According to U.S. Census Bureau estimates, by 2030, 1 in 5 residents will be retirement age. As the senior population over the age of 65 continues to grow through the years, so will age-related cognitive health issues. The Institute of Medicine’s (IOM) book “Cognitive Aging” notes that years of research have shown age debilitates cognitive abilities such as attention, memory and visuospatial function. Changes in the brain have actually been shown to begin happening as early as age 20.¹ CDC data in a brief on subjective cognitive decline indicated it has become a growing public health issue, with signs of cognitive decline showing up among 11.1% of individuals 45 years of age and older, affecting approximately 1 in 9 adults. The current pandemic has significantly curtailed social interactions which some consider an essential activity for cognitive enrichment—particularly in aging populations²—which Nutrition Business Journal (NBJ) reported has driven increased interest in cognition supplementation. Essential minerals can play an important role in cognition and healthy aging.

Magnesium is an essential nutrient. In the aging U.S. population, magnesium intake was found to decrease with age, with mean dietary intakes significantly lower than the recommended amounts.³

In writing about the essential functions of magnesium in the brain, neuroscience researcher Sara Adaes, Ph.D, noted magnesium is a regulator of neurotransmitter signaling. It is key to the main neurotransmitters glutamate and gamma-aminobutyric acid (GABA), through modulating the activation of N-methyl-D-aspartate (NMDA) glutamate and GABA alpha receptors. Magnesium’s involvement in the mechanics of synaptic transmissions—neuronal plasticity—result in its impact on learning and memory.

In a study of aged rats, increased levels of magnesium in the brain were shown to increase synaptic plasticity that can enhance different forms of learning and memory,⁴ indicating potential application for cognitive health support.

Additionally, a systematic review determined that in comparison to healthy and medical illness controls, the magnesium levels in those with Alzheimer’s disease were significantly lower in cerebrospinal fluid and in hair (p<0.05), even though there was no difference in serum magnesium levels.⁵ Another study found that based upon the National Health Research Institute Database of Taiwan, those that had used magnesium oxide were less likely to develop dementia.⁶ This association held when the data was adjusted to compensate for various factors including age, sex, geography and economic variation.

Given the decrease in dietary magnesium intake previously described, and the role magnesium has in cognitive function and brain health, it is important that adequate magnesium be consumed to support brain health as well as the other essential functions in the body.

Zinc is another essential mineral that, like magnesium, has many functions in the body. It is a nutrient of concern for aging populations that are developing deficiency through inadequate consumption and inadequate absorption. One study showed that in adults ages 60 to 65, zinc intake was less than half of the recommended daily allowance.⁷ Interestingly, compared to the rest of the human body, zinc concentrations in the brain are the highest—at about a tenfold increase over zinc serum levels.⁸

One member of the family of zinc transporters, ZnT3, is enriched in the hippocampus and the cortex and has a prominent role in cognitive function, bundling zinc into presynaptic vesicles.⁸ These vesicles then release zinc into the synaptic cleft and aid in regulating the neuronal memory processes and influencing plasticity of the brain. In mice models, the ablation (destruction) of the ZnT3 has shown age-dependent cognitive decline.

Zinc is a structural or functional component of many proteins in the brain. Zinc homeostasis is affected in the elderly, and current evidence points to alterations in the cellular and systemic distribution of zinc in Alzheimer’s disease.⁹ Parkinson’s disease patients have been shown to have a significant decrease in zinc concentrations in the substantia nigra pars compacta area of the brain,¹⁰ the major site of the dopamine receptors. While not necessarily age related, zinc homeostatic disruption has been associated with other neurological abnormalities such as traumatic brain injury, Pick’s disease, depression, schizophrenia, epilepsy, attention deficit hyperactivity disorder (ADHD) and oxidative stress.^8,10

Iron is another mineral known for its essentiality. Iron deficiency is often cited as a leading worldwide nutritional disease and many governments have instituted mandatory iron fortification programs. Iron is another mineral essential for cognitive function. In a study on elderly patients (mean age 72 years), their iron status was assessed and cognitive function was measured using mini mental state examination (MMSE) protocol. Subjects found to have iron deficiency also had lower MMSE scores.¹¹ Other research showed that iron accumulates in portions of the brain as people age, and is associated with some neurological diseases.¹² However, it is not known if the accumulation of iron is the cause of the neurological abnormalities or a consequence.¹³

Maintaining homeostatic control of essential nutrients is necessary for normal cognitive function. The elderly population may be at extra risk for deficiencies of certain nutrients that may need to be addressed.

Stephen Ashmead, MS, MBA, is a senior fellow for Balchem Corp. His area of specialty is in mineral amino acid chelates and their functions.

References

1 Murman DL. “The Impact of Age on Cognition.” Semin Hear. 2015;36(3):111-121.

2 Hertzog C et al. “Enrichment Effects on Adult Cognitive Development: Can the Functional Capacity of Older Adults Be Preserved and Enhanced?” Psychol Sci Public Interest. 2008;9(1):1-65.

3 Ford ES, Mokdad AH. “Dietary magnesium intake in a national sample of US adults.” J Nutr. 2003;133(9):2879-2882.

4 Slutsky I et al. “Enhancement of learning and memory by elevating brain magnesium.” Neuron. 2010;65(2):165-177.

5 Veronese N et al. “Magnesium Status in Alzheimer's Disease: A Systematic Review.” Am J Alzheimers Dis Other Demen. 2016;31(3):208-213.

6 Tzeng NS et al. “Magnesium oxide use and reduced risk of dementia: a retrospective, nationwide cohort study in Taiwan.” Curr Med Res Opin. 2018;34(1):163-169.

7 Mocchegiani E et al. “Zinc: dietary intake and impact of supplementation on immune function in elderly.” Age (Dordr). 2013;35(3):839-860.

8 Portbury SD, Adlard PA. “Zinc Signal in Brain Diseases.” Int J Mol Sci. 2017;18(12):2506-2518.

9 Nuttall JR, Oteiza PI. “Zinc and the aging brain.” Genes Nutr. 2014;9(1):379.

10 Grabrucker AM, Rowan M, Garner CC. “Brain-Delivery of Zinc-Ions as Potential Treatment for Neurological Diseases: Mini Review.” Drug Deliv Lett. 2011;1(1):13-23.

11 Yavuz BB et al. “Iron deficiency can cause cognitive impairment in geriatric patients.” J Nutr Health Aging. 2012;16:220-224.

12 Zecca L et al. “Iron, brain ageing and neurodegenerative disorders.” Nat Rev Neurosci. 2004;5:863-873.

13 Fairweather-Tait SJ et al. “Iron status in the elderly.” Mech Ageing Dev. 2014;136-137(100):22-28.