In one sentence, describe what the following article is about:

Vitamin B12 is found in foods, and if you have a vitamin B12 shortage, you should add these foods to your daily diet as much as possible.  This will help ease the symptoms of hand pain. Your body needs about 2.5 micrograms of vitamin B12 every day. Some good sources of B12 are:  Clams, oysters, mackerel fillet, salmon fillet, sardines, crab, tuna, shrimp and lobsters. Beef liver, beef meat, lamb meat, turkey, turkey liver, and chicken. Swiss cheese, feta cheese, chicken eggs, and skimmed milk. Certain types of cereals that are fortified to have extra vitamin B12. If you are not getting the recommended amount of vitamin B12 in your diet, your doctor will recommend that you get a vitamin B12 supplement to raise your B12 levels.  Some vitamin B12 supplements can be used to supplement your dietary intake. There are many varieties of supplements available in most pharmacies, and B12 is in nearly every multivitamin. Vitamin B12 is available in tablets and coated capsules, and can taken as a daily dose of up to 1mg. It’s also available in liquid dosage forms for children. Vitamin B is considered safe and not harmful in long term usage. If you have a severe vitamin B12 deficiency, get a prescription supplement to achieve the proper levels in your body.  Your doctor may give you a drug that contains vitamin B12 or vitamin B complex to dramatically increase its concentration in your blood. B12 is available as injections, usually prescribed at the beginning of treatment to rectify acute B12 deficiency. Injections will eventually give way to tablets and other supplemental forms of B12. Injections can be given two or three times a week depending on the type of the injection. B12 injections are usually administered intramuscularly. Your injection course will vary according to your condition and may last up to three months.
Eat foods rich in vitamin B12 to correct any dietary imbalances. Incorporate a vitamin B12 supplement into your vitamin regimen. Take a prescription vitamin B12 medication to treat severe deficiencies.