A vitamin B-12 deficiency can occur if you do not get enough of the vitamin in your diet or if you have a condition, such as Crohn's disease, which affects your absorption of the vitamin. The Linus Pauling Institute at Oregon State University notes that 10 to 15 percent of people over the age of 60 have this deficiency. Multiple sclerosis, which affects about 400,000 people in the United States, results from damage to the myelin sheath in the brain and spinal cord, according to 2008 information from the Merck Manuals Online Medical Library. Some of the symptoms of multiple sclerosis and a vitamin B-12 deficiency are similar, but they have different mechanisms.
Both multiple sclerosis and a vitamin B-12 deficiency can cause altered sensations. For example, you may experience tingling or numbness in your arms and legs. With multiple sclerosis, you may have a reduced sensation of touch or a burning sensation. With a vitamin B-12 deficiency, the altered sensations in your hands and feet may feel like pins and needles. But the reason for the altered sensations differ between these two conditions. The deficiency in vitamin B-12 can damage the myelin sheath on peripheral nerves, cranial nerves and spinal nerves, though the Linus Pauling Institute notes that the mechanism is not fully understood. With multiple sclerosis, only the myelin sheath in the central nervous system becomes affected. The inflammation targets the myelin sheath made from oligodendrocytes, which occur only in the central nervous system. Multiple sclerosis does not affect the myelin sheath made from Schwann cells, which occur in the peripheral nervous system.
A deficiency in vitamin B-12 and multiple sclerosis can cause changes in cognitive function, such as memory and attention. The Merck Manuals Online Medical Library notes that in multiple sclerosis, the mental impairment can range from subtle to obvious. Cognitive problems that may arise in multiple sclerosis include attention difficulties, memory loss, issues with problem solving and poor judgment. A vitamin B-12 deficiency may also lead to cognitive changes such as confusion and memory loss. The deficiency may result in dementia, a neurological condition characterized by serious cognitive changes, though treating the deficiency may not reverse the damage, according to the Linus Pauling Institute.
If you have either multiple sclerosis or a deficiency in vitamin B-12, you may experience some changes in your mood. For example, both conditions can cause depression, a mood disorder that causes regular sadness. Multiple sclerosis may cause other mood changes. Instead of depression, you may become unusually happy or giddy. Multiple sclerosis may also cause you to have problems controlling your emotions, according to the Merck Manuals Online Medical Library.
Since a vitamin B-12 deficiency and multiple sclerosis can affect the nerves involved in digestion, you may have gastrointestinal symptoms. With a vitamin B-12 deficiency, you may have diarrhea or constipation, a swollen tongue and a loss of appetite, which may result in significant weight loss. These gastrointestinal symptoms may result from an inflammation of the stomach or affected DNA synthesis, according to the Linus Pauling Institute. Multiple sclerosis can also result in constipation, as well as a frequent and urgent need to urinate, problems starting urination, and urine and stool leakage.
You may experience problems moving if you have either multiple sclerosis or a deficiency of vitamin B-12. Both conditions may cause a loss of balance and problems walking. Multiple sclerosis can also cause weakness, muscle spasms, problems with coordinating movements and tremors.
Both multiple sclerosis and a vitamin B-12 deficiency can cause visual problems. Multiple sclerosis may cause double vision, blurred vision and partial blindness. You may have problems seeing when looking straight ahead. Eye movement may also become affected, resulting in involuntary eye movements. If you have a deficiency in vitamin B-12, you may have problems telling the difference between the colors blue and yellow, according to the New York University Langone Medical Center.