Scientific Opinion on the safety of “conjugated linoleic acid (CLA)-rich oil” (Clarinol®) as a Novel Food ingredient

Guidance on the scientific requirements for an application for authorisation of a novel food in the context of Regulation (EU) 2015/2283

The European Commission requested EFSA to update the scientific guidance for the preparation of applications for authorisation of novel foods, previously developed following the adoption of Regulation (EU) 2015/2283 on novel foods. This guidance document provides advice on the scientific information needed to be submitted by the applicant towards demonstrating the safety of the novel food. Requirements pertain to the description of the novel food, production process, compositional data, specifications, proposed uses and use levels and anticipated intake of the novel food. Furthermore, information needed in sections on the history of use of the novel food and/or its source, absorption, distribution, metabolism, excretion, toxicological information, nutritional information and allergenicity is also described. The applicant should integrate and interpret the data presented in the different sections to provide their overall considerations on how the information supports the safety of the novel food under the proposed conditions of use. Where potential health hazards have been identified, they are to be discussed in relation to the anticipated intake of the novel food and the proposed target populations. On the basis of the information provided, EFSA will assess the safety of the novel food under the proposed conditions of use.

Major dietary lipids in nutrition and health

In this chapter, an overview of the major lipids in the diet with emphasis in nutritional aspects is provided. Triacylglycerols, i.e., glycerol esterified with three fatty acids, are the predominant constituents in dietary lipids. Therefore, this chapter focuses on the nature and nutritional significance of the main fatty acids in the diet and their possible modifications during food processing and commercialization. The main fatty acids in dietary lipids are grouped into saturated, monounsaturated and polyunsaturated fatty acids. Nutritional implications, the latest intervention trials and health recommendations will be discussed. A brief description of the major sources of lipids in the diet is included, oils and fats standing out. Other food sources shortly commented are milk and dairy products, meat, poultry and eggs, fish, and structured lipids designed to improve functional and nutritional properties. Modifications of fatty acids as a result of processing and commercialization are discussed because of their great relevance for their health implications, especially oxidation compounds and trans fatty acids.

Effects of sucrose and sodium chloride pretreatments on cassava and plantain chips fried in CLA-enriched soybean oil: an analysis of acrylamide content, microstructure, and other physical properties

The purpose of this research was to evaluate the effect of soaking plantain and cassava chips in sucrose or sodium chloride (NaCl) on their physical properties and acrylamide content after frying in Conjugated Linoleic Acid (CLA)-enriched soybean oil. Plantain and cassava were cut into 1 mm thick slices and soaked for 20 min in a solution of 30% sucrose or 3% NaCl at 40 °C, separately. Soaking in sucrose and NaCl had no significant effect (p < 0.05) on water loss, porosity, hardness, or microstructure. The acrylamide content ranged from 634 to 3177 µg/kg. The use of CLA-enriched oil had no significant effect (p < 0.05) on the physical characteristics evaluated in this study. Frying reduced the CLA content in the chips from an initial 31.8% in the oil to 22.25 and 21.69% in plantain and cassava chips, respectively.

Measuring Conjugated Linoleic Acid (CLA) Production by Bifidobacteria

The biological significance of conjugated fatty acids (CFAs) has been linked to positive health effects based on biomedical, in vitro, and clinical studies. Of note, conjugated linoleic acids (CLAs) are the most widely characterized fatty acids as geometric isomers cis-9,trans-11 and trans-10,cis-12 CLA occur naturally in ruminant fats, dairy products, and hydrogenated oils. Concerning CLAs, it is known that bacterial biohydrogenation, a process whereby ruminal bacteria or starter cultures of lactic acid bacteria have the ability to synthesize CLA by altering the chemical structure of essential fatty acids via enzymatic mechanisms, produces a multitude of isomers with desirable properties. Bifidobacterium species are classed as food grade microorganisms and some of these strains harness molecular determinants that are responsible for the bioconversion of free fatty acids to CLAs. However, molecular mechanisms have yet to be fully elucidated. Reports pertaining to CLAs have been attributed to suppressing tumor growth, delaying the onset of diabetes mellitus and reducing body fat in obese individuals. Given the increased attention for their bioactive properties, we describe in this chapter the qualitative and quantitative methods used to identify and quantify CLA isomers produced by bifidobacterial strains in supplemented broth media. These approaches enable rapid detection of potential CLA producing strains and accurate measurement of fatty acids in biological matrices.

A multifunctional ingredient for the management of metabolic syndrome in cafeteria diet-fed rats

The body weight-lowering properties of a multifunctional ingredient (MIX) based on conjugated linoleic acid at low doses, the flavonoids proanthocyanidins and anthocyanidins and the chicken feet hydrolysate Hpp11 have been previously reported. The aim of this study was to evaluate the effect of long-term administration of MIX on other cardiometabolic risk factors associated with metabolic syndrome (MetS) in rats fed a cafeteria diet (CAF). Male Wistar rats were fed CAF for 11 weeks, and during the last 3 weeks, animals were orally administered MIX or vehicle. Lipid tolerance tests were performed before and after MIX administration. At the end of the experimental period, serum and inguinal white adipose tissue (iWAT) metabolism were analyzed by metabolomics and biochemical approaches. The metabolite signature of serum and iWAT significantly changed after 3 weeks of MIX administration, suggesting an improvement in lipid and glucose homeostasis in these animals. In addition, MIX also exhibited significant antihypertensive properties. These results suggest that MIX could be a good candidate to ameliorate the cardiometabolic risk factors related to MetS.

Novel foods in the European Union: Scientific requirements and challenges of the risk assessment process by the European Food Safety Authority

The European Food Safety Authority (EFSA) has been involved in the risk assessment of novel foods since 2003. The implementation of the current novel food regulation in 2018 rendered EFSA the sole entity of the European Union responsible for such safety evaluations. The risk assessment is based on the data submitted by applicants in line with the scientific requirements described in the respective EFSA guidance document. The present work aims to elaborate on the rationale behind the scientific questions raised during the risk assessment of novel foods, with a focus on complex mixtures and whole foods. Novel foods received by EFSA in 2003-2019 were screened and clustered by nature and complexity. The requests for additional or supplementary information raised by EFSA during all risk assessments were analyzed for identifying reoccurring issues. In brief, it is shown that applications concern mainly novel foods derived from plants, microorganisms, fungi, algae, and animals. A plethora of requests relates to the production process, the compositional characterization of the novel food, and the evaluation of the product's toxicological profile. Recurring issues related to specific novel food categories were noted. The heterogeneous nature and the variable complexity of novel foods emphasize the challenge to tailor aspects of the evaluation approach to the characteristics of each individual product. Importantly, the scientific requirements for novel food applications set by EFSA are interrelated, and only a rigorous and cross-cutting approach adopted by the applicants when preparing the respective application dossiers can lead to scientifically sound dossiers. This is the first time that an in-depth analysis of the experience gained by EFSA in the risk assessment of novel foods and of the reasoning behind the most frequent scientific requests by EFSA to applicants is made.

Beneficial Effects of a Low-dose of Conjugated Linoleic Acid on Body Weight Gain and other Cardiometabolic Risk Factors in Cafeteria Diet-fed Rats

Conjugated linoleic acid (CLA) is a dietary supplement that has been shown to improve obesity. However, some authors have associated high doses of CLA supplementation with liver impairment and insulin resistance. The aim of this study was to assess whether the consumption of low doses of CLA maintained the beneficial effects on the main metabolic disturbances associated with metabolic syndrome (MetS) but prevented the occurrence of non-desirable outcomes associated with its consumption. Male Wistar rats, fed standard or cafeteria (CAF) diet for 12 weeks, were supplemented with three different low doses of CLA in the last three weeks. Both biochemical and H¹ NMR-based metabolomics profiles were analysed in serum and liver. The consumption of 100 mg/kg CLA, but not doses of 200 and 300 mg/kg, ameliorated the increase in body weight gain as well as the serum concentrations of glucose, insulin, cholesterol, triglyceride, diglyceride, and total phospholipid induced by a CAF diet. In turn, CLA reverted the increase in lactate, alanine, and glucose concentrations in the liver of these animals, but enhanced hepatic cholesterol accumulation without any detrimental effect on liver function. In conclusion, a low dose of CLA corrected the adverse effects associated with MetS without compromising other metabolic parameters.

CLA-supplemented diet accelerates experimental colorectal cancer by inducing TGF-β-producing macrophages and T cells

Conjugated linoleic acid (CLA) has been shown to activate the nuclear receptor PPAR-γ and modulate metabolic and immune functions. Despite the worldwide use of CLA dietary supplementation, strong scientific evidence for its proposed beneficial actions are missing. We found that CLA-supplemented diet reduced mucosal damage and inflammatory infiltrate in the dextran sodium sulfate (DSS)-induced colitis model. Conditional deletion of PPAR-γ in macrophages from mice supplemented with CLA diet resulted in loss of this protective effect of CLA, suggesting a PPAR-γ-dependent mechanism mediated by macrophages. However, CLA supplementation significantly worsened colorectal tumor formation induced by azoxymethane and DSS by inducing macrophage and T-cell-producing TGF-β via PPAR-γ activation. Accordingly, either macrophage-specific deletion of PPAR-γ or in vivo neutralization of latency-associated peptide (LAP, a membrane-bound TGF-β)-expressing cells abrogated the protumorigenic effect of CLA. Thus, the anti-inflammatory properties of CLA are associated with prevention of colitis but also with development of colorectal cancer.

In-vitro toxicological and proteomic analysis of furan fatty acids which are oxidative metabolites of conjugated linoleic acids

Furan fatty acids (furan-FA) are oxidative products of conjugated linoleic acids (CLA) and may therefore be ingested when CLA-containing food or food-additives are consumed. Due to the presence of a furan ring structure the question arises whether furan-FA may have toxic properties on enterocytes and liver cells. Here we show that furan-FA neither have toxic effects in human colon cancer cell line Caco-2 nor in human hepatoma cell line HepG2 at concentrations that could be relevant for humans. At concentrations up to 100 μM, all tested furan-FA isomers showed no pronounced cytotoxicity and did not affect cellular proliferation or apoptosis up to concentrations of 500 μM. In addition, furan-FA was neither genotoxic in the micronucleus test using Chinese hamster lung fibroblasts (V79) nor in the Ames test independent of the presence or absence of rat liver homogenate for enzymatic activation of the furan ring structure. A proteomic approach revealed that 48 proteins were differentially expressed when Caco-2 cells were incubated with up to 1 mM of 10,13-epoxy-10,12-octadecadienoic acid (10,12-furan-FA). Three of the 30 proteins that could be identified by MALDI-TOF analysis were upregulated and were associated with lipid droplet biogenesis. The remaining 27 proteins were downregulated and were considered to be associated with general cellular processes such as DNA replication and transcription, protein biosynthesis and protein processing, lipid and energy metabolism. From the proteomic data we conclude that furan-FA is predominantly stored in lipid droplets thereby downregulating cellular metabolic activity and driving the cells into a state of rest.