Industry calls Cochrane vitamin B review 'misleading'

11-Oct-2009 - Last updated on 12-Oct-2009 at 10:22 GMT

The Health Food Manufacturers’ Association (HFMA) and the International Alliance of Dietary/Food Supplement Associations (IADSA) are both disputing the Cochrane Scientific Review’s conclusion that B vitamins should not be recommended for the prevention of heart disease.

HFMA spokesman Patrick Holford described the recommendation as “completely misleading.” The main reason for the review was to examine whether lowering homocysteine - a proven marker for both heart attacks and strokes – reduces risk, he said.

“A lay person might reasonably assume that the people studied – 24,210 in all – had high homocysteine levels to begin with, and that they were given a cocktail of the B vitamins that are known most effectively lower homocysteine. Not so,” said Holford.

“Just five studies included in the review reported on homocysteine levels, and of those, the mean starting level of 12.4µmol/L could only be described as moderately elevated. But when you consider that the average Briton displays levels of between nine and 12, while those at elevated risk may have levels between 15 and over 100, it does call to question the validity of a review which fails to examine those with high homocysteine – the indicator for increased need for B vitamins.”

Premature

Holford added that there is a lot of evidence linking B vitamins with reduced risk of mortality.

“This review has drawn some vastly premature conclusions,” he said. “There is already a strong scientific basis to link B vitamin consumption with reduced risk in those with cardiovascular disease and raised homocysteine levels. What is needed now is further study involving those without pre-existing heart conditions to see the extent to which B vitamins can prevent it in the first place.”

IADSA pointed out in a scientific response to the review: “There is a significant body of scientific literature to demonstrate that there is a link between B vitamins and a reduced risk of cardiovascular mortality. This review is in conflict with scientific literature already published. The review is therefore not reaching a balanced conclusion.”

Heart attack

IADSA added that only five of the eight studies in the review measured the blood homocysteine at baseline after B vitamins intake.

It said there was no difference in the incidence of heart attack or stroke or mortality in the review between subjects given the B vitamins and control group.

In addition, it noted that varying doses of folic acid, B6 and B12 were administered across the studies and varying health status and levels of cardiovascular risk further compromised the findings.

IADSA also noted the review did not question the safety of B vitamins.

For NutraIngredients.com coverage of the review click here.