High Prevalence of Low Creatine Intake among Individuals Following Common Special Diets

Abstract

Introduction

Creatine is a conditionally essential nutrient central to cellular energy metabolism, with roughly half of daily requirements derived from dietary sources found exclusively in animal-based foods. Insufficient dietary creatine intake has been linked to various adverse health outcomes, yet data on creatine adequacy among individuals following special diets remain limited. This study examined the prevalence of low dietary creatine intake among US individuals adhering to different special diets using cumulative data from the National Health and Nutrition Examination Survey (NHANES).

Methods

Data from NHANES 2003–2023 cycles were merged to identify participants (≥1 year old) reporting adherence to a special diet in the Dietary Data domain. Self-reported diets were categorized into thirteen groups (e.g., weight-loss, diabetic, low-fat, low-carbohydrate, gluten-free). Dietary creatine intake, estimated using established methods and excluding supplements, was classified as adequate (≥1 g/day) or inadequate (<1 g/day). Differences in the prevalence of inadequate creatine intake across diet types were assessed using chi-square tests with Bonferroni-adjusted post hoc comparisons.

Results

Among 8,407 participants (57.8% female; mean age = 45.0 ± 21.5 years) reporting adherence to a single special diet, mean creatine intake was 0.82 ± 0.82 g/day, with 69.5% classified as having inadequate intake. The prevalence of low creatine intake differed significantly across diet types (p < 0.0001), ranging from 83.3% in low-fiber diets to 60.4% in renal diets. Individuals following low-carbohydrate diets exhibited a significantly lower prevalence of inadequate intake (p = 0.00097), while high- and low-fiber, gluten-free, and weight-loss diets were associated with higher prevalence rates. Women showed greater creatine insufficiency than men across several dietary categories.

Conclusion

Inadequate dietary creatine intake is highly prevalent among individuals following a variety of special diets in the US population. Restrictive or plant-forward regimens appear particularly associated with insufficient intake, underscoring the need for nutritional strategies – such as creatine-fortified foods or supplementation – to maintain optimal creatine homeostasis and support metabolic health in at-risk groups.

Introduction

Creatine is a conditionally essential nutrient that plays a vital role in maintaining energy metabolism throughout the human body. Approximately half of the daily creatine requirement is met through exogenous intake, with dietary creatine derived exclusively from animal-based foods (for a detailed review, see [1]). The daily creatine requirement is approximately 2 g, obtained from both dietary intake and endogenous synthesis. The body synthesizes about 1 g/day through enzymatic reactions in the kidney and liver, and individual variability arises from differences in diet, muscle mass, sex, age, and genetic factors [2]. Inadequate dietary creatine intake – commonly defined as <1 g/day – appears to be prevalent in the general population and has been associated with a range of adverse health outcomes, including cardiometabolic disorders, mental health conditions, impaired growth, and cancer [3]. Ensuring sufficient dietary creatine intake may be essential for maintaining optimal creatine homeostasis and preventing creatine insufficiency. Emerging evidence indicates that vegan diets may compromise creatine homeostasis [4]; however, data on the adequacy of creatine intake among individuals adhering to other common special diets are currently lacking. This cross-sectional analysis examines the prevalence of low creatine intake in individuals following various special diets, using cumulative data from the National Health and Nutrition Examination Survey (NHANES) for participants aged 1 year and older.

Methods

For this analysis, data from the NHANES cycles spanning 2003–2023 were merged, specifically incorporating information on special diets obtained through the Dietary Data domain (DR1TOT). Dietary data were collected via in-person interviews, during which participants of all ages were asked whether they were currently following any type of diet, either for weight loss or for other health-related reasons. If applicable, respondents were further queried about the specific type of diet being followed. The responses were not restricted to a predefined list; rather, participants self-reported the type of diet they followed, and trained interviewers subsequently categorized these responses into groups (e.g., low-fat/low-cholesterol diet, low-sodium diet, weight-loss diet, diabetic diet, high-protein diet, or “other special diet”) for analytical purposes. This approach enables NHANES to capture the prevalence and nutrient intakes associated with diverse dietary regimens across the US population; detailed procedures are described in the “Dietary Interview Procedure Manuals” [5]. Daily dietary creatine intake was estimated using previously established methods [6], and intake was subsequently classified as either adequate (≥1 g/day) or inadequate (<1 g/day), in accordance with thresholds proposed in prior literature [1]. Creatine intake from nutritional supplements was excluded from the analysis. To assess differences in the prevalence of inadequate creatine intake across various types of special diets, chi-square tests were applied. Post hoc pairwise comparisons between individual special diets were conducted using chi-square or Fisher’s exact tests, as appropriate based on cell counts. To adjust for multiple comparisons and control the family-wise error rate, the Bonferroni correction was applied. See STROBE checklist in online supplementary file (for all online suppl. material, see https://doi.org/10.1159/000549528).

Results

Out of 90,750 valid cases – after excluding NHANES respondents with missing data and those who were uncertain about their adherence to a special diet – a total of 9,723 individuals (10.7%) reported currently following one or more special diets. For subsequent analyses, individuals who reported adherence to multiple special diets were excluded, yielding a final analytical sample of 8,407 participants (57.8% female; mean age 45.0 ± 21.5 years). Among the thirteen distinct types of special diets reported, the most prevalent were the weight-loss diet (54.2%), followed by the diabetic diet (13.4%), low-fat diet (7.9%), and low-salt diet (6.3%); the remaining dietary regimens were reported less frequently. In this final sample, the mean daily dietary creatine intake was 0.82 ± 0.82 g (95% confidence interval: 0.80–0.84 g; median: 0.62 g; IQR: 0.87 g), and the overall prevalence of low creatine intake was 69.5%. The prevalence of low creatine intake differed significantly across special diet types (p < 0.0001), with the highest rates observed among individuals following a low-fiber diet (83.3%) and a high-fiber diet (82.1%). In contrast, the lowest prevalence was recorded among those adhering to a renal diet (60.4%) and a low-carbohydrate diet (61.3%) (Fig. 1). Post hoc analysis indicated a significantly lower prevalence of inadequate creatine intake among individuals adhering to a low-carbohydrate diet (p = 0.00097), whereas a significantly higher prevalence was observed among participants following other special diets (p < 0.0001). The mean daily creatine intake across different special diets was as follows: weight-loss diet, 0.81 ± 0.77 g (n = 4,541); low-fat diet, 0.85 ± 0.80 g (n = 660); low-salt diet, 0.83 ± 0.96 g (n = 528); sugar-free diet, 0.96 ± 1.21 g (n = 171); low-fiber diet, 0.63 ± 0.62 g (n = 12); high-fiber diet, 0.44 ± 0.58 g (n = 28); diabetic diet, 0.82 ± 0.78 g (n = 1,124); weight-gain diet, 1.07 ± 1.36 g (n = 272); low-carbohydrate diet, 0.94 ± 0.77 g (n = 333); high-protein diet, 1.00 ± 0.96 g (n = 83); gluten-free diet, 0.69 ± 0.66 g (n = 106); renal diet, 0.93 ± 0.84 g (n = 53); and other special diets, 0.62 ± 0.65 g (n = 464). Gender-specific analyses indicated a higher prevalence of creatine insufficiency among women compared to men across several special diets, including weight loss, diabetic, and low-carbohydrate diets (online suppl. Table 1).

Fig. 1.

Prevalence of inadequate creatine intake (%) across different special diets (n = 8,407). * indicates significantly different prevalence rates at p < 0.0001 between individual sample pairs. CHO, carbohydrate.

Discussion

This cross-sectional, population-based study is the first to report a high prevalence of inadequate dietary creatine intake among individuals adhering to a range of special diets followed for weight loss or other health-related reasons. The analysis revealed that the majority of individuals following common dietary regimens – such as low- and high-fiber diets, gluten-free diets, and weight-loss diets – consume <1 g of creatine per day, a level considered insufficient to meet physiological demands [1]. Notably, gender-specific analyses revealed a higher prevalence of creatine insufficiency among women across several dietary patterns.

These findings highlight a potential risk of creatine insufficiency associated with dietary practices that limit or exclude animal-derived foods, the sole natural source of creatine. Interestingly, the prevalence of creatine inadequacy among individuals adhering to various types of special diets was higher than among those not following any special diet (65.2%) [7]. This finding suggests that adherence to certain special diets may elevate the risk of insufficient creatine intake. Dietary restrictions or modifications inherent to these regimens may limit creatine-rich food sources (e.g., meat and fish), thereby reducing overall creatine availability and potentially influencing metabolic health. For example, high-fiber diets are often plant-based and emphasize the consumption of fruits, vegetables, legumes, and whole grains, while minimizing or excluding animal products. Although such diets confer numerous cardiometabolic benefits, they typically lack significant amounts of dietary creatine, which is naturally found only in animal tissues. Furthermore, the high content of certain plant fibers and phytochemicals may indirectly affect creatine metabolism by modulating intestinal absorption or altering gut microbiota composition, potentially influencing the bioavailability of creatine precursors such as arginine and glycine. Conversely, low-fiber diets often include refined carbohydrates and processed foods but not necessarily meat or fish in substantial quantities. Individuals adhering to low-fiber regimens for gastrointestinal or medical reasons may also avoid high-protein or fatty foods, further limiting creatine intake from traditional dietary sources. Similarly, gluten-free, low-protein, and weight-reduction diets often emphasize food elimination or energy restriction that can inadvertently reduce total protein and creatine consumption. As creatine is primarily obtained from skeletal muscle tissue in food, such restrictive eating patterns may place followers at greater risk of suboptimal intake.

Given creatine’s fundamental role in cellular energy metabolism, neuromuscular function, and cognitive performance, such insufficiencies may carry significant physiological consequences over time. To address this nutritional gap, exogenous creatine intake – via creatine-enriched foods or dietary supplements – may offer a targeted and practical strategy for individuals at risk. Special diets such as vegetarian, vegan, gluten-free, low-protein, and weight-reducing regimens are increasingly common, particularly among health-conscious populations [8], yet they may unintentionally result in suboptimal creatine intake. Supplementation could serve as a viable approach to maintaining creatine homeostasis and mitigating the risk of insufficiency-related health outcomes. Given its well-established safety profile and biological relevance, creatine supplementation represents a promising nutritional intervention for individuals following restrictive diets.

This study has several limitations. Its cross-sectional design prevents causal inference, and creatine intake was based on a single 24-h recall, which may not reflect habitual intake. Self-reported diet data may be biased, and excluding individuals on multiple diets may limit generalizability. Differences in the composition and adherence to specific special diets were not accounted for, potentially affecting creatine intake estimates. Additionally, no biochemical markers were assessed. While we adopted a threshold of <1 g/day to define low creatine intake based on previous literature, this cutoff remains somewhat arbitrary and may not universally reflect physiological need across all age, sex, or lifestyle groups. Establishing a robust, evidence-based threshold for optimal dietary creatine intake remains an unmet need in nutrition research. Future longitudinal studies with validated measures are warranted to establish population-specific guidelines, determine optimal intake levels, and evaluate the long-term efficacy of creatine intake in at-risk groups.

Acknowledgment

S.M.O. expresses gratitude to Kali Malone for her transformative works.

Statement of Ethics

Ethical approval for the NHANES study was granted by the US National Center for Health Statistics Ethics Review Board (#98-12, #2005-06, Continuation of Protocol #2005-06, #2011-17, Continuation of Protocol #2011-17, #2018-01, Continuation of Protocol #2018-01, and #2021-05). Written informed consent was obtained from all participants prior to their inclusion in the study. The research was conducted ethically following the World Medical Association Declaration of Helsinki.

Conflict of Interest Statement

S.M.O. serves as a member of the Scientific Advisory Board on Creatine in Health and Medicine (AlzChem LLC). S.M.O. co-owns patent “Supplements Based on Liquid Creatine” at the European Patent Office (WO2019150323 A1) and patent application “Composition Comprising Creatine for Use in Telomere Lengthening” at the US Patent and Trademark Office (# 63/608,850). S.M.O. has received research support related to creatine during the past 36 months from the Ministry of Science, Technological Development and Innovation; Provincial Secretariat for Higher Education and Scientific Research; AlzChem GmbH; Kaneka Nutrients; ThermoLife International, and Vireo System Inc. S.M.O. is the co-founder of KRE-ALL, a company that develops food products enriched with creatine.

Funding Sources

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author Contributions

S.M.O.: conceptualization; formal analysis; investigation; methodology; visualization; writing – original draft, review, and editing.

Funding Statement

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data Availability Statement

The datasets supporting the conclusions of this study are publicly available and can be accessed through the National Health and Nutrition Examination Survey (NHANES) repository maintained by the National Center for Health Statistics at https://www.cdc.gov/nchs/nhanes/. The authors do not own the data. For further information, please contact the corresponding author.