In this investigation, we indicated that the dietary consumption of n3 and n6 fatty acids was negatively correlated with the risk of hyperuricemia, while no significant association between the n6:n3 ratio and the possibility of hyperuricemia was found. Furthermore, the dose‒response analyses showed linear associations between the dietary consumption of n3 and n6 fatty acids and the risk of hyperuricemia.
To the best of our knowledge, this was the first investigation into the correlation between dietary intakes of n3, n6 and the ratio of n6 to n3 fatty acids and the risk of hyperuricemia in US adults using a nationally representative sample. The results of several previous studies were consistent with our findings. An in vitro cell experiment showed that unsaturated fatty acids, especially polyunsaturated fatty acids, could strongly inhibit urate transporter 1 (URAT1), which could reabsorb urate filtered by the glomerulus of the kidney from primary urine into the blood[16]. Akhigbe et al. found that n3 fatty acids decreased testicular uric acid significantly in Torsion/Detorsion rats[15]. However, contrary to our findings, a study comprising 113 participants who were 18 years of age and older at the Hospital of the Federal University of Uberlandia revealed no correlation between n-3 and n-6 fatty acids and blood uric acid[22]. The disparity could be explained by a number of things. First, when compared to that of our study (21,120 American adults), the sample of the above research was too small (113 American adults). Second, the participants in the earlier study were all kidney transplant patients, and their uric acid metabolism was abnormal because of kidney dysfunction.
Although the underlying mechanisms between dietary consumption of n3 and n6 fatty acids and the risk of hyperuricemia are not completely understood, several possibilities have been proposed. First, prior research revealed that n3 and n6 fatty acids were inversely connected to the incidence of hypertension and had a protective effect on defective endothelial cells and nitric oxide-dependent responses[23, 24]. Meanwhile, hypertension could elevate serum uric acid levels by increasing renal vascular resistance and uric acid retention[25]. Thus, n3 and n6 fatty acids might decrease susceptibility to hyperuricemia by lowering blood pressure. Second, polyunsaturated fatty acids could prevent and reverse insulin resistance[26, 27]. Insulin resistance increased serum uric acid levels by damaging urinary endothelial function and reducing uric acid excretion[28, 29]. Therefore, n3 and n6 fatty acids were likely inversely related to elevated serum uric acid levels because of their function of improving insulin resistance. To understand the mechanisms behind the link between dietary consumption of n-3 and n-6 fatty acids and the risk of hyperuricemia, more research is needed.
Previous research revealed that the intake of dairy products[30–32], vitamin C[33], vitamin D[34], soy products[35], dietary fiber[36], magnesium[37], and dietary zinc intake[38] were adversely connected to the incidence of hyperuricemia. Thus, dietary changes may be connected to hyperuricemia. Our findings showed that increased dietary polyunsaturated fatty acids might decrease the risk of hyperuricemia. In addition, green leafy vegetables, legumes, nuts, and seafood are all rich in polyunsaturated fatty acids[11, 39], and these foods are common in our daily meals. It is beneficial for individuals to maintain sufficient polyunsaturated fatty acid intake to prevent the risk of hyperuricemia.
When stratified by age, the dietary consumption of n3 and n6 fatty acids was associated with a nonsignificant lower risk of hyperuricemia among people aged 60 years old and above in the fully adjusted model. This may be explained by the high prevalence of hypertension among older adults. Some antihypertensive medications, such as loop and thiazide diuretics, cause relative hypovolemia, which induces a compensatory increase in proximal uric acid reabsorption[40], and approximately two-thirds of all uric acid is excreted by the kidneys[29].
Our study has several strengths. First, this was the first study to investigate the correlation between dietary n3 and n6 fatty acids and the susceptibility of hyperuricemia with their dose‒response relationship among US adults using the largest nationally representative sample (21,120 participants). Second, to lessen the impact of visceral fat accumulation and kidney on serum uric acid, we performed sensitivity analyses by removing subjects with obesity (BMI 30 kg/m2) and substantial renal dysfunction (eGFR lower than 60 mL/min/1.73 m2)[41, 42]. Third, the utilization of trained personnel who adhered to standardized protocols for measuring essential study data and conducting interviews enhanced the accuracy and efficiency of the data collection process.
Additionally, our study has some flaws. First, it is impossible to determine causality due to the cross-sectional design. Future studies utilizing longitudinal designs are necessary to confirm our findings. Second, two 24-hour food recall interviews were used to collect the dietary data, which may not have provided an accurate representation of long-term average intake. Third, our study did not take into account the intake of n3 and n6 fatty acids from dietary supplements, which could be an important source of these nutrients. Fourth, our study population was limited to Americans, and it is unclear whether our results can be generalized to other countries.