Dr. Piero Anversa of the Harvard Medical School created controversy among his peers when he asserted in 1987 that the human heart completely renews its cells four times by the time a person reaches age 80. Before Dr. Anversa's claim, conventional wisdom among scientists had maintained that heart cells don't regenerate at all -- you die with the heart you were born with, minus wear and tear.
But now, new research has found that heart cells do indeed renew themselves, though a bit more slowly than Dr. Anversa postulated. The research, conducted by Dr. Jonas Frisen from the Karolinska Institute in Stockholm, found that the heart muscle regenerates at the rate of about one percent a year in early adulthood, slowing down over time so that by age 75, the cells renew at the rate of about half a percent annually. That means that by age 50, you'll have about 55 percent of the heart muscle cells you were born with; the rest of your heart will be comparatively new.
The research team reached its conclusions by carbon-dating heart muscle cells of people born prior to 1955, the year that above-ground nuclear tests first were conducted. Apparently, the radioactive carbon-14 released during those tests (which lasted until 1963) affected human cells profoundly. That carbon-14 was "recruited" by new cells in human bodies and was used to build DNA. Think about birds using whatever trash they find in the environment to build nests. As a side note, it's certainly horrifying to think about radioactive carbon-14 becoming a basic building block of our cellular structure, but also rather remarkable from a recycling point of view. Very green...so to speak.
In any case, this means that you can date cells with carbon-14 in their DNA as having come into existence after those tests began. Cells that existed before the tests started would contain no carbon-14 since there was none around to be incorporated into DNA before 1955. The bottom line is that the presence or absence of carbon-14 in heart muscle DNA would determine the date the muscle was created -- pre or post 1955. Surprisingly, the researchers found that people born before 1955 had carbon-14 in heart muscle DNA, indicating they had heart cells that came into existence after 1955 -- after they were born.
In a commentary on the study in Science Magazine, Dr. Charles Murry of the University of Washington writes, "The dogma has always been that cell division in the heart pretty much stops after birth. In medical school, we teach that you'll die with the heart cells you're born with... [We] think this will be one of the most important papers in cardiovascular medicine in years."
The thing that makes the discovery so important is that medical researchers now believe it opens the possibility that the heart's ability to regenerate can be speeded up artificially. Heart attacks leave heart muscles weak, stretched, scarred, and unable to recover, opening the system to future heart failure. But if the muscle could be impelled to regenerate quickly, the heart could regenerate itself, thus preventing future attacks. "Even though cardiomyocyte (heart muscle cell) turnover is low in the adult heart, the fact that it occurs at all suggests that it can potentially be therapeutically exploited," say Drs. Murry and Lee.
Dr. Frisen suggests that the regeneration process can be expedited enough so that an individual might prevent heart failure "[by] taking advantage of the heart's own capacity to generate new cells either using pharmaceutical compounds or, if it is possible, by exercise or any other environmental factor."
It's inspiring that Dr. Frisen believes that exercise and "environmental factors" might trigger healing enough to bypass or at least supplement pharmaceuticals, given his mainstream medical stature -- which brings me to my central point. If the heart muscle regenerates, which now appears to be the case, what would the rate of that regeneration be if you stopped doing those things (diet and environment related) that degrade heart muscle and instead started using natural methods as Dr. Frisen suggests to optimize that regeneration?
Keep in mind -- that the one percent renewal of heart muscle a year quoted in Dr. Frisen's study is based on an analysis of the "average" American following the "average" American diet and "average" American lifestyle. As I frequently say, "If you do what the average American does, you get the results the average American gets. But what if you're not average? What if you incorporate intelligent targeted nutrition and exercise -- can you not accelerate the rate of renewal, even curtailing the possibility of cardiovascular events occurring in the first place?
It certainly makes sense to embrace factors likely to nurture the inborn tendency of heart tissue to renew itself -- whether in order to avoid having heart problems or to repair problems already extant. Such supplements as CoQ10, B vitamins, proteolytic enzymes, Omega-3 fatty acids, heavy metal chelaters, and immune enhancers (or even better, superfoods high in those phytonutrients) all work to give the heart a fighting chance to undo damage created by lifestyle stressors and to optimize the body's natural ability to heal. Considering that we already know that 90% of all heart disease is self-inflicted, you probably don't have to wait for a future study to guess the answer to that question.
For tips on maintaining heart health, see my newsletter on heart disease prevention.
Meanwhile, the media reports that Dr. Anversa was "ecstatic" to learn that the study confirmed his contention that heart cells do regenerate, but he still maintains that the heart turns over multiple times before expiring. Though his colleagues voice skepticism, his view certainly seems more plausible today than it did even a few weeks ago. Stay tuned.