Don't judge by its color: white vegetables offer key nutrients too

When it comes to nutrient content, don't judge a veggie by its color alone, said a panel of leading food and nutrition scientists at a recent American Society for Nutrition (ASN) pre-annual meeting session. Vegetables that are white in color are often overlooked as significant sources of key nutrients recommended in dietary guidelines, such as potassium and dietary fiber, two nutrients that we don't get enough of but that are critical to good health.

The half-day ASN Satellite Symposium: White Vegetables: Addressing the Nutrition Gaps was held from 1-5 pm at the Boston Convention and Exhibition Center in conjunction with the ASN's 77th Scientific Sessions and Annual Meeting and Experimental Biology 2013.

The symposium was sponsored by the Alliance for Potato Research and Education (APRE), a not-for-profit organization dedicated to expanding and translating potato nutrition research into science-based policy and education initiatives.

Tufts University professor and symposium co-chair Johanna Dwyer, DSc, RD, noted that while there is a promising baseline of nutrition research about the metabolic response and health benefits of white vegetables in a well-balanced diet, more research is needed.

"We eat a lot of white vegetables;they add variety, texture and nutrients and they fit in many places on the plate, but we need to know more,"said Dwyer. "As the speakers at this symposium outlined today, white vegetables are classified and placed in many different groupings—starchy vegetables and "'other' categories like snacks or grains, for example.

"As a result,"she continued, "there are some data gaps with regard to how we look at the whole group of white vegetables and the contributions they make to total intakes of nutrients and positive health outcomes. At present, not enough data exists, so it is an area that food and nutrition scientists need to look at more closely."

Co-chaired by Dwyer and Mario G. Ferruzzi, PhD, professor of food and nutrition science at Purdue University, the symposium highlighted emerging research and innovations that enhance the nutritional impact of white vegetables, especially the potato, in a healthy, wellbalanced diet.

Presenters covered a variety of topics, including:

• Ferruzzi, on behalf of Eric A. Decker, PhD, University of Massachusetts-Amherst, presented a comprehensive review of innovations in food chemistry and processing that enhance the nutrient profile of the white potato in all forms, including French fried potatoes, and highlighted the use of new food technologies that improve potato resistant starch content to reduce glycemic response and increase dietary fiber content;fat reduction techniques for fried potatoes;and leveraging the nutritional content of potato skins into processed products.


• Joanne Slavin, PhD, RD, University of Minnesota, offered a review of the science-based evidence on the health benefits of carbohydrates and dietary fiber, which are generally protective against disease;the role of resistant starch in achieving adequate intake of dietary fiber, a shortfall nutrient;and misdirected efforts to reduce consumption of white potatoes that may result in reduced intake of these important, underconsumed nutrients.


• In a second presentation, Slavin gave a historical account of how nutrient and food recommendations are translated into dietary guidance, provided insight into current food classifications for white vegetables, and discussed why the use of color is often used an indicator of a vegetable's nutrient value but is not the sole measure of nutrient content.


• G. Harvey Anderson, PhD, University of Toronto, explored the current scientific thought on the glycemic index (GI) and satiety associated with white potato consumption and metabolic response. In addition, he discussed whether a high GI matters if a vegetable is nutrient-rich, low in energy density, and within a meal, contributes to early satiation and lower food intake. Anderson also suggested that published data indicates that post ad libitum meal responses may be a better measure than GI for dietary effects on glycemia, and that when applied to white potatoes, the GI has led to premature and possibly counterproductive dietary guidance.


• Cheryl Anderson, PhD, MPH, University of California-San Diego, outlined the critical role of dietary potassium in promoting health, especially in light of the fact that less than 3% of the U.S. population consumes the recommended daily intake of 4,700 mg/day. She cited the volume of evidence showing potassium's contribution to blood pressure reduction and emerging studies addressing the nutrient's role in cardiovascular, kidney and bone health, and discussed the role of potassium-rich white vegetables like potatoes in contributing to increases of intake levels.


• Stella Lucia Volpe, PhD, RD, Drexel University, presented an overview of the role of magnesium in disease prevention and overall health, detailed the amount of this nutrient found in white vegetables and other food sources, and highlighted the promising research in this area, including studies showing a connection between magnesium intake and reduction of stroke risk.

Several of the presentations are based on papers slated to be published in a May 2013 supplement to the peer-reviewed journal, Advances in Nutrition.

Source: Alliance for Potato Research and Education (APRE)