Aluminium & Soya Milk
In 1989 the media reported concerns over the levels of aluminium in soya milks and the risk to human health. Reports were based on research that had been carried out at Surrey University from 1986-1988. Baby milk powders had been analysed and found to vary in the amounts of aluminium according to seasonal differences in environmental levels of aluminium, with powders based on soya having the highest levels. Armed with this information word soon spread that soya contained high levels of aluminium and posed a health threat. Scientists believe that there may be a link between the gradual build up of aluminium in the bones, brain and blood, and conditions ranging from a softening of the bones, senile dementia (or Alzheimer's disease), and anaemia.
Use of Aluminium
Aluminium is present all around us. Aluminium sulphates are added to water by many local authorities to clear water and give it a 'clean' appearance. The concentration of aluminium in the water may be higher where authorities add flouride salts. It is also high in areas prone to acid rain.
Aluminium is most likely to be ingested in the form of medicaments e.g. antacids and aspirin (doctors prescribe this combination to control arthritic pain without causing stomach upsets).
Sodium aluminium phosphate (E541) is used as a raising agent in many biscuits and cakes.
Aluminium cookware (now discouraged) was in use for many years in households throughout the country and certainly added to the overall consumption of the metal.
Tea leaves contain very high amounts. In fact, whilst wheat contains 2,000 micrograms per kilo, dried tea leaves contain a staggering 1,000,000.
According to research at the Dept of Renal Medicine at Southmead Hospital aluminium levels in 8 brands of fresh orange juice and 9 brands of reconsituted juice were more than 10 times that in Bristol tap water. Once swallowed, more of the aluminium in the juice is likely to enter the body, they say in a letter to The Lancet, because intestinal absorption of the metal is increased in the presence of citrates in the juice. By contrast, silicates and other compounds in tap water inhibit absorption.
Safe levels of aluminium in food and water are not really known. Although a directive from the European Commission specifies a limit in drinking water of 200 mg per litre.
Normally we would not absorb very much of the aluminium that finds its way into our digestive systems. In fact between 75-95% of the average 4-8ug of aluminium a day most people eat goes straight through their bodies undigested. One of the major problems in comparing levels of aluminium in various foods is that the method of collecting and processing samples itself can add aluminium, which is present everywhere around us. Levels of aluminium in the diet depend on a
variety of factors including the ability of plants to absorb it from the soil and seasonal variations in the environment.
An article in The Guardian (4.1.89) reported that human breast milk contains about 10mg of aluminium per litre. However, other sources have recorded a range of 250 to 2,400ug. This massive variation is due not to real variation in breast milk from different women, but to contamination. Dr Neil Ward of the University of Surrey uses the most precise analytical laser test for aluminium. He believes that breast milk
naturally contains between 30 and 130ug per litre - a relatively low amount because the breast is effective at screening out toxins to protect babies. Where aluminium concentrations are greater in breast milk, it probably reflects contamination from talcum powder or deodorant.
Those At Risk
The aluminium 'scare' really surrounded soya infant formulas rather than soya milk per se. It also concerned those most at risk from aluminium poisoning including patients with kidney disease (who are less able to excrete aluminium); newborn infants during the first week of life (longer for premature babies where the gut is more permeable); and possibly the elderly whose kidneys are not very efficient.
The amount of aluminium in Farleys Soya Formula (formerly Ostersoy) is 2000ug per kilo but when it is made up with water the level is about 400ug per litre. This is the only vegan infant formula currently available.
Whilst the concern about aluminium has primarily been over the level in infant formula powders., almost inevitably there has been concern over soya milks in general. However, soya products - e.g. tofu, miso, soya milk, tamari, soya sauce - have aluminium levels so low that they are difficult to detect. In fact there is far more aluminium in tomatoes, carrots, lettuce and brussels tops.
Plamil Foods Ltd reports 78ug of aluminium per litre in their ready to use soya milk (twice that in the concentrated form). All its soya milks are made in its Folkestone factory where local water is used. The water authority does not add aluminium sulphates or flouride to the water supplies there. The level of aluminium in Plamil milks is well below the maximum aluminium level permitted in drinking water of 4 parts per million. On the question of packaging, although all long-life cartons have an aluminium layer in them, this is prevented from contaminating the contents by two layers of inert polyethylene. Plamil soya milks are intended for use by children and adults and not as a sole infant feed.
Vandemoortele showed that its soya milk contains "less than 5,000ug" of aluminium per litre. They say that"It is recognised that soya milk does have a small aluminium content, as do most other food products, yet this falls well within acceptable limits dictated by the FAO/World Health organisation in relation to aluminium intake. Provamel and other soya milks in our range must not be confused with soya products manufactured from concentrates, such as specially formulated powdered baby milks, where the resulting aluminium level is much higher. Our range of soya milks are manufactured from grown whole soya beans. This process is not to be confused with soya-isolates, the method using solvent extraction and acid precipitation that uses more soya beans, and therefore introduces a higher level of aluminium."
Unisoy's soya milk, suitable for children and adults (but not infant feeding), was measured by the public analyst. It reports that aluminium was just detectable at the limit of the test, suggesting that the amount in the milk was about 50ug per litre - a very low amount which can, according to Dr Neil Ward (of University of Surrey) be believed only if the test was carried out by one of the five laboratories in the world which can detect aluminium at this low level. Unisoy, like the other companies, does not use aluminium vessels in the production of its milk.
Granose Foods Ltd report that its soya milks contain aluminium at the following levels: 500 ug per litre in the organic version and 700ug per litre in the ordinary version.
The contribution of levels of aluminium in soya milks to the possible threat to human health of unexcreted aluminium would appear to have been exaggerated. Soya beans, in common with other plants, do absorb aluminium from the soil but this amount cannot be considered excessive.
The main thrust of the aluminium scare was in relation to infant soya milk formulae, some of which contain higher levels of aluminium than cow's milk formulae. This should not cause problems for normal infants after the first month.
The Lancet; 11.3.89, p565