A, B, C, D, E and K are the main types of vitamins which are essential for normal metabolism, the process which helps maintain life in us. A balanced diet is that diet which contains all types of essential nutrients in correct proportions. There exist several sub-types of vitamin B like B1, B2, B3, etc.
Vitamin C and B vitamins are water soluble vitamins while vitamins A, D, E and K are fat soluble vitamins. This means your body can store vitamins A, D, E, and K in fat; but vitamin C and B vitamins are flushed off regularly through urine and other excretory material. Vitamin B deficiency can affect your mood and brain function.
Vitamin B12 Deficiency
No animal or plant can make vitamin B12. They obtain this vitamin from the microorganisms in the soil. Microorganisms like bacteria, yeasts, molds, and algae are very good sources of vitamin B12. Animals are capable of storing more B12 than plants. Excellent sources of vitamin B12 include shrimp, venison, salmon, scallops and beef. Milk, cheese, eggs, caviar, fish, etc. also contain vitamin B12.
Sea vegetables like kelp, blue-green algae, tempeh, miso, tofu, Brewer's yeast do contain some amount of vitamin B12 but they are not referred to as very good sources of vitamin B12. The main cause of deficiency of vitamin B12 is its limited sources. Vegans and vegetarians often suffer from B12 deficiency as they do not consume animal food. Aging reduces the capacity of intestines to absorb vitamin B12 and other vitamins.
So elderly often suffer from vitamin deficiencies. Those who are diagnosed with stomach problems or digestion problems may develop vitamin deficiencies. For example, those having Crohn's disease, blind loop syndrome, celiac disease, atrophic gastritis, etc. may develop B12 deficiency. Overuse of certain medications can affect absorption of vitamins in the intestines.
Symptoms of B12 deficiency may vary from person to person. Women may experience menstrual problems. Dandruff, difficulty in blood clotting and in swallowing can be noticed. Some may suffer from red and sore tongue, paleness, excessive weakness, decreased reflexes, weak pulse or heart palpitations. Memory problems, nervousness, depression and tingling sensation or numbness in feet are some of the commonly noticed symptoms of B12 deficiency. It has been observed that severe deficiency of vitamin B12 can lead to irreversible nerve and brain damage resulting in dementia. Symptoms of lack of Vitamin B12 give us an idea about the functions of vitamin B12.
Vitamin B12 Deficiency and Depression
One of the main functions of vitamin B12 (along with other B vitamins like B6 and folate) is to produce brain chemicals like 'norepinephrine' that control mood and other brain functions. Norepinephrine plays an important role in mind-body relationship and also in various reactions of the person. Low levels of norepinephrine can lead to reduced energy, low stamina, fatigue, lack of motivation and difficulty in concentrating. Low levels of chemicals in brain like epinephrine and norepinephrine result in mental problems and cognitive problems. They affect the mood of the person seriously, leading to depression.
Scarcity of vitamin B12 can cause various types of nervous system disorders. Studies show that vitamin B12 shots can work great for disturbed sleep-wake rhythms. It is a fact that sleep-wake disturbances can lead to mood disorders. B12 promotes sound sleep during night and alertness during the day. Vitamin B12 is also involved in strengthening the myelin sheath that protects the nerves. B12 promotes proper cycling of proteins in the body. As you know, protein is essential for growth and repair of body cells; so lack of protein (amino acids) due to deficiency of vitamin B12 can affect mental health of an individual. Moreover, vitamin B12 deficiency can also affect carbohydrate and fat metabolism, leading to several health problems, including depression.
Oral doses of vitamin B12 may not be absorbed properly in the intestines. So vitamin B12 injections are often recommended in case of vitamin deficiency. Vitamin B12 supplementation can help lower the symptoms of depression but it won't be as effective as antidepressants. Similarly, psychological counseling is often essential to get rid of depression symptoms. Vitamin supplements should not be taken without prior consultation with the physician. In case of vitamin B12 deficiency and depression symptoms too, you should consult a psychiatrist for proper treatment.