Optimizing clinical trial design for assessing the efficacy of functional foods

The dichotomy between functional and functionalized foods - A critical characterization of concepts

Diet is one of the main drivers of non-communicable chronic diseases (NCD). Modifying the food supply may be an attractive strategy for promoting health and reducing NCD risk. The intentional modification, processing, enrichment, or fortification of foods to produce "functional foods" currently varies according to legal definitions and existing regulatory frameworks, initially intended function, and production methods. This review critically appraises the existing definitions and concepts applied to functional foods, proposing a new concept of "functionalized foods". The conceptual difference between the two categories is that the term "functional foods" is used for products validated for human health through controlled trials, while "functionalized foods" is used for food products obtained through enrichment or (bio)fortification that lack such a validation, yet. Consequently, the review aims to establish a framework for better understanding the range of existing products, enhancing communication, and promoting a more accurate interpretation of the functional food landscape.

Designing Nutrition for Health-Incorporating Dietary By-Products into Poultry Feeds to Create Functional Foods with Insights into Health Benefits, Risks, Bioactive Compounds, Food Component Functionality and Safety Regulations

This review delves into the concept of nutrition by design, exploring the relationship between poultry production, the utilization of dietary by-products to create functional foods, and their impact on human health. Functional foods are defined as products that extend beyond their basic nutritional value, offering potential benefits in disease prevention and management. Various methods, including extraction, fermentation, enrichment, biotechnology, and nanotechnology, are employed to obtain bioactive compounds for these functional foods. This review also examines the innovative approach of enhancing livestock diets to create functional foods through animal-based methods. Bioactive compounds found in these functional foods, such as essential fatty acids, antioxidants, carotenoids, minerals, vitamins, and bioactive peptides, are highlighted for their potential in promoting well-being and mitigating chronic diseases. Additionally, the review explores the functionality of food components within these products, emphasizing the critical roles of bioaccessibility, bioactivity, and bioavailability in promoting health. The importance of considering key aspects in the design of enhanced poultry diets for functional food production is thoroughly reviewed. The safety of these foods through the establishment of regulations and guidelines was reviewed. It is concluded that the integration of nutrition by design principles empowers individuals to make informed choices that can prioritize their health and well-being. By incorporating functional foods rich in bioactive compounds, consumers can proactively take steps to prevent and manage health issues, ultimately contributing to a healthier society and lifestyle.

Oral intake of collagen peptide NS improves hydration, elasticity, desquamation, and wrinkling in human skin: a randomized, double-blinded, placebo-controlled study

Collagen hydrolysate, which contains bioactive peptides, is used as a dietary supplement for the refinement of elasticity, hydration, desquamation, and wrinkling of aging human skin. Here, we conducted a double-blind, randomized, and placebo-controlled oral administration study on the effects of a collagen peptide (CPNS) containing dipeptides, including Gly-Pro and Pro-Hyp, on skin wrinkling, desquamation, elasticity, and hydration. Our results show that an intake of 1650 mg per day of CPNS for 12 weeks had beneficial effects on skin health in a cohort of women aged from 30 to 60 years (n = 100). Compared with the placebo group, skin desquamation, hydration, skin wrinkling, and elasticity were significantly improved after 4, 4, 12, and 12 weeks of administration, respectively. In a safety test of CPNS ingestion, none of the participants showed any side effects during the clinical study period. These results demonstrate that the low molecular weight bioactive peptides contained in CPNS, such as Gly-Pro and Pro-Hyp, exert positive effects on skin hydration, elasticity, desquamation, and wrinkling.

The Effects of Spirulina maxima Extract on Memory Improvement in Those with Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Spirulina maxima is a marine microalga that has been promoted worldwide as a super food. This study was conducted to evaluate its ability to improve memory in the older adults using Spirulina maxima 70% ethanol extract (SM70EE). This randomized, double-blind, placebo-controlled clinical trial comprised 80 volunteers recruited from Jeonbuk National University Hospital in Jeonju, Republic of Korea, who were randomly assigned to two groups. The participants received either 1 g/day of SM70EE or a placebo without otherwise changing their diet or physical activity. The participants were examined at baseline and after a 12-week interval to determine whether there were changes in their results for visual learning, visual working memory, and verbal learning tests from the Korean version of the Montreal Cognitive Assessment, brain-derived neurotrophic factor and beta-amyloid levels, and total antioxidant capacity. Compared to the placebo group, the treatment group showed a significant improvement in visual learning and visual working memory test results and enhanced vocabulary. SM70EE use was shown to improve memory, with no adverse effects. Its efficacy in alleviating Alzheimer’s disease symptoms was verified for the first time through this clinical trial. SM70EE could play a role in the management of patients with dementia. This trial is registered with registration number of clinical research information service (CRIS: KCT0006161).

Use of food and food-derived products in the treatment of gastritis: A systematic review

Gastritis is the acute or chronic inflammation of gastric mucosa and is triggered by diverse factors. Treatments used for non-bacterial gastritis include proton pump inhibitors, histamine H2 receptor inhibitors, and antacids, and their use is linked to various side effects. Research on alternative therapeutics using food or food-based products is extensive, mostly in preclinical research. We aimed at documenting the clinical advances in food-based therapies as alternative therapeutics for gastritis. Articles with information on the treatment of gastritis with food or food-based products published until December 1, 2020 were identified through a systematic search in PubMed Medline Database. Additionally, references of retrieved articles were screened for relevant reviews and meta-analyses. Two investigators independently selected and reviewed the titles and abstracts of articles and extracted the study characteristics (PICO framework) and key findings. Dual quality assessment and data extraction were performed. We found 28 clinical studies evaluating garlic, turmeric, red peppers, broccoli sprouts, cranberry juice, honey, oils, and probiotics contained in different foods, such as juices, yogurt, and cheese. The existing literature presents a high risk of bias, and results of the same should be evaluated and replicated with precaution; more rigorous clinical studies are lacking.

Effects of sesame, canola and sesame-canola oils on body weight and composition in adults with type 2 diabetes mellitus: a randomized, triple-blind, cross-over clinical trial

BACKGROUND

Recent investigations have proposed that sesame and canola oils might affect body fat distribution. The present study aimed to examine the effects of sesame, canola and sesame-canola (a blend of sesame and canola oils) oils on body weight and composition in adults with type 2 diabetes mellitus in the context of a randomized, triple-blind, three-way, cross-over clinical trial.

RESULTS

Eligible participants were randomized to replace their regular dietary oil with sesame oil (SO), canola oil (CO) and sesame-canola oil (SCO) (with 40% SO and 60% CO). Treatment periods lasted 9 weeks and were separated by 4-week wash-out periods. Body weight and composition were measured at the beginning, in the middle and at the end of each intervention phase. In total, 93 participants completed the study. After adjustment for confounders, within-period changes were observed following SO and CO intake for body weight (0.34 ± 0.16 kg and 0.33 ± 0.17 kg) and visceral fat (0.13 ± 0.06% and 0.13 ± 0.05%, P < 0.05), respectively. Body mass index was increased within SO intake (0.13 ± 0.05 kg m^-2 , P = 0.031). All of the treatment oils resulted in reduced waist circumference and index of central obesity (P < 0.05). A significant difference in change values was observed for visceral fat between SCO (-0.14 ± 0.07%) and SO (0.12 ± 0.08%) treatment periods in females (P = 0.02).

CONCLUSION

Sesame and canola oils might lead to a modest favorable body fat redistribution by reducing central adiposity, particularly in females; however, the changes were of little clinical importance. © 2021 Society of Chemical Industry.

Common Bean Baked Snack Consumption Reduces Apolipoprotein B-100 Levels: A Randomized Crossover Trial

Snack alternatives based on common beans (Phaseolus vulgaris L.) have been developed to promote pulse consumption. The purpose of this study was to evaluate the chemical composition, sensory acceptance and the effect of common bean baked snack (CBBS) consumption on blood lipid levels in participants with overweight and altered blood lipid levels. A sensory evaluation by 80 untrained judges was carried out using a hedonic scale. A randomized crossover 2 × 2 trial was performed, where 20 participants with overweight and one blood lipid alteration consumed 32 g of CBBS or did not consume it (control) for four weeks. Blood samples were taken to quantify the triglycerides, total cholesterol, LDL-c, HDL-c, ApoB-100, glucose and insulin. Furthermore, anthropometric, dietary and physical activity parameters were recorded. The overall acceptance of CBBS was similar compared to popcorn (p > 0.05). The consumption of CBBS reduced the apolipoprotein B-100 levels (p = 0.008). This reduction could be associated with the additional dietary fiber consumption during the CBBS period (p = 0.04). Although it did not improve any other blood lipid or glucose parameters (p > 0.05), it did not affect them either, which means that the CBBS could be consumed without compromising cardiovascular health.

Lipid-modifying effects of lean fish and fish-derived protein consumption in humans: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

Consumption of lean fish and fish-derived proteins were effective for improving lipid profiles in published studies; however, evidence remains inconclusive.

OBJECTIVE

To evaluate the effectiveness of lean fish or fish-derived protein on serum/plasma lipid and lipoprotein levels by conducting a systematic review of the literature and meta-analysis of available randomized controlled trials (RCTs).

DATA SOURCES

Medline (Ovid), Scopus, CINAHL, and Food and Nutritional Sciences databases were searched from the start date of each database to September 2019 to identify RCTs determining the effect of lean fish on lipid profile.

STUDY SELECTION INCLUDED

RCTs investigated lean fish and fish-derived proteins intake and determined at least 1 major lipid or lipoprotein measurement.

DATA EXTRACTION

Two reviewers independently evaluated 1217 studies against the inclusion and exclusion criteria. Relevant studies were assessed for risks of bias, and random-effects meta-analysis was conducted to generate average estimates of effect.

RESULTS

A total of 24 studies met the inclusion criteria. Meta-analysis of data from 18 to 21 eligible crossover and parallel-design RCTs with a total of 1392 to 1456 participants found triacylglycerol-lowering effects for lean fish compared with no fish consumption. Lean fish intake showed no significant differences related to total cholesterol or lipoprotein levels. Subanalysis showed that parallel-group RCTs tended to find greater reduction effects on circulating triacylglycerol than did crossover RCTs.

CONCLUSION

Additional better-designed, longer, and larger RCTs, particularly crossover RCTs, are needed to clarify the impact of lean fish and fish proteins on the serum/plasma lipid profile. Findings from such studies would enable practitioners to provide their patients evidence-based recommendations to meet the American Heart Association guidelines for fish consumption to reduce cardiovascular disease risk.

A digital scheme of human trials for the evaluation of functional foods

In this study, we designed a method for conducting a human study by the following process. (1) The host computer stores the subject information. (2) The sample preparer prepares a food sample. (3) The subject (healthy human volunteer) sends the information of an intake of the food sample to the host computer, which creates an event entry for the event. (4) The medical professional (typically a physician) collects and stores the subject's blood sample in a container with the subject's identification (e.g., ID number). (5) The sample analyst analyzes the blood biochemical profiles. (6)The host computer stores the blood biochemical data, and by matching the blood biochemical data with the subject IDs, a final analysis report will automatically be created. In this study, we also run a test case, based on this design, where we obtained a blood biochemical dataset from healthy volunteers. This scheme can reduce the cost of human trials for functional foods and will help acquiring the scientific basis of functional foods.

Resveratrol: A "miracle" drug in neuropsychiatry or a cognitive enhancer for mice only? A systematic review and meta-analysis

BACKGROUND

Over the last decade resveratrol has been trialled for the prevention and treatment of cognitive decline; however, the results have shown a conflict between human studies compared with animal studies, especially on cognition, blood pressure, neuroimaging, and mood.

METHODS

Human clinical trials and animal studies published prior to January 2020, were identified searching across major electronic databases. PRISMA guidelines were used for data extraction, which was independently performed by two authors. Pooled standard mean difference (SMD, random effect model) and odds ratios (ORs) were calculated.

RESULTS

Most publications on animal models reported positive outcomes on cognition and brain function following exposure to resveratrol or grape seed extracts. By contrast, 11 meta-analyses of data from human placebo vs resveratrol, grape or wine treatment trials identified no statistically significant effect on a variety of measures, including cognitive and mood assessments, grey matter volume and blood pressure.

CONCLUSIONS

Based on currently available data, the promising effects of resveratrol in animal models is not replicated in human clinical trials. The effects, if any, of resveratrol on human cognition are likely to be small. This work may be useful for the design and implementation of future pre-clinical and clinical studies using resveratrol in a neurological setting.

The Efficacy of Squalene in Cardiovascular Disease Risk-A Systematic Review

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of death worldwide. Squalene (SQ), an intermediate for the cholesterol biosynthesis, has been proposed to act similarly to statins via inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in the liver.

PURPOSE

This paper explores the effects of SQ in CVD.

METHODS

A systematic review of the literature was performed to identify relevant studies about SQ and CVD. A comprehensive search in Medline and Scopus for relevant studies published between the years 1946 and 2019 was performed. The main inclusion criteria were that the study was published in English; that the study reported association or effect of SQ and CVD; and that CVD should be related to lifestyle variables, aging, or experimentally induced conditions.

RESULTS

The literature searches identified 5562 potentially relevant articles, whereby 21 studies met the inclusion criteria. There were three human studies and 18 animal experimental studies included in this paper. Only one human study reported positive outcome of SQ in CVD. The remaining two studies reported inconsistent and/or no effect. For animal studies, 15 studies reported positive effect while the remaining reported negative and/or no effect of SQ on various related parameters.

CONCLUSIONS

This evidence-based review emphasizes the potential of SQ being used for cardiovascular-related diseases. The effect of SQ, especially of plant-based warrants further exploration. Controlled human observational studies should be performed to provide comprehensive evidence.

Roles of Phenolic Compounds in the Reduction of Risk Factors of Cardiovascular Diseases

The population is now living longer during the period classified as "elderly" (60 years and older), exhibiting multimorbidity associated to the lengthening of the average life span. The dietary intake of phenolic compounds (PC) may affect the physiology, disease development and progression during the aging process, reducing risk factors of age related diseases. The aim of this review is to briefly describe some of the possible effects of a series of PC on the reduction of risk factors of the onset of cardiovascular diseases, considering their potential mechanisms of action. The main actions described for PC are associated with reduced platelet activity, anti-inflammatory effects, and the protection from oxidation to reduce LDL and the generation of advanced glycation end products. Preclinical and clinical evidence of the physiological effects of various PC is presented, as well as the health claims approved by regulatory agencies.

Diets Low in Saturated Fat with Different Unsaturated Fatty Acid Profiles Similarly Increase Serum-Mediated Cholesterol Efflux from THP-1 Macrophages in a Population with or at Risk for Metabolic Syndrome: The Canola Oil Multicenter Intervention Trial

Background

Cholesterol efflux plays an important role in preventing atherosclerosis progression. Vegetable oils with varying unsaturated fatty acid profiles favorably affect multiple cardiovascular disease risk factors; however, their effects on cholesterol efflux remain unclear.

Objective

The objectives of this study were to examine the effects of diets low in saturated fatty acids (SFAs) with varying unsaturated fatty acid profiles on serum-mediated cholesterol efflux and its association with the plasma lipophilic index and central obesity.

Methods

The present study is a randomized, crossover, controlled-feeding study. Participants [men: n = 50; women: n = 51; mean ± SE age: 49.5 ± 1.2 y; body mass index (in kg/m2): 29.4 ± 0.4] at risk for or with metabolic syndrome (MetS) were randomly assigned to 5 isocaloric diets containing the treatment oils: canola oil, high oleic acid-canola oil, DHA-enriched high oleic acid-canola oil, corn oil and safflower oil blend, and flax oil and safflower oil blend. These treatment oils were incorporated into smoothies that participants consumed 2 times/d. For a 3000-kcal diet, 60 g of treatment oil was required to provide 18% of total energy per day. Each diet period was 4 wk followed by a 2- to 4-wk washout period. We quantified cholesterol efflux capacity with a validated ex vivo high-throughput cholesterol efflux assay. Statistical analyses were performed with the use of the SAS mixed-model procedure.

Results

The 5 diets increased serum-mediated cholesterol efflux capacity from THP-1 macrophages similarly by 39%, 34%, 55%, 49% and 51%, respectively, compared with baseline (P < 0.05 for all). Waist circumference and abdominal adiposity were negatively correlated with serum-mediated cholesterol efflux capacity (r = -0.25, P = 0.01, r = -0.33, P = 0.02, respectively).

Conclusion

Diets low in SFAs with different monounsaturated fatty acid and polyunsaturated fatty acid profiles improved serum-mediated cholesterol efflux capacity in individuals with or at risk for MetS. This mechanism may account, in part, for the cardiovascular disease benefits of diets low in SFAs and high in unsaturated fatty acids. Importantly, central obesity is inversely associated with cholesterol efflux capacity. This trial was registered at www.clinicaltrials.gov as NCT01351012.

Health Claims and Methodological Controversy in Nutrition Science

This article analyzes the debate about data acquisition and assessment in health claims regulation by identifying the underlying controversies on methodological choice. Regulation in the European Union imposes the need for a scientific substantiation of all health claims (claims about a relationship between consumption of certain food ingredients and positive health effects). Randomized controlled trials (RCTs) are the method that generally is considered to provide the highest quality data for decision making in claims regulation because they allow for establishing cause-effect relationships. The latter are demanded in European regulatory practice for authorization of a claim. This requirement has contributed to a debate about the advantages and limitations of the RCT methodology in nutrition research and regulation. Our analysis identifies five types of tensions that underlie the controversy, with respect to evidence, cognitive values, standards of proof, future lines of research, as well as expert judgment. We conclude that there is a direct and mutual interaction between methodological decisions in nutrition science, and different strategies in health claims regulation. The latter have social and public health consequences because not only may they affect the European market for functional foods, as well as concomitant consumption patterns, but also the generation of future regulation-relevant evidence in nutrition.

Effects of canola and high-oleic-acid canola oils on abdominal fat mass in individuals with central obesity

OBJECTIVE

To determine the effect of diets low in saturated fatty acids and high in monounsaturated fatty acids (MUFA) or polyunsaturated fatty acids on body composition in participants at risk for metabolic syndrome (MetS).

METHODS

This study was a randomized, crossover, controlled feeding study. Participants (n = 101, ages 49.5 ± 1.2, BMI 29.4 ± 0.4 kg/m² ) were randomized to five isocaloric diets containing treatment oils: Canola, CanolaOleic, CanolaDHA, Corn/Safflower, and Flax/Safflower. Each diet period was 4 weeks followed by a 2- to 4-week washout period.

RESULTS

Canola (3.1 kg, P = 0.026) and CanolaOleic oil diets (3.09 kg, P = 0.03) reduced android fat mass compared with the Flax/Saff oil diet (3.2 kg), particularly in men. The decrease in abdominal fat mass was correlated with the reduction in blood pressure after the Canola (systolic blood pressure: r = 0.26, P = 0.062; diastolic blood pressure: r = 0.38, P = 0.0049) and CanolaOleic oil diets (systolic blood pressure: r = 0.39 P = 0.004; diastolic blood pressure: r = 0.45, P = 0.0006). The decrease in abdominal fat mass also was associated with a reduction in triglyceride levels after the CanolaOleic oil diet (r = 0.42, P = 0.002).

CONCLUSIONS

Diets high in MUFA (compared with PUFA) reduced central obesity with an accompanying improvement in MetS risk factors. Diets high in MUFA may be beneficial for treating and perhaps preventing MetS.

High Molecular Weight Barley β-Glucan Alters Gut Microbiota Toward Reduced Cardiovascular Disease Risk

The physiological cholesterol-lowering benefits of β-glucan have been well documented, however, whether modulation of gut microbiota by β-glucan is associated with these physiological effects remains unknown. The objectives of this study were therefore to determine the impact of β-glucan on the composition of gut microbiota in mildly hypercholesterolemic individuals and to identify if the altered microbiota are associated with bioactivity of β-glucan in improving risk factors of cardiovascular disease (CVD). Using a randomized, controlled crossover study design, individuals received for 5-week either a treatment breakfast containing 3 g high molecular weight (HMW), 3 g low molecular weight (LMW), 5 g LMW barley β-glucan, or wheat and rice. The American Heart Association (AHA) diet served as the background diet for all treatment groups. Phases were separated by 4-week washout periods. Fecal samples were collected at the end of each intervention phase and subjected to Illumina sequencing of 16S rRNA genes. Results revealed that at the phylum level, supplementation of 3 g/d HMW β-glucan increased Bacteroidetes and decreased Firmicutes abundances compared to control (P < 0.001). At the genus level, consumption of 3 g/d HMW β-glucan increased Bacteroides (P < 0.003), tended to increase Prevotella (P < 0.1) but decreased Dorea (P < 0.1), whereas diets containing 5 g LMW β-glucan and 3 g LMW β-glucan failed to alter the gut microbiota composition. Bacteroides, Prevotella, and Dorea composition correlated (P < 0.05) with shifts of CVD risk factors, including body mass index, waist circumference, blood pressure, as well as triglyceride levels. Our data suggest that consumption of HMW β-glucan favorably alters the composition of gut microbiota and this altered microbiota profile associates with a reduction of CVD risk markers. Together, our study suggests that β-glucan induced shifts in gut microbiota in a MW-dependent manner and that might be one of the underlying mechanisms responsible for the physiological benefits of β-glucan.

Consumption of low-fat dairy foods for 6 months improves insulin resistance without adversely affecting lipids or bodyweight in healthy adults: a randomized free-living cross-over study

Background

Given the highly debated role of dairy food consumption in modulating biomarkers of metabolic syndrome, this study was conducted to examine the influence of long-term (6 month) dairy consumption on metabolic parameters in healthy volunteers under free-living conditions without energy restriction.

Methods

Twenty-three healthy subjects completed a randomized, crossover trial of 12 months. Participants consumed their habitual diets and were randomly assigned to one of two treatment groups: a high dairy supplemented group instructed to consume 4 servings of dairy per day (HD); or a low dairy supplemented group limited to no more than 2 servings of dairy per day (LD). Baseline, midpoint, and endpoint metabolic responses were examined.

Results

Endpoint measurements of body weight and composition, energy expenditure, blood pressure, blood glucose, and blood lipid and lipoprotein responses did not differ (p > 0.05) between the LD and HD groups. HD consumption improved (p < 0.05) plasma insulin (-9%) and insulin resistance (-11%, p = 0.03) as estimated by HOMA-IR compared with the LD group.

Conclusions

Study results suggest that high dairy consumption (4 servings/d) may improve insulin resistance without negatively impacting bodyweight or lipid status under free-living conditions.

Trial registration

Trial registration: NCT01761955

Effect of high-oleic canola and flaxseed oils on energy expenditure and body composition in hypercholesterolemic subjects

OBJECTIVE

The fatty acid profile of dietary fats may contribute to its channelling toward oxidation versus storage, influencing energy and weight balance. Our objective was to compare the effects of diets enriched with high-oleic canola oil (HOCO), alone or blended with flaxseed oil (FXCO), on energy expenditure, substrate utilization, and body composition versus a typical Western diet (WD).

MATERIALS/METHODS

Using a randomized crossover design, 34 hypercholesterolemic subjects (n=22 females) consumed 3 controlled diets for 28 days containing ~49% energy from carbohydrate, 14% energy from protein, and 37% energy from fat, of which 70% of fat was provided by HOCO rich in oleic acid, FXCO rich in alpha-linolenic acid, or WD rich in saturated fat. Indirect calorimetry measured energy expenditure and substrate oxidation. Body composition was analyzed by dual-energy x-ray absorptiometry.

RESULT

After 28 days, resting and postprandial energy expenditure and substrate oxidation were not different after consumption of the HOCO or FXCO diets compared with a typical Western diet. No significant changes in body composition measures were observed between diets. However, the android-to-gynoid ratio tended to increase (P=.055) after the FXCO diet compared with the HOCO diet.

CONCLUSIONS

The data suggest that substituting a typical Western dietary fatty acid profile with HOCO or FXCO does not significantly modulate energy expenditure, substrate oxidation or body composition in hypercholesterolemic males and females.

Guidelines for the design, conduct and reporting of human intervention studies to evaluate the health benefits of foods

There is substantial evidence to link what we eat to the reduction of the risk of major chronic diseases and/or the improvement of functions. Thus, it is important for public health agencies and the food industry to facilitate the consumption of foods with particular health benefits by providing consumer products and messages based on scientific evidence. Although fragmentary advice is available from a range of sources, there is a lack of comprehensive scientific guidelines for the design, conduct and reporting of human intervention studies to evaluate the health benefits of foods. Such guidelines are needed both to support nutrition science in general, and to facilitate the substantiation of health claims. In the present study, which presents the consensus view of an International Life Sciences Institute Europe Expert Group that included senior scientists from academia and industry, the term 'foods' refers to foods, dietary supplements and food constituents, but not to whole diets. The present study is based on an initial survey of published papers, which identified the range and strengths and weaknesses of current methodologies, and was finalised following exchanges between representatives from industry, academia and regulatory bodies. The major factors involved in the design, conduct and reporting of studies are identified, summarised in a checklist table that is based on the Consolidated Standards of Reporting Trials guidelines, and elaborated and discussed in the text.

Design considerations on the proof of efficacy of functional foods

Functional food research encompasses several types of study designs, including observational studies and randomized clinical trials (RCTs). Markers that can predict potential benefits or risks relating to certain health conditions are often the primary endpoints of such studies since a direct measurement of the effect of food on health and well-being and/or reduction of disease risk is often not possible. Whether RCT should be at the top of the pyramid also in nutritional research remains a controversial issue. Undoubtedly, further research is needed to redesign RCT methodology that would adequately serve the need to demonstrate the health effects of foods. We address this functional food research question by assuming that there is a known relationship between the surrogate and the true endpoint explored during the surrogacy assessment. Statistical inference on the true (unobserved) endpoint is derived on the basis of its predicted values. We illustrate this approach through a motivating example from the literature on coronary heart disease, integrated with simulated scenarios.