When nickel gave Indian chocolates a bad name

India has not forgotten Cadbury’s worm-gate crisis of 2003, but does anyone remember the nickel-in-chocolate controversy that started in 1991 and kept returning like a mystery fever for years?

It was ironic in a way that middle-class India got into a flap over the nickel content of chocolates eaten occasionally when unhealthy ‘vanaspati’ or hydrogenated vegetable oil, which was used in urban kitchens daily those days, contained plenty of nickel from its manufacturing process.

Nickel is used as a catalyst to turn vegetable oils into artery-clogging vanaspati ghee. Bureau of Indian Standards even now allows up to 1.5mg of nickel residue per kilogram of vanaspati. And vanaspati was the alleged chief culprit in the nickel-chocolate mess.

A private lab’s findings

The controversy started slowly on August 1, 1991 when The Times of India reported that Environmental Research Laboratory, a little-known private laboratory in Lucknow, had claimed all the popular brands of chocolate in India had a very high nickel content, 150–400 times the permissible level.

This was an exaggeration because Government of India did not prescribe any limit for the nickel content of food.

Lab director M C Saxena claimed Indian chocolates contained 15–41.5 parts per million (ppm) of nickel. By weight, he said, there was 600–1,380 micrograms of nickel in each bar of chocolate tested, as against a safe limit of 4 micrograms (also an arbitrary figure).

One microgram is a thousandth part of a milligram, which is a thousandth part of a gram.

Where was this nickel coming from? Saxena alleged all 11 brands of chocolate he tested contained vanaspati instead of cocoa butter as a hardening agent. That was enough to dent reputations, but he made an even more damaging claim: nickel causes cancer, premature greying and reduced immunity. Since children were the target market for chocolates, sales crashed immediately.

How bad is nickel?

Does nickel cause cancer? Yes, if you are breathing it, but probably not if you eat it. World Health Organization even now maintains “there is a lack of evidence of a carcinogenic risk from oral exposure to nickel.” Check out Page 14 of this WHO document.

Government of India did not bother about the private report or the controversy at first. Asked about it in Parliament on September 3, 1991, it replied: “No such study has come to the notice of the Directorate General of Health Services indicating that some leading brands of chocolates manufactured in the country have any content of nickel.”

That was not enough to quell the public’s fears. Two public interest litigation were filed before the Delhi high court and the Lucknow bench of Allahabad high court. The government then asked Hyderabad-based National Institute of Nutrition to analyse chocolate samples.

The government lab’s results did not agree at all with Saxena’s claims. It reported a mean nickel level of 1.26mg/kg in chocolate. In other words, on eating an entire 40g bar of chocolate worth 10 rupees — the family pack size in those days — you would have ingested no more than 50.4 micrograms or 0.05 milligrams of nickel.

“Latest report of WHO has mentioned that there is lack of evidence of a carcinogenic risk from oral exposure of nickel,” then minister of state for health and family welfare D K Thara Devi Siddhartha said on March 4, 1992. “In fact nickel has been shown as an essential trace metal in some plants and bacterial enzymes. Based on this information, the National Institute of Nutrition, Hyderabad, has opined that there is no need to lay down any maximum limit of nickel in chocolate.”

“There is no prescribed limit for nickel in chocolate under the provisions of the prevention of Food Adulteration Act & Rules made thereunder,” then health minister M L Fotedar confirmed on Nov 25, 1992.

Safe or not?

Is it true that nickel occurs naturally in plants? You can read all about it here. I am citing an abstract:

“Tea is consumed throughout India; dried tea leaves used for beverage making have been found to contain high nickel concentration which is about 3.9–8.2mg/kg. Similarly, coffee, which is very popular in south India, is found to contain high nickel concentration of 43mg per 100g of coffee beans (roasted, ground). Cocoa beans, from which cocoa and chocolate are made, may contain up to 10mg/kg of nickel and are common constituents of fast-foods in India.”

Conspiracy theorists said the government had rigged its lab result under pressure from the chocolate companies, so between September 1991 and August 1992, chocolate samples were picked at random and sent to these six national laboratories for analyses:

  1. Central Food Laboratory, Calcutta
  2. Central Food Laboratory, Pune
  3. Central Food Technological Research Institute, Mysore
  4. Defence Food Research Laboratory, Mysore
  5. National Institute of Occupational Health, Ahmedabad
  6. National Institute of Nutrition, Hyderabad

All of them reported that the nickel content of Indian chocolates ranged from not-detectable to 2.08ppm — far below Saxena’s claim. The government also claimed that World Health Organization, Food and Agriculture Organization, and UK, USA, Canada and the European Economic Community had not set any limit on the nickel content in food.

The government had set up two expert groups, one headed by the director general of Indian Council of Medical Research and the other by the director of National Institute of Occupational Health, to go into the question of nickel in chocolates. Both agreed that the nickel content of Indian chocolates was no more than that of chocolates sold abroad, and that there was no need to fix any limit for nickel content in normal food articles “as there is no cause for concern for nickel toxicity through oral ingestion.”

The controversy continued but the Indian public recovered its appetite for chocolate. From the government’s side, then health and family welfare minister B Shankaranand reassured Parliament on December 15, 1993: “Chocolates manufactured in India are comparable to any chocolates in the world and they are not injurious to health.”

The villain abroad

Ten years later, the focus had shifted to nickel in imported chocolates. The Indian delegation of Codex (the food standards code of FAO and WHO) reported in July 2001 that “the use of hydrogenated vegetable fat in chocolate imported into that country resulted in highly elevated levels of the heavy metal nickel being present in the imported chocolate.”