It may well have been a Welsh bard who, wishing to avoid the local physician, sang about the healthy virtues of the lovely apple: late nineteenth-century records trace the proverb to that rugged land. Interest in the saying has not been limited to folklorists. Scientists have parsed the proverb empirically by probing the apple for its healthful merits. A short list of what they've found is worth noting: vitamins A, C, and E; pectin, to lower blood pressure; quercetin, to reduce cancer risk, and boron, to build bone. The proverb, it seems, holds at least a few seeds of truth.
While this issue of Harvard Medicine isn't an ode to the apple, it does draw inspiration from its image. And what better for an issue on diet and health? Within these pages, you can read about how science is carefully dicing the data on associations between diet and disease, eating and aging, and even peanuts and therapeutic success. You will also find how research is clarifying those associations using the power of reports from multiyear epidemiological studies and the nuance offered by controlled laboratory investigation. The role of nutrition in healing has not been overlooked either, as you can read about how the critically ill were served in the past and how they are sustained today.
If you wish to clear your palate of analyses, you might explore the beauty of biodiversity and the joy of using the fruits of the garden prescriptively. And for those who enjoy a mystery, this issue tells two, one a tale that begins in Siberia and ends with a new branch of our family tree, and another that describes the search for a vaccine against HIV—a story without resolution, but not, you will find, without progress or hope.
Perhaps science will one day certify apples as our best medicine. But until that day, we can take guidance—and heart—from what research is revealing about diet, disease, and well-being, and, using that knowledge as our guide, recognize food for what it truly is, an indispensable path to lifelong health.