Vitamin B12 is extremely important for health, which is why it is one of the few vitamins that most doctors routinely measure when their patients have general examinations. Vitamin B12 participates in many important processes in the body, such as DNA synthesis, energy production and the proper functioning of the nervous system. Vitamin B12 is abundant in many foods, but many people are deficient in this vitamin, because its absorption is complex and requires very good functioning of both the stomach and the small intestine. Which is unfortunately not very common, especially in older people. Also, many commonly prescribed medications significantly reduce the absorption of vitamin B12, such as stomach pain relief medications and some diabetes medications. If you are taking medication to protect your stomach it is very likely that the levels of vitamin B12 in your body are low. In a study I published while I was working in the hospital I noticed that one in four people over 65 had some form of vitamin B12 deficiency. Much confusion is also caused by the fact that the limits of ideal vitamin B12 in the blood have not been clarified, so you hear conflicting information about them. It is good to remember that vitamin B12 should be above 300 pg/mL to be sure that there is sufficiency of the vitamin in your body. If the levels of vitamin B12 in the body are low enough, it is very likely that you will experience one of the following symptoms that I will describe. Fatigue. Vitamin B12 is necessary for cells to function normally. When there is a lack of vitamin B12 then fatigue occurs. Traditionally this is because B12 deficiency leads to anemia, but recent evidence shows that fatigue can occur even in people who do not have the typical megaloblastic anemia. Pale skin color. Fortunately, the typical megaloblastic anemia from vitamin B12 deficiency is no longer seen. However, if the lack of vitamin B12 is accompanied by anemia, then we will also see the color of the skin becoming paler. Headache. Headache is one of the most common symptoms of vitamin B12 deficiency. Studies have shown that people who are vitamin B12 sufficient are up to 80% less likely to experience migraines than people who are vitamin B12 deficient. There is also clear evidence that in these cases vitamin B12 administration reduces the frequency of migraine headaches. Mood disorders. As we said in the introduction, vitamin B12 is very important for the proper functioning of the nervous system. Studies have shown that people who are low in vitamin B12 are much more vulnerable to depression and anxiety. Gastrointestinal disorders. Vitamin B12 deficiency can lead to a range of digestive problems such as diarrhoea, nausea, constipation, bloating and gas. Obviously, these symptoms are also associated with other conditions, such as irritable bowel syndrome, so in this case vitamin B12 deficiency should not be the first condition that comes to mind. Difficulty concentrating. As we have already said in this video twice, vitamin B12 plays a very important role for the proper functioning of the nervous system. So, it's no surprise that people who are low in vitamin B12 report impaired concentration. In fact, in 2020 there was a study that proved that when people with low B12 who report low concentration ability take B12 supplements that correct the levels of vitamin B12 in the blood then they report a significant reduction in these problems. Pain and inflammation of the tongue and mouth. When the body lacks vitamin B12, inflammation occurs in the tongue and oral cavity medically described as glossitis and stomatitis and is characterized by redness and pain that are very annoying. I remind you that the same symptoms can also appear from deficiencies of other nutrients. Distorted sensation in hands and feet. Paresthesia is the medical term for the numbness and burning sensation in the hands and feet that sometimes comes from a lack of vitamin B12. Other complaints. As vitamin B12 is involved in many functions in the body, there are some other symptoms that may occur, some of which are muscle cramps and weakness, balance difficulties and vision disturbances. These are the most important problems that occur if you are deficient in vitamin B12. I remind you that the vitamin B12 that is measured with a blood test is indicative and in order to get a complete picture you should also ask for a homocysteine test. Homocysteine is a substance that increases when there is a lack of B12 or folic acid from the body. Thank you very much.