By Andrea Hargraves 
Foods of plant origin do not contain enough vitamin B12 to be considered sources of the vitamin, as do animal proteins. (photo: clone)
Vitamin B12 is an essential nutrient for the proper functioning of blood cells, nerves, and the body. Per day, the recommended amount is only 2.4 micrograms, which is a small amount – obtainable in 100 grams of beef – but which directly affects health and quality of life.
Because it can only be found in animal foods, it is rare in the diet, and many people who are deficient report fatigue, tiredness, or extreme fatigue. Symptoms, common to many diseases, can “mislead” doctors, delaying diagnosis and treatment.
In more severe cases, a vitamin B12 deficiency can lead to neurological problems, as well as tingling in the extremities, confusion, memory loss, depression, and difficulty maintaining balance. If nutrients are not replaced, it is possible for symptoms to become permanent.
To understand the health problems caused by a vitamin B12 deficiency, it is important to know how this vitamin is absorbed and works in the body.
absorb
Much is said about the diet and the need to replace vitamins in people whose diet is based solely on plants, such as vegans and vegetarians. However, millions of people who eat meat may also suffer from a deficiency in the nutrient, mainly because the body cannot properly absorb vitamin B12.
Absorption of this vitamin involves a complex, multi-step process: It begins in the mouth and ends at the end of the small intestine. When we chew, food is mixed with saliva, forming a food bolus. When we swallow, a substance in saliva called R-protein, which protects B12 from being destroyed by stomach acid, passes into the stomach with food.
Certain cells in the lining of the stomach, called parietal cells, secrete two substances that are important for vitamin B12 absorption. One is stomach acid, which is responsible for separating food from vitamin B12, allowing the vitamin to bind to the R protein in saliva. The other substance, called intrinsic factor, mixes with the contents of the stomach and travels with it to the first part of the small intestine, the duodenum.
Once in the duodenum, pancreatic juices release B12 from the R protein and deliver it to intrinsic factor. This allows B12 to be absorbed. Helps maintain nerve cells and make healthy red blood cells. Vitamin B12 deficiency usually involves a breakdown at one or more of these points in the way of absorption.
loss
Without saliva, vitamin B12 does not bind to the R protein and the body’s ability to absorb it is inhibited. There are hundreds of different medications that can cause dry mouth, which leads to a severe decrease in saliva production. They include opioids, inhalants, decongestants, antidepressants, blood pressure medications, and benzodiazepines, which are used to treat anxiety.
Another factor that contributes to a vitamin B12 deficiency is low levels of stomach acid. Millions of people take ulcer medications that reduce the stomach acids that cause ulcers. Various researchers associate the use of these medications with vitamin B12 deficiency, although this possibility does not outweigh the need for the medications.