Milk – The Devil in Disguise?
by Maurice McKeown, BDS, PhD(our New Zealand correspondent)
Milk is a controversial food. Some believe it is unnatural for any species that has been weaned to continue to consume the milk of another species. Others believe that milk causes allergies or contains a microbacterium which wreaks havoc with our immune system.
If milk is a cause of type 1 diabetes the disease ought to be very prevalent in societies where a lot of milk is drunk. The obvious focus would be the Masai people of Kenya who consume very large quantities. The problem is that they do not seem to get type 1 diabetes. Professor Elliott decided to ask New Zealand milk scientists whether the milk drunk in Kenya was in any way different from that drunk here in New Zealand. The scientists revealed that there was a difference in a protein component of the Masai milk which involved the structure of the casein molecules. That type of milk is now designated A2, while the variety commonly consumed in New Zealand is designated A1. (Milk is made up of carbohydrates, fats and proteins. The precise nature of the protein content is determined by the genetic makeup of the animal producing the milk. Milk protein is made up of approximately 5% whey protein and 21% casein protein. It is the nature of the casein which can vary among different animals, breeds and species.)
These observations lead to epidemiological and lab research. The most significant epidemiological study was published in 2003 in the NZ Medical Journal. (1) It examined the relationship between type 1 diabetes, ischaemic heart disease and cows' milk containing A1 beta casein - the type of milk commonly available in New Zealand and many other western countries. The twenty-country study reported very high correlations between A1 milk casein consumption and type 1 diabetes - in the order of 0.92 - a remarkable association in the biological field. There was a 300-fold variation in the incidence of type 1 diabetes in the countries involved which is notable in itself!
Other research at the University of Iceland has compared milk consumption in Iceland with that of other Scandinavian countries. Most Icelandic milk comes from A2-producing cows and the incidence of Type 1 diabetes there is substantially lower than the other northern countries. Milk in Iceland comes from an ancient Norse breed of cow, which produces A2 milk. The studies have confirmed that Icelandic milk is indeed low in beta casein A1 (2) and also that consumption of milk is much higher in Iceland than the other Scandinavian countries.(3) This suggests that the nature of milk may be a risk factor for type 1 diabetes.
Research by Boales and associates published in 2002 (5), involving rats and mice, only weakly support Professor Elliott's earlier work. It has, up until recently, formed the main rebuttal to his findings. It has now been revealed however that the feed used in that study was incorrectly formulated and the milk, supposedly free of the A1 protein, was contaminated with the key casein protein from A1 milk. Unfortunately it has now been alleged that those associated with the study failed to make this information public; indeed, that they may have deliberately withheld the information - thus leading to intense controversy in New Zealand over the role of Fonterra, New Zealand's major milk export corporation.
A University of Queensland study in 2003 determined that rabbits fed A1 milk developed arterial plaque while those fed A2 milk did not (7). Note: There is also some evidence that the responsible component in A1 milk may lead to oxidation of LDL cholesterol.
Research by the Elliott group has found that A1 beta casein per capita consumption in the milk and cream supply was significantly and positively correlated with IHD (ischaemic heart disease) in 20 affluent countries. The study used a five-year time lag, over a 20-year period – thus providing an alternative hypothesis to explain the high IHD mortality rates in northern compared to those of southern Europe. In Crete for example where heart disease is the lowest in Europe, the locals drink only small amounts of milk, about 40% of which is reported to be from sheep and goats who do not produce A1 casein. In 1995, A1 milk per capita intake varied greatly among many countries, from about 0.3 g/day in Guernsey, to 3.0 g/day in Finland. (Consumption is even lower in Japan). Comparison has also been drawn between Ireland and France. The French have much lower heart attack rates in spite of similar total fat consumption levels. The research concluded that the Irish/French IHD rate of 3.8:1 was in line with the milk protein type ratios (total milk protein per capita ratio 3.1:1; A1 per capita ratio 4.1:1) Overall it was noted that countries with the highest IHD rates all consume more than 2 grams of A1 milk per capita per day in their diet.
A potential link between milk consumption and autism was postulated many years ago. A University of Florida researcher Robert Cade reported in 1999 that beta-casomorphin-7 is found in high concentrations in the blood and urine of patients with either schizophrenia or autism. It is believed that in some children fragments of casein can leak through the gut wall into the blood, and from there into the brain causing significant behavioural problems. A2 Corporation, a NZ company involved in the testing and production of A2 milk, say that comments on the University of Florida website have stated that preliminary research findings have shown that 95% of autistic children have 100 times the normal level of milk protein in their blood. They go on to state that at least 8 out of 10 patients no longer had symptoms of autism or schizophrenia when put on a milk- free diet. Unfortunately the work does not appear to have been published to date and thus cannot be scientifically assessed.
How could some milk be much safer than others?
It is however unclear how we have arrived at a situation today where some breeds produce the original milk and others produce A1 milk which by definition is now the most common variety in many parts of the western world.
How could a molecular change in a component of milk lead to disastrous results for
A2 researchers also believe that gut permeability in some individuals, particularly young children, leads to abnormal protein ingestion into the blood and probably the brain. It has been shown that type 1 diabetics have specifically higher levels of antibodies to A1 beta casein than non-diabetics.
Health Friendly Cows
The mutation, which occurred in cows in the past, has lead to a situation in which some breeds of cows appear to have changed little and still produce purely A2 milk. Examples are native Icelandic cows, Jersey and Guernsey animals together with many French cows. Asian and African cows and other milk producing species like camels and goats all produce A2 milk. In Western countries dairy herds are a genetic mixture. Thus in New Zealand approximately one third of animals produce A2 milk, one third produce A1 milk and the rest produce a mixture. The A2 Corporation produces these testing kits so that individual animals from mixed producing breeds like Red Danish, Holstein/Friesian and Ayrshires can be assessed to determine what type of milk individual animals produce. It is thus possible to create herds producing the desired type of milk. In New Zealand it has been estimated that in ideal circumstances the entire national dairy herd could be converted to A2 production in eight years.
A2 milk is available in supermarkets and health shops in New Zealand and Australia. Over 1000 US health stores are now reported to stock it. In New Zealand A2 milk is only guaranteed to contain 95% A2 beta casein.
Feeding Infants and Young Children
The milk of cows varies from that of humans in a large number of ways. The minerals sodium, potassium, calcium, magnesium and chloride are present in much larger quantities in cow's milk. Carbohydrate levels are also much higher (notably lactose). The most dramatic difference however lies in the casein content. Human milk contains very little. (It is also rich in whey protein of a different type to that present in the cow.)
The possible role of A1 milk in precipitating type 1 diabetes in susceptible children, and possibly laying the foundations for heart disease and other diseases in later life, creates some problems for prudent new parents. There doesn't appear to be any A2 baby milk food products currently available. (Some studies have identified high levels of BCM-7 in infant formulas.) No doubt A2- derived formulas will become available in the foreseeable future. Until they become available, it may be prudent for new mothers to breast-feed for as long as practicable. Some believe that the digestive and immune systems of infants may be better able to tolerate A1 milk products as they grow older.
Until there are more answers, it seems that a prudent approach, regarding the consumption of regular A1 milk products, should be applied to babies and young children. Those who are not breast-fed might consume A2-based products, including goat's milk, if available. Failing that they could consume baby formulas containing only whey protein, thus avoiding the possible offending casein derivative of A1 milk.
Adult Milk Products
Red wine has now become a health imperative believed to be responsible for the French cardiovascular advantage. What if the real advantage was A2 milk drunk by the French and few others? As a result of the unresolved controversy the author is hedging his bets and drinking A2 milk plus a glass or two of red wine daily!
The extensive publicity surrounding the A2 (or is it A1) issue here in New Zealand has lead to the government announcing an investigation into the safety of A1 milk. Subsequent to that it has now been announced that the investigation will not proceed as the European Food Safety Authority is taking over the investigations. Hopefully the regulatory authorities in Canada and the US will finally become aware of the issues involved. Until that happens the onus lies with the educated consumer. Will we eventually see health warnings on regular A1 milk? I suspect that the A2 Corporation hopes so.
Readers who would like to explore this fascinating controversy further are recommended to read "Devil in the Milk" by Keith Woodford Craig Potton Publishing Nelson New Zealand ISBN 978-1-877333-70-5