Quality Of Dietary Supplements Research Articles

Analytical Assessment of the Quality of Dietary Supplements and Cosmetic Products Containing Xanthohumol by Thin-Layer Chromatography Along with the Estimation of Its Antioxidant Potential

Xanthohumol, a prenylated chalcone in the flavonoid group, naturally occurs in many plants and exhibits antioxidant, anticancer, anti-inflammatory, antibacterial, and antiviral effects. The growing interest in xanthohumol due to its potential therapeutic properties has led to the increase in the pool of products available on the market. The novelty of this study is the proposal of a rapid and cost-effective procedure useful for performing quality control on products containing xanthohumol in the form of dietary supplements and cosmetics as well as testing their stability. For this purpose, the thin-layer chromatography method with densitometric detection was used, which was validated in accordance with ICH (International Conference on Harmonization) guidelines. The mobile phase was toluene, 1,4-dioxane, and glacial acetic acid (37:10:1.5 v/v/v), and TLC silica gel 60 F254 plates were used as the stationary phase. The validation process assessed linearity, with a correlation coefficient (r) of 0.9987. The calculated LOD (limit of detection) and LOQ (limit of quantification) values were 3.82 and 11.57 ng/spot, respectively. Accuracy was evaluated by determining percentage recovery at three concentration levels (80, 100, and 120%), with an average recovery of 100% and RSD below 1%, confirming good accuracy. Precision was indicated by an RSD of less than 2.20%. The average content of xanthohumol in dietary supplements ranged from about 8 to 29% of the content declared by the manufacturers. The stability tests showed that XN decomposes most slowly in water (t0.5 = 10.86 h) compared with acidic (t0.5 = 10.80 h) and alkaline solutions (t0.5 = 7.39 h), as well as in the presence of an oxidizing agent (t0.5 = 18.38 h), at all tested temperatures, which is confirmed by the calculated kinetic parameters. In the tests of antioxidant capacity, xanthohumol shows significantly higher radical scavenging capacity than vitamin C in the entire range of analyzed concentrations (0.03–2.40 mmol/L).

Pharmaceutical availability testing − can a drug-specific test be relevant for assessing the quality of dietary supplements?

Our current novel analytical approach focuses on testing the quality of dietary supplements. Specifically, we examine the release of substances such as proline, tryptophan, tyrosine, carnitine, and vitamin C sourced from the EU, Switzerland, and the USA.In tablet-form supplements, release levels were low in both pharmacopoeial dissolution tests (Trp5 – 23%; Trp6 – 12%; VitC4 – 23%) and those simulating biorelevant conditions (Trp5 – 53%; Trp6 – 24%; VitC4 – 68%). The implementation of biorelevant conditions PhysioCell for capsule-form supplements led to an enhanced release of substances (from 11 to 106 percentage points) compared to pharmacopoeial dissolution tests. This indicates that the release of their active substance is strongly influenced by gastrointestinal motility, which, due to its high intra- and inter-individual variability, will result in inconsistent and unpredictable release and biological response.Thus, pharmacopeial methods serves as a reliable screening approach for the quality of dietary supplements.

Application of In Vitro Digestion Models in the Evaluation of Dietary Supplements.

Nowadays, dietary supplements are a permanent part of our diet. Using various simulated in vitro digestive models, the bioavailability of dietary supplement ingredients has also been investigated. In most cases, static models are used instead of dynamic ones. This article focuses on the division of applications of in vitro methods, such as assessing the quality of dietary supplements (in chemical and pharmaceutical form), the impact of diet on the assessment of the bioavailability of product ingredients, the impact of supplement ingredients on the state of intestinal microflora, and the development of new products using various encapsulation methods. The review included publications from 2000 to 2024 showing the use of in vitro methods in dietary supplements containing polysaccharides, proteins, elements, vitamins, and bioactive substances, as well as probiotic and prebiotic products. The impact of components in dietary supplements on the human digestive tract and their degree of bioaccessibility were determined through the use of in vitro methods. The application of in vitro methods has also become an effective tool for designing new forms of dietary supplements in order to increase the availability and durability of labile ingredients in these products.

Solid state NMR study of the bioenhancer piperine, supported by GIPAW DFT calculations

Piperine, an alkaloid found in black pepper fruits, has the properties of promoting the absorption of other substances (e.g. curcumin), therefore it is used in solid forms of dietary supplements as an additive increasing bioavailability. The aim of the study was to analyze piperine in a solid state and then to use it in the analysis of solid dietary supplements with the addition of piperine as an absorption promoter. The 13C CP MAS NMR spectra were recorded using variable contact time and dipolar dephasing experiment. The calculation of theoretical chemical shift values for three polymorphic forms of piperine allowed us to create a database of NMR parameters enabling the identification of polymorphic forms based on the analysis of the 13C CP MAS NMR spectrum. Additionally, the analysis of cross-polarization kinetics parameters was performed. Then, the 13C CP MAS NMR technique was used to confirm the authenticity and determine the presence of curcumin in dietary supplements containing curcumin with the addition of piperine. The presence of piperine could be confirmed even when the mass content of piperine was 70 times lower than that of curcumin. This method can be used to test the quality of dietary supplements containing the addition of piperine as an absorption promoter.

Pharmacists' perception about efficacy, safety, and quality of dietary supplements that used for rheumatic disorders in the Iraqi pharmaceutical market.

Rheumatic diseases are common progressive diseases that associated with chronic pain. Most patients seek to reduce the pain of these diseases by using dietary supplements (DS). Yet, most DS have limited benefits to reduce pain and/or disease progression. Therefore, this study aimed to explore the perceptions of community pharmacists about the efficacy, safety, and quality of the DS for treatment of rheumatic diseases (DSTRD) in the Iraqi pharmaceutical market. A qualitative study was conducted during February-2023 through face-to-face interview with community pharmacists with ≥6 months of working experience. The interviews were guided through semi-structured open-ended questions. The interviews were recorded using iPhone-11. A hybrid framework-model was used to analyze the data. Interviews were performed with 20 pharmacists. Only 30% of pharmacists considered DSTRD to be effective, whereas 75% of them perceived DSTRD to be safe. One-quarter of the participants considered the quality of DSTRD to be good. All interviewed pharmacists reported that prescribing DSTRD become a common practice. Eleven participants reported that deals with pharmaceutical companies are the main trigger for prescribing DSTRD. Three-quarter of participating pharmacists mentioned that they educate their patient about the dispensed DSTRD. However, only 10% of them educate patients about the possible side effects and interactions of DSTRD. In conclusion, most of the participating pharmacists have doubts about the efficacy, safety, and quality of DSTRD in the Iraqi market. The prescribing of such products by physicians is common and usually triggered by deals with pharmaceutical companies. Pharmacist-education to the patient on these supplements is poor.

The Importance of Dissolution Tests to Evaluate Quality of Dietary Supplements: Case Study of Controlled Release Caffeine Capsules

The Importance of Dissolution Tests to Evaluate Quality of Dietary Supplements: Case Study of Controlled Release Caffeine Capsules

The potential of the radiation technologies to improve the quality of dietary supplements

The use of dietary supplements has much increased over recent decades, principally due to the need to correct dietary deficiencies but also for their supportive role in certain medical treatments. While they are regulated as food, with certain specific regulations and requirements that distinguish them from conventional foods, the manufacturers can choose to adhere to higher standards, that allows them a future upgrade as pharmaceuticals or medical devices. This paper presents the results of exploratory studies for the introduction of gamma irradiation as a method of control of the microbial contamination for egg lyophilizates currently marketed as dietary supplements. Characterization studies were performed with the goal of upgrading the products for the pharmaceutical market. The irradiation treatment improved their microbiological quality by the exerted microbicidal e􀵵ect and it can be used as long as the other properties (physico-chemical and/or therapeutic) are not affected.

Assessment of Physicochemical Parameters and Contaminants in Herbal Dietary Supplements Used in the Treatment of Inflammatory Bowel Disease.

Inflammatory bowel disease is a complex disorder characterized by chronic gastrointestinal inflammation. Thus, patients prefer to use herbal dietary supplements containing turmeric, Indian frankincense, green chiretta, and black pepper in an attempt to cope better with their chronic condition. The dietary supplements' dosage forms and herbal ingredients were assessed in terms of the products' physicochemical parameters (weight uniformity, friability, disintegration, rupture test, tablet's breaking force, and powder flowability) in view of the USP-NF requirements. In addition, contaminants such as organic solvents and ethylene oxide were evaluated using gas chromatography. Assessment of gluten via an Enzyme-Linked Immunosorbent Assay was also performed. Most of the products met USP requirements. The high average weight of one multicomponent tablet sample with a high breaking force value can explain the observed negative results of the disintegration test. A total of 26% of samples tested positive for gluten, but the most alarming fact is that the ethylene oxide levels found in two samples were up to 30 times higher than the EU limit. Accordingly, dietary supplement quality control is of fundamental importance.

Horizon scan of DNA-based methods for quality control and monitoring of herbal preparations.

Herbal medicines and preparations are widely used in healthcare systems globally, but concerns remain about their quality and safety. New herbal products are constantly being introduced to the market under varying regulatory frameworks, with no global consensus on their definition or characterization. These biologically active mixtures are sold through complex globalized value chains, which create concerns around contamination and profit-driven adulteration. Industry, academia, and regulatory bodies must collaborate to develop innovative strategies for the identification and authentication of botanicals and their preparations to ensure quality control. High-throughput sequencing (HTS) has significantly improved our understanding of the total species diversity within DNA mixtures. The standard concept of DNA barcoding has evolved over the last two decades to encompass genomic data more broadly. Recent research in DNA metabarcoding has focused on developing methods for quantifying herbal product ingredients, yielding meaningful results in a regulatory framework. Techniques, such as loop-mediated isothermal amplification (LAMP), DNA barcode-based Recombinase Polymerase Amplification (BAR-RPA), DNA barcoding coupled with High-Resolution Melting (Bar-HRM), and microfluidics-based methods, offer more affordable tests for the detection of target species. While target capture sequencing and genome skimming are considerably increasing the species identification resolution in challenging plant clades, ddPCR enables the quantification of DNA in samples and could be used to detect intended and unwanted ingredients in herbal medicines. Here, we explore the latest advances in emerging DNA-based technologies and the opportunities they provide as taxa detection tools for evaluating the safety and quality of dietary supplements and herbal medicines.

13C CPMAS NMR as an Alternative Method to Verify the Quality of Dietary Supplements Containing Curcumin.

Turmeric is a traditional Indian spice that has recently become very popular worldwide because it contains a powerful ingredient called curcumin, which has strong anti-inflammatory properties. Hence, dietary supplements containing extracts rich in curcumin have gained great popularity. The main problems related to curcumin-containing dietary supplements are poor water solubility and the fact that they are often faked by using synthetic curcumin instead of the plant extract. In this article, we propose the use of the 13C CPMAS NMR method to control the quality of dietary supplements. The analysis of 13C CPMAS NMR spectra supported by GIPAW computations allowed us to identify a polymorphic form present in dietary supplements (which affected the solubility of curcumin) and to point out a dietary supplement that could be faked by using synthetic curcumin. Further PXRD and HPLC investigations confirmed that the examined supplement contained synthetic curcumin instead of the genuine extract. Our method can be used for routine control, especially because the investigation is performed directly from the capsule/tablet content and does not require any special sample preparation.

Quality Control of the Dietary Supplements Containing Selected Fat-Soluble Vitamins D and K

Nowadays, the most important aspect related to the use of dietary supplements seems to be their quality. There are many reports indicating their insufficient quality primarily related to a much lower content of ingredients or even their absence. Currently, there is an increasing interest in supplementing the diet with various kinds of supplements, including those containing combinations of vitamins and minerals, among which preparations with vitamin D are very popular. This is probably due to the reduced production of this vitamin, depending on the amount of time spent in the sun and the use of UV-filters. Very often, preparations with cholecalciferol also contain vitamin K2, which is associated with their synergistic effect. Therefore, the question arises about the effectiveness of supplementation, which may be correlated with the quality of commonly available dietary supplements. In the presented work, it was undertaken to develop optimal conditions for the qualitative and quantitative determination of vitamins D2, D3 and K2 in dietary supplements available in various forms, using thin-layer chromatography with densitometric detection. As a result, the methodology for analyzing the content of three vitamins from various matrices was developed, optimized and validated in accordance with ICH requirements. The obtained results allow us to conclude that it is reliable and meets the requirements for analytical procedures used in the analysis of medicinal products. Based on the results obtained for examined dietary supplements, it can be stated that the amount of vitamin D3 in analyzed products is basically similar to that declared by the manufacturer, in contrast to vitamin K2, the content of which is diverse. The developed methodology seems to be a good, low-cost and quick way to control the quality of dietary supplements so that they can supplement the human diet and be a wholesome product.

What Should Clinicians Know About Dietary Supplement Quality?

Increase in dietary supplement use in the United States suggests a great need for clinicians to be aware of the range of supplements' quality parameters. Regulatory requirements exist, but specific quality parameters for each ingredient are not set by regulators. This article considers how clinicians can evaluate dietary supplement product quality, assess manufacturers' adherence to public quality standards, and encourage use of verification and certification programs.

Application of Liquid Chromatography Coupled to Mass Spectrometry in Quality Assessment of Dietary Supplements-A Case Study of Tryptophan Supplements: Release Assay, Targeted and Untargeted Studies.

Dietary supplements are widely consumed in the EU and the USA. Based on their similarity to pharmaceuticals, consumers mistakenly believe that dietary supplements have also been approved for safety and efficacy. However, in the absence of mandatory testing, data on supplement quality is scarce. Thus, we applied liquid chromatography coupled with tandem mass spectrometry to analyse the quality of dietary supplements containing tryptophan (Trp). We examined 22 supplements in tablets or capsules, produced in the USA, Great Britain, Germany, France, Czech Republic, and Poland. Trp release, crucial for bioavailability and efficiency, was assessed. Additionally, we performed a qualitative analysis of the main ingredient and screened for contaminants. Among the contaminants, we detected Trp’s metabolites, condensation products of Trp and carbonyl compounds, Trp degradation products, degradation products of kynurenine, and other contaminants such as glucosamine and melatonin. The main ingredient content was in the range of 55–100% in capsules and 69–87% in tablets. Surprisingly, almost no Trp release was noted from some supplements. Our study confirms the need to advance research on supplements. We believe that the high-quality analysis of supplements based on reliable analytical techniques will be an important contribution to the discussion on the regulatory framework of these products.

Analytical Challenges and Metrological Approaches to Ensuring Dietary Supplement Quality: International Perspectives.

The increased utilization of metrology resources and expanded application of its’ approaches in the development of internationally agreed upon measurements can lay the basis for regulatory harmonization, support reproducible research, and advance scientific understanding, especially of dietary supplements and herbal medicines. Yet, metrology is often underappreciated and underutilized in dealing with the many challenges presented by these chemically complex preparations. This article discusses the utility of applying rigorous analytical techniques and adopting metrological principles more widely in studying dietary supplement products and ingredients, particularly medicinal plants and other botanicals. An assessment of current and emerging dietary supplement characterization methods is provided, including targeted and non-targeted techniques, as well as data analysis and evaluation approaches, with a focus on chemometrics, toxicity, dosage form performance, and data management. Quality assessment, statistical methods, and optimized methods for data management are also discussed. Case studies provide examples of applying metrological principles in thorough analytical characterization of supplement composition to clarify their health effects. A new frontier for metrology in dietary supplement science is described, including opportunities to improve methods for analysis and data management, development of relevant standards and good practices, and communication of these developments to researchers and analysts, as well as to regulatory and policy decision makers in the public and private sectors. The promotion of closer interactions between analytical, clinical, and pharmaceutical scientists who are involved in research and product development with metrologists who develop standards and methodological guidelines is critical to advance research on dietary supplement characterization and health effects.

Simultaneous Determination of Vitamins D3 (Calcitriol, Cholecalciferol) and K2 (Menaquinone-4 and Menaquinone-7) in Dietary Supplements by UHPLC.

The content and composition of dietary supplements is of great interest due to their increasing consumption and variety of available brand offered in the market. Accurate determination of vitamins is important for the improvement of dietary supplement quality and nutrition assessments. In this regard, the simultaneous determination of vitamin D3 (calcitriol—CT and cholecalciferol—CHL) and K2 (menaquinone-4—MK-4 and menaquinone-7—MK-7) in dietary supplements was developed by using ultra-high-pressure liquid chromatography (UHPLC). The overall runtime per sample was above 35 min, with the retention times of 2.40, 6.59, 7.06, and 32.6 min for vitamin D3 (CT and CHL) and vitamin K2 (MK-4 and MK-7), respectively. The limits of detection and limits of quantification for the target nutritional compounds ranged between 0.04–0.05 µg/mL, respectively. The validation results indicated that the method had reasonable linearity (R2 ≥ 0.9990), good recovery (>82%), satisfactory intra-day precision (≤1.9%) and inter-day precision (≤3.5%), and high selectivity and specificity. The validated UHPLC method was demonstrated to be precise, accurate, and robust for the simultaneous determination of vitamins D3 (CT and CHL) and K2 (MK-4 and MK-7) in dietary supplements.

Phytochemical investigation of Mimosa pigra leaves, a sensitive species

Mimosa pigra L. is an invasive species that grows with related species called M. pudica L. M. pudica is a dietary supplement, marketing in the United States, with a claim of supporting the immune system. It is known that M. pudica has been misidentified with M. pigra L. As part of our ongoing research endeavors to identify the chemical constituents of broadly consumed herbal supplements or their adulterants, a detailed phytochemical investigation of M. pigra was undertaken. As a result, seven specialized metabolites, including six flavonoid-O-glycosides were isolated from the leaves of M. pigra. The isolated chemical constituents in this study could be used as chemical markers to differentiate M. pigra-based raw materials in various finished products, including the quality of dietary supplements claimed to contain M. pudica.

Evaluation of Physicochemical Properties of Beetroot-Based Dietary Supplements.

In the European Union, no specific requirements for the physicochemical parameters of dietary supplements have been established, contrary to the United States of America. This research aimed to assess the selected physical parameters of 31 commercially available beetroot-based dietary supplements in the form of tablets and capsules following the United States Pharmacopoeia (USP) guidelines and the Food and Drug Administration (FDA) recommendations. There was also estimated zinc and iron content by atomic absorption spectroscopy with flame detection. Results showed that nine products did not meet the USP requirements. Seven supplements needed more than 30 min to disintegrate. Two products in the form of tablets did not pass the friability test because of cracking. The hardness values varied significantly between manufacturers, demonstrating values from 59.1 to 455.8 N. The iron-enriched supplements differed significantly in iron content compared with the manufacturers’ declaration (84.91–140.69%). Inappropriate quality of dietary supplements, which may constitute a potential risk to consumers, can be related to the lack of specific regulations in Europe; hence, similar to the USA requirements should be considered in the European Union. The work emphasizes the need to better control the quality of dietary supplements before they are introduced to the European market.

Evaluation of Dietary Supplements Containing Viable Bacteria by Cultivation/MALDI-TOF Mass Spectrometry and PCR Identification.

The insufficient quality of products containing beneficial live bacteria in terms of content and viability of labelled microorganisms is an often-reported problem. The aim of this work was to evaluate the quality of dietary supplements containing viable bacteria available in Slovenian pharmacies using plate counting, matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and species- or subspecies-specific PCR with DNA isolated from consortia of viable bacteria, from individual isolates, or directly from the products. Twelve percent of the products (3 of 26) contained insufficient numbers of viable bacteria. Eighty-three of the labelled species (111 in total) were confirmed by PCR with DNA from the product; 74% of these were confirmed by PCR with DNA from viable consortium, and 65% of these were confirmed by MALDI-TOF MS analysis of colonies. Certain species in multi-strain products were confirmed by PCR with DNA from viable consortia but not by MALDI-TOF MS, suggesting that the number of isolates examined (three per labelled strain) was too low. With the exception of Lacticaseibacillus casei and closely related species (Lacticaseibacillus rhamnosus and Lacticaseibacillus zeae), PCR and MALDI-TOF identification results agreed for 99% of the isolates examined, although several MALDI-TOF results had lower score values (1.700–1.999), indicating that the species identification was not reliable. The species L. zeae, which appeared in 20 matches of the Biotyper analysis, was identified as L. rhamnosus by PCR. The MALDI-TOF MS analysis was also unsuccessful in detecting Lactobacillus acidophilus La-5 and Bacillus coagulans due to missing peaks and unreliable identification, respectively. Mislabelling was detected by both methods for two putative L. casei strains that turned out to belong to the species Lacticaseibacillus paracasei. PCR remains more successful in subspecies-level identification as long as the database of MALDI-TOF MS spectra is not expanded by building in-house databases. The lack of positive PCR results with viable consortia or colonies, but positive PCR results with DNA isolated directly from the products observed in 10% (11/112) of the labelled strains, suggests the presence of non-culturable bacteria in the products. MALDI-TOF MS is a faster and simpler alternative to PCR identification, provided that a sufficient number of colonies are examined. Generation of in-house library may further improve the identification accuracy at the species and sub-species level.

Using “Text Mining” Analysis for the Assessment of the Health Quality of Dietary Supplements

Abstract Techniques of text data analysis have been known for many years and commonly used in many areas of life. Text mining enables, among others, the acquisition of information from the text, its filtering, and studying of similarities and relationships. The aim of this paper is to design a method that would make it possible to assess the health quality of dietary supplements, on the basis of text mining techniques. A fictional plant-based product was used in the study, which was compared with other products containing at least one of the tested ingredients registered in the years 2007–2019 in the register of dietary supplements kept by the Chief Sanitary Inspectorate (GIS), which were given either the “consistent” or “to be clarified” status. The obtained results concern the frequency of occurrence of the individual ingredients (St John’s wort/Hypericum, melissa, rose root/Rhodiola) in other products, considering their status in the register. The data thus obtained was subjected to classical statistical analysis in order to find correlations between the presence of a given ingredient and the product status. In view of the obtained results, the text mining analysis may be considered as a helpful tool in the process of internal risk assessment performed by manufacturers of dietary supplements.

Health-, medication- and dietary supplement-related behaviors and beliefs relatively unchanged during the COVID-19 pandemic lockdown.

BackgroundThe lockdown imposed to counter the coronavirus disease 2019 (COVID-19) pandemic has evoked an unprecedented phenomenon that could affect health behaviors and beliefs.ObjectiveTo examine how medication-, dietary supplement- and health-related behaviors, beliefs and other psychological constructs changed in Polish online health service users during the COVID-19 pandemic lockdown.MethodsA one-time online survey accessed through a health service website was completed before and during the pandemic lockdown by separate samples of respondents. The survey examined beliefs about medicines and dietary supplements, consumption of dietary supplements, trust and contact with their advertisements, sources of dietary supplement knowledge as well as perceived health, diet, physical activity and smoking, among other things.ResultsThe study included 1560 participants. Most examined outcomes remained unchanged over COVID-19 pandemic lockdown. Beliefs that the dietary supplement quality is well controlled became significantly more pronounced during the lockdown (adjusted ratio of estimates 1.16, 95%CI 1.06–1.27, p = 0.001). Fewer people reported having contact with dietary supplement advertisements (adjusted odds ratio 0.59, 95%CI 0.43–0.83, p = 0.002).ConclusionsThe results may help understand some health-related issues associated with COVID-19 pandemic lockdown and may be used to shape aspects of health-related policy.