Health claims on foods are a way of informing consumers about the ‘treats’ of a product. This is an opportunity for the food industry to distinguish their products in the broad market range. In 2006, the European Union approved a set of rules concerning the use of nutrition and health claims for foods (Regulation (EC) No 1924/2006) [1
]. One of the main goals of this regulation is to ensure that claims are not misleading for the customer and that regulations are uniform across EU member states for fair market operation and promoting innovation.
The European Food Safety Authority (EFSA) evaluates the scientific basis of claims on nutritional or health benefits of foods. The EFSA only assesses submitted health claims when (a) the food or the food constituent is defined and sufficiently characterized, (b) the claimed effect is based on the essentiality of a nutrient, or the claimed effect is defined and has a beneficial effect on human health, (c) sufficient evidence is present on the cause and effect relationship between consumption of a product and the claimed health effect, and (d) the quantity that is needed to consume the food constituent fits into a normal diet pattern [2
]. This is of interest as citizens are becoming more aware and are more actively involved in taking care of their own health. In judging health claim dossiers, the EFSA mainly accepts health claims based on validated and established biomarkers [3
]. Currently, validated efficacy biomarkers and measurement methods originate mainly from medical research and focus on showing medical treatment effects on the diseased state. Therefore, most biomarkers which are currently in use and accepted by regulatory authorities are focused on showing effects on disease rather than on health improvement in a healthy range of the population. This complicates the design and execution of science-based intervention studies focusing on the demonstration of health effects in healthy consumers. Recently, the scope on what is a biologically relevant effect (i.e., response of a biological system) has been widened by the EFSA scientific committee, providing opportunities for alternative approaches of demonstrating health effects [4
Based on the conclusions of an International Invitational Conference on the concept of health, Huber et al. proposed changing the definition of health from the World Health Organization (WHO) formulated in 1948—health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity—towards resilience—or “the ability to adapt”—[5
]. Resilience is the installed capacity of all physiological processes (i.e., metabolism, inflammation, oxidation) to return to homeostatic levels upon a short-term disturbance. Due to ageing, an unhealthy lifestyle or disease, these processes become less flexible. Flexibility (resilience) can be measured by perturbation of homeostasis with a so-called challenge test [7
] followed by postprandial measurement of recovery time and amplitude of an array of markers using different analytical platforms [8
]. A physiological system which is healthier has a better ability to adapt to external stressors than a system with suboptimal health. Here, we would like to introduce an opportunity for future scientific substantiation for health claims of food products by using whole-grain wheat as an example.
2. Whole-Grain Wheat and Its Health Effects
Whole-grain wheat intake has been promoted for its beneficial health effects already since the 1900s, when Dr. Thomas Allinson advocated Allinson bread for a healthier lifestyle. In population studies, increased intake of whole grain has been convincingly shown to be associated with a lower risk of a range of chronic diseases and overall mortality [10
]. In most cohort studies (all except for Nordic European populations), wheat is the main source of grains. However, evaluation of individual RCT (randomized controlled trial) intervention studies focused on traditional outcomes (diagnostic biomarkers) provides mixed results. In contrast, a meta-analysis which pooled results from 21 RCTs found that a higher whole-grain intake lowers fasting blood glucose, insulin, total and low density cholesterol, blood pressure, and weight gain [13
]. Probably due to the variability in study design, differences in composition of the grains, degree of processing and the definition of the whole-grain intervention provides mixed results in individual RCTs [22
]. In 2016, Yamini and Trumbo illustrated this problem by explaining why the relation between whole grains and type 2 diabetes did not lead to a qualified health claim by the US Food and Drug Administration (US FDA) [23
]. Of 41 reports of intervention studies reviewed, scientific conclusions could not be drawn from 35 out of 41 studies. Furthermore, for 31 of these studies, the study duration (90 min–12 h) was too short to provide information on long-term health effects. Similar findings are presented for whole-grain consumption and effect on cardiovascular disease risk when limiting evidence only to the strict US FDA definition of whole grains [24
]. This is also the case for recent evaluation of health benefits on post-prandial glucose regulation [26
], lipid regulation [27
] and obesity [28
]. These opposing results, in combination with weak evidence from classical intervention studies and unclear use of definitions of whole grain, contribute to non-substantiation of health claims, especially when they are not focused on one simple parameter (i.e., cholesterol or glucose reduction) but are aimed at more complex health issues such as cardiovascular disease or type 2 diabetes.
3. Chronic Low-Grade Inflammation as a Targetable Example
The six reports identified by Yamini and Trumbo
as eligible to constitute a qualified health claim for whole grains all unsuccessfully focused on glycemic control [23
]. One of the reasons for the absence of beneficial effects may be the fact that other processes precede effects on glucose metabolism. Chronic low-grade inflammation, for example, provides an early mechanistic link between whole-grain effects and cardiometabolic diseases [29
]. Indeed, recently, beneficial effects of whole-grain wheat versus refined wheat were shown on inflammation and liver health, but not glucose metabolism [35
Chronic low-grade inflammation is a condition closely associated with metabolic disorders. Inflammation and metabolism share several signaling pathways, for example the nucleotide-binding oligomerization domain, leucine rich repeat family pyrin domain containing 3 (NLRP3) inflammasome and the c-Jun N-terminal kinase–nuclear factor kappa-light-chain-enhancer of activated B cells (JNK-NFkB) pathway, along which chronic low-grade inflammation is initiated and further developed [30
]. This occurs within metabolic tissues and eventually presents systemically with mildly elevated levels of pro-inflammatory biomarkers (e.g., C-reactive protein, interleukin-6 (IL-6), tumor necrosis factor-alpha) and reduced levels of anti-inflammatory biomarkers (e.g., adiponectin, interleukin-10 (IL-10), transforming growth factor-beta) [32
]. Given the common signaling pathways, chronic low-grade inflammation can induce several metabolic disturbances within tissues and, systemically, including insulin resistance and atherosclerosis as precursors of diabetes type 2 and cardiovascular disease [31
Whole grains contain multiple bioactive compounds, including dietary fiber, vitamins, minerals, and antioxidants, that exert beneficial health effects, including anti-inflammatory effects [38
]. Individual components or combinations thereof increase the production of short chain fatty acids via microbial fermentation in the colon, positively affect lipid production in and removal from the liver, as beneficial indirect anti-inflammatory effects [32
]. Additionally, polyphenols (mainly ferulic acid), short chain fatty acids, and other bioactive compounds from whole grains may exert a direct anti-oxidant and anti-inflammatory effect [34
Regardless of the fact that anti-inflammatory effects of whole grains have been studied in RCTs [41
], no qualified health claims have been granted for anti-inflammatory effects of whole grains (Supplemental Table S1
]. In response to the question how to apply for claims on supporting and maintaining immune function, an EFSA panel stated [44
]: “changes in outcome variable(s) which can be measured
in vivo in humans by generally accepted methods may not be considered beneficial physiological effects per se if they do not refer to a benefit on a specific function of the body, and thus cannot be the claimed effect (i.e., constitute the only basis for the scientific substantiation of a health claim)”
. The panel explicitly stated that markers of chronic low-grade inflammation do not suffice for the constitution of a health claim. New methods that provide quantitative interpretation for effects on these markers are thus needed.
4. Alternative Method for Measurement of Health Effects
As current evidence is accepted for lending credence to the recommendation of incorporating whole grains in general dietary recommendations worldwide [45
], it raises the question as to what kind of approach would be useful in the substantiation of health claims. Classically, a biomarker is defined as “a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes or pharmacologic responses to a therapeutic intervention” and biomarker evaluation depends mostly on overnight fasting values [46
]. Our proposal for new biomarkers is to also take the dynamic nature of biological health processes into account and in line with the rephrased definition of health to ‘the ability to adapt’ [5
]. This has been taken up into the EFSA guidance document on the assessment of the biological relevance of data in scientific assessment [4
The first nutritional intervention studies are appearing that show a health impact when evaluating postprandial responses, which is more sensitive than evaluating health in a traditional way by only evaluating overnight fasting values [35
]. For example, the effect of flavonols in dark chocolate on long-term vascular health, substantiated in EFSA health claim “cocoa flavanols help maintain endothelium-dependent vasodilation, which contributes to normal blood flow” [51
] could be reproduced in healthy overweight middle-aged men by evaluating flow mediated dilation (FMD), augmentation index (AIX), total leucocyte counts, and plasma soluble adhesion molecules in response to an oral lipid tolerance test (OLTT) [49
The next step would be the subsequent integration of these combined data [52
], which will yield a quantified degree of resilience of an individual which can be compared to others [50
]. This approach will deliver us a next generation of biomarkers [8
] or early biomarkers of disease or effects (Figure 1
adapted from [58
]). Based on the results of the Dutch public private partnership PhenFlex and the FP7 EU project Nutritech, a standardized nutritional challenge test (PhenFlex challenge test, PFT) was developed which characterizes how different processes of phenotypic flexibility are being modulated that differentiate between health states in the sequel from optimal health to suboptimal health to diseased [50
]. The ‘amplitude’ and the ‘duration’ of disturbance (time needed to get back to homeostatic conditions) were quantified for a multitude of biomarkers covering different organs and processes related to metabolic health. This set of biomarkers includes accepted markers by EFSA, scientific well-known markers, not yet accepted by EFSA, and new types of markers generated with modern technologies such as metabolic profiling. This set of biomarkers could be able to empower validity for nutritional health claims by showing the system’s flexibility for optimal health [8
5. Health Claims on Whole-Grain Wheat: Status, Issues and Perspectives
In the European Union, no health claims for whole-grain wheat exist, since no proposals for claims have been submitted. However, a number of claims have been submitted to EFSA for whole-grain foods, diets rich in whole grain and whole grain and whole-grain flour. Most of these claims were focused on either ‘heart health’ or ‘gut health’. Furthermore, beneficial effect upon glucose metabolism, ageing, inflammation/immune and maintenance of a normal body weight are claimed (full overview in Supplemental Table S1
). None of these claims were evaluated, and rejections were based on”insufficient characterization for a scientific assessment of this claimed effect”. According to the EFSA Panel, whole grains and whole-grain foods were also defined differently across countries.
As stated in Regulation (EC) No 1924/2006, health claims can refer to the health relationship of a food category, a food or to one of its constituents. Whole grains can be considered as a food category. In current definitions of whole grain where the grains are specified, a wide range of grains are included—mostly all grains used for human consumption of the Poaceae family, (including, e.g., wheat, spelt, barley, oats, rye, rice and maize) and often also pseudo-cereals (e.g., amaranth, buckwheat and quinoa) [59
The EFSA Panel concluded for all submitted health claims for food categories that ‘this food is not sufficiently characterized in relation to the claimed effects’. This applies for broad food categories such as ‘vegetable rich diets’, and ‘fruits and vegetables’ [61
], but also for food categories specified in more detail, as was done for the claims ‘for peanuts and tree nuts (almonds, hazelnuts, pecans, pistachios and walnuts), excluding brazil, macadamia and cashew nuts)’
]. As an exception, the health claim “Meat or fish contributes to the improvement of iron absorption when eaten with other foods containing iron” has been authorized; all types of meat and fish are well characterized for this claim, since they contain at least the required amount of haem-bound iron [64
]. Apart from this exception, the EFSA Panel considered only specific products or ingredients as being sufficiently characterized, such as walnuts [65
], where a number of the proposed health claims were assessed with favorable outcome.
The well-defined food category, “dietary fiber” (EU, 2008) was also considered by the EFSA Panel as ‘not sufficiently characterized in relation to the claimed effects’
, since these effects can vary depending on the unique physical and chemical characteristics of the specific fiber component [66
So far, the EFSA Panel considered a wide range of specific fibers as sufficiently characterized, and has substantiated a number of the submitted health claims, including wheat bran fiber for a reduction in intestinal transit time and for an increase in fecal bulk [67
], rye fiber for contributing to normal bowel function [68
], oat and barley grain fiber for an increase in fecal bulk [69
], and beta-glucans from oats and barley for a reduction in post-prandial glycemic responses [70
], and for maintenance of normal blood cholesterol levels [70
]. As is apparent from these examples, the EFSA panel is only considering individual products ‘as sufficiently characterized’; or combinations of ingredients or products if they are similar regarding the component(s) relevant for the claimed effect (e.g., beta-glucans of oats and barley).
Characterization of Whole Grains, Whole Wheat and Whole Wheat Products
The composition of various whole grains and their flours varies considerably. The level of dietary fiber, an important component in relation to health benefits of whole grains [11
], ranges from 4% for rice via 7% (maize), 12% (wheat) and 15% (rye) to 16% for barley (USDA Food composition database). As was the case for dietary fiber, the EFSA Panel will most probably only consider individual whole grains as sufficiently characterized.
The minimum level of whole grain in a product required for calling it a whole-grain product varies considerably between countries, both in- and outside the EU. For example, in Denmark and other northern European countries, at least 50% of the flour in whole-grain bread needs to be whole-grain flour, whereas in many other countries, 100% whole-grain flour is required. It should be noted, however, that the level of whole-grain flour, refined grain flour and all other ingredients needs to be specified in the mandatory list of ingredients.
Contrary to definitions of whole-grain food products, whole grains and whole-grain flour are defined rather uniformly in Europe and worldwide [59
]. All definitions describe whole grains with wordings such as in the HEALTHGRAIN definition [59
]: “Whole grains shall consist of the intact, ground, cracked or flaked kernel after the removal of inedible parts such as the hull and husk. The principal anatomical components the starchy endosperm, germ and bran are present in the same relative proportions as they exist in the intact kernel.”
In summary, in EFSA assessments of health claims, the characterization of food categories such as fruits and/or vegetables and whole grains is—with one exception—considered as insufficient, whereas the characterization of individual products and ingredients is considered as sufficient. Therefore, we may assume that EFSA will consider whole wheat grains and whole wheat flour as sufficiently characterized for a scientific assessment for health claim substantiation.
In order to facilitate future health claim substantiation related to food products from which meta-analyses generate a positive association with beneficial health outcomes, the resilience approach could be a solution. The example of whole-grain wheat teaches us that characterization of one product is preferred above the food category and that whole wheat grains and whole wheat flour probably would be considered as sufficiently characterized by the EFSA. Meta-analysis provides the evidence that whole-grain wheat is beneficial for health although scientific evidence is not always straightforward with classic measurement methods. An alternative measurement approach using a combination of accepted markers showed changes in resilience for whole-grain wheat. Quantification of ‘resilience’ or ‘disturbance of homeostasis’ after a standardized challenge test was accepted by the EFSA scientific committee as a methodology to determine beneficial health effects from food and nutrition. However, the proposed method of measurement of resilience (e.g., differential responses to a standardized oral protein glucose lipid tolerance test as measured by the disruption and rate of response of selected blood markers) needs validation, for example, on long-term clinical relevance. Furthermore, the effect of whole-grain wheat on liver and inflammatory resilience should be confirmed in an independent study showing similar results in addition to showing that changes to the defined response of aggregated markers for liver and inflammatory resilience indeed are related to a beneficial physiological effect. In summary, when these steps to deliver the scientific argumentation that the confirmed observed changes that long-term whole-grain wheat consumption improve liver- and inflammatory resilience, a health claim for whole-grain wheat could be achievable in the near future.