Vegetarian diet linked with 22 per cent lower risk of heart disease | New Scientist
Kind of – but the reason may not be due to vegetarian eating but because the vegetarian/vegan group was not overweight.
Here is the actual study: Risks of ischaemic heart disease and stroke in meat eaters, fish eaters, and vegetarians over 18 years of follow-up: results from the prospective EPIC-Oxford study | The BMJ
I read the study:
- There is a 22% relative risk reduction; the absolute risk reduction is small.
- After they adjusted for weight, blood pressure, diabetes, and so on, the “affects were attenuated” and barely statistically significant. Thus, the “protective” effects may be due to weighing less and not having diabetes – and not eating vegan/vegetarian.
Vegetarian/vegan diets are not necessarily “healthier” – but it is harder to be overweight eating that way. Weight was the main factor in the relative risk reduction, not that they were eating vegetarian/vegan.
Vegetarians and vegans tend to have BMI’s about 10-15% lower than meat eaters (in this study). Furthermore, younger people (late teens/20s) are far more likely to try vegetarian and vegan eating styles, but long-term adherence is very low – the overwhelming majority will eventually give it up. The older people get, the less likely they pursue vegetarian eating (about 1% over 65). Additionally, women are much more likely than men to try vegetarian eating.
I asked an AI to evaluate this study too.
“22% lower risk” is a relative risk difference
The EPIC‑Oxford paper reports:
- Vegetarians had a 22% lower rate of ischemic heart disease than meat‑eaters (HR 0.78).
But the authors also translate this into absolute risk:
- This equals 10 fewer cases per 1000 people over 10 years.
The benefit shrinks after adjusting for BMI, blood pressure, cholesterol, and diabetes
The authors explicitly state:
- The lower heart‑disease risk in vegetarians was “partly attenuated” after adjusting for:
- high blood cholesterol
- high blood pressure
- diabetes
- body mass index
After adjustment, the hazard ratio moves from 0.78 → 0.90, which is barely statistically significant.
This means:
Much of the apparent benefit of vegetarian diets is explained by vegetarians being leaner and having better metabolic profiles.
What does “attenuated” mean here?
In epidemiology, attenuation means:
- The association weakens after adjusting for mediators or confounders.
In this case, the “vegetarian advantage” weakens because:
- Vegetarians in EPIC‑Oxford had lower BMI, lower LDL, lower blood pressure, and lower diabetes rates.
These factors are independently protective against heart disease.
So the diet itself may not be the primary driver — the metabolic profile is.
Does “being skinny” mean healthier than being overweight,” not “vegetarianism is healthier”?
Based on the EPIC‑Oxford data:
✔ Yes — a substantial portion of the benefit is due to lower BMI and better cardiometabolic risk factors.
The study authors themselves say:
- The difference in heart‑disease risk was “partly attenuated” after adjusting for BMI, cholesterol, blood pressure, and diabetes.
And the companion review notes:
- Vegetarians and vegans have lower BMI, lower LDL, and lower blood pressure than meat‑eaters.
These are well‑established drivers of lower heart‑disease risk.
So the study supports the idea that:
The health advantage is largely due to being leaner and having better metabolic markers, not necessarily the absence of meat per se.
Vegetarians had higher stroke risk
This is important:
- Vegetarians had 20% higher total stroke risk, mostly hemorrhagic stroke.
- This risk did not attenuate after adjusting for BMI or metabolic factors.
This suggests that:
- Lower BMI and lower LDL may reduce heart‑disease risk
- But very low LDL or certain nutrient deficiencies (B12, omega‑3, etc.) may increase hemorrhagic stroke risk
The metabolic profile matters more than the diet label.
The bottom line
Based strictly on EPIC‑Oxford:
