national public health institute, finland fish to eat or not to eat; that is the question olli...

National Public Health Institute, Finlandww

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FISH To Eat or Not to Eat; that is the question

Olli LeinoNational Public Health Institute

KTL KuopioEKO/WET research seminar, Konnevesi May 7th 2008


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Outline

1. Fish consumption2. Chemical contaminants in fish

3. Beneficial nutrients in fish4. Benefit-Risk comparisons

5. Conclusions


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Fish consumption in Finland

RKTL


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Fish consumption in Europe• Top consumers: Spain, Mediterranian and

Scandinavian countries

• Salmon and herring are particularly popular in the Scandinavian countries

• Other seafood (mollusc, crustaceans) not included

in this presentation


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Chemical contaminants

I Dioxin/PCB

II Mercury

III Other toxins • Polybrominated diphenyl ethers (PBDE)• Tributyltin (TBT)• Heavy metals (cadmium, led, and arsenic)


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I Dioxins and PCBs• Highly toxic (TCDD)

• Very persistent

• Lipid soluble, accumulate in food web

• TCDD a human carcinogen

• Developmental disorders, hormone disruptors, effects on immune system

• Information based mostly on animal studies!


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Domestic cases: River Kymijoki

http://www.kymisun.com

http://www.perho.info

http://www.ymparisto.fi


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Other dioxin cases• Seveso (Italy)

– Explosion in a chemical factory → a massive exposure to the environment

– Increase in cancer incidence was not detected in the

exposed population.- Less boys than girls were born - Dental aberrations

• Viktor Justsenko (Ukraine)– presidential candidate Justsenko was poisonned with dioxin →

chloroacne (very high dose)

© Wikipedia


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Mercury• Found everywhere on the globe• Accumulates in food web, particularly rich in

predatory fish (In Finland e.g. pike, perch, and pike-perch)

• The most toxic form is called methyl mercury- Affects central nervous system (CNS) and the brains - Effects on blood-vascular system - High dose effects:

- Malfunction on limbs - Visual impairment- Hearing and speaking impaired- Insanity, paralysis, coma and death- Cognitive effects to children

© Fish and wildlife research institute, Florida


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Mercury cases• Minamata disease 1956 Japan

– Sewage from a factory contained huge amounts of mercury– Fish, animals, and people were exposed to the extremely high

mercury concentrations– Over 2000 victims, nearly 1000 deaths

• Niigata Minamata disease 1965 Japani– ”crazy cats” – Human symptoms later on

• Iraq 1971 seed grain– 459 casualties, thousands of people with symptoms in CNS

• Extreme global cases: nothing similar to this has happened in Finland– Ecological effects?

© Wikipedia


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Polybrominated flame retardants (PBDE)

• Used widely to coat plastic and rubber• Accumulative• Preliminary human health studies

– Acute toxicity low– Some liver, and nervous system damage in chronic

animal studies. – No proven direct risk to humans found yet


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Health benefits of fish consumption• Omega-3 fatty acids

– EPA, DHA, ALA• Vitamin D

– Fat soluble vitamin– Trough diet, skin can manufacture it with sunlight

(Sunlight in Finland?)– Finns get 50% of vitamin D from fish consumption

• Many other micronutrients


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Other health benefits• Healthy low-fat diet

– Lowers prevalence of national diseases due to overweight (cardiovascular diseases, cancers, diabetes)


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Omega-3 fatty acids• Very beneficial to heart and blood-vascular system

(e.g. coronary heart disease, myocardial infarctions) – Lowers several risk factors (blood pressure,

arrhytmias, liquidity of blood, elasticity of blood veins)

• Several beneficial effects on brains– (antidepressant, vision, IQ, memory,

ADHD, Alzheimer…) – Skin and joints (rheumatism)

www.nu-mega.com

Wikimedia.org

olex

Vankilassa suoritettu koe vähensi aggressiota testihenkilöillä, samankaltaisia tuloksia aggressiivisten lasten kohdalla.


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Health benefits of vitamin D• Contributes to development of bone and muscles • Improves immunesystem and helps fighting

against infections• May prevent/slow down some cancers (prostate,

breast, ovary, colorectal) • Helps preventing diabetes

– Young children in particular need vitamin D


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How to assess risks/benefits originating from our environment?

• The goal is to serve the decision-making – E.g. fish consumption from the Baltic Sea

• Open Risk Assessment vrt. YVA• Assessing benefits as well is crucial


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Comparing risks and benefits• Difficult if there are no commensurable end points• Easy comparisons e.g.

– Deaths (cancer deaths vs.) avoided coronary heart disease deaths

– IQ points (mercury vs. omega-3)• Difficult e.g.

– Malfunctions of arms vs. decreased prevalence in depression

– Dental aberrations vs. decrease in blood pressure


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Benefit/Risk study on the domestic fish (Leino et al, Risk Analysis 2008)

• Commensurable and relevant end points→ avoided coronary heart disease deaths vs.

cancer deaths– Commensurable = same unit (number of deaths)– Very relevant diseases societally


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Cancer deaths vs. avoided coronary heart disease deaths

Health effects of domestic fish consumption in the Helsinki metropolitan area

Avoided coronary heart disease deaths due to omega-3 from fish

Cancer deaths due to dioxins exposure from fish

+170/year-1/year

Note: Risk estimate was calculated by intentionally using pessimistic assumptions whereas calculation of health benefits relied on the best available knowledge. This was performed not to underestimate the risk.

Leino et al 2007


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Two different consumption scenarios

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DEROGATION NO DEROGATIONCURRENT

PRACTICE PM EURO IV&V PM

Scenario/decision

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Benefits

Risks

-0.7

Leino et al 2008


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Risks

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Benefits

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Cancer deaths in Helsinki due to fish consumption

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Leino et al 2008


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Risks and benefits

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Benefits

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Avoided coronary heart disease deaths due to omega-3 intake from fish

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Leino et al 2008


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Lower fish consumption and the effects on human health

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Benefits

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Situation if commerial sale of salmon and herring were banned = Commission Regulation (EC) No 1881/2006

Difference -38

Difference +0.5

Päätös

-0.7

Leino et al 2008


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In comparison fine particles from heavy-duty vehicles

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Benefits

Risks

In comparison, the annual deaths caused by the fine particles from heavy-duty vehicles alone in Helsinki



Situation after decreased salmon and herring consumption

-0.7-0.7

Leino et al 2008

olex

Raskas liikenne vastaa n. 60% pienhiukkasten kokonaispäästöistä. N. 13% kulkuneuvoista on raskasta liikennettä.


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Some open questions• Selection of endpoints (cancer deaths for

dioxins, avoided CHDs for omega-3)? • Geographical variation in concentrations in fish?• Exposure-response for nutrients/contaminants?• Imported fish and the effect on health? • Vitamin capsules instead of eating fish?• Sensitive population subgroups (pregnant

women, children)?


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Other comparisons/future studies• Methyl mercury and omega-3 and childs IQ

– Preliminary results show close to zero effect• New methods to assess risks/benefits

– DALY (Disability adjusted life years)– ORA (Open risk assessment)

• Comprehensive benefit/risk study– All fish consumption health endpoints included

(Beneris EU-project)• All end points summarized into one answer using DALYs and

Bayesian Belief Networks (BBN)


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Other studies/literature• Mozaffarian and Rimm. 2006. Journal of the

American Medical Association. • Turunen et al 2008. Manuscript. • Hites et al. 2004. Science. • Tuomisto et al. 2004. Science.


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Conclusion• Fish contains both beneficial and harmfull

ingredients• Assessing risks and benefits is not straightforward• Majoriry of both national and international studies

consider the benefits larger than the risks• The most interesting/challenging step in the future

is an attemp to combine apples and oranges (make risks and benefits commensurable)


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To eat or not to eat?


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To eat or not to eat?• Go ahead!

• The official recommendation is 2-3 times a week. It is also advisable to eat various fish species.

• Sensitive population subgroups (pregnant women, young children) should follow special guidelines


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Thank you!

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