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.]

Donald Trump shows his anti-vaccine craziness, and Ben Carson's response is worse

Donald Trump used the latest Republican debate as an opportunity to express wildly inaccurate anti-vaccine claims, embracing the thoroughly discredited position that vaccines cause autism. This claim has been exhaustively debunked, by countless scientific studies and by reports from the Institute of Medicine and the CDC. It started with a now-retracted 1998 study by one of the great villains in medicine, Andrew Wakefield, who continues to push his fraudulent views despite having lost his medical license.

Trump's comments were nutty and dangerous, but Ben Carson's response was, in some ways, worse. Carson had the chance to set the record straight, and because of his medical credentials, he could have been effective. He failed.

Trump has been an anti-vaxxer for years, so his comments were not surprising. Science blogger Orac posted a 2007 Trump quote that almost exactly mirrors what he said in the debate.

What was much more surprising, and deeply disappointing, was the response of candidate Ben Carson, who until last year was a pediatric neurosurgeon at Johns Hopkins School of Medicine. (Note that although I too work at Hopkins Medicine, I've never met Dr. Carson.) Carson did point out vaccines don't cause autism, but then he made a series of false claims that come right out of the anti-vax playbook.

When the moderator asked Carson to respond to Trump's anti-vaccine rant, Carson had a golden opportunity to do some real good: he could have corrected the record and pointed out the real harm that comes from anti-vaccination misinformation. Instead, he said things like this:

“Vaccines are very important, certain ones, the ones that would prevent death or crippling. There are others, a multitude of vaccines that don’t fit in that category, and there should be some discretion in those cases.”

Forbes bogger Tara Haelle has already explained the grievous error here: all our vaccines prevent death.  Carson's claim is simply false, and it's shocking that a highly trained physician would make this statement, on a national stage, without knowing the facts. What Carson should have said–but didn't–was this, from the Every Child By Two organization:

"Each and every vaccine added to the list of recommended immunizations will save the lives and/or reduce the number of disabilities of children in the United States. With the introduction of every new vaccine, rates of both disease and deaths have fallen across the country."

Carson then dug himself even deeper into the anti-vaccine camp with this claim:

"But it is true that we are probably giving way too many in too short a period of time."

This claim is right out of the anti-vaccine playbook: it was the basis of the "too many, too soon" campaign launched by Jenny McCarthy's Generation Rescue, the country's leading anti-vaccine activist group. In fact, the vaccine schedule is very safe, and misinformation like this trope leads to parents withholding vaccines from their children, which in turn can cause sickness, disability, and death.

Let me show you what Carson could have done. Six years ago, Bill Maher–one of the most left-wing talk show hosts in the media, and an anti-vaxxer himself–was interviewing former Republican Senate majority leader Bill Frist, who is also an M.D. Here's what happened:

Dr. Frist interrupted Maher and said "wait, this is important," and proceeded to school Maher on how vaccines save lives. I wasn't a big fan of Frist, but he did a fantastic job here. Carson, in contrast, just pandered to the audience, and to Trump.

The moderator also asked Rand Paul, the other M.D. among the candidates, to respond to Trump's anti-vax claims. He too repeated the anti-vaccine trope that he "ought to have the right to spread my vaccines out a little bit." This is nonsense as well: Paul does have that right, and no one has ever proposed taking it away. It's bad medicine, though, and as doctor, Paul should know better. He failed as well.

It's far more harmful to the public when a high-profile doctor makes anti-vaccine statements than when a blowhard like Trump makes them. Dr. Ben Carson and Dr. Rand Paul should both know better.

“Shocking Report” on flu vaccines is neither shocking nor correct

Flu season is coming, and once again it’s time to get your flu shot (or snort, if you prefer FluMist). It’s not perfect, but the vaccine is your best protection against the influenza virus.

So I was surprised to stumble upon an article titled “Johns Hopkins Scientist Reveals Shocking Report on Flu Vaccines,” which popped up on an anti-vaccine website two weeks ago. Johns Hopkins University is my own institution, and I hadn’t heard any shocking new findings. I soon discovered that this article contained only a tiny seed of truth, surrounded by a mountain of anti-vaccine misinformation. Most of it focused on a report published in early 2013 by Peter Doshi, a former postdoctoral fellow at Hopkins.

First, as Snopes.com has already pointed out, Doshi is not a virologist or an epidemiologist, but rather an anthropologist who studies comparative effectiveness research. He never conducted influenza research at Hopkins. (He’s now an Assistant Professor at the University of Maryland’s School of Pharmacy.) Second, Doshi’s 2013 article was an opinion piece (a “feature”), not an original research article, and it did not report any new findings. Third, it is highly misleading to suggest (as the anti-vax article’s title does) that Doshi somehow represents Johns Hopkins University. At Johns Hopkins Hospital, the flu vaccine is required of all personnel who have contact with patients, as a good-practices effort to minimize the risk that a patient will catch the flu from a caregiver.

But what did Doshi’s article say? Even though it isn’t new, why are the anti-vaccine sites recycling it? His central argument is this:

“The vaccine might be less beneficial and less safe than has been claimed, and the threat of influenza appears overstated.”

Let’s look at this statement. It’s almost obviously true: one only has to find a few overstated claims about the risks of flu, which isn't hard to do. But it’s also completely consistent to state that the vaccine is enormously beneficial and that the threat of influenza is very serious. See how that works? 

Doshi uses this slight-of-hand to suggest that the vaccine may not be beneficial at all. He never says this outright—instead, he just questions, again and again, whether the precise percentages reported in published studies are accurate. For example, he makes a big deal of a CDC announcement in 2013 that the vaccine’s effectiveness was only 62%. He casts doubt with phrases like 

“the 62% reduction statistic almost certainly does not hold true for all subpopulations”

which is almost certainly true, but is meaningless from the point of view of public health. Of course the vaccine doesn’t have the same effectiveness in everyone. The point is that it works most of the time. 

Doshi cites another study that showed a clear benefit for the flu vaccine, only to cast doubt on it with this argument: 

“No evidence exists, however, to show that this reduction in risk of symptomatic influenza for a specific population—here, among healthy adults—extrapolates into any reduced risk of serious complications from influenza such as hospitalizations or death in another population.”

Again, Doshi’s argument doesn’t prove that the original study was wrong, only that it doesn’t apply to everyone. But Doshi’s motivation, as evidenced by the relentlessly negative slant of his entire article, seems to be to convince people that the flu vaccine is bad.

Not surprisingly, the anti-vaccine movement has embraced Doshi (for example, here and here). And unfortunately, he seems to have accepted their acclaim: in 2009, he spoke at an anti-vaccine conference hosted by NVIC, a notorious (and misleadingly named) anti-vaccination group.

Perhaps even more disturbing is that Doshi signed a petition arguing that the HIV virus is not the cause of AIDS, joining the ranks of HIV denialists. He signed this statement while still a graduate student, so I contacted him to ask if he still doubted the link between HIV and AIDS. I also asked him if he supports flu vaccination, if he agrees with the anti-vaccine movement's use of his statements, and if he believes the flu is a serious public health threat.

On the question of signing the HIV/AIDS petition, Doshi responded that "Seeing how my name was published and people have misconstrued this as some kind of endorsement, I have written the list owner and asked for my name to be removed." (He declined to state directly - and I gave him the chance - that he agrees that the HIV virus causes AIDS.)

As for the flu itself, Doshi says "I don’t agree with CDC’s portrayal of influenza as a major public health threat." So he and I have a serious disagreement there. I asked if he agrees with the anti-vaccinationist who are using his writings to claim that the flu vaccine is ineffective, and he replied that while "ineffective" is "too sweeping," he has found "no compelling evidence of hospitalization and mortality reduction in [the] elderly."

Doshi’s argument against the flu vaccine boils down to this: the vaccine is much less than 100% effective. This is undeniably true, and the research community makes no secret of it. In fact, many of us have repeatedly called for more research into better vaccines, in the effort to create a vaccine that is not only more effective, but that (like most other vaccines) only needs to be taken once for lifetime immunity. We’re just not there yet. Meanwhile, though, the annual flu vaccine is usually effective: a recent study showed, for example, that it reduced children’s risk of ending up in a pediatric intensive care unit by 74%.

So get your flu shot (or snort) now, before flu season hits, because it takes a couple of weeks for your body to develop immunity. By getting immunized, you’ll not only increase your chances of getting through the winter flu-free, but (because you won’t spread the flu to others) you might also save someone whose immune system would be overwhelmed by influenza.