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Backed by science or just another Facebook rumor?
For years, concerns have circulated about cadmium— a heavy metal present in trace amounts in air, water, soil, and food—negatively affecting cognitive health. Yet, scientific research has yielded mixed results, leaving questions about cadmium's long-term impact on memory and thinking skills unanswered.
In light of this ongoing debate, a recent study published in the online issue of Neurology explored the connection between cadmium exposure and cognitive decline, tracking 2,172 individuals over a 10-year period. Interestingly, the results showed no significant association when analyzing the group as a whole. However, when researchers looked at the data for black and white participants separately, they discovered that cadmium exposure may be linked to cognitive decline in white individuals, while no such association was found in black individuals.
This article will delve into the findings of the study and examine the broader context of environmental toxins and their effects on cognitive health.
What is Cadmium?
Cadmium is a naturally occurring heavy metal found in trace amounts in the Earth's crust. It enters the environment primarily through industrial and agricultural activities, contaminating air, water, and food— and primarily enters the food supply through contaminated soil. Neuroscientific research reveals that cadmium can cross the blood-brain barrier, disrupt calcium regulation in neurons, and trigger inflammation, leading to oxidative stress and the death of neural cells.
These effects are linked to cognitive decline and neurodegenerative diseases such as Alzheimer's. Cadmium’s long half-life allows it to accumulate in the brain over time, making its effects particularly concerning.
Findings from the Study
The REasons for Geographic and Racial Differences in Stroke (REGARDS) study measured the urinary cadmium levels and cognitive function of 2,172 participants averaging 64 years old, over a 10-year period.
While no overall association was found, high urinary cadmium concentration was linked to approximately a two-fold increase in the risk of global cognitive impairment in white participants, but not black participants.
This racial difference may be influenced by smoking habits, as white participants had higher median smoking pack-years, a key source of cadmium exposure (read this for more information on smoking pack years). Cadmium inhaled through smoking accumulates in the lungs and bloodstream, potentially triggering proinflammatory markers, contributing to cognitive decline.
A previous cohort study in a Chinese population suggested a similar link between blood Cd levels and cognitive decline, with higher smoking rates and cadmium exposure likely contributing factors. Despite the differences in exposure between groups, the average cadmium levels in this study were similar to national data, supporting the potential for long-term cadmium accumulation to affect cognition.
Cadmium– a Friend or Foe to Our Cognition?
So, should we be wary of cadmium? The answer is yes, absolutely.
Research suggests this heavy metal could be linked to cognitive decline, and its ability to accumulate in the body over time underscores the need for caution. To minimize risks, stricter environmental policies, improved soil management, and lifestyle changes like reducing tobacco use are essential. Raising public awareness and promoting further research can help mitigate cadmium’s potential dangers and protect cognitive health. Empowerment through knowledge is key!
Reference list
Cohen, F. (2024). Cadmium exposure may be linked to memory problems in some people. [online] Medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/heavy-metal-cadmium-exposure-linked-memory-problems-some-people#Does-cadmium-exposure-lead-to-dementia? [Accessed 5 Oct. 2024].
Kabir, Md.T., Uddin, Md.S., Zaman, S., Begum, Y., Ashraf, G.M., Bin-Jumah, M.N., Bungau, S.G., Mousa, S.A. and Abdel-Daim, M.M. (2020). Molecular Mechanisms of Metal Toxicity in the Pathogenesis of Alzheimer’s Disease. Molecular Neurobiology, 58(1), pp.1–20. doi:https://doi.org/10.1007/s12035-020-02096-w.
Lu, L., Zhang, Y., Angley, M., Bejerano, S., Brockman, J.D., McClure, L.A., Unverzagt, F.W., Fly, A.D. and Kahe, K. (2024). Association of Urinary Cadmium Concentration With Cognitive Impairment in US Adults. Neurology, 103(7). doi:https://doi.org/10.1212/wnl.0000000000209808.
News, N. (2024). Cadmium Exposure Linked to Memory Issues - Neuroscience News. [online] Neuroscience News. Available at: https://neurosciencenews.com/cadmium-memory-neurology-27610/ [Accessed 5 Oct. 2024].
Zhang, T., Xu, Z., Wen, L., Wang, G., Li, S., Wang, J., Huang, J., Wang, N., Durkan, C., Liao, X. and Wang, G. (2021). Cadmium-induced dysfunction of the blood-brain barrier depends on ROS-mediated inhibition of PTPase activity in zebrafish. Journal of Hazardous Materials, 412, pp.125198–125198. doi:https://doi.org/10.1016/j.jhazmat.2021.125198.
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