Update on Vegetarian Stroke Risk

"Update on Vegetarian Stroke Risk" Healthy plant-based diets
have been associated with lower all-cause mortality,
up to a 34 percent lower risk of death from any cause over an average
of an eight-year period, just being in the top
versus bottom quarter of healthy plant-based consumption. If sustained, that could translate
into more than four extra years of life. A meta-analysis of a dozen studies
prospectively following more than a half a million people
for up to 25 years similarly found significantly lower
heart disease and overall death rates among those eating more plant-based. No surprise,
a systematic review concluded since plant-based diets
may arrest or even reverse our number one killer—
cardiovascular disease. Those eating wholly plant-based
tend to be significantly slimmer with lower LDL cholesterol, triglycerides,
blood sugars, blood pressures, significantly less inflammation,
and less carotid artery wall thickening (a sign of atherosclerosis measured
via ultrasound in the neck), as good as what you see
in endurance athletes who’ve run an average of 50,000 miles,
which is like twice around the globe. And changes in risk factors
can happen fast, as evidenced by results
from one to three-week ad libitum (eat-all-you-want)
plant-based “kickstart” programs.

For example, the results from the first
few hundred participants of the at-home
15-day Jumpstart program created by the nonprofit Rochester
Lifestyle Medicine Institute were recently published. On a whole food plant-based diet,
obese patients lost an average of 7 pounds without controlling portions
or counting calories or carbs. Diabetics saw their fasting blood sugars
drop 28 points. Those with LDL cholesterol
over 100 experienced a 33-point drop (comparable to some statin drugs), and hypertensive individuals
experienced a 17-point drop in systolic blood pressure,
which is better than drugs, and all within just two weeks! Studies dating back nearly 40 years
show those eating meat-free diets also have improved blood “rheology,”
meaning fluidity or flowability, which may play a role
in cardiovascular protection.

Subsequent interventional studies putting
the cross-sectional findings to the test, show that switching people
to a plant-based diet can improve rheology measurements
within three to six weeks. But might the blood of vegetarians flow
a bit too well, though? In 2019, a study of thousands
of British vegetarians called EPIC-Oxford found that they were at higher risk
of hemorrhagic (bleeding) stroke. They had such a lower risk
of heart disease that they still had less
cardiovascular disease overall (and a half dozen studies show no overall
increased risk of stroke mortality), but why the greater stroke incidence? I suggested it might be vitamin B12
deficiency, which can lead to excessive levels
of a stroke- associated metabolite called homocysteine
which is normally detoxified by B12.

This is thought to be the reason
why vitamin B12 supplementation can improve artery function
of vegetarians. Vitamin B12 supplements
or fortified foods are critical for anyone eating plant-based,
but my 12-part video series on vegetarians and stroke risk
triggered by the 2019 publication was all in vain. It turns out vegetarians don’t appear
to have higher stroke risk after all. In response to the EPIC-Oxford results,
researchers around the world scrambled to see if the findings
were merely a fluke. In 2020, UK Biobank, a massive study
following more than 400,000 volunteers, confirmed that vegetarians
had lower cardiovascular disease rates and importantly,
no increased incidence of stroke.

And two studies from Taiwan
found vegetarians had significantly
lower risk of stroke. Following tens of thousands
of vegetarians for up to ten years, they only had about half the stroke risk
compared to nonvegetarians (including a 64 percent lower risk
specifically of hemorrhagic stroke). By 2021, Harvard researchers
had finished and published their analyses of the 200,000+ participants
of the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals
Follow-Up Study. They too found no increased stroke risk
for vegetarians and indeed a decreased risk of stroke among those eating
healthy plant-based diets. A meta-analysis putting all the studies
together found that indeed the EPIC-Oxford data appeared
to be a fluke after all, finding, if anything, a lower risk
of stroke in a subgroup analysis. A 2022 systematic review
concluded that vegetarian and low-animal product diets are associated with a significantly
lower risk of bleeding strokes, a significantly lower risk
of clotting strokes, and a significantly lower risk
of total strokes across the board..