A B12 deficiency may start as fatigue, weight loss, constipation, and loss of appetite. If not treated, lack of vitamin B12 can lead to nerve damage, tingling and weakness in hands and feet, problems with balance, confusion, and depression. This type of deficiency causes anemia in the body, which means the body doesn't have enough red blood cells. Certain conditions include Crohn's disease, celiac disease, pernicious anemia, alcoholism and make it hard for the body to absorb enough of the vitamin. Lack of this essential vitamin can cause fatigue, and even in some severe cases paralysis and nerve damage.  Treatment with a balanced diet or B12 supplements or shots brings levels back to normal.

Vitamin B12 generates DNA and red blood cells. 

Causes of a Vitamin B12 Deficiency

• Atrophic gastritis, in which your stomach lining has thinned
• Pernicious anemia, which makes it hard for your body to absorb vitamin B12
• Surgery that removed part of your stomach or small intestine, including weight loss surgery
• Conditions affecting the small intestine, such as Crohn's disease, celiac disease, bacterial growth, or a parasite
• Heavy drinking
• Immune system disorders, such as Graves' disease or lupus
• Long-term use of acid-reducing drugs. Stomach acids help break down animal proteins that have vitamin B12.

Almost 15% of the U.S. population has vitamin B12 deficiency. Depending on what causes low levels of vitamin B12, treatment may include: 

• Eating a more balanced diet 
• Vitamin B12 supplements 
• Vitamin B12 injections 
• Avoiding alcohol

People over 65 and vegans are more likely to develop vitamin B12 deficiency, since animal products are where most of the vitamin comes from. 

Should you take a supplement? According to the Centers for Disease Control and Prevention (CDC), approximately half of adults in the U.S. take at least one daily dietary supplement – the most popular being a multivitamin.  This translates into about $28 billion per year spent on vitamins, supplements, and minerals. 

B vitamins maintain our nerves and brain cells and are used up in converting food into energy in the body. Salmon, among other fish, is a great source of omega 3 fatty acids and B vitamins. 

It's important that your diet has a heavy amount of B12. It's especially important if one suffers from anxiety and can have trouble sleeping. Serotonin is vital in the regulation of mood, appetite and sleep. 

Just like some of the other stress busters on this list, almonds are loaded with B vitamins and magnesium, which are involved in the production of serotonin, which helps regulate mood, relieve stress and improve sleep.  

VITAMIN B12 FOR A HEALTHY NERVOUS SYSTEM

• Older men may have an increased need for vitamin B12, which boosts brain health.
• Vitamin B12 supports the normal functioning of the nervous system, including memory
• Depression and dementia are symptoms of a low serum B12
• The recommended amount for B12 is 2.4 mcg daily, which you can easily get from your diet. 
• One serving of fortified breakfast cereal will provide all that you need.
• B12 may be included in your daily multivitamin. 
• Although high doses have not been shown to be harmful, you should not need to supplement this vitamin unless your doctor recommends it.
• Good food sources for B12 include salmon, shrimp, beef, chicken, clams, eggs, milk, and cheese