Fish: The good and the bad

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Fish The good and the bad

• Leslie E. Dorworth
• Illinois-Indiana Sea Grant College Program
• Purdue University Calumet
• Hammond, IN

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Fish is Good Food!

• Source of protein and some minerals
• Source of Omega-3 fatty acids

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Fish is Good Food!

• Easy to prepare
• Economical to catch locally
• Culturally important to many populations

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U.S Fish Consumption - 2004

• Shrimp
• Canned Tuna
• Salmon
• Pollock
• Catfish
• Tilapia
• Crab
• Cod
• Clams
• Flatfish

• 4.2 lbs/person
• 3.3
• 2.1
• 1.3
• 1.1
• 0.7
• 0.6
• 0.6
• 0.5
• 0.3
• 16.6 (Per Capita)
• H.M. Johnson Assoc., 2005

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Whats the Concern?

• Fish consumption is the major pathway for
  exposure to mercury and PCBs in the diet
• DeRosa, ATSDR 1998
• http//water.usgs.gov/wid/FS_216-95/FS_216-95.htm
  l

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Bioaccumulation/magnification

1. Pollutants get into the sediment or water from
   man-made or natural processes
2. Plants and small organisms absorb/ingest the
   pollutants, including juvenile fish.
3. Large fish eat smaller fish.
4. Top predators (man, eagles, raccoons, etc) eat
   the big fish.

Some pollutants can be found at much higher
levels in fish compared with sediment!
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Overview

• Healthy Fats in Fish
• Mercury
• PCBs and TEQ
• Fish Advisories

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Omega-3 Fatty Acids

• EPA eicosapentaenoic acid C205 n-3
• DHA docosahexaenoic acid C226 n-3

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Healthy Fats in Fish

• DHA important for brain/eye development
• NAS, 2002
• An estimated 250,000 Americans die each year from
  sudden cardiac death
• AHA
• consumption of long chain omega-3 fatty acids
  as found in fatty fish may reduce the risk of
  coronary heart disease
• ISSFAL, 1994

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Possible Mechanisms

• Preventing arrhythmias
• Decreasing platelet aggregation
• Decreasing plasma triglycerides
• Moderately decreasing blood pressure
• Reducing atherosclerosis
• Small increase in HDL cholesterol
• Modulating endothelial function
• Decreasing pro-inflammatory eicosanoids
• NAS, 2002

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Dietary Recommendations

• National Academy of Sciences (NAS) 2002
• EPA DHA 0.14 g/day for nursing and or
  pregnant women
• Dietary Guidelines Advisory Committee Report
  2004
• 8 oz fish/week
• American Heart Association (AHA)
• 2 servings (2-3 oz per serving) of fatty
  fish/week
• EPA DHA 1 g/d for heart disease patients

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What of the recommended levels do you get if
you consume 8 oz/week?
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Mercury
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Mercury and Omega-3 Fatty Acids
Fish Hg (ppm) Omega-3 FA (g/3oz)
Shark 0.99 0.90
Swordfish 0.97 0.70
Tilefish 1.45 0.80
King Mackerel 0.73 0.34
Fresh/frozen Tuna 0.38 0.24-1.28
Tuna, albacore 0.32 0.7
Tuna, light 0.12 0.26
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Mercury Toxicity in Adults

• Patients living in San Francisco
• High-end consumers of higher Hg fish
• Symptoms including fatigue, headache, decreased
  memory, decreased concentration, muscle and joint
  pain
• Symptoms gone after diet changes

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Methylmercury

• Crosses placenta and into breast milk
• Clearance from body 1 year
• FDA Action Level (fish tissue) 1 ppm
• Canadian Limit (fish tissue) 0.5 ppm

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Why focus on women of child-bearing age?
Toxins can cross the placenta and are found in
breast milk Fetal exposure can effect behavioral
, neurological and cognitive function in infants
and children Many of the most pronounced effects
occur in the first trimester and chemicals like
PCBs have a long half-life in the blood
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NHANES (19992002) - Mercury

• 6 of U.S. women have mercury levels in their
  blood that exceed the RfD (gt5.8 µg/L)
• CDC, MMWR. 2004. 53(43)1018-1029

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EPA Projection

• 15 (630,000 babies of the 4 million born
  annually) may be exposed to excessive mercury
  when in the womb
• Mahaffey, EPA 2004

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Mercury in Fish Sandwiches

• Fish in sandwiches from 6 restaurant chains
• Dairy Queen, McDonalds Burger King, White
  Castle, Long John Silvers and Subway
• 5 sandwiches from 4 stores for each chain
• Range 5-132 ppb hg well below FDA Action Level
  for Hg of 1000 ppbcan exceed EPAs RfD by 1.4x
  for 2 products
• Low in EPA/DHA (92-620 mg/sandwich)
• Shim et. al., 2005

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Mercury in Canned Fish

• Canned tuna (n240), salmon (n16), and mackerel
  (n16)
• All samples were well below FDA Action Level for
  Hg of 1,000 ppb
• Tuna (all types) 188 ppb salmon 45 ppb
  mackerel 55 ppb
• Chunk light tuna in water 54 ppb but also lower
  in EPA/DHA
• Shim et. al., 2004

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Canned Tuna and Mercury

• Main source of dietary mercury exposure
• Served in school lunch programs and provided by
  WIC clinics to lactating women
• Consumer reports recommends women who are
  pregnant or nursing to not consume any canned
  tuna

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PCBs TEQ
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Polychlorinated Biphenyls (PCBs)

• 209 Congeners
• Aroclors include 60 congeners
• Aroclor 12 68
• 12 represents 12 carbons
• 68 represents the chlorine

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PCBs

• 6 years to clear from the body
• Passes throough the placenta and into milk
• U.S. and Canadian Limit (fish tissue) 2 ppm
  (expected to increase cancer risk by 1 in
  100,000)
• Infants exposed at high levels
• Have altered postnatal development, lower birth
  weight, smaller head circumference, poorer
  short-term memory
• Safe 1992 EPA/823-R-93, 1993

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Total PCBs in Coho Salmon Fillets (Lake Michigan)
EPA/823-R-93-003, 1993
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Maximum Total PCB in Sportfish

• Creek Chub
• White Sucker
• Rock Bass
• White Crappie
• Spotted Bass
• Green Sunfish
• Black Bullhead
• Channel Catfish
• Carp

• PCB (ppm)
• 426
• 355
• 300
• 235
• 220
• 110
• 64
• 41
• 35

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Sources of PCB (TEQ) in U.S. Diet
13.6 Farmed Salmon (2.5 g/d) 8.4 Other Fish
(16 g/d)
NAS, 2003
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Fish Advisories
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Fishy Characteristics
How can you tell if the fish you caught has a lot
of mercury or other contaminants? Does it smell,
look, act or taste different?
General Guidelines -Larger fish vs. smaller
fish -Fish that are top predators (bioaccumulatio
n) -Older fish -Source?
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FDA EPA Advisory for Women of Childbearing Age
and Children
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Advice For Women Who Are Pregnant, Or Who Might
Become Pregnant, and Nursing Mothers About
Avoiding Harm To Your Baby Or Young Child From
Mercury In Fish

• Do not eat Shark, Swordfish, King Mackerel,
  Tilefish
• Eat up to 12 oz. (2 average meals) of a variety
  of fish and shellfish that are lower in mercury.
• For recreationally-caught fishcheck local
  advisories.
• Eat up to 6 oz. of Albacore/white tuna per week,
  and on other fish in the same week
• FDA/EPA 2004

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Choose Fish Low in Mercurywww.americanheart.org
Fish Hg (ppm) Omega-3 FA (g/3oz.)
Canned Tuna (light) 0.12 0.26
Shrimp ltLOD0.01 ppm 0.27
Ollock 0.06 0.46
Salmon 0.01 0.68-1.83
Cod 0.11 0.13-0.24
Catfish 0.05 0.15-0.20
Clams ltLOD0.01 ppm 0.24
Flounder/sole 0.05 0.43
Crabs 0.06 0.34-0.40
Scallops 0.05 0.17
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For Advisory Information

• Current state and local advisories available at
• http//fn.cfs.purdue.edu/fish4health/
• http//www.idph.state.il.us/public/press06/2.2.06f
  ishadv.htm

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Other Educational Materials

• Sensitive populations
• http//fn.cfs.purdue.edu/anglingindiana/FishAdviso
  ry2006.PDF (English)
• http//fn.cfs.purdue.edu/anglingindiana/FishAdviso
  ry200620Span.PDF (Spanish)
• http//fn.cfs.purdue.edu/anglingindiana/FishAdviso
  ry20Kosher2006.PDF (Kosher)

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Ways To Educate Others

• Local stakeholder involvement
• Translation of health education materials
• Signage
• Mass media
• Outreach at fairs and festivals
• One-on-one counseling
• Small grants for community programs
• FSNEP Fish Connection
• Collaboration with WIC

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I would like to thank Dr. Charles Santerre of
Purdue University for providing the bulk of the
slides for this presentation.
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Questions?