In this 2026 observational study published in Neurology Open Access,² researchers measured blood vitamin D levels in nearly 800 healthy men and women in their 30s and 40s. About 16 years later, the subjects underwent scans of their brain to assess levels of tau protein and amyloid plaque deposits—two key markers that, when elevated, are closely tied to dementia. After adjusting for multiple variables, the researchers found that having higher serum vitamin D levels in midlife was significantly associated with lower tau accumulation in the brain later on, though no association was found with amyloid plaque.

Further exploratory analyses revealed that, compared with vitamin D levels below 30 ng/mL, levels of 30–54 ng/mL and 55–99 ng/mL were both linked to lower tau burden, with the strongest and statistically significant effect observed in the 55–99 ng/mL range. Notably, over one-third of the study participants had vitamin D levels below 30 ng/mL at the start of the study, with only 5% reporting using vitamin D supplements.

Given the challenge of obtaining enough vitamin D from diet and sun exposure alone, supplementation offers a reliable way to help maintain optimal vitamin D status throughout life. By keeping levels sufficient, as this study suggests, it may provide meaningful protection against age-related cognitive decline and the onset of neurodegenerative conditions.

Ubiquinol Reduces Oxidized LDL in Prediabetic Adults

When it comes to cardiovascular health, low-density lipoproteins (LDL) are often misunderstood. In their healthy state, LDL particles play an essential role, transporting fat-soluble nutrients through the bloodstream. It’s only when LDL is damaged and becomes oxidized (oxLDL) that it can promote plaque build-up, vascular inflammation, and the progression of cardiovascular disease. As researchers explore ways to shift the balance toward healthy LDL and away from oxidation, the nutrient ubiquinol is emerging as a promising ally.

Ubiquinol is CoQ10 in its reduced form, which functions as a potent fat-soluble antioxidant. In a small but intriguing pilot study,³ researchers explored whether daily ubiquinol supplementation could improve oxLDL in 20 adults with prediabetes—a group at an elevated cardiovascular risk due to insulin resistance and increased oxidative stress.

Participants received either 100 mg of ubiquinol daily or a placebo for 12 weeks. By the end of the study, the ubiquinol group showed a statistically significant reduction in oxLDL levels compared to their own baseline, while the placebo group did not experience a significant change.

How might ubiquinol exert this effect? As a fat-soluble nutrient, it must be transported in the blood by lipoproteins, and it appears to have an affinity for LDL.^{1 4} This positions ubiquinol to deliver antioxidant support directly to these vulnerable lipoproteins, helping to protect them from oxidation. Ubiquinol also plays a broader role in helping to reduce oxidative stress by regenerating other antioxidants like vitamin E, and by supporting efficient mitochondrial function, which may help limit the production of excess free radicals.

Taken together, these findings suggest a potential role for ubiquinol in supporting healthy LDL by reducing oxidative damage. While larger studies are needed to confirm these effects and determine their clinical significance, this early evidence adds to a growing body of research exploring how targeted antioxidant support may help maintain cardiovascular health, particularly in individuals with elevated metabolic risk.

References

1. Binkley, N., Ramamurthy, R., et al. (2010). Low Vitamin D Status: Definition, Prevalence, Consequences and Correction. Endocrinol Metabl Clin North Am. 39(2):287–contents. doi: 10.1016/j.ecl.2010.02.008
2. Mulligan, M., Scott, M., et al. (2026). Association of Circulating Vitamin D in Midlife With Increased Tau-PET Burden in Dementia-Free Adults. Neurol Open Access;2:e000057. doi:10.1212/WN9.0000000000000057
3. Leaovitavat, R., Palakornkitti, P., Thetsana, P., & Teng-umnuay, P. (2026). Effects of ubiquinol on oxidized low-density lipoprotein in prediabetic patients: A randomized, double-blinded, placebo-controlled study. BioMed Research International: 8739655. https://doi.org/10.1155/bmri/8739655
4. Wang, Y., Lilienfeldt, N., & Hekimi, S. (2024). Understanding Coenzyme Q10. Physiol Rev, 104: 1533–1610. doi:10.1152/physrev.00040.2023