Factory Farming - A View from New Zealand
by Maurice McKeown, BDS, PhD
Salmon are not the only fish that are now being farmed as the world's natural fisheries become depleted. Currently turbot, sea bass, tuna, halibut and rainbow trout are also being farmed, primarily around European coasts. This year Norway hopes to produce 10,000 tons of cod; quantities which they plan to dramatically increase in the near future. Norwegian fish farmers anticipate that they could end up producing more farmed cod than is currently being caught in the North Sea.
Consumers have, in theory, got choices. If they want to eat wild salmon or any wild fish species, they will probably have to be prepared to pay up to three times as much. (Often it may not be clear where fish originated and whether they are from a natural environment.) Consumers have the power to vote with their teeth.
Choosing healthy fish or other seafood is however not a simple matter. Everyone now believes that fish have many nutritional benefits. Clearly seafood other than salmon can be chosen, but wild tuna and other big fish like king mackerel and shark contain significant mercury levels that are dangerous for pregnant women. The ongoing controversy over acceptable mercury levels in fish has been re-ignited with the recent release of new data from the Faeroe Islands study on the effects of mercury on children whose mothers have been exposed to mercury during pregnancy. The new information, derived from tests on 14-year-olds, suggests that such children suffer long-term, probably permanent neurological damage. The US EPA (Environmental Protection Agency) now believes that one in eight US newborns have potentially unsafe levels of mercury in their blood. For detailed information on the mercury controversy see http://www.ewg.org/
Unfortunately food regulatory authorities provide advice which varies significantly from country to country. For example - Health Canada advises Canadians to limit consumption of shark, swordfish and fresh and frozen tuna, to one meal per week. Pregnant women, those of child-bearing age and young children are advised that they should eat no more than one meal of the fish concerned, per month. Currently Food Standards Australia / NZ recommends only four portions of high mercury fish per week for pregnant women. They also advise that canned tuna has very low levels of mercury and can be eaten without restriction. Mercury levels vary according to tuna species. Albacore tuna has approximately three times the amount of other tuna species. The FDA in the US now advise women of childbearing age to eliminate swordfish, king mackerel, shark and tilefish from their diet. The US researchers, who have just completed the extensive salmon survey mentioned above, recommend that Scottish salmon should only be eaten three times a year to minimise toxin exposure. (Note: Salmon does not contain high mercury levels.) Scottish fish farmers are understandably unhappy!
Concerned consumers may opt for chicken, which is widely praised by nutritionists as a healthier food than red meat. Unfortunately the news from the chicken farm is not reassuring. The latest research by the US Department of Agriculture paints a depressing picture. (Environ Health Perspect 112:18-21 2004.) [Online 1 October 2003]
Concern about chicken meat has in the past been focused on high levels of bacterial infection, the presence of growth hormones and antibiotic residues. The reality may be much worse however. USDA researchers have now found that chicken is the primary source of arsenic in the US diet. Readers old enough to have read a Victorian melodrama will realise that arsenic is a deadly poison. In fact it is now a well recognised cancer- causing substance linked to a variety of important human cancers. Its presence in water in many regions of the world is a major health problem. It is arsenic in the inorganic form which is considered most dangerous. Organic arsenic is readily excreted from the body and in tiny quantities may even be a necessary dietary element. The research has found that:
The mean concentration of total arsenic in young chickens was 0.39 ppm, 3- to 4-fold higher than in other poultry and meat. At mean levels of chicken consumption (60 g/person/day), people may ingest 1.38-5.24 g/day of inorganic arsenic from chicken alone. In people who consume the most chicken their daily intake could be 21.13-30.59 g inorganic arsenic/day and 32.50-47.07 g total arsenic/day from chicken.
Many readers will wonder how chickens can possibly contain arsenic. The reason, surprising to most of us, is that chicken farmers are allowed to feed it to them (in the US at least), to kill intestinal parasites. To be fair, it has to be pointed out that those who pass judgment on risks to our health do not regard the levels of these substances as specifically hazardous. The US researchers have however carried out a very detailed analysis of just how much arsenic various chicken eaters might be exposed to. Those who eat chicken frequently could be getting significant amounts of the substance. Young children could be at greater risk than adults. They also noted that chicken livers contain substantially elevated amounts. It seems prudent to avoid chicken livers.
There is no doubt however that many toxic substances from food and other environmental sources do get into our bodies. It is the ultimate long-term effects that are uncertain. Last year 270,000 people were diagnosed with cancer in the UK - an all time high. A UK newspaper reported last November the results of a study done by the Worldwide Fund for Nature. They took blood samples from 155 people in 13 UK cities. They found that dangerous man-made chemicals were present in the blood of all the participants. The average number of the various chemicals in an individual's blood was twenty-seven! Seventy different banned chemicals were found overall. Some like DDT have been banned in the UK for over 30 years; but clearly still linger in the environment. The newspaper reported that PCBs - another banned chemical group, were found in the blood of 99% of the participants.
It seems inevitable that modern factory-style food must contain various contaminants in greater amounts than most naturally produced foods. There may however be other problems to address such as methods of food handling and processing. A good example is the recent revelations that some processed carbohydrate foods contain significant amounts of acrylamides; substances thought to be mild human carcinogens. The discovery of acrylamides in people is a timely warning on complacency in human nutrition. A tunnel fire in Sweden exposed workers to a cocktail of toxic chemicals, one of which was suspected to be acrylamides. Diligent investigators compared levels of the chemical in the victims' blood with a control group of unexposed citizens. It soon became clear that the control group had high levels of acrylamides in their blood. That was the beginning of the search for acrylamides in the human diet, substances previously unknown to be present. Research has now determined the origin of acrylamide and the mechanism of its formation. Manufacturers of a variety of bread and potato foods which contain the highest levels, are racing to develop safer products containing lower acrylamide levels.
Much maligned red meat may not be so bad after all. There is little solid evidence that it causes cancer or heart disease, particularly when eaten with healthy items like fruit and vegetables. Serious overcooking does result in the formation of cancer causing chemicals however. A substantial portion of the fat in red meat is of the mono- unsaturated variety. Much depends on the origin of the meat. Here in New Zealand we are fortunate that most of our animals graze throughout their lives on pasture. Thus beef, lamb, venison and goats are 'natural products'. The exception is pork. Pigs are mostly raised indoors. In the US totally pasture fed beef currently accounts for only 5% of beef consumed. It is widely accepted that grass fed animals produce flesh that is nutritionally superior to animals fed grains in the latter part of their lives. Pastured meat is lower in fat, higher in omega 3 fats, conjugated linoleic acid (CLA), vitamins E and A. Grass-fed animals are also healthier. They should also, in theory, be largely free of BSE. It has been suggested that if US consumers were able to change to grass fed beef the result would be that the average meat eater would consume 18,000 less calories annually. That would help with the obesity epidemic!
Dairy products from grass fed animals contain similar beneficial advantages. The more grass and fodder consumed by an animal the higher the level of CLA in their milk. CLA may be beneficial for weight control and the management of diabetes. It is now the focus of growing interest in agricultural and human nutritional research. Current CLA intake in the US has been estimated to be approximately one fifteenth that required for health and weight control benefits. For information about European CLA research see http://www.flair-/ Note: Strict vegetarians can use CLA supplements derived from vegetable oils. It appears that grass fed everything ought to be the future goal for every country where environment permits. Hopefully extra costs could eventually be recouped in reduced health care bills.
One of the main problems with our current system is consumer ignorance. This is not the fault of the consumer. There is usually no readily available information on how the product was produced. No legal requirements exist to disclose such information either. Information on the label, where present, is of limited value and often only readable with a strong magnifying glass. Surely consumers in future will demand to know much more about how their food is produced. Perhaps information technology will come to the rescue. Cheap computer chips are predicted to become available soon which, when incorporated into packaging, will act as super bar codes. There seems to be no reason why such chips could not contain consumer advice and detailed product information.