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Confessions of a Fish Killer
The McDougall Newsletter
By John McDougall, MD
I fell in love with the ocean at age 5 (in 1952) after watching a film
in my kindergarten class about undersea life: fish, corals, giant clams,
and hermit crabs. When I was 12, I became a SCUBA diver, but my
underwater explorations were limited to the murky waters of Michigan
lakes. During my early teens, our family vacations were to the Outer
Banks of North Carolina, where we always included some deep sea
fishing—catching and eating flounders, blues, and Dorado. My first ocean
SCUBA diving experience at age 18 was at John Pennekamp National
Underwater Park in the Florida Keys—here thousands of colorful fish swam
through a forest of corals. I enjoyed this experience so much that Mary
and I returned to the Keys and more diving for our honeymoon in 1972.
That same year we moved to Hawaii. Here we collected small tropical fish
for our saltwater aquariums from the shallow waters surrounding Oahu.
Unfortunately, within a few days of being removed from their natural
environment, most of them we found floating belly-up.
For the first time I realized I was living with a grim conflict: I
was a fish lover and a fish killer. Once or twice a year for the next
two decades, I captured large edible fish like mahi-mahi, tuna, and
salmon with lines and spears in Hawaii and California. I considered it
my right to eat them. The constant drone about their health benefits
from doctors and dietitians helped me justify my slaughter of these
The oceans have changed over my sixty-year lifetime. Ninety percent
of the large fish—the ones that make baby fish—are gone. Thirty-eight
percent of all animal sea life, including bluefin tuna, Atlantic cod,
Alaskan king crab, and Pacific salmon have had their populations cut by
more than 90%, and seven percent of the fish species have become
extinct.1 Because of the rarity of blue fin tuna, the Japanese are now
making some of their sushi with beef. The price of fresh wild salmon has
increased to $11 a pound, when it’s available, which is only a few times
a year. Fishing industries have collapsed worldwide and many of coral
reefs are now bleached and barren. Reliable predictions warn that by the
middle of this century (2048) all fish and seafood species will have
collapsed—they will be extinct or on the verge of extinction.1
The human demand for fish as food has been the major reason for the
devastation of the oceans and part of that demand comes from the belief
that fish-eating is essential for good health. This is not correct—in
fact, in our polluted world, eating fish has become a well-established
I Hated Fish Fridays
I grew up in the suburbs of Detroit, Michigan, in a neighborhood that
was predominately Catholic. That meant every Friday fish was served for
dinner. No matter how much it was breaded, salted, seasoned, and/or
fried to disguise the taste; come dinner time, I dreaded Fridays.
When consumers have a choice—like they do at every fast food
restaurant—between beef and chicken or fish—what do they choose?
Considering fish’s relative unpopularity, I would say most people don’t
like the taste of fish. The word “fishy” connotes a message of a quite
unpleasant-smelling sulphurous aroma that resembles fresh fish.
Anchovies are synonymous with bad taste—unless you like salt.
The taste of the flesh of a fish depends to a large extent upon that
fish’s diet. Many of the most popular fish; tuna, swordfish, salmon, and
rockfish, are carnivores, feeding off small unpleasant-tasting sea
animals, like anchovies, herring, and squid. But people have the ability
to adapt their taste buds and learn to like almost anything, even the
repugnant odor of sulfur.
Sulfur compounds are another reason for fish’s lack of gustatory
appeal. Rotten eggs and spoiled fish are malodors because of the
hydrogen sulfide gas that is released by bacterial actions. Sulfur also
taints many well waters. Foul body odors (halitosis, and smelly flatus
and perspiration) are primarily the result of sulfur compounds—the
origin of this sulfur is our diet in the form of sulfur-containing amino
acids, like methionine. The sulfur content of fish is particularly high,
for example salmon has 12 times more methionine than do sweet potatoes.
Seasonings make fish- and seafood-eating more tolerable. Most people
swallow these sea animals only after they are blackened on a barbecue,
smothered with cocktail sauce, or blended with bisque.
The Health Claims Are Fishy
“Fishy,” apart from meaning “like a fish,” also
inspiring doubt or suspicion, dubious, questionable, suspect,
suspicious, shady, funny, odd, implausible, unlikely, not
honest, and not legitimate.
Consumers are taught fish are their only reliable sources of
essential omega-3 fatty acids, called eicosapentaenoic acid (EPA)
and docosahexaenoic acid (DHA), and therefore they believe that by
avoiding fish they would suffer serious malnutrition. Sellers of
fish oil supplements go so far as to warn, “Supplementation with
fish oils that are rich in EPA and DHA is necessary to ensure you
are receiving adequate amounts of these nutritionally important
Most health organizations worldwide, including the American Heart
Association, the American Medical Association, the American Diabetic
Association, the British Dietetic Association, and Australia’s
leading health research body, the National Health and Medical
Research Council (NHMRC) (to name a few) also recommend that people
eat fish, primarily for the omega-3 fats. These same groups also
warn of the hazards of methylmercury and other environmental
contaminants in the fish—appearing balanced.
Recommendations to eat fish are based on laboratory research, but
originate primarily from observations of various populations of
people worldwide. For example, the rate of heart disease among
fish-eating populations, such as the Japanese, is very low, and this
has been attributed to the so-called “good fats” they receive from
eating fish. Researchers overlook the marked differences between
overall Western and Japanese diets. The primary ingredient in the
Japanese diet is rice and this is the reason they enjoy better
health, are trimmer, and more active. The small amount of fish eaten
daily is incidental.
But the “fish is health food” theory flourishes because, for many
people this is the easy road—simply add a serving or two of fatty
fish to their weekly diet—rather than giving up the real causes of
heart disease. Don’t think I overlooked the positive consequences of
adding fish a couple of times a week—it does replace some of roast
beef, pork, cheese, and chicken that would have otherwise been
Good Fats Are from Plants
The possibility of brain damage, especially to the unborn or
young children, strokes the emotional cords of our hearts.2 A number
of writers claim that only a diet based on seafoods can provide the
necessary quantity of essential fat (docosahexaenoic acid) to
support the human brain and that a switch to such a diet early in
human evolution was critical to human brain evolution.2,3 However, a
critical review of this claim by John Langdon of the departments of
Biology and Anthropology of the University of Indianapolis came to
this conclusion, “There is no evidence that human diets based on
terrestrial food chains with traditional nursing practices fail to
provide adequate levels of DHA or other n-3 fatty acids.
Consequently, the hypothesis that DHA has been a limiting resource
in human brain evolution must be considered to be unsupported.”3
Only plants can make the omega-3 fats—fish don’t; nor do cows or
people. Alpha linolenic acid (ALA) is made by plants and converted
into DHA by infants and adults in sufficient amounts to supply all
of our needs including those for brain function and development.
After all, the African elephant with a brain volume of 3000 to 4000
cm3, compared to the human brain of 1400 cm3, has no trouble making
all the essential fats its brain, and the rest of its huge body,
needs from plant foods.3 You can safely assume a comparatively puny
human being can do the same.
Do Fish Have a Metallic Taste? Or Has My Fish-eating Caused Me
When discussing healthy brain development and fish, let’s not
forget mercury. It may be all in my mind, but I swear the last tuna
I ate had a metallic taste. Mercury is a natural element found in
the earth, and is released as industrial pollution during various
manufacturing processes. Much of this metallic substance accumulates
in the rivers, streams and oceans, and is converted in the
environment into a highly toxic form called methylmercury. In this
organic form mercury becomes concentrated in the food chain by
processes referred to as bioaccumulation. Fish, especially those
predatory species high on the food chain, like, fresh water pike,
walleye and bass, and salt-water tuna, swordfish, and mackerel,
become heavily contaminated with mercury.
The consumption of mercury-contaminated fish is the main exposure
for people. Almost all of the mercury consumed is efficiently
absorbed by the intestinal tract. Since our bodies have no way of
excreting this toxin, mercury continues to accumulate throughout
life, exerting its detrimental effects. Serious health risks include
damage to the nervous system, heart, kidneys and immune
system—particularly for young children and the developing fetus.
The results of mercury poisoning for the brain are motor
dysfunction, memory loss, and learning disabilities; as well as
depression-like behaviour.4 The Food and Drug Administration (FDA)
and the Environmental Protection Agency (EPA) are advising women who
may become pregnant, pregnant women, nursing mothers, and young
children to avoid some types of fish, and eat fish and shellfish
that are lower in mercury.5 Other toxic compounds, such as fat
soluble dioxins, and polychlorinated biphenyls, are also found in
fish and fish oils.6
Fish-Eating Does Not Decrease Heart Disease
Eating fish may be healthier for the heart for people in Western
countries simply because it replaces some of the saturated fats that
would otherwise be found in the livestock on their dinner plates. A
study published in the May 2007 issue of the American Journal of
Cardiology came to this very conclusion and reported, “The data
supporting the inverse correlation of fish or omega-3 fatty acid (eicosapentaenoic
acid plus docosahexaenoic acid) consumption and coronary heart
disease are inconclusive and may be confounded by other dietary and
The research published in our major medical journals, which says,
“Fish are bad for the heart,” somehow fails to influence doctors,
dietitians, and health organizations who are telling us how to live
healthfully. Therefore, the public rarely hears about the following
Two recent studies have shown that people with the higher amounts
of mercury in their bodies, caused primarily by fish-eating, have
more heart trouble. The first one, published in the New England
Journal of Medicine in 2002, found that higher levels of mercury in
toenail clippings predicted a greater chance of future heart
attacks.8 The next study looked at the mercury content of the hair
and found, “High content of mercury in hair may be a risk factor for
acute coronary events and CVD (coronary vascular disease), CHD
(coronary heart disease), and all-cause mortality in middle-aged
eastern Finnish men. Mercury may also attenuate the protective
effects of fish on cardiovascular health.”9 More plainly, the
authors of this study concluded the high mercury content negated the
so-called protective effects of the “good” fish fats (like EPA and
DHA) on the blood vessels and heart. Those people with the higher
amounts of mercury in their hair (indicating more consumption of
fish) also had higher total cholesterol and LDL “bad” cholesterol
levels, and higher rates of hypertension and diabetes. Higher blood
cholesterol levels for fish-eaters should not be surprising since
fish has twice the amount of cholesterol as beef, chicken, and pork.
Cholesterol and Fish
A recent study of a total of 3114 men under 70
years of age with angina (chest pain due to clogged heart
arteries) who had been advised to eat two portions of oily fish
each week or to take three fish oil capsules daily were found to
have a higher risk of cardiac death compared to men not given
Patients with coronary heart disease documented
by angiograms received either fish oil capsules or olive oil
capsules for an average duration of 28 months.11 Fish oil
lowered triglyceride levels by 30%, but not these patients’
cholesterol. The amount of closure (stenosis) increased by 2.4%
and 2.6%, respectively. The authors concluded, “Fish oil
treatment for 2 years does not promote major favorable changes
in the diameter of atherosclerotic coronary arteries."11
A recent review of 48 randomized controlled
trials involving 36,913 participants taking fish oils or eating
oily fish, found no health benefits from these “healthy fats,”
and concluded, “Long chain and shorter chain omega 3 fats do not
have a clear effect on total mortality, combined cardiovascular
events, or cancer.”12
The Underlying Reasons Fish Components May
The reason fish, high in omega-3 fats, are felt
to protect people from heart disease is that this kind of fat
“thins” the blood and thereby helps prevent a blood clot
(thrombus) from forming in a heart artery and shutting off
circulation to the heart muscle. However, “good fat” from eating
fish, thus causing “good effects,” is only a small part of the
Much attention has been focused on the
artery-damaging effects of the environmental contaminant,
mercury. Adverse effects of mercury on blood vessels are from
oxidative stress (free radical formation), inflammation,
thrombosis (blood clots), and muscle dysfunction of the blood
vessel walls.13 However, mercury contamination is not the whole
story, and even if “clean” fish were available—and they are
not—fish-eating would still not be heart healthy.
There are many qualities of fish which encourage
heart disease. Fish are high in cholesterol which elevates blood
cholesterol.14 Even small doses of fish oils have been shown to
raise the “bad” LDL-cholesterol.15,16 Fish is also loaded with
sulfur-containing amino acids (like methionine) which raise
homocysteine levels in the body. Homocysteine is a well-accepted
risk factor for heart disease and feeding people methionine will
cause dysfunction of their arteries, which may promote blood
vessel disease.17 (Remember, salmon has 12 times more methionine
than sweet potatoes.) Even fish oil alone can increase
Other Adverse Consequences
from Consuming Fish:
Fish cause a rise in blood cholesterol levels similar to the
rise caused by beef and pork.13
Their highly-acidic animal proteins accelerate calcium loss,19
contributing to osteoporosis and kidney stones. The addition
of 5 ounces of skipjack tuna (34 grams of animal protein) a
day increases the loss of calcium from the bones, into the
urine, by 23%.20
No dietary fiber or digestible carbohydrates are present in
fish—thus having a negative impact on bowel function and
physical endurance, like winning a foot race.
Although omega-3 fats “thin” the blood, preventing thrombus
formation (heart attacks); this same anticoagulant activity
can increase the risk of bleeding complications from other
sources, like a hemorrhagic stroke or an auto accident.21
These good fats have antiinflammatory properties, which can
reducing arthritis pain, for example, as well as
deleterious—causing immune suppression, increasing the risk
of cancer and infection.22,23 Omega-3 fish fats
have been demonstrated to induce 10-fold more metastases in
number and 1000-fold in volume in an animal model of colon
cancer metastasis than does a low-fat diet.24
Fatty fish, commonly recommended salmon for example, is half
fat and loaded with calories, adding to one’s risk for
developing obesity and type-2 diabetes.
Omega-3 fats inhibit the action of insulin, thereby
increasing blood sugar levels and aggravating diabetes.25
Fish-eating prolongs gestation, increasing birth weight, and
the possibility of birth injury and increased mortality.26,27
Fish Farming Is Not Guilt-free
The cost of fresh wild fish and concern for the
oceans has caused many consumers to buy farmed fish—this may not
be a wise decision. Farmed fish are loaded with toxins because
they are fed a diet of fish oils and fish meal obtained from
small pelagic fish which themselves contain high levels of
environmental chemicals. Farmed salmon, for example, have higher
contaminant loads than do wild caught salmon.28
Because of the higher cost of meals made with
so-called good fats, farmed fish are fed rations containing
palm, linseed, rapeseed and other cheaper oils. The ultimate fat
composition of fish depends upon what they are fed. Therefore,
many farmed fish have a balance of fats that would not be
considered “heart healthy.”29
Other important issues that weigh heavily on the
fish farming businesses are the environment and animal rights.
Wastes from fish cages, including fecal matter and uneaten food,
along with chemicals used in farming, such as pesticides,
herbicides, and antibiotics, are dumped into the oceans. When
fish and other organisms are kept in close proximity, they breed
diseases. In most cases farmed fish are carnivores, and their
feed comes from the ocean; for example, herring is used as
salmon feed. Catching herring depletes the food supply for the
native fish, including salmon, trout, tuna, grouper, and cod.
And if you were wondering, fish do have feelings too30—and life
in a fish farm must be like living in prison, on death row.
I Am No Longer Conflicted or Confused
I have lived long enough to have witnessed the
first-hand destruction of our environment—it is real and now. I
worry that in the very near future when I want to take my
grandchildren to see the wonders of the ocean that I discovered
in my youth, the sea life will be gone. By correcting
misinformation, the downward spiral devastating our oceans can
be reversed. The situation is not hopeless, not yet.
I know the truth about human nutritional needs.
Therefore, I eat a diet of starches, vegetables, and fruits and
enjoy excellent health. Fish are not health food. Every day I
try to make choices that slow or reverse the loss of our oceans;
for example, I eat tofu tacos (see the April 2006 McDougall
newsletter)—they are far tastier and healthier than fish tacos.
By being informed, and making conscious choices,
you can make a difference too.
1) Worm B,
Barbier EB, Beaumont N, Duffy JE, Folke C, Halpern BS, Jackson
JB, Lotze HK, Micheli F, Palumbi SR, Sala E, Selkoe KA,
Stachowicz JJ, Watson R. Impacts of biodiversity loss on ocean
ecosystem services. Science. 2006 Nov
2) Hibbeln JR,
Davis JM, Steer C, Emmett P, Rogers I, Williams C, Golding J.
Maternal seafood consumption in pregnancy and neurodevelopmental
outcomes in childhood (ALSPAC study): an observational cohort
study. Lancet. 2007 Feb 17;369(9561):578-85.
3) Langdon JH.
Has an aquatic diet been necessary for hominin brain evolution
and functional development? Br J Nutr. 2006
C, Castoldi AF, Onishchenko N, Manzo L, Vahter M, Ceccatelli S.
Neurobehavioural and molecular changes induced by methylmercury
exposure during development. Neurotox Res. 2007
5) The Food
and Drug Administration (FDA) and the Environmental Protection
Agency (EPA): http://www.cfsan.fda.gov/~dms/admehg3.html.
6) Domingo JL,
Bocio A Levels of PCDD/PCDFs and PCBs in edible marine species
and human intake: a literature review. Environ Int. 2007
DK, Lanou AJ, Nigg CR. Relation of omega-3 Fatty Acid intake to
other dietary factors known to reduce coronary heart disease
risk. Am J Cardiol. 2007 May 1;99(9):1230-3.
8) Guallar E,
Sanz-Gallardo MI, van’t Veer P, Bode P, Aro A, Gomez-Aracena J,
Kark JD, Riemersma RA, Martin-Moreno JM, Kok FJ; Heavy Metals
and Myocardial Infarction Study Group. Mercury, fish oils, and
the risk of myocardial infarction. N Engl J Med. 2002
9) Virtanen JK,
Voutilainen S, Rissanen TH, Mursu J, Tuomainen TP, Korhonen MJ,
Valkonen VP, Seppanen K, Laukkanen JA, Salonen JT. Mercury,
fish oils, and risk of acute coronary events and cardiovascular
disease, coronary heart disease, and all-cause mortality in men
in eastern Finland. Arterioscler Thromb Vasc Biol. 2005
10) Burr ML,
Ashfield-Watt PA, Dunstan FD, Fehily AM, Breay P, Ashton T,
Zotos PC, Haboubi NA, Elwood PC. Lack of benefit of dietary
advice to men with angina: results of a controlled trial. Eur
J Clin Nutr. 2003 Feb;57(2):193-200.
11) Sacks FM,
Stone PH, Gibson CM, Silverman DI, Rosner B, Pasternak RC.
Controlled trial of fish oil for regression of human coronary
atherosclerosis. HARP Research Group. J Am Coll Cardiol.
12) Hooper L,
Thompson RL, Harrison RA, Summerbell CD, Ness AR, Moore HJ,
Worthington HV, Durrington PN, Higgins JP, Risks and benefits
of omega 3 fats for mortality, cardiovascular disease, and
cancer: systematic review. BMJ. 2006 Apr
MC. The role of mercury and cadmium heavy metals in vascular
disease, hypertension, coronary heart disease, and myocardial
infarction. Altern Ther Health Med. 2007
Davidson MH, Hunninghake D, Maki KC, Kwiterovich PO Jr, Kafonek
S. Comparison of the effects of lean red meat vs lean white
meat on serum lipid levels among free-living persons with
hypercholesterolemia: a long-term, randomized clinical trial.
Arch Intern Med. 1999 Jun 28;159(12):1331-8.
15) Harris WS,
Dujovne CA, Zucker M, Johnson B. Effects of a low saturated fat,
low cholesterol fish oil supplement in hypertriglyceridemic
patients. A placebo-controlled trial. Ann Intern Med.
1988 Sep 15;109(6):465-70.
16) Wilt TJ,
Lofgren RP, Nichol KL, Schorer AE, Crespin L, Downes D, Eckfeldt
J. Fish oil supplementation does not lower plasma cholesterol in
men with hypercholesterolemia. Results of a randomized,
placebo-controlled crossover study. Ann Intern Med. 1989
MF, McDowell IF, Ramsey MW, Brownlee M, Bones C, Newcombe RG,
Lewis MJ. Hyperhomocysteinemia after an oral methionine load
acutely impairs endothelial function in healthy adults.
Circulation. 1998 Nov 3;98(18):1848-52.
18) Holdt B,
Korten G, Knippel M, Lehmann JK, Claus R, Holtz M, Hausmann S.
Increased serum level of total homocysteine in CAPD patients
despite fish oil therapy. Perit Dial Int. 1996;16 Suppl
Welch AA, Bingham SA, Reeve J, Khaw KT. More acidic dietary
acid-base load is associated with reduced calcaneal broadband
ultrasound attenuation in women but not in men: results from the
EPIC-Norfolk cohort study. Am J Clin Nutr. 2007
W. The effect of high animal protein intake on the risk of
calcium stone-formation in the urinary tract. Clin Sci (Lond).
J, Bang HO. Haemostatic function and platelet polyunsaturated
fatty acids in Eskimos. Lancet. 1979 Sep
22) Meydani SN,
Lichtenstein AH, Cornwall S, Meydani M, Goldin BR, Rasmussen H,
Dinarello CA, Schaefer EJ. Immunologic effects of national
cholesterol education panel step-2 diets with and without
fish-derived N-3 fatty acid enrichment. J Clin Invest.
23) Stripp C,
Overvad K, Christensen J, Thomsen BL, Olsen A, Moller S,
Tjonneland A. Fish intake is positively associated with breast
cancer incidence rate. J Nutr. 2003 Nov;133(11):3664-9.
Cancer Res. 1998 Aug 1;58(15):3312-9
L, Fehres O, Griffini P, Van Noorden CJ, Frederiks WM. Promotion
of colon cancer metastases in rat liver by fish oil diet is not
due to reduced stroma formation. Clin Exp Metastasis.
25) Hendra TJ,
Britton ME, Roper DR, et al. Effects of fish oil supplements in
NIDDM subjects. Controlled study. Diabetes Care. 1990
26) Olsen SF,
Osterdal ML, Salvig JD, Weber T, Tabor A, Secher NJ.. Duration
of pregnancy in relation to fish oil supplementation and
habitual fish intake: a randomised clinical trial with fish oil.
Eur J Clin Nutr. 2007 Feb 7;
27) Olsen SF,
Hansen HS, Sorensen TI, Jensen B, Secher NJ, Sommer S, Knudsen
LB. Intake of marine fat, rich in (n-3)-polyunsaturated fatty
acids, may increase birthweight by prolonging gestation.
Lancet. 1986 Aug 16;2(8503):367-9.
28) Foran JA,
Carpenter DO, Hamilton MC, Knuth BA, Schwager SJ.Risk-based
consumption advice for farmed Atlantic and wild Pacific salmon
contaminated with dioxins and dioxin-like compounds. Environ
Health Perspect. 2005 May;113(5):552-6.)
29) ll JG,
Henderson RJ, Tocher DR, McGhee F, Dick JR, Porter A, Smullen
RP, Sargent JR. Substituting fish oil with crude palm oil in the
diet of Atlantic salmon (Salmo salar) affects muscle fatty acid
composition and hepatic fatty acid metabolism. J Nutr.
30) Lund V,
Mejdell CM, Rocklinsberg H, Anthony R, Hastein T. Expanding the
moral circle: farmed fish as objects of moral concern. Dis
Aquat Organ. 2007 May 4;75(2):109-18.
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