As global populations age, the prevalence of neurodegenerative diseases such as Alzheimer’s disease (AD) continues to rise. Increasing evidence suggests that nutritional factors may play an important role in protecting cognitive function and delaying neurodegeneration. Recent research from Shanghai Sixth People’s Hospital indicates that daily supplementation with certain vitamins—including folic acid, B vitamins, vitamin D, and coenzyme Q10—may significantly reduce the risk of cognitive impairment in adults over 50 years old. In addition, vitamin D supplementation may help slow the progression from mild cognitive impairment to Alzheimer’s disease. Complementary findings from a large UK Biobank study further show that higher dietary magnesium intake is associated with larger brain volumes and fewer white matter lesions, both indicators of better brain health. Together, these findings highlight the potential importance of adequate micronutrient intake in supporting cognitive resilience and reducing the long-term risk of dementia.
“Alzheimer’s disease is like taking a walk in the park—except that after developing Alzheimer’s, my park is always changing.”
With the acceleration of population aging, the prevalence of age-related neurodegenerative diseases has increased significantly.
However, AD does not develop overnight; it has an insidious onset and progresses through several stages.
The earliest stage of AD is subjective cognitive decline (SCD). The initial feature is impaired ability to encode and store new memories, often manifested as frequent mild distraction. As the condition progresses, it may develop into mild cognitive impairment (MCI), which can be identified through neuropsychological testing and represents the earliest stage at which AD can be diagnosed. With further deterioration of cognition and functional ability on the basis of MCI, the disease eventually progresses to Alzheimer’s disease.
Current clinical evidence indicates that the progression of AD cannot be reversed, making early prevention particularly important. As one of the modifiable factors, dietary nutrition plays an important role in the prevention of AD, especially vitamins and minerals.
Recently, a research team from Shanghai Sixth People’s Hospital investigated the impact of vitamin supplementation on preventing cognitive decline. The study found that daily supplementation with vitamins—including folic acid, B vitamins, vitamin D (VD), and coenzyme Q10 (CoQ10)—can effectively delay cognitive decline and neurodegeneration in older adults. For individuals who have already developed cognitive impairment, VD supplementation may also benefit brain health.
DOI: 10.3390/nu15051243
The researchers evaluated the cognitive status of 892 adults aged over 50 years and categorized them according to the severity of cognitive impairment: 185 individuals in the normal cognition (NC) group, 227 in the subjective cognitive decline (SCD) group, 296 in the mild cognitive impairment (MCI) group, and 184 in the Alzheimer’s disease (AD) group.
The results showed the following findings (all data were derived from models adjusted for confounding factors including education, age, sex, and cognitive medications):
Folic acid: Compared with individuals who did not take folic acid supplements, participants with normal cognitive function who took folic acid daily had a 43.0% lower risk of developing cognitive impairment.
B vitamins: Compared with individuals who did not supplement with B vitamins, people with normal cognition had a 36.1% lower risk of cognitive impairment even when taking them occasionally. When taken daily, the risk decreased significantly by 60.9%.
CoQ10: When CoQ10 supplements were taken daily, the risk of developing cognitive impairment among cognitively normal participants decreased by 40.6%.
Vitamin D: Among individuals with normal cognition, daily supplementation with vitamin D significantly reduced the risk of cognitive impairment by 46.8%.
Vitamin D May Slow Disease Progression
A unique feature of vitamin D supplementation is that, in addition to its preventive role, it may also help slow disease progression in individuals who already have objective cognitive impairment. Compared with individuals who did not take vitamin D supplements, those who took vitamin D daily or occasionally experienced a 60.5% and 42.8% reduction, respectively, in the risk of progression from MCI to AD.
Multivariate analysis results therefore suggest that daily supplementation with folic acid, B vitamins, vitamin D, and CoQ10 may help prevent the development of cognitive impairment. For older adults who already exhibit cognitive decline, vitamin D supplementation may help slow progression to AD.
Researchers explain that vitamin D is a steroid hormone whose biologically active form is 1.25 (OH)₂D. Vitamin D plays important roles in cell proliferation and differentiation, calcium signaling in the brain, neurotrophic support, and neuroprotection. It can also influence neurotransmission and synaptic plasticity. Although current evidence cannot clearly establish a direct relationship between vitamin D and cognitive function, its neuroprotective effects may be related to reductions in amyloid-β–associated biomarkers.
The B-vitamin family includes thiamine, riboflavin, niacin, pantothenic acid, vitamin B6, folic acid, biotin, and vitamin B12. Prospective analyses have found that adequate intake of folic acid, vitamin B6, and vitamin B12 is associated with greater cognitive reserve. Possible mechanisms include increased methylation of redox-related genes (NUDT15 and TXNRD1) and reduced oxidative damage. Nevertheless, the specific effects of individual B vitamins require further detailed investigation.
As for CoQ10, recent studies suggest that it may promote mitochondrial function and protect endothelial cells, thereby slowing age-related peripheral vascular aging.
Professor Guo Qihao, one of the corresponding authors of the study, stated that vitamin supplementation appears to be a protective factor against cognitive impairment among cognitively normal individuals over 50 years of age in China.
For those who may need it, it may be worth considering increasing vitamin intake.
Magnesium Intake and Brain Structure
In fact, among the seven essential nutrients, certain minerals—besides vitamins—may also benefit the brain and help reduce the risk of dementia. A recent study published in the European Journal of Nutrition reported that dietary magnesium (Mg) intake is associated with brain health. Higher magnesium intake in daily diets is linked to larger brain volumes and fewer white matter lesions, indicating better brain health and a lower risk of dementia, particularly in women.
https://doi.org/10.1007/s00394-023-03123-x
Researchers collected data from more than 6,000 participants from the UK Biobank. Dietary magnesium intake was assessed using dietary questionnaires, and brain volumes were measured using magnetic resonance imaging (MRI).
The results showed that higher baseline magnesium levels were closely associated with larger brain volumes. Specifically, when baseline magnesium intake exceeded 350 mg/day, each additional 1 mg increase corresponded to the following changes in men: total gray matter (GM) increased by 0.0011%, the left and right hippocampus (LHC and RHC) increased by 0.0008% and 0.0023%, respectively, while white matter (WM) decreased by 0.0011% and white matter lesions (WML) decreased by 0.001%. In women, the observed changes were slightly different: GM, WM, LHC, RHC, and WML all increased by 0.001%, 0.001%, 0.0018%, 0.0023%, and 0.0012%, respectively.
For example, when dietary magnesium intake exceeded 550 mg/day, GM and RHC volumes were 0.20% and 0.46% higher than normal levels.
This suggests that among individuals with an average age of 55 years, consuming 550 mg/day of magnesium may significantly improve brain health, equivalent to making the brain approximately one year younger. Improvements in brain health naturally help maintain cognitive function and reduce the risk of developing dementia later in life.
The association between dietary magnesium intake and brain volume
Previous mouse studies have shown that magnesium deficiency can lead to activation of microglia and the production of pro-inflammatory cytokines, including interleukin-1β (IL-1β), IL-6, and tumor necrosis factor (TNF). In contrast, increasing dietary magnesium intake can reduce neuroinflammatory mediators, thereby exerting anti-inflammatory effects and reducing neurodegeneration.
Therefore, researchers believe that higher dietary magnesium intake is associated with larger brain volumes and lower WML levels, and the neuroprotective effects of magnesium appear to be more pronounced in women.
So where does dietary magnesium come from? In fact, magnesium is widely available in foods such as green vegetables, whole grains, and nuts. In contrast, highly refined foods often lack magnesium. As a “frequently overlooked element,” magnesium deficiency can be difficult to detect. If one does not regularly consume vegetables but drinks large amounts of coffee or alcohol, it may be advisable to consider increasing magnesium intake.
In short, if there are early signs of declining cognitive function, it may be beneficial to ensure adequate intake of vitamins and magnesium in advance.
References
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Alateeq, K., Walsh, E. I., & Cherbuin, N. (2023). Dietary magnesium intake is related to larger brain volumes and lower white matter lesions with notable sex differences. European Journal of Nutrition. https://doi.org/10.1007/s00394-023-03123-x
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Jiang, X., Guo, Y., Cui, L., Huang, L., Guo, Q., & Huang, G. (2023). Study of Diet Habits and Cognitive Function in the Chinese Middle-Aged and Elderly Population: The Association between Folic Acid, B Vitamins, Vitamin D, Coenzyme Q10 Supplementation and Cognitive Ability. Nutrients, 15(5). https://doi.org/10.3390/nu15051243