Tue, Dec-31-19, 08:29
B12 deficiency: what vegans (and others) need to know
Dr Mark Porter: B12 deficiency: what vegans need to know
In a timely warning on the eve of Veganuary, two eminent professors — Tim Key from Oxford and Tom Sanders from King’s College London — have highlighted the importance of vitamin B12 supplementation in people who don’t consume animal products. The number of vegans in the UK has quadrupled over the past five years to more than 600,000, a number that is likely to grow considerably during the next month as tens of thousands more try the Veganuary challenge.
However, it’s not just vegans who are at risk: B12 deficiency is common, easily missed and often undertreated in the rest of society too.
The vitamin is essential for the production of red blood cells and normal functioning of the brain and nervous system. Deficiency can cause numerous symptoms (see below) ranging from lack of energy, memory issues, weakness and pins and needles, to breathlessness, confusion and, rarely, even paralysis and death. It can be a hard diagnosis to clinch because it tends to develop slowly over a few years, and the signs may not show up in routine blood tests (which don’t check levels of the vitamin unless specifically requested).
Anyone can develop B12 deficiency at any age, but the older you are, the more likely you are to suffer. Estimates vary, but at least 1 in 50 of the UK population is thought to be deficient, rising to 1 in 10 or more in the elderly. B12 is found naturally in animal products such as meat, fish, milk and eggs, so vegans and vegetarians are at particular risk unless they take supplements. However, it is a hard vitamin to assimilate even if you follow a normal diet because it requires specific conditions for absorption — plenty of stomach acid, the presence of a protein called “intrinsic factor” (IF) and a healthy bowel. And herein lies the problem.
In some people — most commonly in those with autoimmune conditions such as thyroid disease and vitiligo or a family history of B12 deficiency — the protein IF stops working as they get older. In others, widely prescribed medicines, such as the antacid omeprazole or the type 2 diabetes drug metformin, can interfere with absorption. And then there is another group who don’t absorb nutrients well because of bowel problems such as coeliac disease (gluten sensitivity).
The trick with B12 deficiency is to consider it in the first place and listen to the patient. We test levels far more often than we used to, not least because it is now routinely included when screening people with memory problems, but the blood test is not infallible. Normal ranges can differ from hospital to hospital, and there is still some disagreement as to what constitutes optimal levels. Suffice to say that blood results should always be interpreted alongside the patient’s signs and symptoms. It is a foolish doctor who dismisses lack of B12 as a cause for fatigue and pins and needles just because a blood test comes back as “low normal” or borderline.
If you are otherwise healthy and have a normal bowel, oral supplements may be all that is required to prevent deficiency, but they won’t help most people who already have depleted stores because they will struggle to absorb the vitamin properly no matter how much they consume. This is why injections form the mainstay of therapy, typically given as a course of 6 over 12 weeks, followed by boosters every two to three months when required (and they often are).
It can be a very rewarding condition to treat, particularly in middle-aged and older people who, because of the insidious onset, often put their symptoms down to advancing age. Sometimes you see a response within a week, but in more severe cases recovery can take months. And in an unlucky few, whose deficiency has been prolonged because it has been missed, symptoms such as weakness caused by nerve damage may never fully disappear.
And treatment should go beyond correcting B12 levels. It is important to look for an underlying cause too. Further investigation will depend on the individual, but would generally include asking about diet, blood tests for antibodies to the protein IF, thyroid tests and screening for gluten sensitivity (coeliac). Levels of another key B vitamin (folate) are routinely checked whenever B12 is measured and, if the patient is anaemic, iron levels should be assessed too. Most cases are easily managed by GPs, but some patients will require onward referral to a haematologist or other specialities depending on what investigations turn up.
Most of the B12 checks I do come back as normal, and because of the vague nature of symptoms there are often myriad other possible causes for someone’s symptoms, but you won’t find B12 deficiency unless you look for it. And if you are cutting out animal products from your diet, heed the professors’ warning and read the advice about supplementation on the Vegan or Vegetarian Societies websites, vegansociety.com and vegsoc.org.
For the latest guidance on diagnosing and treating B12 deficiency visit Nice at bit.ly/365AyQw.
The signs and symptoms of B12 deficiency
● Anaemia isn’t always present, but if it is, people may look pale, notice that they are breathless on exertion or complain of a fast-beating heart (palpitations) or chest pain on exertion.
● Because B12 is essential for normal neurological function it can have wide-ranging effects on everything from mental agility to sensation and muscle innervation. Symptoms may include poor memory, mood changes, headache and occasionally confusion that can mimic or aggravate dementia. Peripheral nerve damage can cause altered sensation, often in the hands and feet, and may also lead to unexplained weakness, unsteady gait or a tendency to drop things.
● Fatigue, listlessness and lack of energy are common complaints too.
● The tongue can sometimes give the diagnosis away. Low levels may lead to inflammation (glossitis) that leaves the tongue feeling sore and looking red and swollen (beefy). Glossitis can also be a sign of folate and iron deficiency.
Last edited by Demi : Tue, Dec-31-19 at 08:35.