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Healthful plant-based diet may decrease risk for CHD
Participants who ate a healthier plant-based diet had a decreased risk for CHD, according to a study published in the Journal of the American College of Cardiology.
“When we examined the associations of the three food categories with heart disease risk, we found that healthy plant foods were associated with lower risk, whereas less healthy plant foods and animal foods were associated with higher risk,” Ambika Satija, ScD, a postdoctoral fellow at the Harvard T.H. Chan School of Public Health, said in a press release. “It’s apparent that there is a wide variation in the nutritional quality of plant foods, making it crucial to take into consideration the quality of foods in a plant-based diet.”
Researchers reviewed data from 73,710 women from the Nurses’ Health Study, 92,329 women from the Nurses’ Health Study II and 43,259 men from the Health Professionals Follow-Up Study who did not have chronic diseases at baseline. Participants completed a semiquantitative food frequency questionnaire every 2 to 4 years.
Plant-based diet indices
Three kinds of a plant-based diet were developed based on questionnaire responses: plant-based diet index, healthful plant-based diet index and unhealthful plant-based diet index. The overall plant-based diet index included mainly plant-based foods with no animal-based foods, including dairy, fish and meat. The healthful plant-based diet included everything from the overall plant-based diet without less healthy foods such as refined grains, potatoes, sugar-sweetened beverages and fruit juices. The unhealthful plant-based diet featured less healthful plant-based foods known to be associated with elevated risk for certain diseases.
Throughout 4,833,042 person-years of follow-up, CHD occurred in 8,631 participants. A pooled multivariable analysis showed that an overall plant-based diet index was inversely linked to CHD (HR comparing extreme deciles = 0.92; 95% CI, 0.83-1.01). The association was stronger in the healthful plant-based diet index (HR comparing extreme deciles = 0.75; 95% CI, 0.68-0.83). The unhealthful plant-based diet index had a positive association with CHD (HR comparing extreme deciles = 1.32; 95% CI, 1.2-1.46).
The links between the risk for CHD and either overall plant-based diet index or healthful plant-based diet index were similar by age, sex, family history of CHD and BMI.
Diet recommendations
“Dietary guidelines and lifestyle interventions could recommend increasing intake of healthy plant foods while reducing intake of less healthy plant foods and certain animal foods for improved cardiometabolic health,” Satija and colleagues wrote.
The healthful plant-based diet index “means both a challenge and an opportunity for cardiology,” Kim Allan Williams Sr., MD, professor of cardiovascular disease at Rush University Medical Center in Chicago, past president of the American College of Cardiology and a Cardiology Today Editorial Board Member, and Hena Patel, MD, a cardiologist at Rush University Medical Center, wrote in a related editorial. “Until recently, as a group, cardiologists have not delved deeply into nutrition, treating CVD’s downstream effects rather than obliterating its roots, leaving primary and secondary prevention opportunities on the table. It is time that we educate ourselves on dietary patterns, risk and outcomes and focus more on ‘turning off the faucet’ instead of ‘mopping up the floor.’” – by Darlene Dobkowski
Disclosures: This study was supported by research grants from NIH. Patel, Satija and Williams report no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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There have been several recent studies showing that a vegetarian diet is a more healthful diet than a non-vegetarian diet. What was less clear were the differences between the types of vegetarian diet. This study is a first attempt to compare a healthy vegetarian diet such as whole-grain plant-based diet and an unhealthful one. It is important to have data like these out there, because a lot of people think they are healthy vegetarians, but they continue to eat fried foods and believe them to be healthy because they are vegetarian.
Physicians in general have a lack of understanding about nutrition and its role in CVD. That has to do of our own lack of education in medical schools. We know that cardiologists spend less than 3 minutes of their time counseling patients on diet. Studies like this are slowly changing the way physicians are advocating for a healthy diet. Unfortunately, so much more needs to be done to educate physicians to improve their counseling of patients.
A limitation of this study is that it was not randomized. It is based on survey data, which is often associated with bias. I am very interested in seeing a large randomized controlled trial looking at the Mediterranean-style diet vs. the whole-grain plant-based diet, which is the next area of interest. We have a lot of good data showing the vegetarian diet is better than the non-vegetarian diet. We now have evidence that there are differences been eating a healthy vegetarian diet vs. an unhealthy one. The next question is comparing Mediterranean-style diet vs. the whole-grain plant-based diet. It will be exciting to see which is better. The Mediterranean-style diet is approximately 30% fat, and the plant-based diet is typically much lower in fat. Does that difference affect CV mortality? I would love to know that.
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If the reader has an opportunity to transfer the information from the article into practice, they will see that it is possible to take the leading killer of women and men in Western civilization, which is CHD, and absolutely bring a halt to any disease progression and often have significant disease reversal with a whole food, plant-based diet without oil, as described by Dean Ornish, MD, and myself. Once the CV clinician sees the power and effectiveness of this lifestyle and nutritional translation, it will be seismic.
I don’t think there’s any question that the article will add to the depth of information about nutrition and CVD.
Although the pioneering studies have been done, it is reasonable to have a study where the usual approach of interventions such as stents, operations and drugs are compared with whole food, plant-based nutrition without oil. That’s the kind of hard data that will make it a lot easier to change the entire paradigm of how CV medicine is practiced today, because without a focus on the causation of the illness, all the devotion to drugs and procedures will come up short, as has been clear over the last 40 years since these approaches have been instituted.
I have nothing but great confidence in the CV community, because a recent survey done by the nutrition committee of the ACC has indicated that a vast number of CV practitioners have essentially almost zero knowledge about nutrition. They don’t receive it in medical school and they don’t receive it in their postgraduate training. If we can make an all-out effort to have them be aware of this, that will greatly enhance the resolution of this epidemic.
It is crucial that patients learn how to institute this and become adherent to this lifestyle change. Physicians will need an understanding of the techniques that are available to have patients become empowered to halt their disease.