Is mercury toxicity from fish a real health hazard?

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Is mercury toxicity from fish a real health hazard?

By Bill Sardi

 

Recently published studies are shedding more light on the subject of potential

mercury toxicity from fish and fish oil supplements. Should consumers be

concerned about mercury levels in fish? What about pregnant mothers? Can't the

mercury pass through to the baby in the womb?

 

Millions of Americans are unduly cautious or avoid eating fish due to reports of

mercury toxicity. It is true that fish contain a natural form of mercury and

that this heavy metal is toxic to brain cells and can be transferred to the

placenta and amniotic fluid surrounding an unborn baby.

 

However, adults have developed detoxification systems in their liver (primarily

the production of glutathione, an antioxidant) that rids the body of most heavy

metals. Adults who are concerned about mercury toxicity from dietary sources, as

well as from vaccines and dental amalgams, may want to employ N-acetyl cysteine

or melatonin, oral dietary supplements which elevate glutathione levels and

remove mercury. [Pharmacol Toxicol. 2003 Dec; 93(6):290-6; Tohoku J Exp Med.

2000; 191(4):241-6] N-acetyl cysteine (but not lipoic acid) works in a profound

manner to accelerate urinary mercury excretion. [Environ Health Perspect. 1998;

106(5):267-71]

 

Bran from cereal contains phytic acid (IP6) which is also a good natural

chelator (removal agent) for heavy metals such as mercury, lead and cadmium. [J

Agric Food Chem. 1999; 47(11):4714-7] IP6 rice bran extract, available in health

food stores, is far more potent a chelator than bran cereal and is preferred and

should be consumed with water on an empty stomach for a period of a few days to

weeks.

 

Fish oil supplements are OK

 

Commercial fish oil supplements are generally free of heavy-metals and are good

alternatives to dietary fish consumption. Brands of fish oils recently tested at

Harvard Medical School did not exhibit significant amounts of mercury. [Arch

Pathol Lab Med. 2003 Dec; 127(12):1603-5] A 1989 study of 22 brands of fish oil

in Germany found negligible amounts of heavy metals. [Z Ernahrungswiss. 1989;

28(1):76-83]

 

But about pregnant moms?

 

When the FDA issued its widely-publicized January 2001 FDA advisory, which

recommended that pregnant women limit their intake of certain fish because of

concerns about mercury contamination, consumption of fish fell among fertile

women. However, a report from Harvard Medical School states: " Because fish

consumption may confer nutritional benefits to mother and infant, public health

implications of these changes remain unclear. " [Obstet Gynecol. 2003;

102(2):346-51] In other words, the FDA advisory to avoid fish during pregnancy

may do more harm than good. Fish oil prolongs gestation and minimizes the

occurrence of premature birth. [int J Epidemiol 2001 Dec; 30(6):1272-8] The

baby's nervous system requires omega-3 oils provided by fish. Obviously, fish

oil supplements offer a clear advantage here over fresh or canned fish (about

3000 mg of supplemental fish oil is recommended per day during pregnancy).

 

Furthermore, the U.S. Food and Drug Administration recommendation that pregnant

women, women of childbearing age, and young children avoid eating fish due to

concerns over potential mercury toxicity, suggested avoidance of fish that are

not commonly consumed (shark, swordfish, mackerel, and tilefish). [J Obstet

Gynecol Neonatal Nurs. 2002] Women backed away from canned tuna and salmon,

which are not rich sources of mercury.

 

Is mercury from fish really a health hazard to infants?

 

Recently National Institutes of Health researchers investigated 779

mother-infant pairs residing in the Seychelle Islands. Mothers reported

consuming fish about 12 times per week. Fish in Seychelles contain much the same

concentrations of mercury as commercial ocean fish elsewhere. The researchers

assessed language, memory, motor, perceptual-motor, and behavioral functions in

children. The researchers did not find any evidence for nervous system

developmental problems in children at 9 years of age. [Lancet. 2003 May 17;

361(9370):1686-92]

 

In another study conducted in French Guiana, mercury contamination from gold

mining activities is prevalent. Yet among children exposed to high levels of

mercury there were no major nervous system problems noted. [Environ Res. 2002;

89(1):1-11]

 

Some groups of humans apparently find ways to nullify or minimize the health

threat posed by mercury in fish. For example, in a fish-eating community of

Brazilian Amazon native women, mercury levels were reduced with increasing

consumption of fruit. [Environ Res. 2003 Oct; 93(2):123-30]

 

While further research studies are likely to provide more needed information on

this topic, for now, human populations that consume that most fish appear to be

among the healthiest on the planet, namely the Japanese and the Eskimos. For

concerned individuals, fish oil supplements are a reliable source of beneficial

omega-3 oils without significant amounts of heavy metals.

 

-Bill Sardi, Knowledge of Health, Inc.

Copyright 2003 All rights reserved.

 

 

 

 

 

 

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