Impact of caffeine consumption on oxidation of fats: common themes and future research

By Pooja Toshniwal PahariaOct 12 2023Reviewed by Lily Ramsey, LLM

In a recent study published in Nutrients, researchers visually evaluated the association between caffeine consumption and fat oxidation to identify the most common themes and guide future research, emphasizing the significance of balancing caffeine intake with fat oxidation.

Study: Research Trends in the Effect of Caffeine Intake on Fat Oxidation: A Bibliometric and Visual Analysis. Image Credit: Volgastudio/Shutterstock.com

Background

Caffeine use is gaining popularity due to its possible health advantages, particularly in improving athletic performance. Several studies have investigated the impact of caffeine consumption on the oxidation of fats during rest and exercise.

This action stimulates the sympathetic nervous system, which increases fatty acid release and improves lipolysis. Although this action may be useful for weight loss and fat mass reduction, it is crucial to consider caffeine's influence on blood pressure and sleeplessness.

Bibliometric analysis can aid in determining the level of scientific attention to caffeine consumption as an approach to increasing fat oxidation.

About the study

In the present bibliometric review, researchers investigated published studies that evaluated the association between oral caffeine consumption and the rate of fat oxidation.

The Web of Science (WoS) database was searched to retrieve relevant records published between the database's creation (1992) and December 31, 2022.

The publication counts and their citations, citation journals, H-indexes, co-citation, keyword co-occurrence, and co-authorship were all gathered as qualitative and quantitative data. Data were extracted, including the title, publication year, keywords, abstract, author affiliations, and document type.

The "topic" selection filter was used with keywords such as "fat oxidation" and "caffeine" for data search. The examination includes caffeine administration data ranging from "pure" forms of caffeine in tablets and capsules to caffeinated meals and beverages such as tea, coffee, and energy drinks.

On May 6, 2023, two researchers conducted a language-free data search, and a third researcher resolved disagreements between the two.

Book chapters, abstracts from conferences, and early-access publications were not included. Price's law was utilized to assess the exponential growth in relevant publications. The Lotka analysis determined the writers with the most publications on the topic.

H-index values were used to identify writers who contributed the most to the research field. Furthermore, Zipf's law was applied to identify the most frequently used keywords in the selected papers (372 keywords).

Discussion

The objective of this research was to evaluate the body of work pertaining to oral caffeine consumption and its impact on fat oxidation over the past few decades. This was achieved by conducting a comprehensive bibliometric and visual analysis using the keywords "caffeine" and "fat oxidation." The primary aim of this review was to trace the evolution of research related to the effects of oral caffeine intake on fat oxidation from 1992 to 2022, identifying recurring research themes and guiding future investigations.

The analysis uncovered a total of 182 relevant documents, with a noteworthy increase of 20.1% in the number of publications between 1997-2009 (73 documents) and 2009-2022 (109 documents). Key journals for publication included "Nutrients" (12 documents) and the "British Journal of Nutrition" (10 documents), mainly falling within the nutrition and dietetics category on the Web of Science (WoS) platform. While collaborative networks often involved authors from Japan, the most prolific countries in terms of document count and citations were the United States and the Netherlands.

Interestingly, the analysis revealed a shift in the choice of keywords, moving towards associations with caffeine's use in exercise performance as opposed to its role in obesity. This shift was more pronounced in recent publications, indicating a changing focus in research.

Out of the 182 documents identified, 157 were original articles and 25 were review articles, demonstrating a substantial proportion of studies with novel data. The research was primarily categorized into two domains on the WoS platform: "nutrition and dietetics" (108 documents) and "sport sciences" (48 documents). These two categories accounted for the vast majority (85.71%) of documents in the study, emphasizing the need for research papers to cater to readers with mixed knowledge in both nutrition and sports sciences.

Although the number of journals included in the WoS has increased over the years, the data showed no exponential growth, suggesting a relatively consistent level of scientific interest in caffeine's impact on fat oxidation. The peak year for publications was 2014, with a subsequent decline in the number of papers, indicating reduced attention to the topic in recent years.

Furthermore, the H Index analysis revealed that several authors had garnered significant citations, with studies by Dulloo et al. and Graham being the most cited documents, even though they were over 20 years old. The analysis also highlighted key researchers and institutions in the field, which can inform future research directions.

Examining the keywords used in the documents, it was found that the terms "caffeine," "fat oxidation," "green tea," "energy expenditure," and "obesity" were most frequently employed. However, there was a shift in the trend towards more recent keywords such as "performance," "carbohydrate," and "ergogenic aid," suggesting an increasing interest in the use of caffeine to influence fat oxidation during exercise among athletes and physically active individuals, with a decreasing emphasis on its role in treating obesity. This shift may point to a changing landscape of scientific inquiry in this domain.

Conclusions

The findings of this bibliometric analysis, centered on the relationship between caffeine intake and its impact on fat oxidation during both rest and exercise, revealed a total of 182 documents, comprising 157 scientific articles and 25 review articles. These documents span the period from 1992 to 2022. It is worth noting that the volume of publications in this field appears to have plateaued, with the highest number of documents being recorded in 2014, and a subsequent decrease in annual publications. This trend suggests that this topic may have reached a state of saturation.

Nevertheless, it is evident that the subject remains a point of significant interest within the scientific communities of nutrition and exercise physiology. The documents in this domain, on average, received 130 citations, indicative of sustained academic interest. Notably, 52 authors have accumulated a minimum of 52 citations, underscoring the impact of their contributions.

These documents predominantly found their place within the categories of nutrition and dietetics as well as sport sciences on the Web of Science platform. Collaborative networks among authors were notably observed, particularly involving researchers from Japan.

Furthermore, a notable shift in research emphasis is observed, with a growing interest in the utilization of caffeine to enhance fat oxidation in the context of athletic performance, as reflected by the increased use of keywords like "ergogenic aid" and "performance."

Future research endeavors in this field may consider investigating the influence of variables such as gender and caffeine tolerance, thereby broadening the assessment of the efficacy of oral caffeine intake as a nutritional strategy to enhance fat utilization, given the limited inclusion of these aspects in the identified documents.