Pernicious anemia

Authorities in the US and other countries have proposed fortifying foods with folic acid in order to reduce the incidence of neural tube defects. The safety of such fortification has been questioned, however, on the grounds that increased folic acid intake might mask the anemia of vitamin B12 deficiency, thereby delaying the diagnosis of this disorder, with possible permanent neurologic damage.

Two recent articles by British authors dispute the idea that folic acid fortification would be harmful to patients with B12 deficiency. In one commentary, Dr CJ Dickinson of St. Bartholomew's Medical College, London, reviews the early literature on folic acid and pernicious anemia and finds no convincing evidence that the speed of neurological deterioration is faster in [B.sub.12] deficient patients treated with folic acid than in untreated patients.

Dr. Dickinson acknowledges that folic acid can correct the anemia of [B.sub.12] deficiency. "Thus it could mask the underlying disease, and allow the development or progression of neurological deterioration, if diagnosis depended on the presence of anemia symptoms. This possibility can readily be overcome by adequate education of doctors, so that a macrocytic anemia is not regarded as a necessary accompanying sign of the neurological disorder. The hypothetical and avoidable side-effects of food fortification with folic acid have to be balanced against the certain benefit of preventing neural tube defects in unplanned pregnancies, and also against the probability that adults may be spared the neuropsychiatric and other ill-effects which result from inadequate dietary folic acid."

Similarly, in an editorial in the British Medical Journal, Dr Nicholas J Wald and Dr Carol Bower, also of St. Bartholomew's Medical College, argue that a selective approach to prevention of neural tube defects (in which only women planning a pregnancy would take extra folic acid) is unlikely to be successful. In general, selective approaches to public health problems have been less effective than population-based approaches. Also, a selective policy would fail to prevent neural tube defects in unplanned pregnancies.

Dr Wald and Dr Bower contend that the problem of folic acid masking the anemia of vitamin [B.sub.12] deficiency can be solved by educating physicians. They also argue that possible interference by folic acid with anticonvulsant therapy can be solved by increasing the doses of anticonvulsant drugs.

"The solution, then, is to fortify food with folic acid," according to these editorial writers. "A public health initiative is urgently needed; the tragedy of a pregnancy in which the fetus has a neural tube defect is even greater when it can be so easily prevented .... If this opportunity is missed, the costs - the needless suffering of seriously disabled children, unnecessary terminations of pregnancy carried out because of an antenatal diagnosis of a neural tube defect, and wasted financial resources - will be great."

CJ Dickinson, Does Folic Acid Harm People with Vitamin [B.sub.12] Deficiency? Medicine Medicine88(5):357-364 (May 1995) [Correspondence: Professor CJ Dickinson, Wolfson Institute of Preventive Medicine, Medical College of St Bartholomew's Hospital, Charterhouse Square, London EC1M 6BQ, UK]

Nicholas J Wald and Carol Bower, Folic Acid and the Prevention of Neural Tube Defects, BMJ 310(6986); 1019-1020 (22Apr 1995) [Correspondence: Professor Nicholas J Wald, Department of Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, Medical College of St Bartholomew's Hospital, London EC1M 6BQ, UK]

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