IS FOLATE GOOD FOR BOYS TOO?

Folic acid and zinc may increase sperm counts in men with fertility problems, say Dutch researchers — but Australian experts are cautious about the results.

Scientists at the University Medical Center Nijmegen in the Netherlands gave fertile and subfertile men folic acid and zinc sulphate for 26 weeks. Subfertile men showed a 74 per cent increase in the number of normal sperm after taking the supplements, compared to those taking a placebo.

The results appeared in the March issue of Fertility and Sterility.

But while the study was well designed, randomly allocating men to receive either the supplements or a placebo, the numbers of participants were too low to be statistically sure of the outcome.

"The results are interesting but they really need to be explored with a much bigger study," commented Dr David DeKretser, founding director of Melbourne's Monash Institute of Reproduction and Development.

"It's a great pity they didn't enlarge the numbers."

Participants numbered 108 fertile men and 103 subfertile men in total, but the men were spilt into four subgroups — receiving zinc sulphate and folic acid, zinc sulphate and placebo, folic acid and placebo, or two placebos. This left as few as 22 people in each group.

Dr Jeffrey Persson, a visiting medical officer at Sydney IVF, agreed that low numbers were a problem.

"I would not have constructed the study this way," he said.

"There were not many people in the treatment group, which makes it difficult to conclude the differences observed are because of the treatment."

"It would have been smarter to look at zinc and folic acid together and doubled the size of the groups."

Folic acid is a well-established birth-defect preventative for pregnant women. The researchers were working on the theory that folic acid together with zinc would improve sperm quality because of their importance to gene function. Zinc also helps stimulate testosterone production.

"It would do no harm for men to take folic acid and zinc, and they might be a useful adjunct, but it is not a cure [for infertility]," said Dr Persson. The 74 per cent increase in sperm counts of the subfertile men was not enough to put them into the fertile range — and in any case, sperm numbers are an indirect measure of fertility.

"You need to look at the bottom line, the final gold standard is an increase in the number of children resulting from treatment."

Each man's sperm count was only tested once during the study. Dr Persson suggested that an average of several semen analyses would have been more accurate, because sperm numbers tend to vary greatly even within one individual.

Men considered fertile have sperm counts of more than 20 million per millilitre. The study did not involve men who were infertile, defined as a sperm count of less than 5 million per millilitre.

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