New Delhi, May 15: India's food safety regulator has ordered three companies to stop the manufacture, sale and distribution of their energy drinks that contain both caffeine and ginseng, calling the combination irrational and impermissible.

The Food Safety and Standards Authority of India (FSSAI) has stopped the sale of at least nine products that belong to the category of energy drinks, at times promoted as a way to relieve fatigue and improve physical and intellectual alertness.

The nine are: Monster Energy Absolutely Zero and Monster Energy made by the Mumbai-based Monster Energy India; Cloud 9 Pomegranate, Cloud 9 Red Grapes, Cloud 9 Wild Berry and Cloud 9 Premium from the Pune-based Pushpam Foods and Beverages; and Tzinga Lemon Mint, Tzinga Tropical Trip and Tzinga Mango Strawberry produced by Hector Beverages in Gurgaon (Haryana).

The regulatory agency said a scientific panel had recommended that the combination of caffeine and ginseng - a compound extracted from a herb used in traditional Chinese medicine - was irrational as ginseng and caffeine have "opposing effects".

The agency made public the letters it had sent to the companies through announcements on its website this week. It had sent the letters to the companies on different dates from November 2014 through May 2015.

The FSSAI directives come amid concerns among sections of health activists that the caffeine content in energy drinks remains unregulated in India. While caffeine is generally regarded as safe, scientists caution that in extreme high doses it can lead to serious side-effects.

While food regulations limit the amount of caffeine in carbonated beverages to 145 parts per million (ppm), there is no such limit on caffeine in energy drinks. "The government had come up with a draft proposal to create a separate category of energy drinks, setting the maximum caffeine levels at 320 ppm, but it has not been implemented or notified yet," said Amit Khurana of the non-government Centre for Science and Environment, New Delhi.

In April this year, a team of Spanish and US researchers had cautioned about the dangers of certain energy drinks for the heart. In a paper published in the Canadian Journal of Cardiology, an international team led by Fabian Sanchis-Gomar at the Research Institute of Hospital 12 de Octubre in Madrid, Spain, had noted that some energy drinks have the potential to trigger sudden cardiac deaths in young, apparently healthy individuals.

The researchers had cautioned that adolescents with clinically relevant underlying medical conditions should consult cardiologists before drinking energy drinks and should not combine them with alcohol or other drugs.

Sanchis-Gomar had in a media release issued by the journal said: "It is important for physicians to understand the lack of regulation in caffeine content and other ingredients of these high-energy beverages and their complications so that parents and children can be educated about the risk of cardiac arrhythmias and the potential development of anxiety and phobia accompanying excessive consumption of energy drinks."