In this magazine a year ago we highlighted the loss of essential minerals—calcium, sodium, phosphorus, magnesium, iron, etc—from our fruit and vegetable supply.
The figures made alarming reading. Comparing the mineral levels in the 1930s with those in the 1980s showed that modern fruits and vegetables were typically depleted in minerals by 20%. The fact that modern fruit and vegetables contained more water could only explain some of the losses. Intensive farming on exhausted land was likely to be the major cause of the decline in the nutritional quality of the food, along with the selection of varieties for qualities other than nutrition.
Now, researcher David Thomas has analysed data on meat and dairy foods, comparing their levels in the 1930s (published by McCance & Widdowson in 1940) with the most recent government tables, published in 2002. Once again, the figures make alarming reading.
Table 1. Changes in mineral composition
of milk 1940-2002
| 1940 | 2002 | change
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| values in milligrams
| Sodium | 50 | 43 | down 14%
| Potassium | 160 | 155 | down 3%
| Phosphorus | 95 | 93 | down 2%
| Magnesium | 14 | 11 | down 21%
| Calcium | 120 | 118 | down 2%
| Iron | 0.08 | 0.03 | down 62%
| Copper | 0.02 | >0.01 | all gone
Sources
McCance and Widdowson 1940
McCance and Widdowson 6th edition 2002
Commentary on changes in mineral composition
David Thomas, unpublished
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As we show on this page, the mineral content of popular meats and milk products has fallen significantly. Looking at 15 different meat items, Thomas found the iron content to have fallen on average 47%, with some products showing a fall as high as 80%. The iron content of milk had dropped by over 60% while for cream and eight different cheeses the iron loss was over 50%.
The calcium loss from milk was only slight, but from cheeses it averaged over 15%—and in high-value Parmesan cheese the loss was an extraordinary 70%, implying a considerable dilution of the original highly concentrated recipe for this cheese, or some other significant shift in ingredients to account for this change.
Copper and magnesium, essential for enzyme functioning, also showed losses in meat products (typically, 10% fall for magnesium, and 60% fall for copper) and dairy foods (typically, 25% fall for magnesium, and an extraordinary 90% fall in copper).
Should we worry?
Table 2. Mineral levels in selected foods
showing 1940 values and amount lost by 2002
| Magnesium | change | Calcium | change | Iron | change
| values in milligrams per 100 grams
| Cheddar | 46.9 | down 38% | 810 | down 9% | 0.57 | down 47%
| Stilton | 27.2 | down 45% | 362 | down 10% | 0.46 | down 57%
| Parmesan | 49.6 | down 70% | 1220 | down 70% | 0.3 | all gone
| Beef rump steak | 24.8 | down 7% | 5.2 | down 4% | 6 | down 55%
| Corned beef | 29 | down 48% | 12.8 | down 45% | 9.8 | down 76%
| Streaky bacon | 25.1 | down 16% | 52.3 | down 87% | 3.2 | down 78%
| Chicken roast | 23 | no change | 24.5 | down 31% | 2.6 | down 69%
| Turkey | 28.2 | down 4% | 38.3 | down 71% | 3.8 | down 79%
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We live longer than ever, and we have access to abundant food supplies, so are these changes in nutrients any reason to be concerned?
We believe so. Minerals and trace elements play a major role in our physical and psychological well being. The recent changes in dietary habits towards highly processed foods means we are likely to be over-fed yet malnourished in terms of these micronutrients. Medical science may help keep us alive longer, but we are not necessarily healthier, nor happier. As Thomas concludes, "minerals are what we are made of, (to quote the Bible: 'ashes to ashes, dust to dust') and it would be very difficult to overestimate their importance as a catalyst for developing and maintaining good health'.*
The recent National Diet and Nutrition Survey of adults showed that young women, particularly, were likely to have diets seriously deficient in essential minerals. Up to 8% were below the Lower Reference Nutrient Intake (LRNI) for calcium, 20-22 percent were below the LRNI for magnesium, and 40% were blow the LRNI for iron. LRNI is the amount of a nutrient that is enough for only the small number of people who have low requirements (about 2.5% of the population).The majority need more.
These women were the key age group for childbearing, and so, to continue the biblical analogy, the sins of our agricultural practices may yet be visited many-fold upon the next generation.
* David Thomas is a researcher, nutrition adviser and mineral supplement supplier
email: david.mri@btconnect.com
Mineral Levels Plummet
in Meat and Milk Over 60 Years
Study blames the decline on intensive farming
Food industry contests comparative methods
by Felicity Lawrence
Guardian Newspapers Limited, UK, Thursday, February 2, 2006
...today's agriculture does not allow the soil to enrich itself, but depends on chemical fertilisers that don't replace the wide variety of nutrients plants and humans need."
—Dr. Tim Lobstein
The Food Commission
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The mineral content of milk and popular meats has fallen significantly in the past 60 years, according to a new analysis of government records of the chemical composition of everyday food.
The research looked at government tables published in 1940, and again in 2002, in the nutritional bible, The Composition of Foods, to establish levels of important minerals in dairy products and meat before the Second World War and today.
The research, which is contested by the food and farming industry, found a marked decline in nutritional value during the period. The analysis is published in this month's Food magazine by the consumer watchdog the Food Commission.
The levels of iron recorded in the average rump steak have dropped by 55%, while magnesium fell by 7%. Looking at 15 different meat items, the analysis found that the iron content had fallen on average by 47%. The iron content of milk had dropped by more than 60%, and by more than 50% for cream and eight different cheeses. Milk appears to have lost 2% of its calcium, and 21% of its magnesium too.
Most cheeses showed a fall in magnesium and calcium levels. According to the analysis, cheddar provides 9% less calcium today, 38% less magnesium and 47% less iron, while parmesan shows the steepest drop in nutrients, with magnesium levels down by 70% and iron all gone compared with its content in the years up to 1940.
The reseach was conducted by David Thomas, a chiropractor and nutritionist who prescribes and sells mineral supplements. He published an earlier historical analysis of the nutrient content of fruit and vegetables in 2000 which showed a similar decline in those foods. He attributes the loss of nutrients to intensive farming and industrial production.
Academics in the US and Denmark have also reported signficant changes in the nutritional profile of modern foods.
The Food Commission believes that changes in the methods of measuring the composition of food cannot account for the huge difference in nutrient content, and has called for independent research on the effects of different farming methods.
"Minerals are easy to detect and measure, and have been since the 19th century. It is almost impossible that methods have changed so much that it would explain the huge difference between these figures," said the Food Commission's director Dr. Tim Lobstein. "One of the key arguments is that today's agriculture does not allow the soil to enrich itself, but depends on chemical fertilisers that don't replace the wide variety of nutrients plants and humans need."
Scientists at the University of Newcastle's agriculture school have looked at differences in the fat and vitamin composition of milk produced in different farming systems. "We know that the faster grass grows, the more you dilute the uptake of trace elements," said Gillian Butler, a researcher. Another explanation might be that in traditional farming, clover, which is higher in minerals than grass, also played a greater part in feeding animals.
Leo Bertozzi, director of the Italian parmesan consortium, said the figures were a puzzle. "Our methods of making cheese have not changed, but milk in 1940 was not the same as milk today. Today cows yield five to six times as many litres a day, and their feed is different, with cereals and soya added to hay. But I find these figures surprising," he said.
The research has, however, been challenged by the food and farming industries, which argue that the testing methods have changed. They also say that huge changes in the varieties grown and the ways in which food is transported and stored, make direct comparison difficult.
The Food Standards Agency, which publishes The Composition of Food, agrees that using the government tables to make historical comparisons is problemmatic. "Any differences over time could be due to a wide variety of factors, including variety and breed, animal husbandry, growth, storage conditions, preparation and cooking methods as well as diferences in analytical methodology," it said in a statement.
The Dairy Council said it believed that changes in farming practices and environmental factors would account for only a small reduction in mineral content. "It is more likely that the differences are due to improvements in analytical methods used to measure minerals in milk," said its director Judith Bryans.
The Meat and Livestock Commission also attributed the decline in nutrients to better testing methods. "What goes in is what comes out, and the only signficant shift in beef production has been from hay to silage. If these figures were true, we'd expect to see a lot of anaemic cows wondering around," said Mike Attenborough, an MLC technical expert.
