The signs associated with low B12 levels generally take years to develop, because once absorbed into the liver, B12 is able to sustain the body for prolonged periods of time. As symptoms start appearing initially, they can be hard to pick up due to their subtlety. They will gradually worsen with time, sometimes inflicting weakness, fatigue or lightheadedness. Occasionally, painful sensations can arise in the legs, with some health sources saying the symptoms may occur exclusively at night.
The dangers of vitamin B12 deficiency lie mainly in the damage it causes to the nerve endings.
B12 helps produce a substance called myelin in the nervous system, which coats and shield nerves throughout the body, helping them transmit sensations.
Without this coating, the nerves become damaged, giving rise to a plethora of problems, including pain.
Pain associated with low B12 levels is often concentrated in the hands, and feet, but can sometimes wreak havoc in the legs as well.
When it does arise in the legs, it is often described as a sudden and stabbing pain or deep aching.
The health website Love to Know reports that the peripheral neuropathy in the legs may feel like “muscle cramps or simple deep leg pain, numbness or tingling.
“Cramps of pain associated with B12 deficiency-related neuropathy can happen at any time of day – or just at night.”
Most conditions that cause leg pain or numbness improve with rest, but symptoms that persist could be signalling an underlying deficiency.
Fortunately, supplementation with B12 can potentially correct the deficits associated with impaired nerve function.
In one recent study published in the Nutrition Research and Practice, researchers wrote: “Studies have demonstrated that supplementation with vitamin B-complex improves nocturnal leg cramps, suggesting a possible nutritional method for the management of certain types of sleep disorders.
“Restless leg syndrome is often a compilation among anaemic individuals.
“For this, iron supplements and improvement in iron status have been reported to have reducing effects, indicating a relationship between sleep quality and nutritional deficiencies.”
Other symptoms that may accompany leg pain may include weakness and fatigue, light-headedness and dizziness, palpitation and rapid heartbeat, shortness of breath, or a sore, red tongue.
How to avoid B12 deficiency
B12 is naturally present in animal products such as meat, offal, milk, fish and eggs, but the richest sources are liver, clams, kidneys and oysters.
Harvard Health notes: “Vegans can develop vitamin B12 deficiency because they lack vitamin B12 in their diets.
“In patients with bulimia or anorexia nervosa, vitamin B12 deficiency can also be related to diet. However, your liver can store vitamin B12 for up to five years, so it’s rare for diet to cause this anaemia.”
Injections are sometimes administered to individuals with long-standing deficiencies or those who are unable to absorb the nutrient properly.
Elderly people sometimes suffer a shortfall of intrinsic factor, the protein secreted by cells of the stomach lining, making them prone to deficiency.
Intrinsic factor is crucial for synthesis because it attaches to vitamin B12 and takes it to the intestines to be absorbed.
People who undergo weight loss surgery can also suffer decreased levels of intrinsic factor, which may warrant supplementation or injection with B12.