On any given Friday morning at our community clinic, which serves low-income individuals and families in San Bernardino County, California, we see younger and younger patients coming in with the devastating, lifelong consequences of strokes.
A stroke occurs when the blood vessels in the brain are blocked by a blood clot or rupture, resulting in clinical features such as aphasia (difficulty and inability to speak), hemiparesis (complete paralysis of one side of the body), and even death. The brain contains more than 87 billion neurons and nearly a trillion supporting cells, such as glial cells, which require hundreds of billions of microvascular tributaries. In fact, the brain is the most vascular organ and also the hardest-working organ in the body. This means that its microvessels are especially susceptible to injury over a lifetime of metabolic and physical trauma caused by poor diet, sedentary behavior, smoking, and other unhealthy behaviors.
Although stroke occurs suddenly, the damage accumulates for years before the event. Often, we only see that damage once an individual is in the emergency room.
The overarching numbers are shocking. Nearly 800,000 new cases of stroke occur every year in the US, straining our already overburdened healthcare system.[1] Someone has a stroke every 40 seconds in the US, and someone dies of stroke just over every three minutes. These statistics pale in comparison to the vast number of people who do not experience a full-blown stroke but suffer the long-term consequences of cumulative microvascular disease, such as cognitive decline and dementia.
Billions of dollars have been spent on research over the last few decades to prevent and treat stroke and dementia.[2] Yet the results have been dismal. We have reduced stroke mortality and made progress in treating stroke in emergency rooms, with the use of thrombolytics (a type of therapy that dissolves clots when used within the first 4.5 hours) and therapies focused on removing clots (physically pulling out the clot from the blocked vessel), but the stroke burden remains immense.[3] Mobile stroke units with advanced imaging and top-of-the-line technology have been in use for years, but the latest data show that such expensive tools (each unit costs hundreds of thousands of dollars, if not more than a million dollars, not including the cost of maintenance) may not significantly improve the most important outcomes: stroke-related neurological events or in-hospital mortality.[4]
Given that stroke remains a leading cause of disability in the US, we have not focused enough effort on strengthening or protecting the brain to avoid this disease in the first place.[1] Sadly, recent studies show that we’ve made little progress in reducing the leading modifiable risk factors for stroke; in some cases, we are worse off today than in years or decades past: the prevalence of diabetes and hypertension, for example, have increased in recent years.[5][6]
A patient who comes to the emergency room with a stroke usually ends up paying thousands of dollars, if not tens of thousands of dollars, for the mandatory CAT scan, MRI, carotid ultrasound, and echocardiogram, as well as the emergency room and ICU stay, before ultimately being released to rehabilitation with an antiplatelet agent, such as aspirin or Clopidogrel, and the cholesterol-lowering medication of the day.[7]
The odds of suffering a second stroke (or more) after a first-ever ischemic stroke are not something anyone would want to chance (around 20 percent, according to one study); diabetes and congestive heart disease are both significant risk factors for recurrence.[8] Likewise, the chances of a hemorrhagic (bleeding in the brain) stroke increase substantially after a first hemorrhagic stroke.[9] Other research shows that after four decades of decline, stroke rates are now increasing in certain subpopulations.[10] For example, in Florida, the stroke death rate trend reversed from 2013–2015, with a significant increase of 10.8 percent per year. For Hispanics, after a 3.6 percent average annual decline in stroke death rate from 2000–2013, the death rate increased to 5.8 percent per year from 2013–2015.
What are we to do with this information? How can we take matters into our own hands?
Plenty of data demonstrates that lifestyle can have a profound effect on the prevention of primary stroke. We now know that 80 percent of stroke risk may be due to lifestyle factors: smoking, an unhealthy diet with a high intake of salt and sugar, and low levels of physical activity all contribute to increasing risk.[11] Unsurprisingly, these are the same behaviors that affect overall brain health and increase the risk of dementia (plus numerous other chronic diseases that sometimes occur alongside stroke, such as diabetes).
Along with avoiding hypertension and diabetes, lowering blood cholesterol is a common target for stroke prevention. Multiple trials have shown that aggressively lowering LDL cholesterol with medication can be effective in primary and secondary prevention of ischemic stroke.[12] However, recommendations to use these drugs are based on the fact that having low cholesterol is, to begin with, associated with a lower risk of stroke and heart disease. There are, of course, nonpharmaceutical means of lowering cholesterol. But as with all health issues, the focus is usually on medication regardless of its effects (or lack of effects) on underlying causes. And so, billions of dollars are spent yearly on cholesterol and blood pressure medications, even though we know the lifestyle factors that reduce stroke risk. Most of these medications are initiated after the onset of a stroke—after disability manifests, and when the focus is on damage control rather than thriving.
These medications are not benign. Each of them has tremendous side effects and often necessitates other medications to blunt those side effects. Meanwhile, there is ample evidence that a diet high in fruits, vegetables, and whole grains is associated with reduced stroke risk in a dose-responsive manner. Adherence to a traditional Mediterranean diet, studied repeatedly, is inversely associated with stroke. In the PREDIMED study, adding an ounce of nuts to the diet and not changing anything else cut stroke risk by nearly half.[13]
But what’s so healthy about a Mediterranean diet? Wine, fish, and cheese? We took it upon ourselves to find the most robust database possible, one with the numbers and follow-up to validate what we suspected about the relationship between stroke and lifestyle factors, including the elements and behaviors that have the greatest impact on stroke risk. Not many long-term, large-scale population studies have investigated stroke risk and comprehensive lifestyle intervention, but we were lucky to gain access to the California Teachers Study, which has followed more than 133,000 subjects for over 20 years and provides unique insight into the relationship between lifestyle factors and disease. We focused specifically on the Mediterranean diet to try to determine what types of foods in this dietary pattern have the greatest influence on stroke.
The diet was scored for adherence. A high score was given for plants—vegetables, whole grains, fruits, legumes, nuts and seeds, and omega-3 fatty acids—and a low score for meat, poultry, dairy, and processed sugar. We found that not only were higher scores associated with a lower risk of stroke but also the beneficial effect of the Mediterranean diet was stepwise. Every step toward greater adherence to a plant-heavy Mediterranean diet was associated with a lower risk of stroke. In other words, every small lifestyle change had a measurable effect.
This is incredibly encouraging, given that a major impediment to lifestyle change in clinical settings is its perceived binary nature. Doctors and patients alike seem convinced that lifestyle change is all or nothing and that diet must change completely to produce positive results. Knowing that every step towards change will reduce your risk is empowering and motivating.
Our second finding was that the most beneficial components in the Mediterranean diet were not wine, cheese, or olive oil—the popular misconception—but the unprocessed plant-based components. Those participants with the highest adherence to a whole food, plant-based pattern reduced their risk of stroke by as much as 30 percent.
This is a remarkable discovery, which we implore the healthcare system to embrace as we all struggle to treat—or better yet, prevent—this devastating disease. If a whole food, plant-based diet has such a profound effect on the prevalence of vascular diseases such as stroke, imagine its effect on the cumulative microvascular disease that affects millions and puts them at a greater risk for cognitive decline and dementia. Vascular diseases of the brain account for a great majority of both degenerative and non-degenerative neurological conditions. They are debilitating, difficult to treat, expensive to manage, increasingly developing earlier in life, and, in almost all cases, preventable. That’s why it’s so critical to promote a whole food, plant-based lifestyle, which is the best dietary method we have of protecting the brain and dramatically reducing our risk of both stroke and dementia.
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