Vitamin and mineral deficiencies can lead to a wide range of neurologic problems. Deficiencies are most commonly caused by malnutrition, including not getting enough to eat, not eating nutritious foods like fruits and vegetables, eating disorders, and extreme or fad diets. They also can occur because of certain diseases, such as cystic fibrosis, that affect absorption of vitamins and minerals.
A deficiency of vitamin B12 can cause cognitive impairment and myeloneuropathy—damage to the spinal cord and peripheral nerves in the legs—resulting in difficulty walking, weakness, numbness, and poor coordination. Doctors recommend checking B12 levels, especially for anyone being evaluated for dementia or neuropathy. If caught early, the deficiency is treatable. The vitamin is abundant in red meat, chicken, eggs, and dairy. The recommended daily dose is 2.4 micrograms (mcg), according to US Food and Drug Administration (FDA) guidelines.
Myeloneuropathy is also associated with a copper deficiency. Enzymes use copper to maintain the health of the spinal cord, insulating it so signals can be transferred between the brain and the rest of the body. Without sufficient copper, these enzymes don't work as well, and signals are relayed less efficiently. Copper deficiencies may be due to genetic conditions such as Menkes disease or malabsorption syndromes—disorders in which the small intestine can't absorb adequate nutrients and fluids. Copper deficiencies also can be seen after bariatric surgeries if patients do not take the necessary treatments prescribed by their health care providers. The mineral is found in liver, green leafy vegetables, and dark chocolate. The recommended daily dose is 1,400 mcg for men and 1,100 mcg for women, according to FDA guidelines.
Low levels of vitamin D have been linked to an increased risk for multiple sclerosis. Research shows that this deficiency is associated with an increase in autoimmunity as well as susceptibility to infection. Salmon, sardines, herring, mackerel, red meat, liver, and egg yolks are all rich in vitamin D, so adding them to your diet will help. Sit in the sun for at least a few minutes a day: Sunlight helps the body convert vitamin D from food into a nutrient. People with limited access to sunlight may be advised to take vitamin D supplements. The daily dose recommended by the FDA is 20 mcg, or 800 international units.
Vitamin E is one of the body's main antioxidants. Insufficient levels can cause oxidative stress and contribute to nerve damage, resulting in numbness in the legs and arms, an inability to control body movements, speech difficulties, and peripheral neuropathy, causing a loss of reflexes in the legs. In ataxia with vitamin E deficiency—a degenerative disease of the nervous system that impairs walking, talking, and fine motor skills—the body cannot use vitamin E from food, which affects movement. Food sources of vitamin E include nuts, seeds, green leafy vegetables, and vegetable oils such as sunflower, olive, and coconut. The FDA recommends a daily dose of 15 milligrams.
A deficiency of folate or folic acid during pregnancy can cause spinal malformations in a fetus by interfering with proper development of the embryonic neural tube. Folate may be diminished in people who have trouble absorbing it from their diets or who drink too much alcohol. It can be found in green leafy vegetables and citrus fruits. The FDA-recommended daily dose is 400 mcg for adults and 600 mcg for teens and pregnant women.
To address a possible vitamin insufficiency, your doctor will assess any symptoms, such as difficulty with movements. Your doctor may determine if additional blood tests are needed to measure vitamin levels. Depending on the results, the physician may recommend taking oral supplements or adding specific foods.
Most people should be able to get adequate vitamins and minerals from a well-rounded diet that includes produce, whole grains, fish, and dairy. Without a confirmed deficiency or problem absorbing certain vitamins and minerals, they typically don't need supplements.
Dr. Pressman is assistant professor of cognitive and behavioral neurology at the University of Colorado in Aurora, where he specializes in frontotemporal dementia and primary progressive aphasia.
