November 26, 2002
Lenny Lecture traces link between diet and health
If the story of our lives is inscribed in our genes, the outcome is profoundly dependent on what we eat.
Research in the emerging science of "molecular nutrition" is revealing the precise ways that substances within food — vitamins, nutrients, and a host of lesser-known compounds — interact with genes and alter the behavior of cells. The result, according to the presenter of this year's "Lenny Lecture" at Dana-Farber, is a new appreciation of diet's far-reaching impact on health and disease.
Jeffrey Bland, PhD, director of the Institute for Functional Medicine, delivered two talks on Nov. 14 — one in the morning for medical staff; one in the afternoon for patients — on the mechanics of nutrition's link to cancer. His presentation, the third annual lecture in memory of former DFCI patient Leonard P. Zakim, mixed hard science and homespun examples to bring a sprawling, complex subject into focus.
Bland began by noting that although cancer risk was once viewed as hard-wired into our genes, research over the past dozen years — particularly the charting of the human genome — has given rise to a more intricate understanding. Aside from a relatively small number of genes that, in mutated form, are directly linked to cancer, most tumors arise from a subtle interplay of genes and factors in the environment, including diet.
At each stage of a cell's metamorphosis into a cancer cell, nutrients play a role, either accelerating the process or retarding it. "Food is information," Bland remarked. "When nutrients from the food we eat wash over our genes, they have the potential to either increase or decrease genetic messaging. The result is a change in the cell's basic physiological function."
To illustrate that environment plays at least as large a role as genes in the development of disease, Bland cited the Pima Indians of the American southwest, who have high rates of diabetes despite lacking any gene mutation associated with the disease. From his own research with the Indians, Bland explained that their traditional lifestyle — a nomadic existence in an arid climate where food is sometimes scarce — caused them to develop "warrior genes," which enable cells to retain nutrients for long periods of time. When the Indians' diet changed as a result of American influence, the high levels of nutrients hoarded by their cells made them especially susceptible to diabetes.
Bland also cited a recent Swedish study of thousands of twins that found only 30 percent of cancers are hereditary. "That means 70 percent of a person's long-term cancer risk is related to environmental factors — how we live, what we eat, whether we get enough sleep and exercise, and the substances we're exposed to on a regular basis," Bland stated.
From micro to macro Science, he commented, is beginning to make the connection between what happens in individual cells and the fact that, as it is sometimes crudely put, "if you eat junk, you're going to look and feel like junk." Investigators now can trace dozens of molecular "pathways" within cells by which food nutrients affect genes, which affect the proteins cells produce, which affect how cells function.
Unfortunately, these findings do little to endorse the standard high-fat, high-sugar, low-fiber American diet. Bland remarked that our diet suffers from what might be termed "too much of too little" — too much food in which too many nutrients have been removed. Highly processed foods, including those made from refined flour, are primary culprits. An irony is that many of the substances commonly removed from food find their way into pet food. As a result, "we have frisky pets and tired owners," Bland quipped.
How does this relate to the question of diet for cancer patients? Overwhelmingly, Bland said, it speaks in favor of a macrobiotic diet, which is built on whole-grain foods, foods that contain a lot of color (indicating they haven't been bleached or extensively processed) and are low in fat.
"The macrobiotic diet represents a different way of thinking about eating," Bland observed. "Our genes are pretty much the same as they were in the Paleolithic Era [the early Stone Age], but our diet is radically different. We need to speak to our genes in a language they were designed to understand."
The lectures, sponsored by the Leonard P. Zakim Center for Integrative Therapies, drew near-capacity crowds to the morning and afternoon sessions. At both, Bland expressed his honor at delivering presentations named in memory of Zakim, who co-led efforts to bring complementary therapies such as acupuncture and reiki therapy to fellow DFCI patients.
