Identifying whole grain foods: a comparison of different approaches for selecting more healthful whole grain products

The health benefits of whole grain (WG) foods are well established, including lower risk of CVD, weight gain and diabetes(1). Such benefits are likely related to multiple factors including higher contents of micronutrients, polyphenols, fatty acids and dietary fibre alone or in combination; lower glycaemic index; and also their replacement of more refined grains and sugars in one's diet(1–3). Based on this evidence, the US Department of Agriculture's (USDA) 2010 Dietary Guidelines recommends that Americans consume at least 3 servings of WG products daily(4), and the new US Nutrition Standards for the National School Lunch and School Lunch Programs require that at least half of all grains be WG-rich(5). Many countries worldwide include an emphasis on eating whole grains (WG) in their dietary recommendations(6,7). Industry has responded with an explosion of products marketed to consumers as being or containing WG. In 2010, the number of new grains marketed as WG was nearly twenty times higher than the number introduced in 2000(6). The global market for WG foods is expected to exceed $US 24 billion by 2015(8). Remarkably, this formulation, marketing and promotion of ‘whole grain’ foods has come with relatively little standardization to assist individuals and organizations in identifying and selecting healthful WG options. Internationally, requirements vary for industry to be able to add a specific WG health claim. In the UK and the USA, in order to use a health claim, WG foods must contain at least 51% WG ingredients by wet weight; in Sweden and Denmark, at least 50% WG ingredients by dry weight; and in Germany, at least 90% WG in bread(9). However, not all products that are eligible to use the WG health claim actually include it on the package, limiting the utility of this criterion for guiding consumers. Furthermore, the health claim is based on partial WG content alone, without any limitations or guidelines on contents of sugars, sodium, energy or trans-fats, so that products using the health claim can still be unhealthy in other aspects. More problematic, for grain products that do not include a health claim, there are currently few regulations on what can be defined as WG, called a WG, or marketed as having or containing WG. Many products marketed as WG foods contain a mixture of WG, refined grains and sugars, with unknown relative proportions that are closely guarded as proprietary information by food manufacturers(7,10). The variety of terms used to describe ‘whole grains’ as well as the unclear and inconsistent labelling of WG ingredients by manufacturers make it challenging for consumers and organizations such as schools and workplaces to identify more healthful WG products(7,11,12). Thus, we aimed to determine the best identification criteria to assist consumers, food service personnel, and policy makers to select healthful WG products, for example to meet recommended dietary guidelines or programmatic requirements such as the new US National School Lunch Program Guidelines. Furthermore, the relative performance of these diverse identification criteria could be used to inform potential future WG labelling policy. Several criteria have been proposed for identifying WG foods. One criterion, and the only one directly visible on food packages, is the Whole Grain stamp (WG-Stamp)(6). The WG-Stamp is a front-of-pack icon used in thirty-six countries worldwide and is promoted and regulated by a non-governmental organization with funding support from industry. The WG-Stamp is the most common front-of-package symbol dietitians report recommending to their clients as a reliable way to identify healthful WG products(13). In addition, the USDA and the European Food Information Council recommend other criteria to help consumers and organizations identify WG products, each of which makes use of the ingredient list. Notably, even USDA guidance is inconsistent across publications, and at least three different criteria exist (Table 1, second to fourth criteria)(4,14–16). The American Heart Association 2020 Strategic Impact Goals Committee also recently developed a criterion to define WG, based on the relative contents of total carbohydrate and fibre(17). Table 1 Recommended criteria for identifying a grain product as ‘whole grain’ Given the importance of identifying healthful WG foods, information is needed regarding the proportions of different grain products identified as WG by each of these criteria and, more importantly, their relative discrimination of health-related factors. If a metric identifies healthful WG foods but only a limited number of products meet the metric, then consumers and organizations (e.g. schools, workplaces) will have a relatively small selection of products to choose from and could also have trouble actually finding the healthful products in their stores or distributors. Conversely, if a metric identifies healthful WG foods and also includes many options, then this greater selection will make it more likely that consumers and organizations can find healthful WG products that they both prefer and are available to them. Most relevantly, it is unknown whether any of these metrics actually identify healthful WG products. To elucidate these issues, we investigated how these five different recommended criteria to identify WG products compared in terms of distinguishing contents of dietary fibre, sugars, sodium, trans-fats and energy. Because a second potential limitation for people to consume more WG products may be perception of higher cost(12,18,19), we also evaluated whether products identified as WG by each criterion were more expensive than non-WG options.