State of Science :: Nutritional Quality
Food Quality Belongs Front and Center in "An Integrative View of Obesity"
Author(s): Dr. Charles Benbrook
The Organic Center
Dr. Alan Greene
Board Chair, The Organic Center and
The November 9th issue of Science Magazine contains a provocative and important article entitled "An Integrative View of Obesity" (Wisse et al., 2007).
The authors explain why progress in preventing overweight, obesity, and diabetes, and mitigating the complications triggered by these diseases, depends on "more integrative approaches for studying metabolic disease." Drug therapy, differences in people's metabolism, dietary changes, and health status are among the factors the authors identify that must be merged into an integrated approach to reduce the frequency and severity of these diseases.
Wisse et al. miss one important factor that surely belongs in an integrated approach to prevent obesity and diabetes - changes in food quality, including changes in the nutritional quality of our fruits and vegetables.
The American diet has clearly played a major role in driving upward the prevalence of these diseases, but when the role of diet is studied, the focus is almost always on excess caloric intake and increased consumption of saturated fat. Changes in the nutritional quality of food are rarely addressed.
It's time to move beyond simply blaming too much food for these problems. The real problem is surely more complex, and likely involves too much of the wrong kinds of food, and not enough of the right kinds.
In trying to unravel linkages between farming systems, food nutritional quality, and human health, the work of The Organic Center points to the importance of changes in our produce over the last four decades in sugar levels, form, and glycosylation patterns, coupled with reductions in several micronutrients (e.g., vitamins, minerals, antioxidants).
In recent months at scientific meetings, we have raised two novel questions. Do conventionally-grown plants suffer from a diabetes-like syndrome? And, are there human health implications when people consume food harvested from plants afflicted with such a syndrome?
The increase in human obesity and diabetes has roughly tracked the remarkable increases in crop yields, which in turn have been made possible by progressively higher and now clearly excessive levels of nitrogen fertilizer. The authors of the Science article (Wisse et al.) point out that -
"Metabolic dysfunction arises from exposure of the body's cells to an excess of nutrients."
Essentially the same thing happens in plants. It is very clear that excessive nitrogen in the soil leads to elevated, abnormal sugar levels in plant cells. This, in turn, leads to nutrient dilution, through mechanisms described in detail in the Center's Critical Issue Report "Still No Free Lunch" by Brian Halweil.
Excess nitrogen is a fact of life on virtually all intensive, conventional farms. Published research shows that between 30% and 100% extra nitrogen is typically applied on conventional cropland. An overload of nitrogen impacts plants in many of the same ways that excess calories impact humans.
Over-amped plants grow faster and the fruits and vegetables harvested from them tend to be larger. Fruit size increases mostly because existing cells become, on average, larger. There also tends to be more space between larger cells, space devoid of nutrients. These physiological changes lead to nutrient dilution, and cell walls that become stretched, like a balloon with extra air in it. The more stretched a cell wall, the easier time pathogens have in penetrating it.
A large body of research suggests that these changes in plant cells lead to elevated risk of damage from reactive oxygen species, increases in the plant's vulnerability to a range of pathogens and bacteria, nutrient dilution, less intense flavors, and reduced storage stability.
Too much sugar in the blood of human diabetics does many of the same things, and maybe for some of the same reasons. The long-term impacts on infants and children of elevated sugars in common foods, coupled with reduced nutrient density and flavor, may be both qualitatively and quantitatively distinct from impacts on adults.
These are among the reasons why scientists need to look more deeply at qualitative changes in food, especially sugar levels and forms. That deeper look might identify relatively simple ways to help people stabilize their blood sugars and weight, short of major life-style changes and drug interventions. A growing body of evidence points to consumption of nutrient-dense organic fruits, vegetables, herbs, and spices as one such simple intervention which deserves a fresh look as part of a truly integrated approach to health promotion.
B.E. Wisse, F. Kim, M.W. Schwartz. "An Integrative View of Obesity," Science, Vol. 318. November 9, 2007, pps. 928-929. Accessible at: http://www.sciencemag.org/cgi/reprint/318/5852/928.pdf