The most comprehensive definition of whole grain termed to date has been published this week in the journal Food and Nutrition Research. The effort to create the definition, which is intended to assist in the production and labeling of foods rich in whole grains, was born of the HEALTHGRAIN EU project, the largest project ever focusing on cereals and health; and was led by a multi-disciplinary team from some of Europe’s leading universities and food research institutes.
Historically, there’s been no complete, legally endorsed definition of whole grain flour and products,” explains Jan-Willem van der Kamp, corresponding author of the paper and Senior Officer of International Projects at TNO Food and Nutrition. “Most supermarkets today are stocked with foods that originate from many different countries. When you read ‘25% whole grain flour’ on one product label; the same claim on a different label could mean something quite different nutritionally. If use of this definition is adopted broadly, this inconsistency eventually would cease.”
The HEALTHGRAIN definition is the next step in reaching a precise, common understanding of what constitutes whole grain in food products – from breads to pasta to breakfast cereals – regardless of where they originate, adds van der Kamp.
Almost universally, the term whole grain indicates inclusion of all three components of the cereal grain kernel – endosperm (this is the largest part of the grain and provides mostly starch), germ (comprises only a small part of the grain; this is where sprouting begins) and bran (the grain’s protective outer layer; it is rich in dietary fibre). Variances, however, arise around the particular grains considered “whole”, precise combination of the three components once processed, and processing practices which can affect the resulting flour’s nutritional value. The HEALTHGRAIN definition addresses all three of these issues detailing a permitted list of grains and “pseudo grains” (such as quinoa and amaranth) and processing guidelines that take into account current milling practices.
The need for developing a more comprehensive, detailed whole grain definition was identified during the course of the HEALTHGRAIN EU project, an initiative intended to increase the use of whole grains and their health protecting constituents in food products for improved nutrition and health benefits. The expansive project has involved everything from research to better understand specific health benefits of whole grains to exploration of new ways to get products high in their healthy compounds onto the market.
The HEALTHGRAIN definition was developed by a committee led by van der Kamp, representatives of the Swedish Nutrition Foundation; DPR Nutrition Ltd., UK; and VTT and University of Eastern Finland; in cooperation with a multidisciplinary group of nutrition scientists, cereal scientists and technologists, plant breeders, flour milling specialists and experts in regulatory affairs from throughout Europe.
The article with the complete HEALTHGRAIN definition, including the permitted grains, can be accessed in the current volume of Food and Nutrition Research (http://www.foodandnutritionresearch.net/index.php/fnr/article/view/22100).
Eating more fiber may modestly reduce the risk of stroke, although details remain uncertain and it might just be a surrogate for other healthy behaviors, a meta-analysis determined.
Each additional 7 g of daily dietary fiber intake was associated with a significant 7% lower risk of hemorrhagic and ischemic stroke combined, Diane Threapleton, MSc, of the University of Leeds, England, and colleagues reported online in Stroke.
“Our study supports current guidelines to increase fiber consumption,” the researchers concluded, although they noted that too little data were available to narrow down what sources or types of fiber were most protective.
They called a 7-g per day boost in roughage doable, it being the equivalent of an extra serving of beans or two servings of fruit like apples and oranges.
The average American falls short of the daily recommended fiber intake by more than that, though, getting an average of just 13 g for women and 17 g for men compared with the 21 to 25 g and 30 to 38 g, respectively, called for by guidelines.
Although the observational data couldn’t ascribe causality, a role for dietary fiber is plausible, Threapleton’s group noted.
“Soluble types of fiber form gels in the stomach and small intestine, slowing the rate of nutrient absorption and slowing gastric emptying, which increases satiety and influences the overall amount of food eaten, resulting in lower levels of overweight,” they wrote. “Bacterial fermentation of resistant starch and soluble fibers in the large intestine produces short-chain fatty acids which inhibit cholesterol synthesis by the liver, consequently lowering serum levels.”
Prior studies have shown links to stroke risk factors, including hypertension and high cholesterol, as well as insulin resistance.
The literature search turned up eight prospective cohort studies from the U.S., northern Europe, Australia, and Japan reporting on fiber intake in healthy individuals (defined as not recruited based on history of disease or poor health) and incidence of first ever stroke.
Pooled results showed a steadily declining stroke risk with higher total fiber intake, with a relative risk of 0.93 per 7 g per day (95% CI 0.88 to 0.98).
Few individuals had fiber levels above 25 g per day, “so extrapolation of risk at higher intakes should be undertaken with caution,” the researchers warned.
There was some evidence of heterogeneity among the studies, with a difference by study size.
Ischemic stroke appeared less common with higher total dietary fiber intake in two of the four studies that reported on this outcome, while a third showed a similar trend but with wide confidence intervals.
Hemorrhagic stroke occurred less often at higher fiber levels in one of the three studies looking at that outcome.
Soluble fiber showed a nonsignificant trend, with 6% lower relative risk of stroke per 4 g/day increase in daily intake across the studies.
The insoluble fiber results couldn’t be pooled. One of the three studies reporting on this measure suggested a 38% lower stroke risk, while the others indicated no association.
Fiber from grain sources appeared protective in several studies, as did vegetable fiber, but again results couldn’t be pooled.
The reviewers cautioned about the “inherent problem of unadjusted confounding” since fiber may be acting as a surrogate for other healthy behaviors like less smoking and more exercise that also would reduce stroke risk.
“All of the pooled studies did, however, include adjustment for potentially important confounding variables such as age, body mass index, blood pressure or history of hypertension, smoking status, alcohol intake, physical activity, and sex (where applicable), and also a variety of other health and lifestyle variables,” Threapleton and colleagues noted.
The main systematic review was funded by the U.K. Department of Health for England.
Threapleton reported that her PhD studies are sponsored by Kellogg Marketing and Sales Company.
From the American Heart Association: