What do medical studies say about cardiovascular disease and diet?
Is there a connection between cardiovascular disease and diet?
At the bottom of this article, you'll find a short recording in which Dr. Mehta talks about cardiovascular disease and diet. He refers to a few studies, but to keep the content short, he lists others in his document of references, so that we can read them when we have more time.
A summary of a range of studies that looked at the potential link between diet and cardiovascular disease
Below you'll find a brief look at a range of studies. For each one I've shared some information consistently e.g. the number of subjects, the results, the duration of the study. I've done this to make it easier for you to compare the results from each one.
Associations between diet and cancer, ischemic heart disease, and all-cause mortality in non-Hispanic white California Seventh-day Adventists | Published by the American Journal of Clinical Nutrition
The subjects: Non-Hispanic white California Seventh-day Adventists
Number of subjects: 34000
The research: Associations between diet and cancer, ischemic heart disease, and all-cause mortality
Year of the study: 1999
Diet: 50% of the subjects were vegetarian and ate some eggs, or ate meat less than once per week and the remaining 50% ate meat 3 or more times per week, which is half the amount that 'most' Californian meat eaters consume
Duration of the study: 12 years
Results:
- vegetarian men lived 3.21 years longer
- vegetarian women lived 2.52 years longer
- there was 37% less death caused by cardiovascular disease in vegetarian males
- there was an increase of Relative Risk 1.88 of colon cancer in non vegetarians
- there was an increase of 1.54 in non vegetarians
- consuming legumes was found to be associated with less instances of colon and pancreatic cancer
- consuming nuts was found to be positive in terms of reducing occurrences of heart disease
- higher consumption of fruits and vegetables was connected to less subjects being diagnosed with prostate, lung and colon cancers
- there were less instances of diabetes, hypertension, arthritis amongst the vegetarians
- the benefits were partly attributed to absence of meat, as well as, being partly due to higher intake of specific foods
- The prevalences of obesity, hypertension, diabetes, and arthritis at baseline, were strikingly different among the 3 dietary subgroups of Seventh-day Adventists
- Obesity, as measured by body mass index (in kg/m2), increased as meat consumption increased, such that a 1.78-m- (70-in-) tall male non-vegetarian weighed 6.4 kg (14 lb) more on average than did his vegetarian counterpart
- A similar comparison for a 1.63-m- (64-in-) tall female revealed a weight difference of 5.5 kg (12 lb)
- These results were for subjects aged 45–60 y, but similar results were seen for the other ages
- The prevalences of hypertension and diabetes were both 2-fold greater in the non-vegetarians than the vegetarians
- The prevalence of rheumatoid arthritis and rheumatism was 50% greater in the non-vegetarians than the vegetarians
More information:
http://www.ncbi.nlm.nih.gov/pubmed/10479227
http://ajcn.nutrition.org/content/70/3/532s.full
A provegetarian food pattern and reduction in total mortality in the Prevención con Dieta Mediterránea (PREDIMED) study | By the American Journal of Clinical Nutrition
The subjects: Had a mean age 67 who were at high risk of cardiovascular disease
Number of subjects: 7000
The research: To see if a pro-vegetarian food pattern brought about a reduction in total mortality by scoring them on how plant based their diet was, (even if some foods were chips and french fries). Point were deducted for all animal foods.
Year of the study: 2014
Diet:
Duration of the study: 5 years
Results:
- those with higher plant based consumption had 40% less mortality, even though they were not fully vegetarian
- omnivorous food consumption with low meat and high plant foods decreased mortality in those who were at a high risk of cardiovascular disease
- among omnivorous subjects at high cardiovascular risk, better conformity with a provegetarian food pattern that emphasized plant-derived foods was associated with a reduced risk of all-cause mortality
More information: http://www.ncbi.nlm.nih.gov/pubmed/24871477
Saturated Fats Compared With Unsaturated Fats and Sources of Carbohydrates in Relation to Risk of Coronary Heart Disease: A Prospective Cohort Study | Published by the Journal of the American College of Cardiology
The subjects: Nurses and other Health Professionals
Number of subjects: 84000 women and 43000 men
The research: To see if saturated fats (as opposed to unsaturated fats), and sources of carbohydrates affected the risk of coronary heart disease
Year of the study: 2015
Diet: ???
Duration of the study: The women were followed for 30 years and the men were followed for 24 years
Results:
- there were 7667 incident cases of coronary heart disease amongst these subjects
- replacing 5% of energy intake from saturated fats with equivalent energy from polyunsaturated fats resulted in 25% decreased coronary heart disease
- replacing 5% of energy intake from saturated fats with equivalent monounsaturated fats resulted in a 15% decrease of coronary heart disease
- replacing 5% of energy from saturated fats, with whole grains resulted in a 9% decrease of coronary heart disease
- changing those calories for refined carbohydrates and sugars resulted in no risk and no reduction
More information:
http://www.ncbi.nlm.nih.gov/pubmed/26429077
http://content.onlinejacc.org/article.aspx?articleid=2445322
http://www.hsph.harvard.edu/news/press-releases/butter-is-not-back-limiting-saturated-fat-still-best-for-heart-health/
Egg consumption and risk of cardiovascular diseases and diabetes: a meta-analysis | This includes the results from 14 studies
Number of subjects: 320,778
The research: To see if there's a relationship between egg consumption and the risk of cardiovascular disease and diabetes
Year: 2013
Results: The study suggests that there is a dose-response positive association between egg consumption and the risk of cardiovascular disease and diabetes.
- 4 eggs per week causes incremental risk
- 1.06 response relationship of cardiovascular disease
- 1.40 response relationship of cardiovascular disease if diabetes is pre-existing
- 1.29 response relationship of diabetes
- 2.0 response relationship of cardiovascular risk in studies done in non USA western countries - subgroup analysis
More information: http://www.ncbi.nlm.nih.gov/pubmed/23643053
Cardiovascular Disease Mortality and Cancer Incidence in Vegetarians: A Meta-Analysis and Systematic Review | This involves the analysis of the findings from seven different studies
The subjects:
Number of subjects: 124 000
The research: A meta analysis of seven studies looking at subjects in the UK, Japan, California, USA overall, Germany and Netherlands
Year: 2012
Diet: Vegetarians and non vegetarians
Results:
- vegetarians had 29% lower heart disease mortality than non vegetarians
- vegetarians had 18% lower cancer mortality than non vegetarians
- vegetarians had 29% lower heart disease mortality than non vegetarians
- vegetarians had 18% lower cancer mortality than non vegetarians
- all-cause mortality was 9% lower in vegetarians than in non-vegetarians after the follow-up
- the results suggest that vegetarians have a significantly lower ischemic heart disease mortality (29%) and overall cancer incidence (18%) than nonvegetarians
This study does not look at vegans who are likely have even lower disease rates
More information:
http://www.ncbi.nlm.nih.gov/pubmed/22677895
http://www.karger.com/Article/FullText/337301
Egg consumption in relation to cardiovascular disease and mortality: the Physicians' Health Study | Published by the American Journal of Clinical Nutrition
The subjects: Participants of the Physicians' Health Study i.e. they were physicians
Number of subjects: 21327
The research: Egg consumption in relation to cardiovascular disease and mortality
Year: 2008
Duration of the study: The average follow up was 20 years
Results: Infrequent egg consumption does not seem to influence the risk of cardiovascular disease in male physicians. In addition, egg consumption was positively related to mortality, and this was stronger in the diabetic subjects.
- eating 7 or more eggs per week increased increased mortality by 23% in all subjects
- For diabetics, those who ate more than 7 eggs per week had a mortality Hazard Ratio of 2.01 compared to those who ate less than 1 egg per week
More information: http://ajcn.nutrition.org/content/87/4/964.long
Here's the short video in which Dr. Mehta shares what medical studies say about cardiovascular disease and diet
“People feel poorly because they are nourished by foods you wouldn’t feed to your dog and cat. The rich western diet is full of fat, sugar, cholesterol, salt, animal protein — all the wrong foods for people.”