August 4th, 2014

Plant-Based Diet, Healthy Heart?


CardioExchange welcomes this guest post, which originally appeared on MedPage Today, from Kim Allan Williams, Chief of Cardiology at Rush University in Chicago and the next president of the American College of Cardiology. Kim explains why he went on a plant-based diet and now recommends the diet to patients, and answers questions from CardioExchange Editor Harlan Krumholz about his experience.

Physicians want to influence their patients to make lifestyle changes that will improve their health, but sometimes the roles are reversed and we are inspired by patients. It was a patient’s success reversing an alarming condition that motivated me to investigate a plant-based diet.

Just before the American College of Cardiology’s (ACC) annual meeting in 2003 I learned that my LDL cholesterol level was 170. It was clear that I needed to change something. Six months earlier, I had read a nuclear scan on a patient with very-high-risk findings — a severe three-vessel disease pattern of reversible ischemia.

The patient came back to the nuclear lab just before that 2003 ACC meeting. She had been following the Dean Ornish program for “Reversing Heart Disease,” which includes a plant-based diet, exercise, and meditation. She said that her chest pain had resolved in about six weeks, and her scan had become essentially normalized on this program.

When I got that LDL result, I looked up the details of the plant-based diet in Ornish’s publications — 1- and 5-year angiographic outcomes and marked improvement on PET perfusion scanning — relatively small numbers of patients, but outcomes that reached statistical significance.

I thought I had a healthy diet — no red meat, no fried foods, little dairy, just chicken breast and fish. But a simple Web search informed me that my chicken-breast meals had more cholesterol content (84 mg/100 g) than a pork chop (62 mg/100 g). So I changed that day to a cholesterol-free diet, using “meat substitutes” commonly available in stores and restaurants for protein. Within six weeks my LDL cholesterol level was down to 90.

I often discuss the benefits of adopting a plant-based diet with patients who have high cholesterol, diabetes, hypertension, or coronary artery disease. I encourage these patients to go to the grocery store and sample different plant-based versions of many of the basic foods they eat. For me, some of the items, such as almond milk or the chicken and egg substitutes, were actually better-tasting.

There are dozens of products to sample and there will obviously be some that you like and some that you don’t. One of my favorite sampling venues was the new Tiger Stadium (Comerica Park) in Detroit, where there are five vegan (nondairy vegetarian) items, including an Italian sausage that is hard to distinguish from real meat until you check your blood pressure — vegetable protein makes blood pressures fall.

In some parts of the country and some parts of the world, finding vegan restaurants can be a challenge. But in most places, it is pretty easy to find vegetarian-friendly options with a little local Web searching. Web searching can also help with the patients who are concerned about taste or missing their favorite foods. I often search with the patient for a substitute of something that they like, and quickly email suggestions back to them.

Interestingly, our ACC/American Heart Association (AHA) prevention guidelines do not specifically recommend a plant-based diet, as the studies supporting are very large and observational or small and randomized, such as those on Ornish’s whole-food, plant-based diet intervention reversing coronary artery stenoses. The data are very compelling, but larger randomized trials are needed to pass muster with our rigorous guideline methodology.

Wouldn’t it be a laudable goal of the ACC to put ourselves out of business within a generation or two? We have come a long way in prevention of cardiovascular disease, but we still have a long way to go. Improving our lifestyles with improved diet and exercise will help us get there.

Krumholz: Kim, this is a really interesting contribution. I am curious how you manage the plant-based diet during your travels. I have thought about this but often have less control over my food. 

Williams: This diet does indeed require some planning, but “there’s an app for that!”  Veg Out or Veggie Passport are two apps to check out. Using such tools to find restaurants has worked for us in Detroit, Melbourne, Rosario (Argentina), Paris, and even Chicago.  However, airplane meals can be challenging — some have healthy eating in mind and some don’t.  Knowing this in advance allows us to bring food when needed.  

Krumholz: How do you ensure that you are getting the protein you need?

Williams: Protein is the easy part of a vegan diet, with soy and wheat proteins in so many meat and dairy substitutes that are widely available. However, as I mentioned, be careful of the blood-pressure falls with plant-based protein.

Krumholz: What do you do when you are unsure of how the food is prepared?

Williams: Learning about how the food is prepared really requires intense questioning of the chef. This is typically done through a wait staff person, who may or may not have a good database for such a discussion.  If not, there are usually fresh vegetables available.  When in doubt, I sometimes eat ahead of time and I generally keep nuts (protein, carbohydrates, and monounsaturated fat) handy for emergencies.

Krumholz: Are you promoting this strongly to your patients? 

Williams: Yes, I am.  But it is only part of a program of cardiac prevention.  With younger people I discuss higher education, lifelong exercise habits, substance abuse, and diet, because they all relate to reducing cardiovascular mortality. A plant-based diet is only part of the overall picture.   

Krumholz: What future studies are needed? Or do you feel we have enough evidence?

Williams: We really do need more evidence. Huge observational studies are available, particularly from Great Britain and Adventist Health Studies, but there is a relative lack of randomized evidence — yet, what it lacks in numbers it packs in consistency of effect. However, without more randomized evidence, the guideline writing committees will not consider making recommendations on this topic.  Further, randomized trials could help uncover if the improvements in outcomes are actually due to the plant-based diet or other healthy lifestyle influences.

5 Responses to “Plant-Based Diet, Healthy Heart?”

  1. carol vassar, MD says:

    The outcome of randomized controlled trials will show an individual what is likely to happen but not what will happen in any individual case. The plant based diet might be recommended as a trial and error attempt similar to the rest of medical recommendations. A reluctance to recommend the diet as improving overall health and cardiovascular health in particular is reasonable because of the risk of missing essential amino acids or fatty acids. The book, Diet for a Small Planet by Adele Davis, addresses nutrition with the plant based diet. The companion book Great Meatless Meals provided menus with all of the recipes for meals that were nutritionally complete. The meals generally took a few hours to prepare for the first time, but they were generally good, sometimes great. There must be pamphlets available that give simple guidelines for combining foods to get the full complement of essential amino acids.

  2. Jeff Dickey, MD says:

    When patients of mine adhere a Mediterranean Diet (precluding sugar, refined grains, and salt) they lose weight and their diabetes and hypertension improve and drugs must be tapered and/or discontinued. When randomized trials of the plant based diet are done, a secondary analysis describing the rate of improvement of various parameters (blood pressure, sugar, lipids) would be very useful to help guide the rate and magnitude of drug tapering.

  3. Enrique Guadiana, Cardiology says:

    I don’t think we have enough evidence to recommend plant based diets. There are many unanswered questions. These diets are high in cooper, low in zinc, very low in the essential sulfur-bearing amino acids such as taurine, cysteine, carnitine and methionine, low in vitamin D and B complex. Don’t forget the concerns in the quantity and quality of the proteins. They are expensive and hard to find for many people.

    I don’t like extreme diets and even when you compare the Atkins, Zone, Ornish,and LEARN Diets for Change in Weight and Related Risk Factors Among Overweight Premenopausal Women (The A TO Z Weight Loss Study: A Randomized Trial). The Atkins diet, which had the lowest carbohydrate intake, lost more weight and experienced more favorable overall metabolic effects at 12 months than women assigned to follow the Zone, Ornish, or LEARN diets. I mention this to show that it is very controversial. I recommend the Mediterranean or the Dash diets.

    My patients usually resolve their chest pain and it is not infrequent that their functional test for ischemia to become essentially normalized. This is accomplished with optimal medical treatment, risk factor modifications, exercise, stress control, diet. Basically a full cardiac rehabilitation program. The diet is not extremely important if the patient is not overweight. I try not to over treat my patients.

    I use this not only for primary and secondary prevention basically is the treatment.

  4. this has been a practice, here in India since ages. with the arrival of globalisation and plenty of money, the practice saw a significant down trend.

    it should be vigorously promoted, it has a lower carbon footprint, too.

  5. Not all plants are good and not all animal products are bad.

    Clearly increased amounts of fruit and vegetables are good. The Interheart trial found that for every incremental serving of any fruit or vegetable, there was a 4% reduction in MI. The Nurses Health Survey found a 32% reduction in heart attacks among the nurses eating the largest amount of pigmented berries compared to those eating the smallest amount of pigmented berries and this seemed to be independent of the total number of servings of fruit and veges.

    Conversely, large amounts of grain carbs has been associated with increased MI risk and increased development of diabetes.

    Certain plant fats have been shown to be good, especially olive oil and tree nut oil however fish oil is also beneficial.

    The benefit of the vegetable based diet is the presence of large amounts of fruit and veges, not the absence of meat.

    Anyone who wants to be vegan for religious purposes has my full support. Anyone who takes the position that vegan is better than a balanced diet with large amounts of fruit and vegetables with a rational amount of meat and dairy products and decreased starches is mis-reading the data.

    It is not the presence of meat in the American diet that is the problem, it is the dearth of vegetables and inadequate olive oil, nuts, and fish.