Should people with Parkinson's take B12? The critical role of this essential vitamin

October 8, 2025 •

4 min read

Studies show that B12 deficiency is more common in people with Parkinson's disease (PD) than in the general population, with low levels linked to worse motor and cognitive symptoms. This raises a critical question for many patients: Should people with Parkinson's take B12? The answer often hinges on monitoring levels and managing potential medication interactions.

Quick Summary

B12 deficiency is common in Parkinson's and can worsen neurological symptoms. Certain medications like levodopa can deplete B12, so monitoring and potential supplementation are recommended under medical guidance.

Key Points

Prevalence of Deficiency: People with Parkinson's are more likely to have low B12 levels than the general population, which can worsen symptoms.
Levodopa Interaction: The common PD drug levodopa can lower B12 levels over time by interfering with the body's methylation cycle.
Exacerbated Symptoms: Low B12 can intensify specific PD symptoms, including cognitive impairment, walking and balance problems, and nerve issues like tingling and numbness.
Medical Guidance is Key: Supplementation should be undertaken only under the guidance of a healthcare provider who can monitor B12 and homocysteine levels and determine the appropriate approach.
Dietary Sources: B12 is primarily found in animal products like meat, fish, and dairy, as well as fortified cereals and nutritional yeasts.
Supplementation Options: Depending on the severity of deficiency and absorption issues, supplementation can be done orally with tablets (including sublingual forms) or via injections.
Potential Neuroprotective Effects: Some research suggests B12, particularly in its active forms, may offer neuroprotective benefits, such as inhibiting a genetic mutation linked to familial PD.

The Connection Between Parkinson's and B12 Deficiency

For many living with Parkinson's, managing symptoms involves a multifaceted approach, and nutritional status is a key piece of the puzzle. One particularly important nutrient is vitamin B12 (cobalamin), a water-soluble vitamin crucial for neurological function. Several factors contribute to a higher risk of B12 deficiency in people with PD:

Aging: B12 absorption can become less efficient with age, and PD is primarily a disease of older adults.
Medication Interaction: The most commonly prescribed PD medication, levodopa, can deplete B12 levels, especially with long-term use. Levodopa's metabolism pathway requires a methyl group transfer, increasing the demand for B12 and folate to metabolize the amino acid homocysteine.
Increased Homocysteine: Low B12 levels lead to elevated homocysteine levels. Hyperhomocysteinemia (high homocysteine) is associated with neurological issues and has been linked to more rapid motor and cognitive progression in PD.
Dietary Restrictions: Some individuals with PD may unconsciously alter their diet, consuming fewer animal products rich in B12, due to swallowing difficulties or side effects from medication.

These factors mean that regular B12 monitoring and, if necessary, supplementation is a crucial part of holistic PD management, as recognized by neurologists and foundations like the Michael J. Fox Foundation.

How Low B12 Impacts Parkinson's Symptoms

While B12 deficiency does not cause Parkinson's disease, it can exacerbate certain motor and non-motor symptoms, making daily challenges more pronounced. Addressing a deficiency can, in turn, lead to improvements in these areas.

Neuropathy: Low B12 can cause peripheral neuropathy, leading to numbness, tingling, and nerve pain, which adds to the discomfort already experienced by many with PD.
Gait and Balance: A deficiency is strongly associated with greater postural instability, walking difficulties, and an increased risk of falls. Improving B12 status can help support nerve health and stability.
Cognitive Decline: B12 plays a role in brain health, and a deficiency can contribute to cognitive impairment, memory issues, and changes in mental function. Correcting this can help differentiate between PD-related dementia and B12-related cognitive issues.
Fatigue: Weakness and tiredness are common symptoms of B12 deficiency, and they can compound the fatigue already common in PD.

The Case for B12 Supplementation

For individuals with PD who are deficient or have low-normal B12 levels, supplementation may be recommended by a healthcare provider. The benefits are tied to B12's core functions in the nervous system. As an active cofactor in methylation, B12 is essential for maintaining myelin, the protective sheath covering nerve fibers. Adequate B12 can support nerve fiber repair and overall nerve function. Additionally, some research has explored potential neuroprotective effects, including inhibiting the LRRK2 kinase, which is associated with some genetic forms of PD.

Sources of Vitamin B12

Obtaining B12 from diet is the first step, but for many with PD, supplementation is necessary. Good dietary sources include:

Animal Products: Meat, fish (like salmon and tuna), poultry, eggs, and dairy products are all naturally rich in B12. Organ meats like liver and kidneys are especially potent sources.
Fortified Foods: Many breakfast cereals, nutritional yeasts, and some non-dairy milk alternatives are fortified with B12, making them excellent sources for vegetarians or those with restricted diets.

Oral Supplements vs. Injections

There are different methods for supplementing B12, and the best approach depends on the individual's specific needs and ability to absorb the vitamin.

Oral Supplements: Over-the-counter tablets or sublingual preparations are effective for many people.
B12 Injections: For those with severe absorption issues, such as pernicious anemia, or whose oral supplements are not raising levels sufficiently, a doctor may prescribe B12 injections.

Comparison of Common B12 Supplement Forms


Supplement Form	Description	Common Use	Benefits for PD	Considerations
Cyanocobalamin	The most common, synthetic form of B12. Stable and widely available.	Found in most oral and injectable supplements.	Readily converted by the body into active forms. Effective for correcting deficiency.	Requires metabolic conversion; may not be ideal for those with certain genetic variations.
Methylcobalamin	An active, co-enzyme form of B12.	Often found in sublingual tablets and specialized supplements.	Directly usable by the body. Some studies suggest benefits for nerve regeneration and sleep.	Can be more expensive than cyanocobalamin; efficacy varies by individual.
Adenosylcobalamin	Another active, co-enzyme form, crucial for mitochondrial function.	Less common in supplements; sometimes combined with methylcobalamin.	Plays a vital role in cellular energy production. Animal studies suggest it can inhibit the neurotoxic LRRK2 kinase.	Limited human data specifically for PD; often used in conjunction with other forms.

Conclusion: A Proactive Approach to Nutrition

For people with Parkinson's, monitoring vitamin B12 levels is a necessary and proactive step. A deficiency can contribute to some of the most challenging motor and non-motor symptoms, including gait instability, neuropathy, and cognitive issues. Since common PD medications like levodopa can deplete B12, regular testing is critical. By working closely with a healthcare provider, patients can determine if supplementation is right for them. A balanced, nutrient-rich diet with B12-rich foods and, if needed, personalized supplementation, can help mitigate symptoms and support overall neurological health. It is an integral part of managing the disease's progression and maximizing quality of life. For further reading on managing Parkinson's through diet and exercise, consider resources from the Parkinson's Foundation.

Frequently Asked Questions

No, B12 deficiency is not a cause of Parkinson's disease. However, low B12 levels can make existing PD symptoms worse, particularly those related to cognition and movement.

Long-term use of levodopa, a primary medication for Parkinson's, can deplete vitamin B12 levels. This is due to an interaction with the body's metabolic processes that use up B12, often resulting in elevated homocysteine levels.

Symptoms of B12 deficiency can overlap with PD symptoms and include numbness and tingling (neuropathy), problems with balance and walking, cognitive decline, memory issues, and increased fatigue.

There is no universally recommended approach, as it depends on the individual's specific needs. A doctor will determine the right course of action based on blood tests and overall health.

The best sources of B12 include meat, fish (especially salmon and clams), poultry, eggs, and dairy products. Fortified breakfast cereals and nutritional yeast are also good options, particularly for vegetarians.

You should discuss this with your neurologist or healthcare provider. Given the known interaction between levodopa and B12, regular monitoring of your B12 levels is recommended. If your levels are low, supplementation will likely be advised to help manage symptoms and prevent complications.

For individuals with specific absorption problems, such as pernicious anemia, B12 injections are necessary and more effective than oral supplements. However, many people absorb oral B12 sufficiently, and efficacy can vary.

While B12 doesn't address the core cause of PD motor symptoms, it supports overall nerve health and can help manage symptoms worsened by deficiency, such as gait instability and balance problems.