When consumed as whole grain, wheat has a high nutrient density that contributes to a healthy diet. Yet, products labeled as whole wheat can still contain a substantial amount of refined grain leading to the confusion for consumers, so a method was designed to determine the whole grain status within wheat‐based foods. Wheat germ agglutinin (WGA), a lectin found in the germ tissue of wheat kernels, was evaluated as a biomarker of whole grain wheat. WGA content strongly correlated with the percentage of whole wheat within premade mixtures of whole and refined (white) flours. Then, commercial flours labeled as whole wheat were tested for WGA content and found to contain up to 40% less WGA compared to a whole grain standard. Commercial pasta products labeled as whole wheat were also tested for WGA content and found to contain up to 90% less WGA compared to a whole grain standard. The differences in WGA content were not likely due to varietal differences alone, as the WGA content in common varieties used in domestic wheat flour production varied less than 25%. The levels of other constituents in wheat kernels, including starch, mineral, phytate, and total protein, were not different among the commercial whole wheat flours and pasta products. WGA is a unique biomarker that can identify wheat products with the highest whole grain content.
The study finds that national brand pastas labeled “whole grain” and “100% whole wheat” have a range of whole grain content from as little as 9% of the nutrient rich germ that one would expect, to 22% germ content. National brand “100% whole grain” flours were found to be as little as 60% to 70% whole grain, as measured by germ content.
Above figure, published on ResearchGate –Quantification of WGA protein in commercial wheat flour and pasta products.
Above figure, published on ResearchGate: Information on commercial wheat flour and commercial wheat pasta products used in these studies. Product brand, description, and SKU/UPC number are shown.
Regulations: Labeling standards and guidelines for “whole wheat-food” (as it is called by the FDA) allow significant content variation in foods labeled “whole grain” and “whole wheat” (terms commonly used interchangeably). Furthermore, the FDA guidelines for “whole grain” describe and recommend procedures for industrial roller milling of the wheat kernel—bran, germ, and endosperm—that separate, sift, and then recombine, not necessarily in the kernel’s entirety. The FDA does not suggest, let alone mandate, a laboratory analysis of the output of the milling process. So what the consumer might learn is what went into the process, not much about the flour that comes out of it.
Health implications: Numerous large-scale studies in the US and Europe have shown that consumption of whole wheat reduces many age-related diseases (including cardiovascular disease, Type 2 diabetes, and colo-rectal cancers), as well as over-all mortality. Strong implications for reduced risk of dementias have also been found.
Nutrition: The nutrient density of true whole wheat is prodigious. Compared with refined flour (that is, endosperm minus bran and germ), whole wheat contains almost all of the vitamins and minerals found in the kernel, plus fiber and important phytochemicals. Defenders of the industrial grain milling process note that nutrients and fiber missing from white and industrial whole wheat flours are commonly available in other foods, but fail to add that they remain absent from most persons’ diets as documented by USDA data which show dramatic nutrient deficiencies within the US population. Those deficiencies would be substantively alleviated—if not totally reversed—by true whole grain wheat consumption at government-recommended levels. (See graph below)
Nutrient bang for the buck: Wheat is a major part of the US diet, providing an estimated 20 to 40% of US caloric intake. The potential for significant health benefits across the entire population could be realized with greater consumption of true whole wheat.
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It is essential to establish an accurate biochemical analysis of wheat food labeled “whole grain” or “whole wheat” at the point of completed processing so consumers can make better-informed dietary choices, scientists can work from a universally accepted baseline definition of “whole grain” for studies on the health effects of whole grain consumption, and so regulators would be motivated to develop more accurate, enforceable labeling standards. “Nutrition Facts” panels should include this information.
To more fully understand the differences among industrially produced “whole wheat” products and those produced on a smaller scale using different milling technologies—and what actually comprises those products—Community Grains brought together a science committee of interested parties, which first convened April 2011. This became a foundational meeting for us, and set, at least in part, Community Grains’ agenda going forward.
In attendance were top scientists in the field (Prof. Bruce Ames, Biochemistry and Molecular Biology, Prof. Russell Jones, Plant and Molecular Biology, both of UC Berkeley; Dr. David Killilea, Associate Staff Scientist, Nutrition and Metabolism Center, CHORI); a best-selling journalist specializing in food issues (Prof. Michael Pollan, Knight Professor of Journalism at UC Berkeley’s Graduate School of Journalism); a leader in artisanal baking (Craig Ponsford, founder of Artisan Bakeries and Chairman of Bread Bakers Guild of America); and a commercial miller (Joseph Vanderliet, President of Certified Foods); along with Bob Klein (co-owner/managing partner of Oliveto Restaurant and President of Community Grains.
Joe Vanderliet, with many years of industrial milling experience before he started his more advanced, smaller milling company, confirmed our suspicions that most of the “whole grain wheat” we find in the grocery store has germ removed and most probably not fully replaced. Then it was Michael Pollan who said we need a test. Biochemist David Killilea said he could do that by isolating wheat germ agglutinin (WGA), a protein marker within the germ, then, using antibodies, measuring the amount present in a sample. Plant Biologist Russell Jones confirmed that that would do it.
A server at the restaurant studying to become a nurse, and a Public Health student of Michael Pollan’s, became the first lab techs for the project. Later, there were more interns, and still later a small paid staff. Community Grains invested about $500 for supplies and $10,000 for facilities. However, Dr. Killilea did not receive a salary or honorarium for developing this test. Community Grains did not control any aspect of experimental design or reporting of the results.
Dr. Killilea’s work demonstrates the effectiveness of measuring whole grain using WGA. The tests were performed on products purchased at local supermarkets and were tested well within their best-by dates. (A more robust test would have tested the same products from many supermarkets in different parts of the country.)
The publication of Dr. Killilea’s study is milestone for us, but new questions and challenges are ahead.
Click here to see our To-Do list via Bob Klein’s Menus of Change presentation.