Dr. Nir Barzilai is a well-known researcher and advocate for longevity studies. He is an MD and the founder or driving force behind many geroscience institutes and initiatives. In 2020, he also became one of a growing number of scientific figures in the aging biology field who have written popular books on the subject for the general public.
Among the aging science books I have reviewed so far, this one is the most casual and conversational. It conveys the impression that the reader is sitting in a living room as a relaxed but enthusiastic Dr. Barzilai shares anecdotes, recollections, and opinions over a few glasses of wine. This approach has both advantages and disadvantages.
The material is easy to read and not overly technical or full of scientific jargon. It is also very loosely organized, even a bit rambling at times, and it is heavy on anecdotes and opinions and light on evidence and critical assessment. One could easily come away with the impression that every idea, every hypothesis about aging is exceptionally promising and that radical transformation of human lifespan and healthspan is just around the corner. Unfortunately, that is probably not the most accurate picture of the field, and it glosses over the complexity of aging biology and the scientific challenges of significant lifespan extension.
Dr. Barzilai does talk quite a bit about the political and financial challenges, going so far as to say “the only thing standing between [a world of healthy, productive elderly people] and the one we have is money.” Much of the book is about commercial ventures he has been involved in that hope to turn promising scientific hypotheses into readily available therapies and products at warp speed; much faster than the painstaking, laborious processes of non-profit scientific investigation and regulatory approval. Again, the reader gets a very clear impression (accurate or not) of Dr. Barzilai’s personality and views on the best way to move forward with geroscience. Though he is a well-respected scientist who has made significant contributions to aging biology, he seems a bit impatient with the speed of progress and inclined to suggest the market could do a better, or at least faster, job of capitalizing on the scientific possibilities with sufficient funding and less conservative regulatory constraints.
The book shares many anecdotes about the human experience of aging, and this fits well with one of the central stories, which is Dr. Barzilai’s work with centenarians attempting to uncover the secrets to their exceptional longevity and health. The predominant message coming from this work appears to be the importance of genetic factors in protecting some individuals against aging and age-related disease. This may disappoint some readers looking for tips to improve their own health and lifespan, but Dr. Barzilai also provides plenty of these. Despite the appropriate caveats about not blindly following his example, he shares with his friend Dr. David Sinclair a willingness to try out new treatments on himself long before the scientific evidence and the drug approval system endorse doing so, and he shares many of these in this book.
In several of these reviews, I have talked about the tricky balance of skeptical optimism. As researchers in a relatively new and rapidly changing field, we must be sufficiently hopeful and open-minded to take up and test new ideas, even with relatively little to go on at first. However, such enthusiasm can easily carry us beyond the boundaries of rigorous science and good sense if we don’t balance it with appropriate skepticism. Particularly when writing for a non-science audience, it is easy to convey the false impression that big problems are easy or on the verge of being solved or that we already have good reason to put treatments into use that, in reality, we have not yet proven are effective or safe. Striking the perfect balance, to sustain excitement and energy without giving in to wishful thinking, is a difficult and ongoing challenge in the field.
Dr. Barzilai leans a bit too far to the side of enthusiasm over skepticism for my taste. He lists many approaches as “promising” even when the evidence or scientific rationale for these is pretty weak. Reasonable advice about exercise and diet are mixed in with questionable ideas about supplements and fasting, and even some pretty fanciful stuff about the benefits of pseudoscience like reflexology or the claim that prayer can lengthen telomeres. In the long list of ideas put forward in the book, little meaningful distinction is made between science, speculation, and fantasy, and that has significant potential to create a misleading picture for many readers.
Overall, Dr. Barzilai’s book is an engaging, relaxed, and relatively personal look at the aging biology field. It skims the surface broadly with limited scientific depth and it leaves a positive, rosy picture of the state of the field. While Age Later may not be the most scientifically detailed or critical assessment of the field, it is easy to see why Dr. Barzilai has been so successful at organizing and leading geroscience research efforts and finding funding for his endeavors. These activities require the kind of exuberance and optimism that comes across quite clearly in his book.