Critics voiced concerns that the unjustified claim could bias research funding and health policy decisions, as well as having a negative impact on patient welfare.
Dr. Peter Garrard, of the Cardiovascular and Cell Sciences Research Institute at St George’s, University of London, said the analysis of previous clinical trial data published last year cast no doubt on the potential of folic acid and vitamin B-12 to prevent dementia, and that the lead author’s comments were “unjustified and misleading.’”
Dr. Garrard pointed out that taking B vitamins lowers blood levels of a molecule (homocysteine), which in high concentrations acts as a potent risk factor for dementia. He highlighted the “first-rate scientific evidence that the use of B vitamins confers both biological and neuropsychological benefits” on individuals aged over 70 who had noticed a recent decline in their cognitive abilities.
He emphasized the urgent need for a definitive trial to establish whether this simple and safe treatment can slow cognitive deterioration in a similar group of people, as such individuals are known to have a heightened risk of developing full-blown Alzheimer’s disease.
In separate letters to the American Journal of Clinical Nutrition, Dr. Garrard and Professor David Smith, of the University of Oxford, pointed out a number of flaws in the new analysis, including: 1) reliance on data from trials of vascular disease prevention rather than dementia; 2) the use of the Mini Mental State Examination (MMSE), which is designed to detect dementia but is unsuitable for assessing small changes in cognitively normal people; and 3) the absence of any cognitive decline in untreated patients, rendering the whole study irrelevant to the question of clinical benefits in cognitive impairment or dementia.
International experts in dementia, nutrition and biochemistry from the Universities of Oxford, Cape Town and Oslo, and Tufts University in Boston, joined Dr. Garrard and Prof. Smith in criticizing the study.