Multi-ingredient, Caffeine-containing Dietary Supplements: History, Safety, and Efficacy

Clinically Relevant Herb-Drug Interactions: A 30-Year Historical Assessment

The Dietary Supplement Health and Education Act, a legislative measure ushering in a novel class of complementary healthcare products known as dietary supplements, will mark its 30th anniversary in October 2024. Over this 30-year period, dietary supplement usage evolved from a few hundred products made up mostly of vitamins, minerals, and select botanical extracts to more than 75,000 single- and multi-ingredient products that are now regular staples in the American healthcare system and used by half of all U.S. consumers. One of the fastest-growing segments of the dietary supplement market during this 3-decade interval has been those products formulated with botanical extracts. Coincident with the growing popularity of botanical dietary supplements (BDS) has been their concomitant ingestion with conventional prescription medications. BDS are complex mixtures of phytochemicals oftentimes exhibiting complex pharmacology. Formulated as concentrated phytochemical extracts, BDS are vehicles for a host of plant secondary metabolites rarely encountered in the typical diet. When taken with prescription drugs, BDS may give rise to clinically significant herb-drug interactions (HDI). Pharmacodynamic HDI describe interactions between phytochemicals and conventional medications at the drug receptor level, while pharmacokinetic HDI stem from phytochemical-mediated induction and/or inhibition of human drug metabolizing enzymes and/or transporters. This review summarizes BDS identified over the last 30 years that pose clinically relevant HDI and whose mechanisms are either pharmacodynamically or pharmacokinetically mediated.

Single Dose of an Energy Dietary Supplement with a Small Amount of Caffeine Prevents an Increase of a Low Frequency Resting State EEG in Possible Mental Fatigue

Due to the increasing needs to enhance our cognitive performance, and decrease fatigue with increasing number of tasks in our everyday life, it's interesting to study whether a small amount of active substance present in dietary supplements, is enough to impact cognition. We investigated an acute effect of an energy dietary supplement containing low amount of caffeine (55 mg) and other stimulatory ingredients by means of a resting state EEG in a double blind, placebo controlled study (N = 47, 27 women). The use of a nonparametric cluster-based permutation analysis allowed us to observed a significant group × block interaction effect after 90 minutes post-ingestion (P = 0.022 cluster corrected) in the 'eyes closed' condition, i.e. an increase in normalized rsEEG power in the placebo group, which was abolished in the study group. This difference corresponded to a broad spatio-spectral cluster between around 6.5 Hz and 10.5 Hz (i.e. high theta and low alpha band) maximal over centro-temporo-parieto-occipital scalp areas. Similar trend but without significant effect was found in the 'eyes open' condition. Our results suggest that low caffeine content dietary supplementation acts as a reversal of the fatigue-related brain activity in the neural networks active in the resting state. These findings not only may help to clarify previous nonconclusive findings, but more importantly, show that an ingestion of caffeinated stimulants before neurocognitive examinations, both in research and diagnostics, should be taken into account, as they may influence cognition, even in small doses and when the effects are absent in the behavioral measures.

Gender Differences in the Frequency of Positive and Negative Effects after Acute Caffeine Consumption

Gender-specific caffeine-related adverse effects should be thoroughly investigated. Sixty-five adult participants were included in the study, 30 men and 35 women (age, 22.5 ± 2.8; body weight, 71.7 ± 16.2 kg; BMI, 23.6 ± 4.4). The participants who were classified as low and moderate caffeine users received 3 mg/kg, and high caffeine users received 6 mg/kg of caffeine in one dose. One hour after ingestion of caffeine and within twenty-four hours, the participants completed a side effect questionnaire. Effects after the ingestion of CAF were divided into two subgroups: negative (muscle soreness, increased urine output, tachycardia and palpitations, anxiety or nervousness, headache, gastrointestinal problems, and insomnia) and positive (perception improvement; increased vigor/activeness). Caffeine ingestion resulted in a statistically significant association between gender and negative effects one hour after ingestion (p = 0.049). Gender and positive effects one hour after ingestion (p = 0.005), and between gender and positive effects within 24 h after ingestion (p = 0.047). There were significant associations between gender and perception improvement (p = 0.032) and gender and increased vigor/activeness (p = 0.009) one hour after ingestion. Nearly 30% of men and 54% of women reported negative effects. At the same time, 20% of women and more than 50% of men reported positive effects. Gender is an important factor in the negative and positive effects of caffeine consumption.

Caffeine-Supplemented Diet Prevents Fatigue-Like Behavior in Tumor-Bearing Mice

Caffeine is a widely consumed stimulant, known for its positive effects on physical and mental performance. These effects are potentially beneficial for ameliorating cancer-related fatigue, which affects the quality of life of patients with cancer. This study aimed to determine the anti-fatigue and antitumor effects of caffeine in tumor-bearing mice. BALB/c mice were intravenously injected with C26 colon carcinoma cells and fed with normal or 0.05% caffeine-supplemented diet. Fatigue-like behavior was assessed by running performance using a treadmill test. Lung, blood, liver, muscle, and epididymal adipose tissue samples were collected on day 13 and examined. The antitumor effect of caffeine was assessed using subcutaneous tumor-bearing mice fed with 0.05% caffeine-supplemented diet, and the tumor volume was measured. C26 tumor-bearing mice showed fatigue-like behavior associated with hypoglycemia, depleted liver glycogen and non-esterified fatty acid (NEFA) levels. C26 tumor-bearing mice fed with 0.05% caffeine-supplemented diet showed improved running performance associated with restored NEFA levels. However, exacerbated hypoglycemia and liver glycogen levels after caffeine consumption may be due to tumor-induced catabolic signals, as the tumor volume was not affected. Collectively, caffeine may exert anti-fatigue effects through enhanced lipolysis leading to restored NEFA levels, which can be used as an alternative energy source.

Development of a Caffeine Content Table for Foods, Drinks, Medications and Supplements Typically Consumed by the Brazilian Population

Background: The lack of a national table informing the caffeine contents in foods, drinks, dietary supplements, and medications sold in Brazil added to the noncompulsory disclosure of caffeine contents on labels of food products makes it difficult to estimate caffeine consumption in the Brazilian population. Therefore, this study aimed to develop the Brazilian Caffeine Content Table (BraCaffT). Methods: A systematic search for caffeine levels in foods, drinks, recipes, supplements, and medications was performed through a literature review, afterward collecting data from the United States Department of Agriculture Food Data Central, information from manufacturers’ and websites, and the Brazilian official medication guide. Subsequently, data systematization was performed in a spreadsheet with standardized values presented in mg of caffeine per 100 g or 100 mL of food or drink and a capsule or pill for medications and some dietary supplements. Results: The BraCaffT presents 57 items, divided into 11 categories: coffees, teas and infusions, cocoa powder, chocolates, cocoa-based beverages, desserts, soft drinks, energy drinks, guaraná powder, dietary supplements, and medications. Conclusions: The BraCaffT emerges as an instrument of great relevance and wide applicability in clinical contexts, in academic research, and as a database for the Brazilian population to better understand the amounts of caffeine in foods, drinks, dietary supplements, and medications consumed daily favoring a safe intake.

Hepatotoxicity due to herbal dietary supplements: Past, present and the future

Dietary supplements (DS) constitute a widely used group of products comprising vitamin, mineral, and botanical extract formulations. DS of botanical or herbal origins (HDS) comprise nearly 30% of all DS and are presented on the market either as single plant extracts or multi-extract-containing products. Despite generally safe toxicological profiles of most products currently present on the market, rising cases of liver injury caused by HDS - mostly by multi-ingredient and adulterated products - are of particular concern. Here we discuss the most prominent historical cases of HDS-induced hepatotoxicty - from Ephedra to Hydroxycut and OxyELITE Pro-NF, as well as products with suspected hepatotoxicity that are either currently on or are entering the market. We further provide discussion on overcoming the existing challenges with HDS-linked hepatotoxicity by introduction of advanced in silico, in vitro, in vivo, and microphysiological system approaches to address the matter of safety of those products before they reach the market.

Acute Effect of Caffeine-Based Multi-Ingredient Supplement on Reactive Agility and Jump Height in Recreational Handball Players

Pre-exercise caffeine and guarana-based multi-ingredient supplement (MS) consumption may be more effective for physical performance improvement than caffeine and guarana alone due to the synergistic effect of biologically active ingredients in multi-ingredient supplements. This study aimed to examine the acute effect of MS on the reactive agility and jump performance in recreational handball male players. A randomized, double-blind, crossover study involved twenty-four male handball players (body mass 74.6 ± 8.8 kg; body height 179 ± 7 cm; age 23.8 ± 1.4 years). Participants were tested under three conditions: placebo, caffeine + guarana (CAF + GUA), or MS ingestion 45 min before exercise tests. Participants performed a reactive agility test (Y-shaped test) and countermovement jump (CMJ). None of the supplements improved countermovement jump height (p = 0.06). The time needed to complete the agility test was significantly (p = 0.02) shorter in the MS condition than in the placebo. The differences in agility between PL vs. CAF + GUA and MS vs. CAF + GUA conditions were not statistically significant (p = 0.88 and p = 0.07, respectively). The results of this study indicate that the caffeine-based multi-ingredient performance was effective in improvement in reactive agility but not in jump height in recreational handball male players. A similar effect was not observed with CAF + GUA ingestion alone.

Cardiovascular effects of doping substances, commonly prescribed medications and ergogenic aids in relation to sports: a position statement of the sport cardiology and exercise nucleus of the European Association of Preventive Cardiology

The use of substances and medications with potential cardiovascular effects among those practicing sports and physical activity has progressively increased in recent years. This is also connected to the promotion of physical activity and exercise as core aspects of a healthy lifestyle, which has led also to an increase in sport participation across all ages. In this context, three main users' categories can be identified, (i) professional and amateur athletes using substances to enhance their performance, (ii) people with chronic conditions, which include physical activity and sport in their therapeutic plan, in association with prescribed medications, and (iii) athletes and young individuals using supplements or ergogenic aids to integrate their diet or obtaining a cognitive enhancement effect. All the substances used for these purposes have been reported to have side effects, among whom the cardiovascular consequences are the most dangerous and could lead to cardiac events. The cardiovascular effect depends on the type of substance, the amount, the duration of use, and the individual response to the substances, considering the great variability in responses. This Position Paper reviews the recent literature and represents an update to the previously published Position Paper published in 2006. The objective is to inform physicians, athletes, coaches, and those participating in sport for a health enhancement purpose, about the adverse cardiovascular effects of doping substances, commonly prescribed medications and ergogenic aids, when associated with sport and exercise.

Caffeine Protects Against Retinal Inflammation

Caffeine, one of the most consumed central nervous system (CNS) stimulants, is an antagonist of A₁ and A_2A adenosine receptors. In this study, we investigated the potential protective effects of this methylxanthine in the retinal tissue. We tested caffeine by using in vitro and in vivo paradigms of retinal inflammation. Human retinal pigment epithelial cells (ARPE-19) were exposed to lipopolysaccharide (LPS) with or without caffeine. This latter was able to reduce the inflammatory response in ARPE-19 cells exposed to LPS, attenuating the release of IL-1β, IL-6, and TNF-α and the nuclear translocation of p-NFκB. Additionally, caffeine treatment restored the integrity of the ARPE-19 monolayer assessed by transepithelial electrical resistance (TEER) and the sodium fluorescein permeability test. Finally, the ischemia reperfusion (I/R) injury model was used in C57BL/6J mice to induce retinal inflammation and investigate the effects of caffeine treatment. Mouse eyes were treated topically with caffeine, and a pattern electroretinogram (PERG) was used to assess the retinal ganglion cell (RGC) function; furthermore, we evaluated the levels of IL-6 and BDNF in the retina. Retinal BDNF dropped significantly (p < 0.05) in the I/R group compared to the control group (normal mice); on the contrary, caffeine treatment maintained physiological levels of BDNF in the retina of I/R eyes. Caffeine was also able to reduce IL-6 mRNA levels in the retina of I/R eyes. In conclusion, these findings suggest that caffeine is a good candidate to counteract inflammation in retinal diseases.

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.

Mental Performance and Sport: Caffeine and Co-consumed Bioactive Ingredients

The plant defence compound caffeine is widely consumed as a performance enhancer in a sporting context, with potential benefits expected in both physiological and psychological terms. However, although caffeine modestly but consistently improves alertness and fatigue, its effects on mental performance are largely restricted to improved attention or concentration. It has no consistent effect within other cognitive domains that are important to sporting performance, including working memory, executive function and long-term memory. Although caffeine's central nervous system effects are often attributed to blockade of the receptors for the inhibitory neuromodulator adenosine, it also inhibits a number of enzymes involved both in neurotransmission and in cellular homeostasis and signal propagation. Furthermore, it modulates the pharmacokinetics of other endogenous and exogenous bioactive molecules, in part via interactions with shared cytochrome P450 enzymes. Caffeine therefore enjoys interactive relationships with a wide range of bioactive medicinal and dietary compounds, potentially broadening, increasing, decreasing, or modulating the time course of their functional effects, or vice versa. This narrative review explores the mechanisms of action and efficacy of caffeine and the potential for combinations of caffeine and other dietary compounds to exert psychological effects in excess of those expected following caffeine alone. The review focusses on, and indeed restricted its untargeted search to, the most commonly consumed sources of caffeine: products derived from caffeine-synthesising plants that give us tea (Camellia sinensis), coffee (Coffea genus), cocoa (Theabroma cacao) and guaraná (Paullinia cupana), plus multi-component energy drinks and shots. This literature suggests relevant benefits to mental performance that exceed those associated with caffeine for multi-ingredient energy drinks/shots and several low-caffeine extracts, including high-flavanol cocoa and guarana. However, there is a general lack of research conducted in such a way as to disentangle the relative contributions of the component parts of these products.

Identification of micropollutants from graywater of different complexity and remediation using multilayered membranes

Graywater reuse is one of the important concepts in attaining water sustainability. A major challenge in this area is to realize various components present in graywater. The present study involves the identification of the chemical components of graywater collected from three different environments and to investigate the efficiency of removal of some of these chemical components using ultrafiltration membranes (polyelectrolyte multilayer (PEM) membranes). The chemical components were analyzed using liquid chromatography connected with quadrupole time-of-flight (UPLC-Q-ToF-MS). A number of micropollutants including surfactants and certain contaminants of emerging concern (CECs) were identified from these samples. Out of 16 compounds identified, 13 were surfactants and the remaining were caffeine, oxybenzone, and benzophenone. These surfactants are mostly the ingredients of various detergents. Low-pressure filtration studies of the collected samples were carried out utilizing chitosan/polyacrylic acid (CHI/PAA) multilayer membranes. A 5.5 bilayer membrane showed more than 95% rejection of the identified compounds in the selected samples and significant improvement in the water quality parameters. This demonstrates that the membrane used in this work is effective in the removal of various chemicals from graywater as well as enhancing the water quality.

Pre-workout supplements marketed in Brazil: Caffeine quantification and caffeine daily intake assessment

The stimulating and performance-enhancing properties of caffeine are often explored in one the most consumed types of supplements: the pre-workout supplements (PWS). However, despite the popularity of PWS, previous studies have reported incompatibilities between what is described in their labels and their actual caffeine content. This study aimed to develop, to optimize, and to validate a gas-chromatography coupled to nitrogen-phosphorus detector (GC-NPD) method to quantify caffeine in PWS and to analyze commercial PWS marketed in Brazil to estimate the caffeine daily intake. For this purpose, three different extraction procedures were evaluated: agitation in vortex, shaker, and sonication. Sonication yielded the best extraction results. Next, the parameters' temperature and time were optimized by using central composite rotatable design (CCRD) and response surface methodology, which revealed the optimal values of 70°C and 10 min. The method was validated and applied to quantify caffeine in 52 PWS. From the 36 PWS labels that specified the caffeine amount, seven (19%) presented more than 120% of the declared quantity, whereas 15 (42%) contained less than 80% of the labeled caffeine. Additionally, six products presented undeclared caffeine. Considering the label stated doses, five supplements exceeded the safe caffeine daily intake (400 mg). On the basis of these findings, supplement quality control remains an issue that deserves more attention from consumers, manufacturers, and regulatory agencies. Finally, we suggest that PWS consumers be careful of the habit of ingesting caffeine through other sources and avoid ingesting two or more different PWS products in the same day.

Assessing and Restoring Patency in Midline Catheters

Maintaining and restoring patency in midline catheters has been a significant issue in the hospitalized patient requiring a multitude of infusates and frequent blood specimen collection. Currently, clinicians may not use this device as often as clinically indicated because they lack an approved intervention to treat thrombotic occlusions. The purpose of this research was to show evidence that alteplase, a US Food and Drug Administration-approved thrombolytic for central vascular access devices, is a safe and effective thrombolytic for midline catheters. A prospective open label study of 497 midline catheters was conducted from July 2018 to December 2018. Of those studied, 112 devices were treated with 1 mg of alteplase, and 109 had patency restored with 1 dose. None of the 112 patients had a major adverse event, and only 1 minor event was recorded and was resolved without removal of the midline catheter. Treating occluded central vascular access devices with 2 mg of alteplase has been safe and effective since 2001. With this research, safety and efficacy appears to be established for 1 mg of alteplase, repeat times 1 mg if necessary, in midline catheters. With the option to treat patients with occluded midline catheters rather than replace, clinicians can reduce cost, increase patient satisfaction, and preserve vein health.

An Analysis for Adulteration and Contamination of Over-the-Counter Weight-Loss Products

Six Australian and five overseas complementary medicines (CM) and meal replacement shake products were analysed for potential adulteration with two common active pharmaceutical ingredients, caffeine and sibutramine, using thin-layer chromatography and mass spectrometry. The declared amount of caffeine in each product was also reviewed. Finally, the products were examined for heavy metal contamination using inductively coupled plasma-mass spectrometry. The results showed that there was no detected adulteration of either caffeine (for those products that did not list caffeine as an ingredient) or sibutramine in the 11 products; however, based on the product labels, one Australian and one overseas (two in total) CM product contained more than the maximum daily safety limit (400 mg) of caffeine. Potentially excessive lead and/or chromium was detected in six products, including four Australian products and two products purchased online. One Australian CM product appeared to contain these heavy metals at concentrations at, or exceeding, the safety limits specified in the United States Pharmacopeia or set by the World Health Organization. The overconsumption of caffeine and heavy metals has the potential of causing significant health effects in consumers.

Involvement of serotonergic pathways in gastric dysmotility induced by fat burning nutritional supplements in mice

Fat burners are a category of nutritional supplements that are claimed to increase the metabolism and promote greater energy expenditure, leading to weight loss. However, little is known about the side effects on gastrointestinal motility. In this study, we evaluated the effect of ingestion with a fat burner named Thermbuterol® (THERM) on the gastric motility and food behavior of mice. THERM compounds were identified using nuclear magnetic resonance (NMR). Mice received variable doses of THERM (10, 50, 100 or 300 ​mg/kg, p.o.) or NaCl 0.15 ​M (control). Gastric emptying (GE) was assessed using the phenol red technique. Another set of mice was pretreated with intraperitoneal administration of hexamethonium (HEXA, 10 ​mg/kg), prazosin (PRAZ, 0.25 ​mg/kg), propranolol (PROP, 2 ​mg/kg), parachlorophenylalanine (PCPA, 300 ​mg/kg) or ondansetron (ONDA, 50 ​μg/kg) 30 ​min before THERM treatment for evaluation of GE. We assessed the gastrointestinal responsiveness in vitro as well as THERM's effects on food behavior. Caffeine was the major compound of THERM, identified by NMR. THERM 100 and 300 ​mg/kg decreased GE compared to the respective controls. Pretreatment with PRAZ or PROP did not prevent gastric dysmotility induced by THERM 100 ​mg/kg. However, the pretreatment with HEXA, ONDA or PCPA prevented GE delay induced by THERM. In vitro, THERM relaxed contractions in strips of longitudinal gastric fundus and duodenum. THERM also increased food intake, which was prevented by PCPA and ONDA treatments. THERM decreased GE of a liquid and increased food intake in mice, a phenomenon mediated by the autonomic nicotinic receptors and serotoninergic receptor.

Caffeine: A potential strategy to improve survival of neonatal pigs and sheep

Caffeine is commonly used to treat pre-and postnatal injuries, including apnoea in premature infants, as well as neurological impairment caused by hypoxia or asphyxiation often associated with difficult birthing. As an adenosine antagonist, caffeine is metabolised rapidly and transported into many tissues. Caffeine stimulates the brain respiratory centre, improving respiratory function in immature infants or neonates, provides neuroprotection to the fetal brain, and initiates non-shivering thermoregulation increasing metabolic rates. Recently, potential benefits of caffeine for animal production have been investigated. This has particularly occurred in pig production, where large litters are associated with relatively long parturition durations, and piglets born near the end of the parturition period have an increased risk of mortality due to asphyxia-related birthing injury. Similarly, in sheep, dystocia or prolonged parturition is a significant problem, where neonatal injury, dystocia and death in utero contributes to approximately 46 % of lamb mortalities. Within these two livestock production systems, large prevalence's of neonatal mortality is a persistent issue contributing to lost revenue, as well as being a significant animal welfare concern. Pre-partum maternal caffeine supplementation is a promising strategy to reduce neonatal mortality; however, there needs to be refinement of appropriate quantities administered, duration and administration pathway to provide producers with an efficient and cost-effective method to reduce mortality rates and increase production output. The information in this review details effects, benefits and important considerations regarding caffeine use in animal production, and identifies areas of limited knowledge where further research is needed.

Caffeine: An Overview of Its Beneficial Effects in Experimental Models and Clinical Trials of Parkinson's Disease

Parkinson’s Disease (PD) is a neurological disease characterized by the progressive degeneration of the nigrostriatal dopaminergic pathway with consequent loss of neurons in the substantia nigra pars compacta and dopamine depletion. The cytoplasmic inclusions of α-synuclein (α-Syn), known as Lewy bodies, are the cytologic hallmark of PD. The presence of α-Syn aggregates causes mitochondrial degeneration, responsible for the increase in oxidative stress and consequent neurodegeneration. PD is a progressive disease that shows a complicated pathogenesis. The current therapies are used to alleviate the symptoms of the disease without changing its clinical course. Recently, phytocompounds with neuroprotective effects and antioxidant properties such as caffeine have aroused the interest of researchers. The purpose of this review is to summarize the preclinical studies present in the literature and clinical trials recorded in ClinicalTrial.gov, aimed at illustrating the effects of caffeine used as a nutraceutical compound combined with the current PD therapies. Therefore, the preventive effects of caffeine in the neurodegeneration of dopaminergic neurons encourage the use of this alkaloid as a supplement to reduce the progress of the PD.

Regulatory framework for dietary supplements and the public health challenge

OBJECTIVE

The new regulatory framework for dietary supplements in Brazil prompted this analysis of the current outlook of these products and the challenges posed by the new guidelines.

METHODS

We conducted a qualitative, observational and descriptive study of dietary supplements commercialized in Brazilian online stores with the help of the Google® search tool. We considered the ingredients on the labels, the effects attributed to these products and the commercial claims used as a means of promoting them to assess the necessary changes for the legal framework in the new guidelines. Finally, with the help of a database, we compared the effects declared by the manufacturers and attributed to certain ingredients with the scientific evidence described in literature.

RESULTS

In total, we purchased 44 dietary supplements from Brazilian online stores (n = 7). Of the samples studied, 34.2% could not be classified in the category Dietary Supplements, as recommended by the new regulation of the Brazilian Health Regulatory Agency due to the presence of prohibited substances; 16% of products should be commercialized as medicines. Regarding the commercial appeals, 97.7% had banned expressions. Numerous claims of effects attributed to certain products were characterized as consumer fraud because they have no scientific evidence.

CONCLUSIONS

The necessary changes represent a major regulatory and production challenge due to the wide range of dietary supplements and markets, an effort that aims to protect the consumers' health. Some previous gaps in the regulatory framework were not fully solved.

A new approach to ion exchange chromatography with conductivity detection for adulterants investigation in dietary supplements

The extent of adulteration of dietary supplements has significantly increased in recent years. This situation worries health authorities and requires auxiliary analytical tools for the investigation of illegal substances purposely added. Ion exchange chromatography with conductivity detection is a consolidated analytical technique for the determination of inorganic compounds in various matrices. This technique has been applied to the pharmaceutical characterization of mainly impurities and degradation products. This work presents a new approach to ion exchange chromatography as a screening method to investigate the presence of amfepramone, femproporex, sibutramine, bisacodyl and amiloride in dietary supplements advertised for weight loss. The method was optimized and validated using a Metrosep C4 100/4.0 cation exchange column. The mobile phase consisted of 1.8 mm HNO₃ containing 2% acetonitrile (v/v), with a flow rate of 0.9 ml min^-1 , and nonsuppressed conductivity detection was applied. The limits of detection and quantification varied from 1.01 to 3.62 mg L^-1 and from 1.48 to 8.72 mg L^-1 , respectively. The proposed method was successful applied to 78 solid dietary supplement samples, in two of which adulterations were found. Moreover, ion exchange chromatography with conductivity detection could be easily used for quality control without prior complex sample pre-treatment.

Decaffeinated Green Tea Extract Does Not Elicit Hepatotoxic Effects and Modulates the Gut Microbiome in Lean B6C3F₁ Mice

The main purpose of this study was to investigate the hepatotoxic potential and effects on the gut microbiome of decaffeinated green tea extract (dGTE) in lean B6C3F₁ mice. Gavaging dGTE over a range of 1X–10X mouse equivalent doses (MED) for up to two weeks did not elicit significant histomorphological, physiological, biochemical or molecular alterations in mouse livers. At the same time, administration of dGTE at MED comparable to those consumed by humans resulted in significant modulation of gut microflora, with increases in Akkermansia sp. being most pronounced. Results of this study demonstrate that administration of relevant-to-human-consumption MED of dGTE to non-fasting mice does not lead to hepatotoxicity. Furthermore, dGTE administered to lean mice, caused changes in gut microflora comparable to those observed in obese mice. This study provides further insight into the previously reported weight management properties of dGTE; however, future studies are needed to fully evaluate and understand this effect.

How to recognize caffeine overdose

Caffeine is the most widely consumed stimulant in the world and can offer a variety of benefits when consumed in moderation. But consuming caffeine in extremely high amounts can lead to an overdose. This article examines how nurses can recognize the signs and symptoms of caffeine overdose and educate patients on how to prevent this common problem.

The influence of citrus aurantium and caffeine complex versus placebo on the cardiac autonomic response: a double blind crossover design

Background

The purpose of this study was to examine the resting cardiac autonomic nervous system’s response to the ingestion of a complex containing Citrus aurantium + Caffeine (CA + C) and its influence on recovery following a high-intensity anaerobic exercise bout in habitual caffeine users.

Methods

Ten physically active males (25.1 ± 3.9 years; weight 78.71 ± 9.53 kg; height 177.2 ± 4.6 cm; body fat 15.5 ± 3.13%) participated in this study, which consisted of two exhaustive exercise protocols in a randomized crossover design. On each visit the participants consumed either a CA + C (100 mg of CA and 100 mg of C) or placebo (dextrose) capsule. After consumption, participants were monitored throughout a 45-min ingestion period, then completed a repeated Wingate protocol, and were then monitored throughout a 45-min recovery period. Cardiac autonomic function (Heart Rate (HR) and Heart Rate Variability (HRV)) and plasma epinephrine (E) and norepinephrine (NE) were taken at four different time points; Ingestion period: baseline (I1), post-ingestion period (I2); Recovery period: immediately post-exercise (R1), post-recovery period (R2). Heart rate variability was assessed in 5-min increments.

Results

A repeated measures ANOVA revealed significant time-dependent increases in HR, sympathetic related markers of HRV, and plasma E and NE at I2 only in the CA + C trial (p < 0.05); however, no meaningful changes in parasympathetic markers of HRV were observed. Participants recovered in a similar time-dependent manner in all markers of HRV and catecholamines following the PLA and CA + C trials.

Conclusion

The consumption of CA + C results in an increase of sympathetic activity during resting conditions without influencing parasympathetic activity. CA + C provides no influence over cardiac autonomic recovery.

Clinically Relevant Herb-Micronutrient Interactions: When Botanicals, Minerals, and Vitamins Collide

The ability of certain foods to impair or augment the absorption of various vitamins and minerals has been recognized for many years. However, the contribution of botanical dietary supplements (BDSs) to altered micronutrient disposition has received little attention. Almost half of the US population uses some type of dietary supplement on a regular basis, with vitamin and mineral supplements constituting the majority of these products. BDS usage has also risen considerably over the last 2 decades, and a number of clinically relevant herb-drug interactions have been identified during this time. BDSs are formulated as concentrated plant extracts containing a plethora of unique phytochemicals not commonly found in the normal diet. Many of these uncommon phytochemicals can modulate various xenobiotic enzymes and transporters present in both the intestine and liver. Therefore, it is likely that the mechanisms underlying many herb-drug interactions can also affect micronutrient absorption, distribution, metabolism, and excretion. To date, very few prospective studies have attempted to characterize the prevalence and clinical relevance of herb-micronutrient interactions. Current research indicates that certain BDSs can reduce iron, folate, and ascorbate absorption, and others contribute to heavy metal intoxication. Researchers in the field of nutrition may not appreciate many of the idiosyncrasies of BDSs regarding product quality and dosage form performance. Failure to account for these eccentricities can adversely affect the outcome and interpretation of any prospective herb-micronutrient interaction study. This review highlights several clinically relevant herb-micronutrient interactions and describes several common pitfalls that often beset clinical research with BDSs.

Detection and determination of undeclared synthetic caffeine in weight loss formulations using HPLC-DAD and UHPLC-MS/MS

Caffeine is present in products marketed for weight loss, with the purpose of increasing thermogenesis and lipid metabolism. The dosage declared by the product manufacturer, or even its presence, is not always correctly described on the label. This work aimed to investigate the undeclared synthetic caffeine in weight loss formulations by a high-performance liquid chromatography with diode array detection (HPLC-DAD) method. From one hundred products purchased through Brazilian e-commerce, seventeen contained caffeine, either naturally or synthetically added to formulation. The caffeine-containing samples were confirmed by an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method, and adulteration was clearly proven in five products. The content highest caffeine contained 448.8 mg per dose. Other irregularities were also found; nevertheless, the most serious was the addition of synthetic drugs without asking the consumers. Additional drugs expose the consumer to more possible side-effects as well as deleterious drug interactions. Intentional adulteration with any unlabeled substance is typically motivated by a desire to increase or alter the claimed effect of the marketed product to gain a commercial advantage.

Ephedrine as a lead compound for the development of new DPP-IV inhibitors

AIM

Extracts from Ephedra species have been reported to be effective as antidiabetics. A previous in silico study predicted that ephedrine and five ephedrine derivatives could contribute to the described antidiabetic effect of Ephedra extracts by inhibiting dipeptidyl peptidase IV (DPP-IV). Finding selective DPP-IV inhibitors is a current therapeutic strategy for Type 2 diabetes mellitus management. Therefore, the main aim of this work is to experimentally determine whether these alkaloids are DPP-IV inhibitors. Materials & methods: The DPP-IV inhibition of Ephedra's alkaloids was determined via a competitive-binding assay. Then, computational analyses were used in order to find out the protein-ligand interactions and to perform a lead optimization.

RESULTS

Our results show that all six molecules are DPP-IV inhibitors, with IC₅₀ ranging from 124 μM for ephedrine to 28 mM for N-methylpseudoephedrine.

CONCLUSION

Further computational analysis shows how Ephedra's alkaloids could be used as promising lead molecules for designing more potent and selective DPP-IV inhibitors.

Safety assessment of the dietary supplement OxyELITE™ Pro (New Formula) in inbred and outbred mouse strains

Herbal dietary supplements have gained wide acceptance as alternatives to conventional therapeutic agents despite concerns regarding their efficacy and safety. In 2013, a spate of severe liver injuries across the United States was linked to the dietary supplement OxyELITE Pro-New Formula (OEP-NF), a multi-ingredient product marketed for weight loss and exercise performance enhancement. The principal goal of this study was to assess the hepatotoxic potential of OEP-NF in outbred and inbred mouse models. In an acute toxicity study, significant mortality was observed after administering 10X and 3X mouse-equivalent doses (MED) of OEP-NF, respectively. Increases in liver/body weight ratio, ALT and AST were observed in female B6C3F₁ mice after gavaging 2X and 1.5X MED of OEP-NF. Similar findings were observed in a 90-day feeding study. These alterations were paralleled by altered expression of gene- and microRNA-signatures of hepatotoxicity, including Cd36, Nqo1, Aldoa, Txnrd1, Scd1 and Ccng1, as well as miR-192, miR-193a and miR-125b and were most pronounced in female B6C3F₁ mice. Body weight loss, observed at week 1, was followed by weight gain throughout the feeding studies. These findings bolster safety and efficacy concerns for OEP-NF, and argue strongly for implementation of pre-market toxicity studies within the dietary supplement industry.

Nutrition Supplements to Stimulate Lipolysis: A Review in Relation to Endurance Exercise Capacity

Athletes make great efforts to increase their endurance capacity in many ways. Using nutrition supplements for stimulating lipolysis is one such strategy to improve endurance performance. These supplements contain certain ingredients that affect fat metabolism; furthermore, in combination with endurance training, they tend to have additive effects. A large body of scientific evidence shows that nutrition supplements increase fat metabolism; however, the usefulness of lipolytic supplements as ergogenic functional foods remains controversial. The present review will describe the effectiveness of lipolytic supplements in fat metabolism and as an ergogenic aid for increasing endurance exercise capacity. There are a number of lipolytic supplements available on the market, but this review focuses on natural ingredients such as caffeine, green tea extract, L-carnitine, Garcinia cambogia (hydroxycitric acid), capsaicin, ginseng, taurine, silk peptides and octacosanol, all of which have shown scientific evidence of enhancing fat metabolism associated with improving endurance performance. We excluded some other supplements owing to lack of data on fat metabolism or endurance capacity. Based on the data in this review, we suggest that a caffeine and green tea extract improves endurance performance and enhances fat oxidation. Regarding other supplements, the data on their practical implications needs to be gathered, especially for athletes.

Engineering a novel biosynthetic pathway in Escherichia coli for the production of caffeine

This work demonstrated a novel biosynthetic pathway to produce caffeine in Escherichia coli.

Acute effects of caffeine-containing energy drinks on physical performance: a systematic review and meta-analysis

PURPOSE

Caffeine-containing energy drinks (EDs) are currently used as ergogenic aids to improve physical performance in a wide variety of sport disciplines. However, the outcomes of previous investigations on this topic are inconclusive due to methodological differences, especially, in the dosage of the active ingredients and the test used to assess performance.

METHODS

We performed a systematic review and meta-analysis of published studies to evaluate the effects of acute ED intake on physical performance. The search for references was conducted in the databases PubMed, ISI Web of Knowledge and SPORTDiscus until December 2015.

RESULTS

Thirty-four studies published between 1998 and 2015 were included in the analysis. Using a random-effects model, effect sizes (ES) were calculated as the standardized mean difference. Overall, ED ingestion improved physical performance in muscle strength and endurance (ES = 0.49; p < 0.001), endurance exercise tests (ES = 0.53; p < 0.001), jumping (ES = 0.29; p = 0.01) and sport-specific actions (ES = 0.51; p < 0.001), but not in sprinting (ES = 0.14; p = 0.06). The meta-regression demonstrated a significant association between taurine dosage (mg) and performance (slope = 0.0001; p = 0.04), but not between caffeine dosage (mg) and performance (slope = 0.0009; p = 0.21).

CONCLUSION

ED ingestion improved performance in muscle strength and endurance, endurance exercise tests, jumping and sport-specific actions. However, the improvement in performance was associated with taurine dosage.

Caffeine Use among Active Duty Navy and Marine Corps Personnel

Data from the National Health and Nutrition Examination Survey (NHANES) indicate 89% of Americans regularly consume caffeine, but these data do not include military personnel. This cross-sectional study examined caffeine use in Navy and Marine Corps personnel, including prevalence, amount of daily consumption, and factors associated with use. A random sample of Navy and Marine Corps personnel was contacted and asked to complete a detailed questionnaire describing their use of caffeine-containing substances, in addition to their demographic, military, and lifestyle characteristics. A total of 1708 service members (SMs) completed the questionnaire. Overall, 87% reported using caffeinated beverages ≥1 time/week, with caffeine users consuming a mean ± standard error of 226 ± 5 mg/day (242 ± 7 mg/day for men, 183 ± 8 mg/day for women). The most commonly consumed caffeinated beverages (% users) were coffee (65%), colas (54%), teas (40%), and energy drinks (28%). Multivariable logistic regression modeling indicated that characteristics independently associated with caffeine use (≥1 time/week) included older age, white race/ethnicity, higher alcohol consumption, and participating in less resistance training. Prevalence of caffeine use in these SMs was similar to that reported in civilian investigations, but daily consumption (mg/day) was higher.

A Retrospective Study of Clinical Effects of Powdered Caffeine Exposures Reported to Three US Poison Control Centers

INTRODUCTION

Anhydrous caffeine, often sold on the Internet as a powdered caffeine product, is sold as "pure caffeine" to be used as an additive to beverages and has also been used as an ingredient in energy supplement products.

METHODS

This is a retrospective multiple-poison center chart review of calls regarding powdered caffeine to poison centers covering Oregon, Alaska, Guam, Washington, and Utah between January 1, 2013 and June 30, 2015.

RESULTS

There were 40 calls to three poison centers over 30 months for powdered caffeine exposure. The majority of patients were over age 19 (52.5 %; 21/40) and male (70 %; 28/40). Sixty percent (24/40) of the patients were symptomatic but only 10 % (4/40) required admission; 52.5 % (21/40) of the patient calls were for inadvertent overdose of powdered caffeine; one patient overdosed in a self-harm attempt.

DISCUSSION

Powdered caffeine calls to three poison centers during a 30-month study period were rare, and severe caffeine toxicity due to exposure was found in few patients. The majority of symptoms were reported after an inadvertent powdered caffeine overdose.

CONCLUSIONS

An analysis of calls to three poison centers for powdered caffeine found that exposures were uncommon, but did result in toxicity, and highlighted that the lack of clear dosing instructions on product packaging may place patients at risk of inadvertent overdose.

Guarana provides additional stimulation over caffeine alone in the planarian model

The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose.

Effects of caffeine and its metabolite paraxanthine on intracranial self-stimulation in male rats

Caffeine is the most widely used psychostimulant in the world, though preclinical studies suggest weaker evidence for abuse-related effects than stimulants with high abuse liability, such as amphetamine or cocaine. Intracranial self-stimulation (ICSS) is 1 procedure used to assess the abuse liability of drugs, and previous studies have produced mixed results regarding whether caffeine produces an abuse-related facilitation of ICSS. This study assessed both caffeine and its main metabolite in humans, paraxanthine, using a frequency-rate ICSS procedure and compared their effects to those of amphetamine and cocaine. Male Sprague-Dawley rats were implanted with intracranial electrodes targeting the medial forebrain bundle and trained to respond under a fixed-ratio 1 schedule for brain stimulation that varied across a range of frequencies (56-158 Hz in 0.05 log increments). Data analysis focused on 3 dependent measures: reinforced responding (defined as responses that produced brain stimulation), nonreinforced responding (defined as responses that occurred during each 0.5 s brain stimulation and that did not produce additional stimulation), and total responding (reinforced plus nonreinforced responding). Both amphetamine and cocaine produced robust increases in total, reinforced, and nonreinforced responses. Caffeine also increased total, reinforced, and nonreinforced responses, but the caffeine dose-effect curve had an inverted-U shape, and peak ICSS facilitation was less than that produced by amphetamine or cocaine. Paraxanthine increased only total responses and nonreinforced responses. These results suggest that paraxanthine has low abuse liability and does not mediate abuse-related effects of caffeine.