What White Blood Cell Count Should We Shoot for?

At the start of my video What Does a Low White Blood Cell Count Mean?, you can see what it looks like when you take a drop of blood, smear it between two pieces of glass, and view at it under a microscope: a whole bunch of little, round, red blood cells and a few big, white blood cells. Red blood cells carry oxygen, while white blood cells are our immune system’s foot soldiers. We may churn out 50 billion new white blood cells a day. In response to inflammation or infection, that number can shoot up to a 100 billion or more. In fact, pus is largely composed of: millions and millions of white blood cells.

Testing to find out how many white blood cells we have at any given time is one of the most common laboratory tests doctors order. It’s ordered it hundreds of millions of times a year. If, for example, you end up in the emergency room with abdominal pain, having a white blood cell count above about 10 billion per quart of blood may be a sign you have appendicitis. Most Americans fall between 4.5 and 10, but most Americans are unhealthy. Just because 4.5 to 10 is typical doesn’t mean it’s ideal. It’s like having a “normal” cholesterol level in a society where it’s normal to die of heart disease, our number-one killer. The average American is overweight, so if your weight is “normal,” that’s actually a bad thing.

In fact, having excess fat itself causes inflammation within the body, so it’s no surprise that those who are obese walk around with two billion more white cells per quart of blood. Given that, perhaps obese individuals should have their own “normal” values. As you can see at 2:06 in my video, if someone with a 47-inch waist walks into the ER with a white blood cell count of 12, 13, or even 14, they may not have appendicitis or an infection. That may just be their normal baseline level, given all the inflammation they have in their body from the excess fat. So, normal levels are not necessarily healthy levels.

It’s like smoking. As you can see at 2:31 in my video, if you test identical twins and one smokes but the other doesn’t, the smoker is going to end up with a significantly higher white cell count. In Japan, for example, as smoking rates have steadily dropped, so has the normal white count range. In fact, it’s dropped such that about 8 percent of men who have never smoked would now be flagged as having abnormally low white counts if you used a cut-off of 4. But, when that cut-off of 4 was set, most people were smoking. So, maybe 3 would be a better lower limit. The inflammation caused by smoking may actually be one of the reasons cigarettes increase the risk of heart attacks, strokes, and other inflammatory diseases. So, do people who have lower white counts have less heart disease, cancer, and overall mortality? Yes, yes, and yes. People with lower white blood cell counts live longer. Even within the normal range, every one point drop may be associated with a 20 percent drop in the risk of premature death.

As you can see at 3:39 in my video, there is an exponential increase in risk in men as white count goes up, even within the so-called normal range, and the same is found for women. The white blood cell count is a “stable, well-standardized, widely available and inexpensive measure of systemic inflammation.” In one study, half of the women around 85 years of age who had started out with white counts under 5.6 were still alive, whereas 80 percent of those who started out over 7 were dead, as you can see at 4:05 in my video—and white blood cell counts of 7, 8, 9, or even 10 would be considered normal. Being at the high end of the normal range may place one at three times the risk of dying from heart disease compared to being at the lower end.

The same link has been found for African-American men and women, found for those in middle age, found at age 75, found at age 85, and found even in our 20s and 30s: a 17 percent increase in coronary artery disease incidence for each single point higher.

As you can see at 5:00 in my video, the higher your white count, the worse your arterial function may be and the stiffer your arteries may be, so it’s no wonder white blood cell count is a useful predictor of high blood pressure and artery disease in your heart, brain, legs, and neck. Even diabetes? Yes, even diabetes, based on a compilation of 20 different studies. In fact, it may be associated with everything from fatty liver disease to having an enlarged prostate. And, having a higher white blood cell count is also associated with an increased risk of dying from cancer. So, what would the ideal range be? I cover that in my video What Is the Ideal White Blood Cell Count?.

A higher white blood cell count may be an important predictor for cardiovascular disease incidence and mortality, decline in lung function, cancer mortality, all-cause mortality, heart attacks, strokes, and premature death in general. This is no surprise, as the number of white blood cells we have circulating in our bloodstreams are a marker of systemic inflammation. Our bodies produce more white blood cells day to day in response to inflammatory insults.

We’ve known about this link between higher white counts and heart attacks since the 1970s, when we found that higher heart attack risk was associated with higher white blood cell counts, higher cholesterol levels, and higher blood pressures, as you can see at 0:53 in my video What Is the Ideal White Blood Cell Count?. This has been found in nearly every study done since then. There are decades of studies involving hundreds of thousands of patients showing dramatically higher mortality rates in those with higher white counts. But why? Why does white blood cell count predict mortality? It may be because it’s a marker of inflammation and oxidation in the body. In fact, it may even be a biomarker for how fast we are aging. It may be more than just an indicator of inflammation—it may also be an active player, contributing directly to disease via a variety of mechanisms, including the actual obstruction of blood flow.

The average diameter of a white blood cell is about seven and a half micrometers, whereas our tiniest vessels are only about five micrometers wide, so the white blood cell has to squish down into a sausage shape in order to squeeze through. When there’s inflammation present, these cells can get sticky. As you can see at 2:20 in my video, a white blood cell may plug up a vessel as it exits a small artery and tries to squeeze into a capillary, slowing down or even momentarily stopping blood flow. And, if it gets stuck there, it can end up releasing all of its internal weaponry, which is normally reserved for microbial invaders, and damage our blood vessels. This may be why in the days leading up to a stroke or heart attack, you may find a spike in the white cell count.

Whether white count is just a marker of inflammation or an active participant, it’s better to be on the low side. How can we reduce the level of inflammation in our body? Staying away from even second-hand smoke can help drop your white count about half of a point. Those who exercise also appear to have an advantage, but you don’t know if it’s cause and effect unless you put it to the test. In one study, two months of Zumba classes—just one or two hours a week—led to about a point and a half drop in white count. In fact, that may be one of the reasons exercise is so protective. But is that just because they lost weight?

Fitness and fatness both appear to play a role. More than half of obese persons with low fitness—51.5 percent—have white counts above 6.6, but those who are more fit or who have less fat are less likely to have counts that high, as you can see at 3:47 in my video. Of course, that could just be because exercisers and leaner individuals are eating healthier, less inflammatory diets. How do we know excess body fat itself increases inflammation, increases the white count? You’d have to find some way to get people to lose weight without changing their diet or exercise habit. How’s that possible? Liposuction. If you suck about a quart of fat out of people, you can significantly drop their white count by about a point. Perhaps this should get us to rethink the so-called normal reference range for white blood cell counts. Indeed, maybe we should revise it downward, like we’ve done for cholesterol and triglycerides.

Until now, we’ve based normal values on people who might be harboring significant background inflammatory disease. But, if we restrict it to those with normal C-reactive protein, another indicator of inflammation, then instead of “normal” being 4.5 to 10, perhaps we should revise it closer to 3 to 9.

Where do the healthiest populations fall, those not suffering from the ravages of chronic inflammatory diseases, like heart disease and common cancers? Populations eating diets centered around whole plant foods average about 5, whereas it was closer to 7 or 8 in the United States at the time. How do we know it isn’t just genetic? As you can see at 5:38 in my video, if you take those living on traditional rural African diets, who have white blood cell counts down around 4 or 5, and move them to Britain, they end up closer to 6, 7, or even 8. Ironically, the researchers thought this was a good thing, referring to the lower white counts on the “uncivilized” diet as neutropenic, meaning having too few white blood cells. They noted that during an infection or pregnancy, when more white cells are needed, the white count came right up to wherever was necessary. So, the bone marrow of those eating traditional plant-based diets had the capacity to create as many white cells as needed but “suffers from understimulation.”

As you can see at 6:26 in my video, similar findings were reported in Western plant eaters, with an apparent stepwise drop in white count as diets got more and more plant based, but could there be non-dietary factors, such as lower smoking rates, in those eating more healthfully? What we need is an interventional trial to put it to the test, and we got one: Just 21 days of removing meat, eggs, dairy, alcohol, and junk affected a significant drop in white count, even in people who started out down at 5.7.

What about patients with rheumatoid arthritis who started out even higher, up around 7? As you can see at 7:03 in my video, there was no change in the control group who didn’t change their diet, but there was a 1.5 point drop within one month on whole food plant-based nutrition. That’s a 20 percent drop. That’s more than the drop-in inflammation one might get quitting a 28-year pack-a-day smoking habit. The most extraordinary drop I’ve seen was in a study of 35 asthmatics. After four months of a whole food plant-based diet, their average white count dropped nearly 60 percent, from around 12 down to 5, though there was no control group nor enough patients to achieve statistical significance.

If white blood cell count is such a clear predictor of mortality and is so inexpensive, reliable, and available, why isn’t it used more often for diagnosis and prognosis? Maybe it’s a little too inexpensive. The industry seems more interested in fancy new risk factors it can bill for.

I touch on the health of the rural Africans I discussed in How Not to Die from Heart Disease.


For more on fighting inflammation, see:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

One Way to Treat Asthma and Autoimmune Diseases with Diet

Cutting two teaspoons of salt’s worth of sodium from one’s daily diet can significantly improve lung function in asthmatics

In the 1960s and 1970s, a mystery was emerging. Why were childhood asthma rates between 2 to 5 percent in the developed world but as low as 0.007 percent in the developing world? For example, in the developing world, instead of 1 in 20 kids affected, or even 1 in 50 kids, it could be more like 1 in 10,000 kids—extremely rare. And, when kids moved from a low-risk area to a high-risk area, their risk went up. What was going on? Were they exposed to something new? Did they leave some protective factor behind?

As I discuss in my video How to Treat Asthma with a Low-Salt Diet, all the way back in 1938, scientists showed they could stop asthma attacks by lowering children’s sodium levels. That was done with a diuretic drug, but subsequent dietary experiments showed that diets high in salt seemed to increase asthmatic symptoms, while “lowering the salt decreased the asthmatic symptoms…” This body of evidence was apparently forgotten…until it was picked up again in the 1980s as a possible explanation for why Western countries had higher asthma rates.

Maybe it was the salt.

As you can see at 1:34 in my video, researchers graphed out childhood death from asthma versus family salt purchases, and it seemed more salt meant more death. Just because a family buys more salt doesn’t necessarily mean the kids are eating more, though. The way to find out how much salt someone is eating is to collect their urine over a 24-hour period and measure the amount of sodium, since how much salt we eat is pretty much how much salt we excrete. The way to test for asthma, called a bronchial challenge test, is to look for an exaggerated response to an inhaled chemical. And, indeed, there was a strong correlation between how their lungs reacted and how much sodium they were taking in. However, there are all sorts of food additives, like preservatives, that can trigger these so-called hypersensitivity reactions, so maybe high sodium intake was just a marker for high processed food intake. Maybe it wasn’t the salt at all.

Or maybe it was other components of the diet. For example, the reason sodium may be a risk factor for another inflammatory disease, rheumatoid arthritis, may be that sodium intake is just a marker for increased fish and other meat intake or decreased fruit and vegetable intake. We needed a study where researchers would take asthmatics, change the amount of salt in their diets, and see what happened—and that’s just what came next.

As you can see at 3:16 in my video, researchers doubled the salt intake of ten asthmatics, and lung sensitivity worsened in nine out of ten. There was no control group, though. Is it possible the subjects would have gotten worse anyway?

In a randomized, double-blind, placebo-controlled trial, researchers put everyone on a low-salt diet, but then gave half of the subjects sustained-release sodium pills to bring their salt intake back up to a more normal level and the other half a placebo. After five weeks, the groups switched regimes for another five weeks. That’s how you can randomize people to a true low-sodium diet without them even realizing it. Genius! So what happened? Asthmatics on the salt got worse. Their lung function got worse, their asthma symptoms got worse, and they had to take more puffs on their inhalers. This study compared asthmatics consuming about three teaspoons’ worth of salt a day to those consuming less than one, so they were effectively able to drop their sodium intake by two teaspoons’ worth of salt, as you can see at 4:04 in my video. If you do a more “pragmatic” trial and only effectively reduce people’s salt intake by a half a teaspoon a day, it doesn’t work.

Even if you are able to cut down your sodium intake enough to get a therapeutic effect, though, it should be considered an adjunct treatment. Do not stop your asthma medications without your doctor’s approval.

Millions suffer from asthma attacks triggered by exercise. Within five minutes of starting to exercise, people can get short of breath and start coughing and wheezing such that lung function significantly drops, as you can see at 0:19 in my video Sodium and Autoimmune Disease: Rubbing Salt in the Wound?. On a high-salt diet, however, the attack is even worse, whereas on a low-salt diet, there’s hardly a significant drop in function at all. To figure out why, researchers had the subjects cough up sputum from their lungs and found that those on the high-salt diet had triple the inflammatory cells and up to double the concentration of inflammatory mediators, as you can see at 0:43 in my video. But why? What does salt intake have to do with inflammation? We didn’t know…until now.

“The ‘Western diet,’ high in saturated fatty acids and salt, has long been postulated as one potential…cause for the increasing incidence of autoimmune diseases in developed countries…” The rapidly increasing incidence of autoimmune diseases may be due to an overactivation of immune cells called T helper 17 (Th17) cells. “The development of…multiple sclerosis, psoriasis, type I diabetes, Sjögren’s syndrome, asthma, and rheumatoid arthritis are all shown to involve Th17-driven inflammation,” and one trigger for the activation of those Th17 cells may be elevated levels of salt in our bloodstream. “The sodium content of processed foods and ‘fast foods’…can be more than 100 times higher in comparison to similar homemade meals.”

And, sodium chloride—salt—appears to drive autoimmune disease by the induction of these disease-causing Th17 cells. It turns out there is a salt-sensing enzyme responsible for triggering the formation of these Th17 cells, as you can see at 2:07 in my video.

Organ damage caused by high-salt diets may also activate another type of inflammatory immune cell. A high-salt diet can overwork the kidneys, starving them of oxygen and triggering inflammation, as you can see at 2:17 in my video. The more salt researchers gave people, the more activation of inflammatory monocyte cells, associated with high-salt intake induced kidney oxygen deficiency. But that study only lasted two weeks. What happens over the long term?

One of the difficulties in doing sodium experiments is that it’s hard to get free-living folks to maintain a specific salt intake. You can do so-called metabolic ward studies, where people are essentially locked in a hospital ward for a few days and their food intake is controlled, but you can’t do that long term—unless you can lock people in a space capsule. Mars520 was a 520-day space flight simulation to see how people might do on the way to Mars and back. As you can see at 3:17 in my video, the researchers found that those on a high-salt diet “displayed a markedly higher number of monocytes,” which are a type of immune cell you often see increased in settings of chronic inflammation and autoimmune disorders. This may “reveal one of the consequences of excess salt consumption in our everyday lives,” since that so-called high-salt intake may actually just be the average-salt intake. Furthermore, there was an increase in the levels of pro-inflammatory mediators and a decrease in the level of anti-inflammatory mediators, suggesting that a “high-salt diet had a potential to bring about an excessive immune response,” which may damage the immune balance, “resulting in either difficulties on getting rid of inflammation or even an increased risk of autoimmune disease.”

What if you already have an autoimmune disease? In the study titled “Sodium intake is associated with increased disease activity in multiple sclerosis,” researchers followed MS patients for a few years and found that those patients eating more salt had three to four times the exacerbation rate, were three times more likely to develop new MS lesions in their brains, and, on average, had 8 more lesions in their brain—14 lesions compared to 6 in the low-salt group. The next step is to try treating patients with salt reduction to see if they get better. But, since reducing our salt intake is a healthy thing to do anyway, I don’t see why we have to wait.


What else can we do for asthma? See:

Have you heard that salt reduction was controversial? That’s what the processed food industry wants you to think. Check out the science in:

What are some of the most powerful dietary interventions we have for autoimmune disease? See, for example:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

The Risks and Benefits of Taking Low-Dose Aspirin

Salicylic acid, the active ingredient in aspirin, has been used for thousands of years as an anti-inflammatory painkiller in the form of willow tree bark extract, which Hippocrates used to “treat fever and to alleviate pain during childbirth.” It became trademarked as a drug named Aspirin™ in 1899 and, to this day, “remains the most commonly used drug in the world.” One reason for its on-going popularity, despite the availability of better painkillers now, is that aspirin also acts as a blood thinner. Millions of people take aspirin on a daily basis to treat or prevent heart disease, which I explore in my video, Should We All Take Aspirin to Prevent Heart Disease?.

It all started in 1953 with the publication of the landmark study “Length of life and cause of death in rheumatoid arthritis” in the New England Journal of Medicine. The paper began with the sentence: “It has often been said that the way to live a long life is to acquire rheumatism.” The researchers found fewer deaths than expected from accidents, which could be explained by the fact that people with rheumatoid arthritis likely aren’t skiing or engaging in other potentially risky activity, but they also found significantly fewer deaths from heart attacks. Why would this be? Perhaps all the aspirin the subjects were taking for their joints was thinning their blood and preventing clots from forming in their coronary arteries in their heart. To find out, in the 1960s, there were calls to study whether aspirin would help those at risk for blood clots, and we got our wish in the 1970s: studies suggesting regular aspirin intake protects against heart attacks.

Today, the official recommendation is that low-dose aspirin is recommended for all patients with heart disease, but, in the general population (that is, for those without a known history of heart disease or stroke) daily aspirin is only recommended “when the potential cardiovascular [heart] disease benefit outweigh the risk of gastrointestinal bleeding.”

The bleeding complications associated with aspirin use may be considered an underestimated hazard in clinical medical practice. For those who have already had a heart attack, the risk-benefit analysis is clear. If we took 10,000 patients, daily low-dose aspirin use would be expected to prevent approximately 250 “major vascular events,” such as heart attacks, strokes, or, the most major event of all, death. However, that same aspirin “would be expected to cause approximately 40 major extracranial bleeding events,” meaning bleeding so severe you have to be hospitalized. Thus, the net benefit of aspirin for secondary prevention—for example, preventing your second heart attack—“would substantially exceed the bleeding hazard. For every 6 major vascular events prevented, approximately 1 major bleeding event would occur; therefore, the value of aspirin for secondary prevention is not disputed.”

If we instead took 10,000 patients who hadn’t ever had a heart attack or stroke and tried to use aspirin to prevent clots in the first place, that is, for so-called primary prevention, daily low-dose aspirin would only “be expected to prevent 7 major vascular events and cause 1 hemorrhagic stroke [bleeding within the brain] and 3 major extracranial bleeding events.” So, the benefits are approximately only 2 to 1, which is a little too close for comfort. This is why the new European guidelines do not recommend aspirin for the general population, especially given the additional risk of aspirin causing smaller bleeds within the brain as well.

If only there were a safe, simple solution free of side effects…and there is! Drs. Ornish and Esselstyn proved that even advanced, crippling heart disease could not only be prevented and treated, but also reversed, with a plant-based diet centered around grains, beans, vegetables, and fruits, with nuts and seeds treated as condiments, and without oils, dairy, or meat (including poultry and fish).

Long-time director of the longest-running epidemiological study in the world, the famous Framingham Heart Study, “Dr. William Castelli was asked what he would do to reverse the CAD [coronary artery disease] epidemic if he were omnipotent. His answer: ‘Have the public eat the diet of the rural Chinese as described by Dr. T. Colin Campbell…’” In other words, as he , “‘If Americans adopted a vegetarian diet, the whole thing would disappear,’ Castelli says of the heart disease epidemic.”

Dr. Esselstyn clarified that we’re not just talking about vegetarianism. “This new paradigm” of heart disease reversal means “exclusively plant-based nutrition.”


Did you know preventing heart disease and stroke aren’t the only benefits of an aspirin a day? A daily aspirin may also decrease the risk of certain cancers. In that case, should we take an aspirin a day after all? See Should We All Take Aspirin to Prevent Cancer? and Plants with Aspirin Aspirations.

For more on preventing, arresting, and reversing heart disease, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: