By Gabe Mirkin, MD
A study of 798 asymptomatic and apparently healthy master athletes (runners, cyclists, triathletes, rowers and hockey players), 35+ years old, who exercised fairly vigorously 3-7 days a week, found that 10 percent had greater than 70 percent blockage of the arteries leading to their hearts (BMJ Open Sport & Exercise Medicine, 2018;4 (1):e000370). This does not mean that exercise increases risk for a heart attack. Exercise helps to prevent heart attacks, but exercise does not prevent plaques from forming in arteries. This study reminds us that even master athletes should follow a heart healthy diet.
Heart attacks are not caused by narrowed arteries. They are caused by plaques suddenly breaking off from a heart artery, followed by bleeding, and then a clot forms that suddenly and completely blocks all blood flow to a part of the heart muscle. The part of the heart muscle suddenly deprived of oxygen then dies, which is a heart attack. Exercise helps to prevent heart attacks by making plaques more stable so they do not break off as easily.
However, a healthful diet, not exercise, prevents plaques from forming. Everyone should follow a heart-healthy diet, especially if you have risk factors for a heart attack such as:
• a family history of heart attacks
• chest pain
• irregular heartbeats
• a big belly (particularly if you also have small buttocks)
• high blood pressure
• high cholesterol
• high blood sugar
Amount of Exercise Does Not Determine Amount of Plaques
A group of men over 60 who had run marathons for 26-34 years and completed 27-171 marathons had plaques in their arteries in amounts that were related to their own risk factors for heart attacks and not to the number of miles or marathons they had run (Med & Sci in Sports & Ex, July 17, 2017). This suggests that plaques in arteries are not related to the amount of endurance training, but are caused by other factors such as a pro-inflammatory diet, high blood pressure, high cholesterol or tobacco use.
A Diet to Prevent Plaques
Master athletes burn a lot of calories, so they can be expected to eat more food than sedentary people do. If they eat a lot of sugar or a lot of meat, they can expect to have plaques in their arteries. A diet that is high in vegetables, fruits, whole grains, legumes and nuts is associated with reduced risk for cardiovascular disease, while less healthful diets that are high in sweets, refined grains, juices, red meats and processed meats are associated with increased risk (Journal of the American College of Cardiology, July 2017; 70(4)).
How Doctors Measure Plaque Stability
A CT scan can show how stable plaques are (American Journal of Roentgenology, March 2015;204(3):W249-W260). X rays and sonograms can also show the difference between stable plaques that are safe and those that are unstable and more likely to break off to cause heart attacks. Stable plaques contain more calcium and are smoother and more homogeneous than unstable plaques. The radiologist estimates plaque stability by looking for an extensive calcification cap on the outside of the plaque, less lipid-rich areas inside the plaque, increased fibrous areas and less structural change. See Exercisers Have More Stable Plaques
My Recommendations
• To help prevent or reduce plaque formation, follow a heart-attack-preventing diet that is high in anti-inflammatory foods and low in pro-inflammatory foods. This means that you should eat plenty of plants and restrict red meat, processed meats, sugar-added foods, all sugared drinks and fried foods.
• Avoid overweight
• Do not smoke
• Limit or avoid alcohol
• To stabilize existing plaques and widen your coronary arteries, try to exercise every day for at least a half hour a day. Exercising more than that may be even more protective.
“However, a healthful diet, not exercise, prevents plaques from forming.” – the only problem, that this statement does not have enough scientific proof. Moreover, the most recent high quality researches strongly indicate on a very weak (if any) link between a diet and forming of plaques.
My advice to anyone – do your own research and see what works for you! Much of this information is being discredited as we move away from crappy epidemiological studies founded on “correleation = causation” and “blame the meat” bias. For my part, red meat makes up > 95% of my diet. I eat zero plants (indigestible fiber), and minimal sugars or grains. After a year on that protocol I look, feel and perform far better than I ever did on a traditional “balanced diet” that included veggies, grains, etc. My recent Coronary Artery Calcium Score was 14 (anything < 100 is generally considered low risk for a cardiac event) and likely on it's way to zero. Others have had the same or better result (often zero). I'm just one person, and not a full scientific randomized trial. However, if we choose to wait for studies like that before we try it ourselves, we'll be dead years before they're done.
I personally believe that if you’re doing your own research and tests, you should go with what you believe to be the best option.
I avoid wheat and most grains and stay very low sugar, but I eat a massive amount of vegetables. I am comfortable with a HFLC approach to diet, but your approach doesn’t sound appealing to me as a long term way to eat, for taste reasons.
I have not gotten a calcium score, but I have had the cholesterol particle test, and my cholesterol was the “light and fluffy” type and not the “small and dense” type, and my triglycerides were very low.
Do people think you are crazy when you tell them how you eat? What do you eat on a long ride? Beef jerky?
I’ve heard of your type of diet, but have not met anyone doing it. Particularly not any cyclists, who are often high carb. It feels to me like too much of an extreme on the opposite end of vegan (which is also too extreme for me).