Vitamin B12 is an essential nutrient because it helps keep the body’s nerve and blood cells healthy and helps make DNA, the genetic material in all cells. Insufficient intake of B12 can therefore undermine these critical functions, causing a cascade of negative effects. Some of the most pronounced effects stem from the nerve damage caused by B12 deficiency.
One telltale sign that vitamin B12 deficiency has damaged the nervous system is blurred or disturbed vision.
According to research, this can occur when an untreated B12 deficiency results in nervous system damage to the optic nerve that leads to your eyes.
The damage can disrupt the nervous signal that travels from your eye to your brain, impairing your vision – this condition is known as optic neuropathy.
Although alarming, it is often reversible by supplementing with B12, studies suggest.
READ MORE: Eight telltale signs you have low vitamin B12 levels – what to look for
Those following a vegan or vegetarian diet are prone to B12 deficiency because vitamin B12 is found naturally in a wide variety of animal foods.
Plant foods have no vitamin B12 unless they are fortified.
According to the National Institutes of Health, you can get recommended amounts of vitamin B12 by eating a variety of foods including the following:
- Beef liver and clams, which are the best sources of vitamin B12.
- Fish, meat, poultry, eggs, milk, and other dairy products, which also contain vitamin B12.
- Some breakfast cereals, nutritional yeasts and other food products that are fortified with vitamin B12.
“To find out if vitamin B12 has been added to a food product, check the product labels,” advises the NIH.
“If your vitamin B12 deficiency is caused by a lack of the vitamin in your diet, you may be prescribed vitamin B12 tablets to take every day between meals,” explains the NHS.
According to the health body, people who find it difficult to get enough vitamin B12 in their diets, such as those following a vegan diet, may need vitamin B12 tablets for life.
“Although it’s less common, people with vitamin B12 deficiency caused by a prolonged poor diet may be advised to stop taking the tablets once their vitamin B12 levels have returned to normal and their diet has improved,” it adds.