Key Points
- A study conducted by researchers at Jiangmen Central Hospital (China) identified a non-linear (J-shaped) relationship between red blood cell (RBC) folate levels and visceral adipose tissue (VAT) mass. Specifically, VAT mass was negatively associated with RBC folate levels below 397.18 ng/mL and positively associated above this threshold.
- The researchers analyzed data from 7,591 U.S. adults across four NHANES cycles (2011–2018). RBC folate was quantified using a two-step process involving microbiologic assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS), ensuring robust and accurate biomarker assessment.
- The findings highlight RBC folate as a potential biomarker for visceral adiposity and metabolic risk, suggesting the need for longitudinal studies to understand whether changes in folate status influence or result from VAT accumulation and related metabolic conditions.
A study conducted at Jiangmen Central Hospital (China) aimed to determine the association between red blood cell (RBC) folate and visceral adipose tissue in young and middle-aged U.S. adults, focusing on the folate’s potential role as a determinant of visceral adiposity. This new study is based on previous research that linked RBC folate levels to obesity. RBC folate levels were quantified using a multi-step process combining microbiologic assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A paper based on this research was published in Frontiers in Nutrition (1).
Associated with an increased risk of a variety of non-communicable diseases (including diabetes, non-alcoholic steatohepatitis, cardiovascular diseases, gout, and various cancers), obesity has emerged as a critical public health concern because of its increasing global prevalence (2–5). Recently, obesity has been defined as a condition distinguished by characterized by an increase in body fat, with clinical obesity particularly acknowledged as a chronic, systemic illness where increased body fat leads to damage of organs, tissue, possibly leading to cardiovascular disease and kidney failure. This revised definition focuses on the need for more thorough methods of assessment of the condition besides body mass index (BMI), as well as more direct measures of body fat and its impact on functional health (6).
Folate, also known as vitamin B9, refers to a group of water-soluble compounds which are essential for a variety of physiological functions, including synthesis of DNA, cell division, and the prevention of neural tube defects (7,8). While naturally occurring folates can be found in leafy green vegetables, legumes, and citrus fruits, mandatory fortification of enriched cereal grains was authorized the United States in 1996 and fully implemented two years later (9,10). Public health concerns have shifted over time from thinking that not enough folates were being taken in through diet, to there being an excessive intake with associated risks (11).
This study utilized data from 7591 individuals taken from four cycles of the National Health and Nutrition Examination Survey (NHANES) conducted between 2011–2012, 2013–2014, 2015–2016, and 2017–2018, managed by the Centers for Disease Control and Prevention (CDC). For each of these cycles, RBC folate was assessed using a multi-step process. First, whole blood folate concentration was measured using a microbiologic assay, followed by an adjustment for RBC volume. Serum total folate concentration, calculated as the sum of individual serum folate forms, was then used to correct the RBC folate values.
Individual serum folate forms were quantified using liquid chromatography–tandem mass spectrometry (LC–MS/MS), resulting in RBC folate levels positively associated with VAT mass. A J-shaped dose–response relationship was observed with a threshold effect identified at an RBC folate level of 397.18 ng/mL. Below this threshold, the association was negative, while above the threshold, the association became positive (1).
