Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
This original research article examined the association between dietary fiber intake and serum concentrations of heavy metals, specifically mercury (Hg), cadmium (Cd), and lead (Pb) among US adults who consume recommended amounts of seafood. The study was motivated by concerns regarding heavy metal accumulation through seafood, a primary dietary source of these toxicants, and the hypothesized protective effect of dietary fiber, which has demonstrated metal-binding and excretion-promoting properties in animal and in vitro studies. By leveraging data from the 2013–2014 National Health and Nutrition Examination Survey (NHANES), this investigation sought to clarify whether increased dietary fiber intake is linked to lower blood levels of these metals in human subjects who are at elevated risk of exposure due to their seafood consumption patterns. The study used linear regression analyses, adjusting for potential confounding factors such as age, sex, race/ethnicity, and income, to evaluate the relationships between fiber intake and serum heavy metal concentrations.
Who was studied?
The study population comprised 422 non-institutionalized US adults, aged 18 years or older, who participated in NHANES 2013–2014. Eligibility was restricted to those who reported consuming at least eight servings of seafood per month, aligning with the American Heart Association’s recommendations. This selection targeted individuals exposed to higher dietary heavy metal loads due to seafood intake. The cohort was demographically diverse, reflecting national representation, with oversampling of Asian, Hispanic, and non-Hispanic Black populations to enhance the reliability of subgroup analyses. Dietary fiber intake was calculated from two 24-hour dietary recalls, and serum Hg, Cd, and Pb levels were measured using standardized laboratory protocols. Covariates included biological sex, age, race/ethnicity, and a ratio of family income to poverty.
Most important findings
| Finding | Detail |
|---|---|
| Inverse association between fiber and metals | After adjusting for covariates, higher dietary fiber intake was significantly associated with lower serum Cd and Pb levels. Each 10-gram increase in dietary fiber was linked to a 6.72% decrease in serum Cd (p=0.0010) and a 5.65% decrease in serum Pb (p=0.0019). No significant association was found between fiber intake and serum Hg. |
| Demographic disparities in heavy metal levels | Non-Hispanic Asian adults had markedly higher serum levels of Hg, Cd, and Pb compared to non-Hispanic Whites, even after adjustments. Age was positively associated with all three heavy metals: with each additional year, serum concentrations of Hg, Cd, and Pb increased by 1.50%, 2.06%, and 1.76%, respectively. Males had higher Pb but lower Cd compared to females. Higher income was linked to higher Hg but lower Cd and Pb. |
| Seafood as a primary exposure source | Participants meeting seafood intake recommendations had measurable levels of heavy metals, underscoring seafood as a dominant exposure route in this population. However, the average fiber intake was below national guidelines, indicating room for dietary improvement. |
| Mechanistic implications | The findings support the hypothesis that dietary fiber may reduce Cd and Pb absorption and promote excretion, possibly through binding and reduced gastrointestinal uptake, but not for Hg in this population. The study suggests that demographic and socioeconomic factors influence heavy metal burden. |
Key implications
For heavy metal certification programs, this study indicates that promoting higher dietary fiber intake may help mitigate cadmium and lead exposure risks in populations with high seafood consumption. Certification standards could consider dietary guidance as part of risk management. The lack of effect on mercury suggests that parallel strategies are needed for comprehensive heavy metal mitigation.
Citation
Guo J, Knol LL, Yang X, Kong L. Dietary fiber intake is inversely related to serum heavy metal concentrations among US adults consuming recommended amounts of seafood: NHANES 2013–2014. Food Frontiers. 2022;3:142–149. doi:10.1002/fft2.114
Cadmium is a persistent heavy metal that accumulates in kidneys and bones. Dietary sources include cereals, cocoa, shellfish and vegetables, while smokers and industrial workers receive higher exposures. Studies link cadmium to kidney dysfunction, bone fractures and cancer.
Lead is a neurotoxic heavy metal with no safe exposure level. It contaminates food, consumer goods and drinking water, causing cognitive deficits, birth defects and cardiovascular disease. HMTC’s rigorous lead testing applies ALARA principles to protect infants and consumers and to prepare brands for tightening regulations.
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
