1. Introduction
Nutrition therapy is a nutritional-based treatment, including identifying a person’s nutritional status and giving the right foods or nutrients to treat various diseases such as cancer, diabetes, and metabolic syndrome. Numerous studies reported that deficiency of certain nutrients proceeds brain dysfunction; moreover, poor nutritional status is associated with the prevalence of pre-metabolic syndrome, hospital stay, and the life expectancy of diabetes patients [
1,
2,
3,
4]. Based on the research, the supply of appropriate nutrients is vitally essential to curing and managing various diseases.
Cancer is a complex disease characterized by the uncontrolled growth of abnormal cells. The effect of malnutrition on health and cost factors in cancer patients has been shown in several studies; especially, cancer patients with malnutrition conditions showed poor outcomes, higher medical costs, and low quality of life [
5,
6,
7]. With the increasing evidence, nutrition therapies, interventions, and assessments have shown its positive effects for managing various cancer types. For instance, studies have shown that the use of nutrition therapy results in better outcomes for patients with head and neck cancer, colorectal cancer, and pancreatic cancer [
8,
9,
10].
Malnutrition is frequent in cancer patients, and the risk is higher in older patients or those treated with chemotherapy [
11,
12]. Aging is one of the most important risk factors for cancer. The rapid growth of the aging population is expected as the number of people with cancer aged 80 or older is expected to triple by 2050 [
13]. More importantly, in older patients with cancer, malnourished patients had higher mortality rates than those who were well-nourished. Additionally, the elderly patients are particularly vulnerable to the impact of malnutrition caused by age-related changes and cancer-induced factors [
14]. Thus, an early assessment of malnourishment is critical for selecting personalized nutritional interventions while preventing sudden nutritional deterioration [
15].
Chemotherapy and radiotherapy are known as the elementary tumor therapeutic strategies used in most cancer cases. However, chemotherapy and radiotherapy often cause various side effects, which are highly susceptible to a malnourished status. Commonly reported side effects from cancer therapies include a decreased appetite, weight loss, fatigue, hair loss, nausea, and vomiting [
16,
17]. It is noteworthy that the recent research has outlined a positive role of nutritional therapy against side effects of cancer patients receiving chemo- and radiotherapy [
18,
19].
In the past, there was a lack of awareness of the clinical benefits and authoritative guidelines of nutritional therapy in cancer treatment due to insufficient evidence-based research on this topic. However, there have been outstanding efforts to promote nutrition for cancer patients. A guideline for nutrition in cancer patients was introduced on a continental level; the evidence-based guidelines were developed by ESPEN by the European Partnership for Action Against Cancer as an EU-level initiative [
20]. A comprehensive review indicated that the nutritional guidelines had shown positive results of a decrease in various types of cancer risks [
21].
Despite the significant interest in utilizing nutrition methodologies for cancer, there has not been enough scientific evidence to give more options for healthcare professionals to consider nutritional interventions [
22]. Therefore, a bibliometric study of the global trend of nutrition-cancer research was considered.
As no bibliometric studies have been conducted to seek the global trends regarding nutrition and cancer, a bibliometric study was carried out over the past 10 years. This bibliometric analysis is essential to evaluate trends, gaps, and research directions in the area of interest; in addition, it is exceptionally effective in grasping the overall trend of the research activity [
23]. Hence, the aim of the study was to perform a bibliometric analysis to explore the current status of research on nutrition and cancer from 2011 to 2021 to global research productivity, promoting future research priorities. In particular, the analysis followed the dimensions: (i) number of publication/years; (ii) authors; (iii) affiliations; (iv) author keywords; (v) journals; (vi) most cited publications; (vii) collaboration among countries.
4. Discussion
This bibliometric analysis on the topic of nutrition and cancer has provided profound findings to consider. First of all, the number of publications has been upward with the substantial growth identified since 2019. As more than 100 publications were increased since 2019, it can be expected to have more than 300 publications in 2022. The trend will continue to rise as cancer is more susceptible to aging population and is one of the leading causes of death in males and females aged 60 to 79 years [
38].
Surprisingly, a majority of the top authors’ affiliations were located in Europe. This perhaps could be associated with the high prevalence of use of complementary and alternative medicine (CAM). Kemppainen et al. mentioned that 25.9% of the general population in Europe has used CAM modalities in 2017 [
39]. The results can be seen oddly since there is a higher prevalence of using traditional medicine in Asian countries since the traditional medicine is embedded in health systems in Korea, Japan, and China [
40]. This may be perhaps cancer patients are more inclined to use herbal medicines rather than nutrition [
41].
With regard to the author keywords, malnutrition was the highest after the nutrition and cancer keywords. Even though nutritional status is regularly examined throughout the patients’ treatment, an accurate nutritional screening is critical. An acute nutritional evaluation ought to be performed at the time of each cancer diagnosis [
42]. In addition, malnutrition and eating disorders are common features during and beyond cancer therapies so that continuous nutritional management can be the key for managing cancer [
43].
From the analysis of the author keywords, breast cancer, head and neck cancer, colorectal cancer, and gastric cancer were within the top 10 list; however, it can be assumed that nutrition is well-applied to various types of cancer treatments from the results on the word cloud visualization. Other than the mentioned cancer types, lung cancer, pancreatic cancer, gastrointestinal cancer, and esophageal cancer were revealed. The reason is that nutrition influences key cellular and molecular processes that characterize cancer cells; therefore, good nutrition is especially important as it can change the illness and the course of treatments [
44].
Regarding the analysis of country collaboration, it is highly one-sided since the promotion of nutrition for cancer is heavily practiced in European countries. Some countries from Asia and North America were identified; however, not enough collaboration occurred to provide in-depth research. A collaborative effort between Asian countries is highly recommended, as the Asian countries have been used herbal medicines for a long time. Furthermore, a collaboration with the African countries is much needed since the concept of nutrition therapies are not much promoted [
45].
This study has a few limitations. First, using only the literature in English may have ignored vital insights from the literature in other languages. Considering only English publications, a few important articles in other languages may have been missed. Since a bibliometric analysis does not address specific research questions, narrow areas of the topic are not identified.
Despite the limitations, future research directions having broader exploratory research questions aimed at mapping keywords and finding gaps in the related existing knowledge and research are distinguishable using a bibliometric analysis. Hence, this bibliometric analysis contributed to a better understand of nutrition and cancer research in a clear way with the vast amount of literature with the key elements.
5. Conclusions
This bibliometric and visualized analysis of nutrition in cancer research revealed that the global trend of research regarding nutrition and cancer has gradually increased. As the number of publications has sparked since 2019, it is expected that the research output will increase in the near future. Based on the analysis of the word-cloud using the author keywords, research applying nutrition in various types of cancer could be effective. Research collaboration was noted worldwide; however, authors from European countries vibrantly worked together. Since the topic was set to be rather broad, further research should highlight in much narrower topics, indicating certain nutritional therapies and interventions with cancer patients. The findings of this study will be insightful for researchers and practitioners working in the field of nutrition and cancer, illuminating and suggesting future research directions for the betterment of cancer care, providing evidence-based solutions for healthcare professionals.