A tax on tinned tuna could lead to an increase in consumer health benefits when implemented in conjunction with a subsidy for canned sardines, a study has said.

A working paper from the Center for Agricultural and Rural Development looked at how economic policy could be used to promote high omega-3 fish, such as sardines, over a fish which may contain harmful contaminants such as methyl mercury.

The study suggested that a sardine subsidy and a tuna tax would help promote the former while putting people off buying the latter. The study could fan the flames of debate over regulatory approaches in health policy, which in the past has looked at the effects of taxation or subsidization of products for dealing with obesity by focusing on a fat tax or a thin subsidy.

In the paper Tax, Subsidy, and/or Information for Health: An Example from Fish Consumption, a laboratory test to see how consumers behaved when buying canned sardines or tuna in France was carried out. Researchers looked at the effects combined with the level of information consumers were given, or already had, on the health benefits or potential risks.

Lead author Stéphan Marette said: “Simulations with the laboratory results show that, for most cases, a per-unit tax on tuna and a per-unit subsidy on sardines without any information revealed to consumers lead to the highest welfare, because both the tax and subsidy directly internalize health characteristics.

“The information policy combined with a per-unit tax on tuna and a per-unit subsidy on sardines is socially profitable only if a large proportion of consumers (greater than 95%) receives health information.”

Researchers were prompted to carry out the study as the safety and nutrition of fish consumption have become an increasing public health concern in recent years, they said.

Marette said: “Fish consumption involves a balance between benefits such as omega-3 fatty acids and risks such as methyl lmercury. There are large differences among fish species regarding their health-promoting content.

“Information is a classical instrument for emphasizing health benefits and risks, but it is often doomed to failure because of consumers' confusion about different species or their lack of attention to health messages.”

The experiment was carried out in Dijon last January with a sample of 120 women randomly selected. Because pregnancy and breastfeeding status, or being a young child, are crucial indications for risks linked to methyl mercury, the study focused on women of childbearing age between 18 and 45.

The full results showed the willingness to pay (WTP) in the lab experimentfor canned tuna and canned sardines is statistically significant after the revelation of health information, Marette said. Information about methyl mercury and omega-3 leads to a WTP decrease for tuna and to a WTP increase for sardines. They also found that if no information was given to consumers or was already known, the tax/subsidy system would still favour the purchasing of sardines.

Marette concluded that: “This paper improves our understanding of how instruments influence consumers' behavior. The information policy combined with a tax on tuna and a subsidy on sardines is socially beneficial only if a large proportion of consumers can receive the health information. This means that a regulator should target many consumers if information is chosen as a regulatory option.”

He added that the “methodology of this paper may be used by administrations, parliaments, or regulatory agencies for forecasting the consequences of their regulatory decisions.”

The omega-3 market has seen rapid growth over the last few years. According to the latest Frost and Sullivan figures the European omega-3 market was worth around €160m (£108m) in 2004 - and is expected to grow at around 8 per cent a year until 2010.

Alex McNally 03/09/2007

Our Chairman comments…

This is erroneous. It is based on the idea that:
(i) methyl mercury at the levels in fish are harmful.
(ii) oily fish are the only thing.
(i) Firstly, the Japanese eat tons of tuna  (often several times a week and often fish or sea food every day) and there is not one scrap of evidence of toxicity which is based on a completely misleading PR campaign (see Hibbeln JR, Davis JM, Steer C, Emmett P, Rogers I, Williams C & Golding J (2007) Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study. The Lancet 369:9561 under articles at www.thelancet.com)

Balance between mercury against benefit is not discussed. The level at which mercury has been seen to be toxic is way far above anything we eat on fish. The scare is derived from Iraqi’s eating grain seed to replace a failed harvest that was laced with mercury and a fungicide. The sacks had skull and cross bones on them. At that level it was bad news. But again the population was badly undernourished if not starving.

In the ALSPAC study the women who ate fish in their pregnancy above the recommendations were the ones with the best performing children at 8 years of age. From the higher incidence of behavioural and mental development problems in those complying with the advisory it could be said this advisory was actually doing harm.

(ii) The epidemiology of benefits refers to fish and sea food, not oily fish. Fish oil contains 12 % EPA and about 8% DHA the rest is saturated and monounsaturated fatty acids. Moreover it is triglycerides ready for burning or dumping in adipose fat. This is not to say it has no benefit.
However, even white cod loin, although low in fat (good!?) provides 600-700 mg of DHA in one serving.
Moreover the DHA is at the level of 47% in the phospholipid which is in the form it used for cell membrane growth, development function and repair. Tuna meat similarly has DHA rich phospholipid. Sardines are OK but so
is tuna. The idea of taxing tuna to favour sardines for health is stupid and ignorant!  The people proposing this clearly know little or nothing about the composition of fish and sea foods.