Arginine and antioxidant vitamins could reduce pre-eclampsia risk
Taking a dietary supplement containing L-arginine and antioxidant vitamins reduces the occurrence of pre-eclampsia in a high risk population, a new study suggests. However, experts say that although the study is important the findings should be interpreted with caution.
A randomised, blinded, placebo-controlled trial was carried out in Mexico City among pregnant women at high risk of developing pre-eclampsia. The study, published online today (20 May 2011) in the BMJ, showed that women receiving a daily supplement of L-arginine and antioxidant vitamins, including vitamins C and E, were less likely to develop pre-eclampsia than women receiving a placebo (see Panel). However, vitamins alone did not significantly reduce the occurrence of pre-eclampsia.
The study authors say: “This relatively simple and low-cost intervention may have value in reducing the risk of pre-eclampsia and associated preterm birth.” But they add that further research is needed among a lower-risk population and to identify whether the effects are due to L-arginine alone or a combination of the amino acid with antioxidant vitamins.
In an accompanying editorial, Liam Smith, professor of clinical epidemiology at the London School of Hygiene and Tropical Medicine and David Williams, obstetric physician at University College Hospital, London, point out that the difference in systolic blood pressure between those taking L-arginine plus vitamins and those taking placebo was 5mmHg or less. The large reduction in relative risk in the L-arginine and vitamin group was partly driven by a small number of women just crossing the diagnostic blood pressure threshold for pre-eclampsia, they add.
They conclude that, although the findings are important, crucial questions remain. For example, what the mechanism of action is for L-arginine and vitamins together, what the potential harmful effects are and what effects the supplements have in other settings and populations.
Study method and results
Pregnant women at high risk of pre-eclampsia were divided into three groups — 228 received daily food bars containing both L-arginine and antioxidant vitamins, 222 received bars containing the vitamins only and 222 received placebo bars. Supplementation began when the women were 20 weeks pregnant and continued until delivery. The proportion of women who developed pre-eclampsia or eclampsia was 30 per cent in the placebo group, 23 per cent in the vitamin-only group, and 13 per cent in the L-arginine plus vitamin group. The risk ratio was 0.74 (95 per cent confidence interval, 0.54 to 1.02; P=0.052) when comparing the vitamin-only group with the placebo group and 0.42 (95 per cent CI, 0.28 to 0.62; P<0.001) for the L-arginine plus vitamin group compared with the placebo group.
Citation: The Pharmaceutical Journal URI: 11076327
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