From the Guidelines
Vitamin B12 and Vitamin D are related in that they both play a role in the management of Parkinson's Disease (PD) patients, with low levels of Vitamin D associated with the risk of developing PD and low levels of Vitamin B12 contributing to elevated homocysteine levels.
Relationship between Vitamin B12 and Vitamin D
- Vitamin D levels have been shown to be lower in PD patients than healthy controls 1, and supplementation may slow disease progression, at least in patients with high-risk genotype of the vitamin D receptor.
- Vitamin B12, along with folate, plays a crucial role in regulating homocysteine levels, which are elevated in PD patients treated with levodopa 1.
- The concomitant use of COMT inhibitors, such as entacapone, may limit the raising of plasma homocysteine levels, but the regulation is closely linked to vitamin B12 and folate status 1.
- Administration of vitamin B12 and folate is effective in reducing homocysteine levels 1 and should be considered to prevent neuropathy and other complications associated with hyper-homocysteinemia.
- PD patients have been shown to have lower circulating levels of folate and vitamin B12, highlighting the importance of monitoring and supplementing these vitamins in PD patients 1.
From the Research
Relationship Between Vitamin B12 and Vitamin D
- The relationship between Vitamin B12 and Vitamin D has been investigated in several studies, with some finding a significant association between the two vitamins 2, 3.
- A study of children found that Vitamin B12 deficiency was common, especially in the adolescent age group, and that Vitamin D deficiency was also present in many cases of Vitamin B12 deficiency 2.
- Another study found that low levels of Vitamin B12 and Vitamin D were associated with depression in children and adolescents, and that there was a negative correlation between depression severity and Vitamin B12 and Vitamin D levels 3.
- However, not all studies have found a significant association between Vitamin B12 and Vitamin D. A study of community-dwelling elders found that low levels of Vitamin B12, but not Vitamin D, were associated with low cognitive functioning 4.
- A study of cancer patients found that serum Vitamin D and B12 levels were higher in patients before chemotherapy, but that there was no correlation between depression and anxiety scores and serum Vitamin D and B12 levels 5.
- A cross-sectional study of elderly people found that individuals with Vitamin D levels >19 ng mL-1 had a lower prevalence of cognitive decline, while those with Vitamin B12 levels of ≥496 pg mL-1 had a higher prevalence of cognitive decline 6.
Key Findings
- Vitamin B12 deficiency is common in certain populations, such as children and adolescents 2.
- Low levels of Vitamin B12 and Vitamin D are associated with depression in children and adolescents 3.
- Vitamin B12, but not Vitamin D, is associated with cognitive functioning in community-dwelling elders 4.
- Serum Vitamin D and B12 levels are affected by chemotherapy in cancer patients 5.
- Vitamin D and Vitamin B12 levels are associated with cognitive decline in elderly people, but the relationship is complex and may depend on the population being studied 6.