The results have important implications to folic acid fortification with European initiatives still on the table and stalling over concerns than fortification may mask vitamin B12 deficiency in the elderly.
The promising results from the study, which involved 142 elderly Dutch people, appear to favour the dual fortification with both B vitamins. The results are published in the American Journal of Clinical Nutrition.
The 12-week double-blind, placebo-controlled trial assigned volunteers between the age of 50 and 75 to eat bread fortified with folic acid and vitamin B12 (cobalamin) daily, or non-fortified bread.
“Bread fortified with modest amounts of folic acid and vitamin B12 will improve folate and vitamin B12 status and a considerable proportion of vitamin B12 deficiency in older people,” wrote lead author Renate Winkels from the Top Institute of Food and Nutrition in Wageningen.
Maternal consumption of folate, or its synthetic form folic acid, is strongly associated with a reduced risk of neural tube defect (NTD) in the early states of pregnancy. Fortification of certain food groups with folic acid has been mandatory in North America since 1998, and the number of pregnancies affected by NTDs is reported to have fallen by 26 per cent.
To date no European country has followed suit, although the wheels have been in motion for some time in countries such as Ireland and the UK to introduce these measures.
The measures have stalled due to various reasons, with the debate raging around the possible adverse effect produced by folic acid fortification, particularly in relation to delaying the detection of vitamin B12 deficiency (which can have severe neurological consequences) in older people.
Dual fortification with folic acid and B12 could therefore be a sensible approach to reducing NTDs in newborns, and improving B12 status in the elderly.
Winkels and co-workers recruited 142 people and randomly assigned them to receive fortified bread giving daily doses of 138 micrograms folic acid and 9.6 micrograms vitamin B12, or unfortified bread.
After 12 weeks, the researchers found that the fortified bread was associated with a 45 and 49 per cent increase in blood levels of folic acid and vitamin B12, respectively.
Moreover, the number of subjects with ‘marginal’ B12 levels in the population decreased from eight per cent to zero after 12 weeks, said the researchers.
They also report a 13 per cent decrease in homocysteine concentrations. Epidemiological studies have reported that high levels of the amino acid homocysteine are associated with suspected or confirmed dementia. Indeed, the Framingham study reported that people with homocysteine levels above 14 micromoles per litre of serum had twice the risk of dementia.
In an accompanying editorial Helga Refsum from the University of Oslo and David Smith from the University of Oxford said that the question addressed in the study was “timely”.
“So, why not introduce vitamin B-12 fortification now?” they asked.
They note that, irrespective of folic acid, B12 fortification “may also be good for those sections of the populations that are known to have compromised vitamin B12 status, such as vegetarians, breastfed infants, and, in particular, the elderly, up to 15 per cent of whom suffer from food-cobalamin malabsorption.”
Furthermore, no adverse effects are associated with excess B12 intake in healthy people, according to the Institute of Medicine, said Refsum and Smith.
While the signs point towards the need for B12 fortification, the editorial argues that more research is necessary before such a measure is taken.
“In relation to folic acid fortification, it was recognized that NTDs were rare but, at the time, those in favour focused on the huge "potential" additional benefits that fortification might have, particularly in relation to cardiovascular disease,” wrote Refsum and Smith.
“The situation is rather different for vitamin B-12 fortification, where the scale of the problem is potentially much greater, including not only a significant proportion of the elderly but also some infants and young children with low vitamin B-12 status.
“Furthermore, there is perhaps less concern about adverse effects with this vitamin than there was with folic acid.
However, we must remember that evidence of benefit and of lack of harm is always needed before introducing mandatory population-level exposures to nutrients,” they wrote Refsum and Smith.
Source: American Journal of Clinical Nutrition
August 2008, Volume 88, Number 2, Pages 348-355
"Bread cofortified with folic acid and vitamin B-12 improves the folate and vitamin B-12 status of healthy older people: a randomized controlled trial"
Authors: R.M. Winkels, I.A. Brouwer, R. Clarke, M.B. Katan, P. Verhoef
Editorial: American Journal of Clinical Nutrition
August 2008, Volume 88, Number 2, Pages 253-254
"Are we ready for mandatory fortification with vitamin B-12?"
Authors: H. Refsum, A.D. Smith