Vegetarianism refers to a diet free of animal products such as meat, poultry, and seafood, and includes different dietary patterns such as strict vegetarianism, lacto-ovo-vegetarianism, lacto-vegetarianism, and ovo-vegetarianism. Some evidence suggests that vegetarian dietary patterns are associated with cardiovascular health, but this association is unclear. This article reflects on the evidence-based basis for vegetarian diets and cardiovascular health and shares it with the general public.
Association of vegetarian dietary patterns with hypertension
Hypertension is known to be an independent risk factor for cardiovascular disease, and the search for non-pharmacological methods to lower arterial blood pressure has become a hot topic of interest.
To evaluate the relationship between vegetarian dietary patterns and blood pressure levels, Dr. Yokoyama and his team from the Preventive Medicine and Epidemiology Research Unit of the National Center for Cardiovascular Diseases in Japan recently conducted a Meta-analysis of relevant clinical trials, the results of which were published in the February 2014 issue of the Journal of the American Medical Association, Internal Medicine (JAMA).
The clinical trials selected for the study were derived from searches of Medline (1946-2013) and WebofScience (1900-2013). The investigators systematically browsed the 258 relevant literature retrieved, and ultimately seven clinical controlled trial studies and 32 observational studies met the inclusion criteria for this Meta-analysis (study population age >20 years; vegetarian diet as the mode of exposure/intervention; mean difference in blood pressure as an outcome indicator; and clinical controlled trial or observational study).
The 7 clinical controlled trials involved 311 participants with a mean age of 44.5 years, and compared with omnivores, vegetarians had a mean reduction in systolic blood pressure of 4.8 mmHg and a mean reduction in diastolic blood pressure of 2.2 mmHg; the 32 observational studies involved 21604 participants with a mean age of 46.6 years, and compared with omnivores, vegetarians had a mean reduction in systolic blood pressure of 6.9 mmHg and a mean diastolic blood pressure by 4.7 mmHg.
The results of this Meta-analysis showed that vegetarians had significantly lower blood pressure compared to omnivores in the same situation, suggesting that a vegetarian dietary approach may be a non-pharmacological treatment for lowering blood pressure.
The relationship between vegetarian diets and cardiovascular health has been of great interest and has been the subject of many clinical studies over the past 20 years, providing much evidence-based medical evidence to elucidate the relationship between vegetarian diets and cardiovascular health. DietaryApproachestoStopHypertension) study, the world’s first randomized controlled clinical study of dietary patterns and blood pressure levels.
Based on this study, the National Heart, Lung, and Blood Institute of the National Institutes of Health (NIH) proposed a “DASH diet” in 1997 to control hypertension. In 1997, the National Heart, Lung, and Blood Institute (NHLBI) proposed a “DASH diet” to control hypertension, which is low in fat, saturated fat, and cholesterol, and emphasizes a combination of foods high in magnesium, potassium, calcium, protein, and fiber.
The relationship between vegetarian dietary patterns and blood lipids
A clinical study published in June 2012 by Chinese scholars in Nu⁃trClinPract (Clinical Practice Nutrition) compared BMI, blood pressure levels, lipid levels, glucose metabolism levels and carotid intima-media thickness in 169 lacto-vegetarians and 126 omnivores between 21 and 76 years of age in China, and calculated the 5-10 year risk of cardiovascular disease in those aged 24 to 55 years. The risk of cardiovascular disease was calculated for 5 to 10 years for those aged 24 to 55 years.
A prospective clinical study (EPIC-Oxford cohort study) published in the American Journal of Clinical Nutrition (AmJClinNutr) in January 2013, with a total of 5-10 years of cardiovascular disease risk, showed a significant reduction in blood pressure, non-HDL cholesterol levels, fasting glucose and carotid intima-media thickness in lacto-vegetarians compared to omnivores. Oxford Cohort Study), involving 44,561 participants with a mean follow-up of 11.6 years. The results showed that vegetarians had significantly lower BMI, non-HDL cholesterol levels and systolic blood pressure compared to non-vegetarians, and their risk of ischemic heart disease was reduced by approximately 32%.
Association between vegetarian dietary patterns and mortality
A prospective cohort study published in the June 2013 issue of JAMAInternalMedi⁃cine evaluated the association between vegetarian dietary patterns and mortality in a total of 73,302 participants whose diets were assessed at baseline by a quantitative food frequency questionnaire and categorized into five dietary patterns: non-vegetarian, semi-vegetarian, fish-vegetarian, lacto-ovo vegetarian, and vegan. The relationship between vegetarian dietary patterns and all-cause and cause-specific mortality was assessed by determining the number of deaths before 2009 from the National Death Index. The results of this study showed that a vegetarian diet was associated with reduced all-cause mortality during a mean follow-up of 5.79 years and was significantly associated with reduced mortality in cardiovascular, renal and endocrine diseases, and that this association was more pronounced in men than in women. The results of the above clinical studies all suggest that a vegetarian diet may promote a healthy cardiovascular system, reduce the risk of cardiovascular disease, and lower the rate of death due to cardiovascular disease.
Dr. YokoyamaY synthesized the available research evidence and analyzed the mechanism of “vegetarian antihypertensive” may be related to the following aspects.
First, vegetarian diets are rich in fiber and low in fat, so vegetarians are generally lighter in weight (lower BMI) than omnivores and have a significantly lower risk of obesity, which is one of the risk factors for hypertension;
Second, vegetarian diets are rich in potassium ions, and studies have shown that a potassium-rich diet can significantly lower blood pressure, the mechanism of which may be related to increased potassium intake to dilate blood vessels, increase glomerular filtration rate and reduce renin levels;
Thirdly, vegetarians usually consume lower amounts of sodium and alcohol than omnivores;
Fourth, vegetarian diets are low in saturated fatty acids and high in unsaturated fatty acids;
Fifth, there is evidence that blood pressure viscosity is significantly lower in vegetarians than in omnivores.
It is important to note that the “vegetarian” diet mentioned here may be more of a “lacto-vegetarian” or “lacto-ovo-vegetarian” diet, and there is evidence that a strict vegetarian diet may have adverse effects on cardiovascular health. There is evidence that a strict vegetarian diet may have adverse effects on cardiovascular health. The author has studied the blood pressure, lipid level and atherosclerosis characteristics of monks and nuns in Beijing monasteries aged >63 years with a vegetarian history of >14 years, with a control group of the same age.
The results demonstrated that a long-term overly strict vegetarian diet and dietary imbalance can lead to endogenous lipid metabolism disorders, and although the body may not be obese, the incidence of cardiovascular disease does not decrease. According to the statistics of the China Cardiovascular Disease Report 2012, there are 290 million patients with cardiovascular disease in China, of which 266 million are patients with hypertension, and this unhealthy dietary pattern is one of the main reasons for the high incidence of cardiovascular disease in China, with an increased fat intake in the Chinese daily diet, an average salt intake >12 g per day, and a significantly lower intake of fruits and vegetables.
The findings of this Meta-analysis provide a stronger evidence-based basis for the choice of vegetarian diet, which has great practical implications for general health or clinical treatment.
From a public perspective, a vegetarian dietary pattern may allow you to maintain moderate arterial blood pressure levels; from a clinical treatment perspective, a vegetarian diet is an alternative non-pharmacological approach to lowering blood pressure. Of course, the results of this Meta-analysis also have some limitations, the number of randomized controlled clinical trials included is small, the sample size is small, and most of the results are observational studies. In the future, more rigorous prospective clinical trials with large samples should be designed to provide a stronger evidence-based basis for the relationship between vegetarian diet and cardiovascular health, and further research on the specific foods or nutrients to promote cardiovascular health. further research on the intrinsic mechanisms of specific foods or nutrients to promote cardiovascular health may provide a reference for non-pharmaceutical prevention and treatment of cardiovascular diseases.