itself changes from year to year), and 9-45 million people get sick. The worldwide totals are far higher. So in terms of numbers, the world is definitely over-reacting to the new coronavirus.
  4. Infectious viruses tended to become milder over time. At least 4 other coronaviruses already circulate among humans, causing little more than mild cold symptoms. It is quite possible that the virus causing COVID-19, nCoV-19, may mutate to become a milder disease as well. RNA viruses mutate extremely rapidly, and from an evolutionary perspective, viruses adapt to their hosts by becoming milder. (My perspective is based in part on my past research on the influenza virus.) From the virus's point of view, it can't spread itself around if the host is too sick.
What can we do? A few things:
  1. Panic isn't helpful. Don't panic.
  2. In the short term, the best response will be to develop a vaccine. (Dr. Peter Hotez and colleagues at Baylor College of Medicine are already working on one.) We need to dramatically increase government investment in vaccine development. It seems that the U.S. is doing that, although not quickly enough.
  3. If you feel sick, stay home.
  4. It's probably best to avoid travel to a location where COVID-19 is known to be circulating widely. Right now this list includes China and Iran, but it could grow in the coming weeks.
  5. In the longer term, we need to increase rather than cut biomedical research funding. Even if we get a vaccine, we still need actual treatments, not only for COVID-19 but for other viruses. (Most viruses are incurable with current technology.) The recent proposal out of the White House aims to cut NIH funding by 7% and CDC funding by 16%. As anyone following the coronavirus news now realizes, the CDC is responsible for tracking the virus in the U.S. and for coordinating our public health measures to respond to the outbreak.
Finally, I should add a note of caution about the bogus treatments already being hawked by peddlers of pseudoscience. There are multiple websites and Facebook pages, including some anti-vaccine sites, already claiming they know how to treat coronavirus illness. (I won't link to any of them, as I don't want to give them the traffic.) These are complete scams. No one has any treatment that will prevent or cure COVID-19, but if we make the investment, we'll get a treatment one day.

(Note: the WHO has renamed the virus SARS-CoV-2, but The Lancet article that first described its genome calls it nCoV-19.)

Would you trust your kids with this man? No? I didn't think so.

Today I want to shine a bit of light on the conspiracy theorist behind the film "Vaxxed" and its recent sequel, "Vaxxed II." I'm not going to provide any links to the movie, or to describe it, except to say that it's a slickly-produced conspiracy theory masquerading as a documentary. Don't watch it.

Anti-vax activists often use conspiracy theory tactics, which work like this: they simply make up a claim, out of thin air, that a secret cabal of doctors (or government scientists, or pharma companies) is out to harm patients by giving them vaccines, and is hiding the "truth" about the risks of vaccination. Never mind how irrational this is, and never mind that there's not a shred of evidence behind it: if you try to argue with the anti-vaxxer, you're part of the conspiracy.

So rather than try to disprove something that was never proven in the first place, let's look instead at the source of the anti-vax propaganda film, "Vaxxed." The source is one man: Andrew Wakefield. Who is this guy, and why is he so obsessed with vaccines?

Wakefield was once a doctor, before he had his license revoked a decade ago. In his former life, he was a gastroenterologist, with no special training in vaccines or infectious diseases. He first gained fame–a lot of fame–for a 1998 paper in a medical journal, The Lancet, in which he claimed to have discovered a link between the MMR vaccine (that's the one that covers measles, mumps, and rubella) and autism.

Here are some things you need to know about Wakefield before watching his movie:


  1. Wakefield's 1998 paper, it eventually turned out, was "an elaborate fraud." Wakefield defrauded the public, his patients, and even his own co-authors on the paper, most of whom were unaware of his elaborate conflicts of interests.
  2. Before he published his 1998 study, Wakefield was hired by a lawyer, Richard Barr, who was trying to build a lawsuit against vaccine makers. Barr paid Wakefield £435,000 (equal to $750,000 US dollars at the time) to help him build his case. Wakefield's co-authors were unaware of this contract.
  3. The study claimed that 8 out of 12 children had been diagnosed with autism soon after getting the MMR vaccine. It described these children as "a consecutive series" of admissions to the hospital where Wakefield worked. That was a lie. It turned out, as investigative journalist Brian Deer revealed, that all 12 children and their parents were referred to Wakefield by Barr–the lawyer who was paying Wakefield to conduct the study, and who was trying to sue vaccine makers.
  4. Wakefield also falsified data on all 12 of the children in his original study.
  5. Wakefield conducted "invasive and distressing procedures" on the children without approval from his hospital's ethics board.
  6. After learning some of the back story, 10 of his 12 co-authors tried to retract the paper in 2004. Wakefield refused to join them, so they published a partial retraction, signed by the 10 co-authors. The Lancet itself later fully retracted the paper (over Wakefield's objections), but it took until 2010 for them to act. By then, the anti-vax movement had spread widely.
  7. Prior to publishing his paper, Wakefield filed a patent claim for a "safer" vaccine for measles, one that would have profited him greatly once he discredited the (perfectly safe) MMR vaccine.
  8. After losing his license in the UK, Wakefield moved to Austin, Texas where he ran an organization called Thoughtful House, through which he paid himself a salary of $280,000. (Perhaps coincidentally, Austin is now a hotbed of anti-vaccination activism.)

For more than 20 years, Andrew Wakefield has made money off false claims that vaccines cause autism, first put forth in his discredited 1998 paper. He gives talks, writes books, conducts seminars, and now makes movies, of which make him money. Since the publication of his paper, dozens of studies involving literally millions of children have shown, time and again, that vaccines do not cause autism. Wakefield has denied every one of those studies, and continues to push his bogus claims.

(Why, you might ask, have scientists conducted studies looking for a link between autism and vaccines, if there was never any evidence for such a link? The answer is simple: anti-vaxxers have been so successful at scaring people about a nonexistent threat that scientists and public health experts felt it necessary to conduct those studies, in order to reassure people. Literally millions of dollars have been spent to prove something we already knew.)

Meanwhile, measles outbreaks have appeared with increasing frequency in the U.S., the UK, other European countries, and around the world, including the deadly outbreak in Samoa late last year, which caused 5,700 infections and 83 deaths in a population of just 200,000. Wakefield's new movie was released in the middle of that outbreak.

So to anyone who watched the movie Vaxxed and is now having doubts about vaccines, I ask: would you trust your children with this man? I wouldn't.

Are you "vaccine hesitant"? You may be in a cult

Edward Jenner, who pioneered vaccination, and two colleagues
 (right) seeing off three anti-vaccination opponents, with the dead
lying at their feet (1808). 
I Cruikshank/Wellcome Images/Wikimedia
Commons
CC BY-SA
The World Health Organization recently declared that "vaccine hesitancy," as they called it, was one of the top 10 threats to global health. That's right: it was up there with air pollution, climate change, influenza, Ebola, and other threats.

For the WHO, "vaccine hesitancy" is a polite phrase designed to engage the public and highlight how serious the problem is, without angering those who are guilty of it. I'm not going to be quite so polite here: "vaccine hesitant" means anti-vax. The anti-vax movement, which aggressively spreads fear and misinformation about vaccines, has become a major, worldwide threat.

It also resembles a cult, as I'll explain.

The most recent anti-vax nonsense centers on the new coronavirus that originated in China, and that has led the Chinese government to impose a massive quarantine affecting millions of people. This is a genuine public health crisis, and it has nothing to do with vaccines. Nonetheless, some anti-vaxxers are claiming, without evidence, that the new virus originated from a failed effort to create a coronavirus vaccine. I don't have time to get into that here, but Orac has a lengthy, detailed takedown of that bogus claim.

"Vaccine hesitancy" sometimes refers to parents who are just learning about vaccines for the first time, and who rely on the Internet to search for information. Unfortunately, these new parents are likely to be flooded with anti-vax messages, especially on Facebook. (In recent years, Google has taken steps to lower the priority of anti-vax sites, which has improved things considerably. Sites such as healthychildren.org now appear near the top of searches for "vaccine safety.") It's entirely reasonable to ask your doctor about the benefits and risks of vaccines.

But the answers that parents hear should be clear: vaccines work. As physician ZDoggMD (a pseudonym, obviously) explains in this video:

"Anti-vaccine sentiment is a poisonous scourge.... There's no debate about vaccines. Let's get over that nonsense that the media and celebrities have created, okay? There is nobody in the medical community of any actual reputation who believes that there are two sides to this."
The problem is that anti-vaxxers are continuously creating new websites, Facebook groups, and even movies to spread misinformation about vaccines, particularly the long-debunked claim that vaccines cause autism.

Why do I suggest that anti-vaxxers resemble a cult? Because they have several of the key features of cults, such as:

  1. Members of the cult have special insights that outsiders cannot comprehend. With anti-vaxxers, this means they are completely convinced that they know that vaccines cause harm, despite mountains of evidence to the contrary.
  2. The group and its leaders are the exclusive means of knowing "truth" or receiving validation, and no other process of discovery is credible. The anti-vax movement has had several prominent leaders, whose followers flock to their speeches and events. These include Andrew Wakefield, the disgraced former doctor who lost his medical license after it was revealed that he had committed fraud. His followers, though, either don't know or ignore his fraudulent past, and regard him as a hero. He makes a living from his books, a movie, and speaking fees, all based on spreading fear about vaccines. An even more prominent anti-vax leader is Robert Kennedy, Jr., who also sells books and gives speeches proclaiming the harms of vaccines. Thanks to his famous name, and despite the fact that he has no medical or scientific training, some people believe him.
  3. Unreasonable fear about the outside world, such as impending catastrophe, evil conspiracies and persecutions. Conspiracy theories are the core of many anti-vax arguments. The most common version holds that the "medical establishment" (whoever that is) are hiding the dangers of vaccines so that they can make money. This is utter nonsense. All of doctors I know in the infectious disease community are motivated by a wish to cure disease. In any case, most doctors make little or no money from the vaccines they administer.
  4. No meaningful financial disclosure regarding budget or expenses. Some anti-vaxxers profit handsomely by selling bogus, ineffective supplements as alternatives to vaccines. (I'm looking at you, Joe Mercola.) Because supplements are largely unregulated, they get away with it. They'd prefer you to think they're "just in it for the children."

I've no doubt that anti-vaxxers like Wakefield, Kennedy, and others would deny that they are conspiracy theorists, because that's how conspiracy theorists operate. If you question them (they argue), you must be part of the conspiracy. By their own reasoning, they can never be wrong.

So if you encounter someone, either on the sidelines at your kid's soccer game, on Facebook, or elsewhere, who is spreading claims that vaccines are harmful, pause for a minute and ask: what is the source of this information? Is it coming from someone who is profiting from this fear-mongering? There's a good chance the answer is yes.

It's ironic that when the world is faced with a true health emergency, such as the Ebola virus or the Wuhan coronavirus, the first thing that public health experts start to work on is a new vaccine. That's because vaccines provide our best protection against infections. We now have effective vaccines for 16 diseases that used to harm and even kill children in large numbers around the world. We've eliminated smallpox worldwide, and we've nearly eliminated polio, thanks to vaccines. Their very effectiveness is what has allowed the anti-vax message to take hold: many people are no longer frightened of dying from infectious diseases.

We're still a long way from conquering infections, but there's no reason for the world to slip back in time to an era when large numbers of people died from preventable infections. Vaccines work, if we'll let them.

Surprise! Many organic foods are GMOs, and they are transgenic

A new study finds that many common foods, including beer and tea, turn out to be "natural" GMOs. What's a health-food purist to do?

Even though no one has found any evidence that genetically modified organisms (GMOs) are harmful, anti-GMO activists have campaigned against them for years, with considerable success. As of this writing, 19 out of 28 countries in the European Union have voted to ban or severely restrict genetically modified plants, and many other countries impose similar bans.

But all of these restrictions may be in vain, because nature got there first. It turns out that many common foods have already been genetically modified, by a bacterium called Agrobacterium. (Read on to see the list.) And, in news that should be even more frightening to the anti-GMO crowd, these foods are transgenic: they contain genetic material from completely different species. Frankenfoods!

First, as I've argued before, genetic modification technology is just a tool, and a very precise one at that. Scientifically, claiming that GMOs are bad for you is nonsensical–it depends entirely on what the genetic modification is. Whether a food scientist modifies a tomato to taste better by traditional breeding or by using GM technology, you still end up with a tomato that has different genetic content. The only difference is that with traditional breeding, you have no idea what exactly you changed in the plant's DNA. And humans have already consumed billions of servings of GM foods with no ill effects. The GM foods we eat today are perfectly safe.

So back to my first point. What are all these natural Frankenfoods, and how did they get that way?

I'll start with the common sweet potato, or yam. Humans eat hundreds of varieties of sweet potatoes, and you can buy them in markets on every continent. Back in 2015, a group of scientists from Belgium, Peru, China, and the US (Tina Kyndt and colleagues) discovered that every cultivated variety of sweet potato has "foreign" DNA integrated into its genome, from a bacterium called (appropriately) Agrobacterium. They tested 291 different varieties, and found the bacterium 100% of the time. They also tested wild relatives of sweet potato, and found that the wild varieties (which humans don't eat) are missing the bacterial DNA.

Agrobacterium is a bacterium with special properties: it has evolved to be able to insert its DNA directly into the genomes of a wide variety of plants. (Don't worry, it doesn't infect humans.) In sweet potatoes, this happened naturally, centuries or millenia ago, long before humans were cultivating it. But then we came along, and (apparently) we liked the taste of these naturally transgenic sweet potatoes, so those are the ones that we chose to cultivate. As a result, all the sweet potatoes we eat are GMOs, although it happened naturally.

That was five years ago. But in a newly published study, scientists Tatiana Matveeva from Russia and Léon Otten from France discovered that Agrobacterium has made its way into dozens of other plants, including some of our favorite foods and drinks. Matveeva and Otten searched through the genomes (the DNA) of hundreds of plants, and found 39 natural GMOs, as they called them.

So without further ado, here are the natural GMO foods, all of them transgenic, with the common name followed by the formal species name in italics:

  • bananas (Musa acuminata)
  • beer (hops) (Humulus lupulus)
  • cranberries (Vaccinium macrocarpon)
  • date-plum (Diospyros lotus)
  • guava (Psidium guajava)
  • peanuts (Arachis hypogaea)
  • pomelo fruit (Citrus maxima)
  • Suriname cherry (Eugenia uniflora)
  • sweet potatoes (Ipomoea species)
  • tea (Camellia sinensis, which is used for most teas)
  • walnuts (Juglans species)
  • yams (Dioscorea alata)


That's right, beer and tea are GMOs–even if they are labelled as "organic." Keep in mind that this list is undoubtedly incomplete: the new study relied on current genome databases, which are still missing many common foods. 

If you're reading this, you've probably already consumed countless servings of transgenic, GMO foods. As I wrote above, there's no reason to believe that GMO foods are harmful in any way. Plenty of plants are naturally poisonous, of course (think hemlock), but widely-consumed foods got that way for a reason: people like to eat them, and they help sustain us.

If you believe the alarmist claims of the anti-GMO movement, then you're going to have to start avoiding many more foods, including everything on the list above. And yes, that includes beer. 

A new kind of fasting provides significant immune system benefits

I've written about fasting and its effects on health before. Six years ago, a study showed that a 3-day fast can essentially reset the immune system, providing many potential benefits. These benefits include better cardiovascular health, better endurance, lower blood pressure, and reduced inflammation.

Newer data, which I'll get to in a minute, shows that you might not have to fast nearly that long to get these benefits.

In the 2014 study, Valter Longo and colleagues at USC found that fasting lowered white blood cell counts, which in turn triggered the immune system to start producing new white blood cells. White blood cells (or lymphocytes) are a key component of your body’s immune system. Once you start eating again, according to Longo, your stem cells kick back into high gear to replenish the cells that were recycled.

The idea behind this strategy is that you have to fast for several days to get the benefits: basically, you have to fully deplete your energy reserves (in the form of glycogen), and it takes your body at least 24 hours, and probably 48 hours or more, to do this. That's the not-so-good news. The good news is that you probably only need to fast once or twice a year to gain the benefits that Longo described.

Last week, in a paper just published in the New England Journal of Medicine, Rafael de Cabo and Mark Mattson reviewed multiple strategies for fasting that have been tested in the years since Longo's study. The news continues to be very encouraging: intermittent fasting is good for you. I don't have time or space here to discuss all the results, but I want to focus on one fasting strategy that has surprisingly good benefits.

It turns out that you can get many of the benefits of fasting without doing a 3-day fast, which for most people is really, really difficult to accomplish. Instead, you can try a much easier type of fasting, called "time-restricted" fasting. With this strategy, you fast every day, by eating all of your food in a 6-hour or 8-hour window. Or you can go with the more difficult strategy (but still easier than a 3-day fast) where you fast for 2 entire days per week. Here, then, are two intermittent fasting strategies that have similar health benefits:

  • Time-restricted: eat lunch starting at 12 noon, and finish dinner by 8:00pm. Fast until the next day at noon (16 hour fast). Do this every day.
  • 5:2 fasting: fast for 2 different days each week, which means eating just 500-700 calories worth of food and drink on those days. Eat normally on the other 5 days.

The first strategy–a daily 16-hour fast–is the easiest, but its benefits might be equal to those of 5:2 fasting and the 3-day fast. (No study has directly compared these 3 fasting regimens.)

The benefits of intermittent fasting are numerous. As de Cabo and Mattson explain, they include
"[improvements in] blood pressure; resting heart rate; levels of HDL and LDL cholesterol, triglycerides, glucose, and insulin resistance.... In addition, intermittent fasting reduces markers of systemic inflammation and oxidative stress that are associated with atherosclerosis."
Fasting also helps with weight loss, for obvious reasons. Cutting out all snacks in the evening, which is the biggest change imposed by time-restricted fasting, means not only a reduction in calories consumed, but also a reduction in the amount of highly processed ("junk") foods in one's diet as well.

Furthermore, because intermittent fasting reduces inflammation, it may also improve symptoms of arthritis and even rheumatoid arthritis.

Why does fasting work? It's all about getting your body to switch over from glucose metabolism to ketone metabolism. Our usual 3-meal-a-day diet provides our body with a constant source of fuel in the form of glucose. Once that glucose is used up, though, our body switches to using fatty acids and ketone bodies. Ketone bodies provide more than fuel: as de Cabo and Mattson explain,
"Ketone bodies regulate the expression and activity of many proteins and molecules that are known to influence health and aging."
Ketone metabolism seems to bring a host of health benefits. The trick is getting our bodies to switch over to it, now and then. If we eat constantly, then our bodies happily subsist on glucose and never make the switch.

Does fasting truly reset your immune system? Six years ago, I concluded that a 3-day fast does the trick, at least partially. The science suggests that, if you can do it, a prolonged fast for 2-3 days will induce your body to clean out some old immune cells and switch on production of new ones. Now we're learning that intermittent fasting, which is easier to do, may work in much the same way, with multiple health benefits.

[Note: one of the authors of the NEJM study, Mark Mattson, is a Professor at Johns Hopkins School of Medicine, making him a colleague of mine. However, we are in different departments and we have never met.]