The B vitamins in B-complex have many important functions and are vital for good health. Most people get enough of these vitamins through diet, but B vitamins are water soluble, which means your body doesn't store them and they need to be replenished every day, increasing he risk of deficiency. Symptoms of a vitamin B deficiency depend on which B vitamin you lack.
What Is B Complex?
Vitamin B complex vitamins are water soluble and include thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folic acid (B9) and the cobalamins (B12). These vitamins have characteristics in common but different functions, none of which require all the B vitamins simultaneously. Vitamins B1, B2, B3 and biotin are needed for energy production; vitamin B6 helps with amino acid metabolism; and vitamin B12 and folic acid are required for cell division, states Michigan Medicine. Each member of the B vitamin group has different recommended daily intakes. When you have a deficiency, it's likely that a certain B vitamin is causing your symptoms.
Read more: How Much Is Too Much Vitamin B Complex?
Who’s at Risk
Certain individuals carry a greater risk of being deficient in some of the B vitamins. A poor diet, vegetarianism, age, genetics, medical conditions, certain medications, alcohol use and exposure to pesticides increase the body's demand for B vitamins.
Read more: Foods That Are High in B Vitamins
B12: A Common Deficiency
Plants don't make vitamin B12. It's found only in meat, eggs, poultry, dairy products and other foods from animals. Vegetarians are often prone to low levels of vitamin B12. Older people are also at risk for a vitamin B12 deficiency due to their reduced ability to absorb it from food. The National Institutes of Health reports that up to 15 percent of the general population are deficient in B12.
Vitamin B12 deficiency often results in cognitive impairment, osteoporosis and depression. Other symptoms may include numbness or tingling sensation in hands, legs or feet; difficulty balancing and walking; anemia; red, swollen tongue; confusion or weakness; and fatigue.
Vitamin B Deficiency and Depression
A deficiency of vitamins B6, B9 (folate) and B12 in the B-complex have been associated with depression and other psychiatric problems, according to University Health News. A clinical trial, published in The Open Neurology Journal, identified the link between vitamin B12 deficiency and depression. Results indicated that 22 percent of patients with depression had a high vitamin B12 deficiency, and 36 percent had a lower-than-normal level of B12.
Vitamin B and Neurological Disorders
Vitamin B deficiency can also result in decreased cognitive ability. The journal International Psychogeriatrics reviewed 43 studies that investigated vitamin B intake and its effect on cognitive impairment and neurodegenerative disease. Findings suggest that low levels of vitamin B12 are associated with Alzheimer's disease, vascular dementia and Parkinson's disease. Vegetarianism and medications to control blood sugar seemed to be contributing factors for this vitamin deficiency.
Niacin Deficiency and Skin Disorders
B-complex usually contains 10 to 25 milligrams of vitamin B3 (niacin). The recommended daily intake is 14 milligrams for women and 16 milligrams for men, says the National Institutes of Health. Although deficiencies are rare, symptoms of mild B3 deficiency include indigestion, fatigue, vomiting, canker sores and depression.
A major deficiency in niacin could lead to pellagra, a rough, scaly dermatitis that appears on areas of the skin exposed to the sun. Pellagra may develop as a result of medical conditions that inhibit the absorption of vitamin B3 or with alcohol use, HIV, AIDS or anorexia, reports MedlinePlus. It can involve neck rash, nervous system problems and gastrointestinal issues such as watery or bloody stools. Other symptoms of severe niacin deficiency can include anxiety, depression, tremors and a reduction in reflexes.
Vitamin B-Deficiency Anemia
Vitamin B6, vitamin B12 and folate all play a role in creating red blood cells that deliver oxygen to cells throughout your body. A deficiency in any of these vitamins can be caused by poor nutrition, alcoholism or certain medications. Symptoms can include irritability, depression and confusion; inflammation of the tongue; and ulcers at the corners of the mouth. In acute cases, anemia may result.
Read More: The Best Form of B-Complex Vitamin
- Michigan Medicine: University of Michigan: Vitamin B-Complex
- The Open Neurology Journal: Vitamin B12 Supplementation in Treating Major Depressive Disorder
- International Psychogeriatrics: Cognitive Impairment and Vitamin B12
- National Institutes of Health: Office of Dietary Supplements: Vitamin B12
- WebMD: Niacin (Vitamin B3)
- MedlinePlus: Pellagra
- University Health News: Vitamin Deficiency Symptoms: Depression, Anxiety and More
- National Institutes of Health: Office of Deitary Supplements: Niacin