A new study conducted by researchers at the University of Oxford in England, and involving 44,561 participants in England and Scotland, has found that those who ate a vegetarian diet were a full 32% less likely to die from or need hospitalization for heart disease than those who ate meat and fish.
“Most of the difference in risk is probably caused by effects on cholesterol and blood pressure, and shows the important role of diet in the prevention of heart disease,” explained Dr Francesca Crowe, lead author of the study at the Cancer Epidemiology Unit, University of Oxford.
This was one of the largest studies ever conducted comparing rates of heart disease between vegetarians and non-vegetarians, according to a news release issued by the University of Oxford.
The new study was published on January 30, 2013 in the American Journal of Clinical Nutrition.
Why is the Study Significant? What is the prevalence of heart disease?
“Heart disease is the single largest cause of death in developed countries,” according to a press release issued by the University of Oxford. “Heart disease is a major blight in Western countries. It kills 94,000 people in the UK each year – more than any other disease, and 2.6 million people live with the condition,” the BBC reports.
In the United States today, “Heart disease and stroke are an epidemic,” according to the American Heart Association, Million Hearts™ campaign. “Heart disease, including stroke, is the leading cause of death for men and women in the United States,” according to the U.S. Department of Health & Human Services (HHS).
The American Heart Association explains that “Heart disease – also called cardiovascular disease and coronary heart disease – is a simple term used to describe several problems related to plaque buildup in the walls of the arteries, or atherosclerosis.” “As the plaque builds up, the arteries narrow, making it more difficult for blood to flow and creating a risk for heart attack or stroke.”
You are at higher risk of heart disease if you are: a woman age 55 or older, a man age 45 or older, or a person with a family history of early heart disease, according to HHS.
As part of a nationwide health observance highlighting the risks and symptoms of heart disease, the American Heart Association has designated February 1 as National Wear Red Day®, and Go Red For Women® day. Key messages of the National Go Red For Women campaign are that, in the U.S., “Heart Attacks are the number 1 killer of women nationwide, heart disease still kills more women than all cancers combined, and the symptoms of heart attack for women are different than the symptoms for men.”
The Study; Methodology
The researchers at the University of Oxford analyzed data from 44,561 men and women living in England and Scotland who were enrolled in a large prospective study, the European Prospective Investigation into Cancer and Nutrition (EPIC)–Oxford study.
Of the participants, 34% (approximately 15,100) were eating a vegetarian diet at the start of the study, and approximately 29,400 people ate a diet including meat and fish.
Over an average follow-up period of 11.6 years, the researchers identified 1,235 cases of ischemic heart disease (IHD) among the study participants, which included 1,066 hospital admissions for IHD and 169 deaths from IHD.
“Ischaemic Heart Disease [IHD] (coronary artery disease or CAD) is a condition in which atheroma (fatty deposits) builds up in the linings of the walls of the coronary arteries. This causes a narrow artery and reduced blood flow to the heart muscle,” according to health information published by the UK Department for Works and Pensions.
In the study, the researchers identified the cases of IHD “through linkage with hospital records and death certificates.”
The researchers used statistical analysis to estimate the IHD risk for the vegetarian participants, as compared to non-vegetarians.
In their analysis they also compared serum lipids and blood pressure measurements of the participants who suffered incidents of IHD to available serum lipids and blood pressure data for 1,519 of the participants who did not suffer incidents of IHD, “who were matched to IHD cases by sex and age.”
As a result of their analysis, the researchers found that “Vegetarians had a 32% lower risk (HR: 0.68; 95% CI: 0.58, 0.81) of IHD [ischemic heart disease - see above] than did nonvegetarians.”
“The Oxford researchers arrived at the figure of 32% risk reduction after accounting for factors such as age, smoking, alcohol intake, physical activity, educational level and socioeconomic background,” the University of Oxford reported in its news release about the study.
This risk level “was only slightly attenuated after adjustment for BMI and did not differ materially by sex, age, BMI, smoking, or the presence of IHD risk factors,” the researchers reported.
The researchers also found that the vegetarians had significantly lower cholesterol levels, blood pressure, and body weight (BMI) than the non-vegetarians. Specifically, the authors reported that “Compared with nonvegetarians, vegetarians had a lower mean BMI [in kg/m2; −1.2 (95% CI: −1.3, −1.1)], non-HDL-cholesterol concentration [−0.45 (95% CI: −0.60, −0.30) mmol/L], and systolic blood pressure [−3.3 (95% CI: −5.9, −0.7) mm Hg]” than the vegetarians.
“The researchers found that vegetarians had lower blood pressures and cholesterol levels than non-vegetarians, which is thought to be the main reason behind their reduced risk of heart disease,” the University reported in its news release.
“Vegetarians typically had lower body mass indices (BMI) and fewer cases of diabetes as a result of their diets, although these were not found to significantly affect the results. If the results are adjusted to exclude the effects of BMI, vegetarians remain 28% less likely to develop heart disease.”
“Consuming a vegetarian diet was associated with lower IHD [ischemic heart disease - see above] risk, a finding that is probably mediated by differences in non-HDL cholesterol, and systolic blood pressure,” the researchers concluded.
“The results clearly show that the risk of heart disease in vegetarians is about a third lower than in comparable non-vegetarians,” Professor Tim Key, co-author of the study and deputy director of the Cancer Epidemiology Unit, University of Oxford, said in the University’s news release.
“The findings reinforce the idea that diet is central to prevention of heart disease, and build on previous work looking at the influence of vegetarian diets, the researchers say,” according to the release.
“The diets are quite different. Vegetarians probably have a lower intake of saturated fat so it makes senses there is a lower risk of heart disease,” Dr Francesca Crowe, lead author of the study, explained to the BBC.
“The main message is that diet is an important determinant of heart health,” said Dr Crowe. “I’m not advocating that everyone eats a vegetarian diet,” she said.
Tracy Parker from the British Heart Foundation (who was not involved in the study), in an interview with the BBC, cautioned anyone contemplating switching to a vegan diet: “If you’re thinking of switching to a vegetarian diet, make sure you plan your meals carefully so that you replace any lost vitamins and minerals, such as iron, that you would normally get from meat.”
In addition, she admonished that “choosing the veggie option on the menu is not a shortcut to a healthy heart. After all, there are still plenty of foods suitable for vegetarians that are high in saturated fat and salt.”
“This research reminds us that we should try to eat a balanced and varied diet – whether this includes meat or not,” Ms. Parker concluded.
The full report of the new study was published on January 30, 2013 in the American Journal of Clinical Nutrition.
For more information on vegetarian diets and heart health, see related HelpingYouCare® reports on:
A Diet to Extend Life (Video)
For further information on a healthy diet and other lifestyle factors that promote wellness and help prevent diseases, see the HelpingYouCare® resource pages on Wellness/ Healthy Living for Seniors & Caregivers, including:
- Diet & Nutrition: Physical Wellness;
- Exercise: Physical Wellness;
- Weight Loss/ Maintaining a Healthy Weight: Physical Wellness;
- Sleep, Hygiene, Quit Smoking & Other Healthy Practices: Physical Wellness; and
- Other Areas of Wellness.
- News on Heart Disease & Stroke;
- What are these conditions; Causes;
- Symptoms & Diagnosis;
Copyright © 2013 Care-Help LLC, publisher of HelpingYouCare®. All rights reserved.