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.Widespread 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
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.
Breast Milk
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.
Infant Formulas
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.
Soya Milks
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
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.
Provamel (Vandemoortele)
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
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
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.
Conclusion
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
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