Sheba Medical Center researchers have discovered that taking slow-release melatonin, the human sleep hormone often taken for jet lag, can reduce high blood pressure at night, which can cause a high risk of heart disease in sufferers.

An article on melatonin and nocturnal hypertension by Prof. Ehud Grossman and colleagues at Sheba, the Rambam Medical Center, Tel Aviv University and Gazi University in Turkey will be published in the October issue of the American Journal of Medicine.

High blood pressure at any time of the day or night is a risk factor for heart disease and stroke, but it can have the most severe implications when blood pressure is high during sleep, when it declines in most patients, writes Grossman. Because night-time blood pressure is a better predictor of cardiovascular risk than daytime blood pressure, the beneficial effects of melatonin on night-time blood pressure will reduce the cardiovascular risk in high-risk patients with high blood pressure at night, they wrote.

Melatonin is naturally produced at night (triggered by darkness) by the pineal gland in the brain; its production declines as people get older. In previous research, Grossman and colleagues found that in hypertension patients whose blood pressure does not drop at night, their melatonin levels don't increase as they should. In the new study, the researchers treated 54 hypertensive patients who had high blood pressure even at night despite taking anti-hypertension medication on a regular basis.

In the randomized, double-blind, controlled study, one group received slow-release melatonin, while the other group received a harmless placebo. The team found that night hypertension was reduced significantly in the patients who took melatonin and not connected with any improvement in sleep.

Unlike in US, where melatonin is freely available without a prescription in health food stores and pharmacies, the drug is supplied in Israel only with a special prescription. The Health Ministry has restricted its use because it is a human hormone whose long-term effects have not been well established.

Source Jerusalem Post