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Historical changes in the mineral content of fruits and vegetables

July 1997
British Food Journal 99(6):207-211

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Implies that a balance of the different essential nutrients is necessary for maintaining health. The eight minerals that are usually analysed are Na, K, Ca, Mg, P, Fe, Cu, Zn. A comparison of the mineral content of 20 fruits and 20 vegetables grown in the 1930s and the 1980s (published in the UK Government’s Composition of Foods tables) shows several marked reductions in mineral content. Shows that there are statistically significant reductions in the levels of Ca, Mg, Cu and Na in vegetables and Mg, Fe, Cu and K in fruit. The only mineral that showed no significant differences over the 50 year period was P. The water content increased significantly and dry matter decreased significantly in fruit. Indicates that a nutritional problem associated with the quality of food has developed over those 50 years. The changes could have been caused by anomalies of measurement or sampling, changes in the food system, changes in the varieties grown or changes in agricultural practice. In conclusion recommends that the causes of the differences in mineral content and their effect on human health be investigated.

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[ 207 ]

British Food Journal

99/6 [1997] 207–211

[ISSN 0007-070X]

Historical changes in the mineral content of fruits

and vegetables

Anne-Marie Mayer

Independent Researcher, Devon, UK

Implies that a balance of the

different essential nutrients is

necessary for maintaining

health. The eight minerals

that are usually analysed are

Na, K, Ca, Mg, P, Fe, Cu, Zn.

A comparison of the mineral

content of 20 fruits and 20

vegetables grown in the

1930s and the 1980s (pub-

lished in the UK Government’s

Composition of Foods

tables)

shows several marked reduc-

tions in mineral content.

Shows that there are statisti-

cally signiﬁcant reductions in

the levels of Ca, Mg, Cu and

Na in vegetables and Mg, Fe,

Cu and K in fruit. The only

mineral that showed no sig-

niﬁcant differences over the

50 year period was P. The

water content increased

signiﬁcantly and dry matter

decreased signiﬁcantly in

fruit. Indicates that a nutri-

tional problem associated

with the quality of food has

developed over those 50

years. The changes could

have been caused by anom-

alies of measurement or

sampling, changes in the food

system, changes in the vari-

eties grown or changes in

agricultural practice. In

conclusion recommends that

the causes of the differences

in mineral content and their

effect on human health be

investigated.

The purpose of this paper is to address the

question: has the nutritional quality (particu-

larly essential mineral content) of fruits and

vegetables changed this century during the

period of changes in the food system and

modernization in agriculture? The UK Gov-

ernment’s Composition of Foods data provides

a source of data at two time points separated

by approximately 50 years; by comparing this

data I attempt to answer this question.

The composition of foods tables

The ﬁrst edition of the UK Chemical Composi-

tion of Foods[1] arose from a need to provide

investigators with information for a wide

range of foods consumed in the UK. The data

on fruit and vegetables were compiled from

previous studies of the composition of

foods[2]. Unfortunately, these reports were

destroyed in a ﬁre during the Second World

War and have been out of print ever since.

This means that exact dates or details of the

analyses are not known.

Since the ﬁrst edition there have been four

subsequent updates of the full Composition of

Foods tables. It wasn’t until the ﬁfth edition,

however, that the tables included substantial

revisions of the original data on fruits and

vegetables that were listed in the ﬁrst edition.

The ﬁfth edition of The Composition of

Foods[3] addressed a need for updates of the

old data. The introductory section states “The

nutritional value of many of the more tradi-

tional foods has changed. This can happen

when there are new varieties or new sources

of supply for raw materials; with new

farming practices which can affect the nutri-

tional value of both plant and animal

products…”

The updated compositions of fruits and

vegetables are based on analytical studies

commissioned by the Ministry of Agricul-

ture, Fisheries and Food (MAFF). The sam-

ples were designed to reﬂect the usual pattern

of consumption in the UK at the time of analy-

sis. The tables are not designed to provide

comparative historical data – the fruit and

vegetables would not necessarily have been

grown in similar conditions, soils, or times of

year or be of the same varieties. The data

were also provided by mixed sources (see

below). More controlled data would have been

better, but this data nevertheless provides a

good starting point for the comparison.

The updated vegetable analyses were car-

ried out by the Institute for Food Research

between 1984 and 1987 and have been used for

all the vegetable mineral data. The updated

fruit analyses were based largely on data

from the Laboratory of the Government

Chemist (LGC). Most of the twenty fruits

listed, however, include data from other

sources for one or more of the minerals. For

instance, the entry for cooking apples makes

use of data from the LGC for P, Fe, Cu and Zn.

The values for Na, K, Ca, Mg are an average of

LGC data and the old Chemical Composition of

foods data from 1936. Table I lists sources of

data for all the twenty vegetables and fruits

that were selected for the comparison.

In this paper I have examined only raw

fruits and vegetables. This has been done to

exclude differences caused by changes in

methods of processing. The updated analyses

provide an opportunity to compare the

changes in purchased raw food over approxi-

mately a 50-year period.

Methods

I analysed twenty vegetables and fruits using

two versions of the Composition of Foods

tables[3,4]. I used the 1960 version for the old

data because it was easily available and

includes the same analyses as the ﬁrst and

second editions. It also reports the results to

one more signiﬁcant digit than the fourth

edition. The fruits and vegetables selected

had to meet the following criteria:

• The old data had been updated for the ﬁfth

edition of the food tables. Some fruits have

also been included when old and new data

were averaged as outlined in Table I.

• The descriptions of the analysed portion of

the food were identical. For example, both

samples were peeled.

• Only raw samples were included.

• The food was not dried or rehydrated and

dry pulses were not included.

• The food was not a condiment (e.g. horse-

radish root).

[ 208 ]

Anne-Marie Mayer

Historical changes in the

mineral content of fruits and

vegetables

British Food Journal

99/6 [1997] 207–211

A total of 20 fruits and 20 vegetables satisﬁed

these criteria and these are listed with their

mineral contents at both time points in Table

III.

I calculated the logarithm of the ratios

(new:old) for each mineral for each fruit and

vegetable and from these computed the geo-

metric means. Students t-test was used to test

whether each mean ratio was signiﬁcantly

different from 1. The logs of the ratios were

used for this test.

Findings

The average ratios and results of the t-test

are listed in Table II. A ratio of 0.81 for

Table I

Sources of data for

The Composition of Foods

tables

Fruits Sources and dates of data

Apricots LGC 85-86 except Na: average of literature

Bananas LGC 85-86 except K, Zn: average of literature

Blackberries LGC 85-86

Cherries LGC 85-86

Cooking apples LGC 85-86 except Na, K, Ca, Mg: average of LGC, MW4

Eating apples LGC 85-86 except Na, K, Cu: average of literature

Grapefruit LGC 85-86 except Na, K, Ca: average MW4, USDA 86, literature

Grapes LGC 85-86 except Na, K, Zn: average of literature

Lemons MW4, USDA, literature.

Melon cantaloupe LGC 85-86

Nectarines LGC 85-86 except K, Mg: literature

Oranges LGC 85-86 except K: literature

Passion fruit Literature sources

Peaches LGC 85-86 except K: literature

Pears LGC 90

Pineapple LGC 85-86, MW4, literature

Plums Recalculated from stewed plums

Raspberries LGC 85-86

Rhubarb Average of USDA 81, MW4

Strawberries LGC 85-86

Notes:

LGC Laboratory of the Government Chemist

MW4

McCance and Widdowson’s Composition of Foods

4th edition (1936 data)[6]

USDA United States Department of Agriculture data

First to third editions: The data used in the ﬁrst four editions of the

Chemical Composition of Foods

were compiled

from the 1936 data[2]

Fourth edition: The data were compiled from the 1936 data with a few additions from the literature. For example Zn

values were added from literature sources

Fifth edition: The data for vegetables in the ﬁfth edition were all taken from the Institute of Food Research between

1984 and 1987. The data for fruits were obtained from mixed sources

Table II

Averagearatio of mineral content (new:old) of 20 vegetables and 20 fruitsb

Ca Mg Fe Cu Na K P Dry matter H

Vegetables ratio 0.81 0.65 0.78 0.19 0.57 0.86 0.94 0.97 1.00

value

0.014* 0.000* 0.088 0.000** 0.013* 0.090 0.487 0.53 0.872

Fruits ratio 1.00 0.89 0.68 0.64 0.90 0.80 0.99 0.91 1.02

value 0.957 0.016* 0.002** 0.006** 0.561 0.000** 0.903 0.023* 0.006**

Notes:

Geometric mean, the antilogarithm of the mean of the logarithm of the ratio of 1980s to 1930s values

See text for data sources and Table III for vegetables and fruits included. Analyses of Mn, Se and I were

only added in the 1991 edition. Zn was only added in the 1978 edition. S was omitted from the 1991

tables although it was analysed in previous editions. C1 was not revised in many cases for the 1991

edition. For these reasons comparisons were only possible for the above 7 minerals, water and dry matter.

Probability that average of logarithm of new:old is statistically different from 0 by

-test. (This is

equivalent to the ratios being different from 1)

* = signiﬁcant at the 5 per cent level

** = signiﬁcant at the 2 per cent level

[ 209 ]

Anne-Marie Mayer

Historical changes in the

mineral content of fruits and

vegetables

British Food Journal

99/6 [1997] 207–211

calcium, for example, means that over an

approximate 50-year period the average con-

tent of calcium in vegetables has declined to

81 per cent of the original level.

There were signiﬁcant reductions in the

levels of Ca, Mg, Cu and Na, in vegetables

and Mg, Fe, Cu and K in fruits. The greatest

change was the reduction of copper levels in

vegetables to less than one-ﬁfth of the old

level. The only mineral that showed no

signiﬁcant differences over the 50-year

period was P. Water increased signiﬁcantly

Table III

Mineral content of vegetables and fruit (mg/100mg)

Dry Dry

Ca Ca Mg Mg Fe Fe Cu Cu Na Na K K P P Matter Matter H

O% H

old new old new old new old new old new old new old new old new old new

Vegetables

Beetroot 24.9 20.0 15.0 11.0 0.37 1.0 0.07 0.02 84.0 66.0 303.0 380.0 32.1 51 12.9 12.9 87.1 87.1

Brussels 28.7 26.0 19.6 8.0 0.66 0.7 0.05 0.02 9.6 6.0 515.0 450.0 78.4 77.0 15.7 15.7 84.3 84.3

Sprouts

Cabbage – winter 72.3 68.0 16.8 6.0 1.23 0.6 N 0.02 28.4 3.0 240.0 270.0 64.1 46.0 9.4 10.3 90.6 89.7

Carrots – old 48.0 25.0 12.0 3.0 0.56 0.3 0.08 0.02 95.0 25.0 224.0 170.0 21.0 15.0 10.2 10.2 89.8 89.8

Celery 52.2 41.0 9.60 5.0 0.61 0.4 0.11 0.01 137.0 60.0 278.0 320.0 31.7 21.0 6.5 4.9 93.5 95.1

Lettuce 25.9 28.0 9.7 6.0 0.73 0.70 0.15 0.01 3.1 3.0 208 220 30.2 28.0 4.8 4.9 95.2 95.1

Mushroom 2.9 6.0 13.2 9.0 1.03 0.6 0.64 0.72 9.1 5.0 467.0 320.0 136.0 80.0 8.5 7.4 91.5 92.6

Mustard and cress 65.9 50.0 27.3 22.0 4.54 1.0 0.12 0.01 19.0 19.0 337.0 110.0 65.5 33.0 7.5 4.7 92.5 95.3

Onions 31.2 25.0 7.6 4.0 0.30 0.30 0.08 0.05 10.2 3.0 137.0 160.0 30.0 30.0 7.2 11.0 92.8 89.0

Parsley 325.0 200.0 52.2 23.0 8.00 7.7 0.52 0.03 33.0 33.0 1,080.0760.0 128.0 64.0 21.3 16.9 78.7 83.1

Parsnips 54.8 41.0 22.4 23.0 0.57 0.6 0.10 0.05 16.5 10.0 342.0 450.0 69.0 74.0 17.5 20.7 82.5 79.3

Peas 15.1 21.0 30.2 34.0 1.88 2.8 0.23 0.05 0.5 1.0 342.0 330.0 104.0 130.0 21.5 25.4 78.5 74.6

Potatoes – old 7.7 5.0 24.2 17.0 0.75 0.4 0.15 0.08 6.5 7.0 568.0 360.0 40.3 37.0 24.2 21.0 75.8 79.0

Pumpkin 39.0 29.0 8.2 10.0 0.39 0.4 0.08 0.02 1.3 0.0 309.0 130.0 19.4 19.0 5.3 5.0 94.7 95.0

Runner beans 33.3 33.0 23.0 19.0 0.74 1.2 0.09 0.02 6.5 0.0 276.0 220.0 25.9 34.0 8.4 8.8 91.6 91.2

Radishes 43.7 19.0 11.4 5.0 1.88 0.6 0.13 0.01 59.0 11.0 240.0 240.0 27.1 20.0 6.7 4.6 93.3 95.4

Swedes 56.4 53.0 10.8 9.0 0.35 0.1 0.05 0.01 52.2 15.0 136.0 170.0 19.0 40.0 8.6 8.8 91.4 91.2

Tomatoes 13.3 7.0 11.0 7.0 0.43 0.5 0.10 0.01 2.8 9.0 288.0 250.0 21.3 24.0 6.6 6.9 93.4 93.1

Turnips 58.8 48.0 7.4 8.0 0.37 0.2 0.07 0.01 58.0 15.0 238.0 280.0 27.5 41.0 6.7 8.8 93.3 91.2

Watercress 222.0 170.0 17.0 15.0 1.62 2.2 0.14 0.01 60.0 49.0 314.0 230.0 52.0 52.0 8.9 7.5 91.1 92.5

Fruits

Apricots 17.2 15.0 12.3 11.0 0.37 0.5 0.12 0.06 N 2.0 320.0 270.0 21.3 20.0 13.4 12.8 86.6 87.2

Bananas 6.8 6.0 41.9 34.0 0.41 0.3 0.16 0.10 1.2 1.0 348.0 400.0 28.1 28.0 29.3 24.9 70.7 75.1

Blackberries 63.3 41.0 29.5 23.0 0.85 0.7 0.12 0.11 3.7 2.0 208.0 160.0 23.8 31.0 18.0 15.0 82.0 85.0

Cherries 15.9 13.0 9.6 10.0 0.38 0.2 0.07 0.07 2.8 1.0 275 210 16.8 21.0 18.5 17.2 81.5 82.8

Cooking apples 3.6 4.0 2.9 3.0 0.29 0.1 0.09 0.02 21.0 2.0 123.0 88.0 16.2 7.0 14.4 12.3 85.6 87.7

Eating apples 3.6 3.0 4.7 3.0 0.29 0.1 0.11 0.02 2.4 3.0 118.0 100.0 7.7 8.0 15.7 14.6 84.3 85.4

Grapes 11.7 13.0 5.3 7.0 0.34 0.3 0.09 0.12 1.7 2.0 283.0 210.0 19.0 18.0 20.0 18.2 80.0 81.8

Grapefruit 17.1 23.0 10.4 9.0 0.26 0.1 0.06 0.02 1.4 3.0 234.0 200.0 15.6 20.0 9.3 11.0 90.7 89.0

Lemons 107.0 85.0 11.6 12.0 0.35 0.5 0.26 0.26 6.0 5.0 163.0 150.0 20.7 18.0 14.8 13.7 85.2 86.3

Melon cantaloupe 19.1 20.0 20.1 11.0 0.81 0.3 0.04 0.00 13.5 8.0 319.0 210.0 30.4 13.0 6.4 7.9 93.6 92.1

Nectarines 3.9 7.0 12.6 10.0 0.46 0.4 0.06 0.06 9.1 1.0 268.0 170.0 23.9 22.0 19.8 11.1 80.2 88.9

Oranges 41.3 47.0 12.9 10.0 0.33 0.1 0.07 0.05 2.9 5.0 197 150 23.7 21.0 13.9 13.9 86.1 86.1

Passion fruit 15.6 11.0 38.6 29.0 1.12 1.3 0.12 N 28.4 19.0 348.0 200.0 54.2 64.0 26.7 25.1 73.3 74.9

Peaches 4.8 7.0 7.9 9.0 0.38 0.4 0.05 0.06 2.7 1.0 259.0 160.0 18.5 22.0 13.8 11.1 86.2 88.9

Pears 7.5 11.0 7.2 7.0 0.21 0.2 0.15 0.06 2.3 3.0 128.0 150.0 9.7 13.0 16.8 16.2 83.2 83.8

Pineapple 12.2 18.0 16.9 16.0 0.42 0.2 0.08 0.11 1.6 2.0 247.0 160.0 7.8 10.0 15.7 13.5 84.3 86.5

Plums 12.4 13.0 7.6 8.0 0.33 0.4 0.10 0.10 1.9 2.0 192.0 240.0 15.4 23.0 15.4 16.1 84.6 83.9

Raspberries 40.7 25.0 21.6 19.0 1.21 0.7 0.21 0.10 2.5 3.0 224.0 170.0 28.7 31.0 16.8 13.0 83.2 87.0

Rhubarb 103.0 93.0 13.6 13.0 0.40 0.3 0.13 0.07 2.2 3.0 425.0 290.0 21.0 17.0 5.8 5.8 94.2 94.2

Strawberries 22.0 16.0 11.7 10.0 0.71 0.4 0.13 0.07 1.5 6.0 161.0 160.0 23.0 24.0 11.1 10.5 88.9 89.5

Notes: Old:

Composition of Foods

3rd edition (1930s data)[4]

New:

Composition of Foods

5th edition (1980s data)[3]

N: No data available

Ca, Mg, Fe, Na, K and P were reported to one fewer signiﬁcant digits in the 1991 tables.

[ 210 ]

Anne-Marie Mayer

Historical changes in the

mineral content of fruits and

vegetables

British Food Journal

99/6 [1997] 207–211

and dry matter decreased signiﬁcantly in

fruits.

What role do the minerals play in human

nutrition?

Minerals all have several roles in human

biochemistry and physiology and all the

minerals mentioned above are essential in

the diet of humans. Many are co-factors for

different enzymes and we are dependent on

them for energy efficiency, fertility, mental

stability and immunity. Although fruits and

vegetables generally supply a small propor-

tion of total mineral dietary requirements,

the reductions could be important to some

groups so the causes of the reductions need

investigating. It is not clear what is causing

the reductions. There are several possibilities

and these are outlined below.

Are the reductions anomalies of

measurement or sampling?

The earlier analyses of some minerals may

have been inaccurate compared to modern

analytical methods. Elsie Widdowson, how-

ever, notes in the introduction to The Compo-

sition of Foods[3] that “those methods were no

less accurate than the modern automated

ones, but they took a much longer time”. If

this is true, we should be able to rely on the

consistency of the analytical methods. How-

ever, there has been much debate over this

question and no clear conclusion has been

reached.

The methods of sampling fruit and vegeta-

bles were designed to reﬂect the usual choice

of foods at the time of the research. There

could be differences in the methods of sam-

pling. It is not possible to compare the details

of the methods used because the original data

are no longer available. Also, the use of mixed

sources of data for the 1991 edition of The

Composition of Foods[3] is an unknown factor

and possible source of bias. It is not known

whether the ﬁrst edition of the Chemical

Composition of Foods[1] used similar methods

of data compilation.

Food system changes

In the past sixty years the food supply system

has changed considerably. For instance we

now eat more “out of season” and imported

foods grown on a wide variety of soils from

many different countries. Some of the fruits

and vegetables have always been imported

but many of those previously grown in the

UK are also now imported. Storage and ripen-

ing systems have changed. Greenhouse crops

are “brought on” more quickly now and often

grown in soil-less mixes. Could these prac-

tices have changed the composition of fruits

and vegetables?

The varieties of plants cultivated now has

also changed. Nowadays we practise sophisti-

cated plant breeding and have bred selec-

tively for qualities that will suit the demands

of, for example, high yield, post-harvest

handling qualities and cosmetic appeal. Also

we select varieties that will respond well to

the methods of agriculture currently

employed. Speciﬁc breeding to enhance nutri-

tional quality is rare.

Agricultural practices

During the early 1930s agricultural chemicals

were hardly used. Manure and compost were

the main fertilizers used. After the war prac-

tices changed and farmers became more

reliant on the use of fertilizers and other

agrochemicals as well as heavy farm machin-

ery.

Agriculture which relies on NPK fertilizers

and pesticides, that adds little organic matter

to the soil and that alternates between soil

compaction and ploughing, could produce

food depleted in minerals. These practices

affect the structure, chemistry and ecology of

the soil in ways that could affect the availabil-

ity of minerals to plants and hence the min-

eral content of crops. For instance, mycor-

rhizal fungi have a symbiotic relationship

with plant roots in which sugars and miner-

als are exchanged. The fungi are reduced by

high levels of available phosphate and nitro-

gen, low pH, waterlogging or excessive

dryness[5].

Another factor could be the differing levels

of contamination of crops with residues of

pesticides containing high concentrations of

minerals – for example Bordeaux mixture

contains high levels of copper and was widely

used as a pesticide.

In principle, modern agriculture could be

reducing the mineral content of fruit and

vegetables. We need to ﬁnd out if this, or any

of the other explanations described above, are

signiﬁcant factors in practice. Considering

the magnitude of the reductions this matter

deserves urgent attention.

The following questions arise from the

ﬁndings:

• Are the data reliable?

• Is the apparent decline caused by dimin-

ished levels of minerals in the soil, poor

availability, the choice of cultivars or other

changes in the food system?

• To what extent is the decline in minerals of

importance to human nutrition?

• Are other countries experiencing similar

changes?

• Are there similar reductions in other

crops – such as cereals?

[ 211 ]

Anne-Marie Mayer

Historical changes in the

mineral content of fruits and

vegetables

British Food Journal

99/6 [1997] 207–211

• Are other minerals of equal importance to

human nutrition, such as Se and Cr, also

reduced?

• Are other nutrients – for example, vita-

mins – also reduced?

• Are some cultivars producing crops that

are lower in minerals than others?

• Does soil contamination – past or present –

affect the mineral content of crops?

To answer these questions existing literature

needs to be reviewed and further research

carried out along the suggested lines;

• an analysis of the effect of the latest Com-

position of Foods data on usual diets;

• compilation of a database of historical data

from different countries, different time

scales and different crops;

• detailed and controlled studies of soils and

the effects of methods of agriculture on

plant nutrition and crop mineral content;

• studies of the mineral content of fruit and

vegetables grown using different cultivars

in common use now and 60 years ago;

• regular monitoring of food composition

with details on cultivars, methods of grow-

ing and soils.

References

1 McCance, R.A. and Widdowson, E.M., The

Chemical Composition of Foods, Medical

Research Council Special Report Series No.

235, HMSO, London, 1940.

2 McCance, R.A., Widdowson, E.M. and

Shackleton, L.R.B., The Nutritive Value of

Fruits, Vegetables and Nuts, Medical Research

Council Special Report Series No. 213, HMSO,

London, 1936.

3 Holland, B., Welch, A.A., Unwin, I.D., Buss,

D.H., Paul, A.A. and Southgate, D.A.T.,

McCance and Widdowson’s Composition of

Foods ﬁfth edition, Royal Society of Chemistry

and the Ministry of Agriculture, Fisheries and

Food, HMSO, London, 1991.

4 McCance, R.A. and Widdowson, E.M., The

Composition of Foods third edition, Medical

Research Council Special Report series No.

213, HMSO, London, 1960.

5 Killham, K., Soil Ecology, Cambridge Univer-

sity Press, Cambridge, 1994.

6 Paul, A.A. and Southgate, D.A.T., McCance and

Widdowson’s Composition of Foods fourth

edition, Ministry of Agriculture, Fisheries and

Food and Medical Research Council, HMSO,

London, 1978.

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Jun 2023

Human nutrition, and what can be considered “ideal” nutrition, is a complex, multi-faceted topic which many researchers and practitioners deliberate. While some attest that basic human nutrition is relatively understood, it is undeniable that a global nutritional problem persists. Many countries struggle with malnutrition or caloric deficits, while others encounter difficulties with caloric overconsumption and micronutrient deficiencies. A multitude of factors contribute to this global problem. Limitations to the current scope of the recommended daily allowances (RDAs) and dietary reference intakes (DRIs), changes in soil quality, and reductions in nutrient density are just a few of these factors. In this article, we propose a new, working approach towards human nutrition designated “Foundational Nutrition”. This nutritional lens combines a whole food approach in conjunction with micronutrients and other nutrients critical for optimal human health with special consideration given to the human gut microbiome and overall gut health. Together, this a synergistic approach which addresses vital components in nutrition that enhances the bioavailability of nutrients and to potentiate a bioactive effect.

Changes in Nutrient Content in Indian Food Over Thirty Years

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Jul 2024

Monitoring the Mineral Content of Plant Foods in Food Composition Databases

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Jul 2024

Declines in the mineral content of food have been reported in several countries. This study monitored reported changes in the mineral content of plant foods in Australian food composition databases between 1991 and 2022. Commonly consumed plant foods (n = 130), grouped as fruit, vegetables, legumes, grains, and nuts in raw unprocessed form, were matched between three reference databases from 1991, 2010, and 2022. Absolute and percentage differences in mineral content (iron, zinc, calcium, and magnesium) were calculated. During this 30-year period, 62 matched foods had updated mineral content. Iron content decreased significantly for fruit (48%) and vegetables (20%), although absolute differences were small (0.09–0.14 mg/100 g). Zinc content declined by 15% for fruit (<0.1 mg/100 g, absolute difference 0.03 mg/100 g), but no differences were observed for calcium and magnesium content. Potential reasons for any reported differences could not be explored using food composition data alone, likely due to biological, agricultural, and/or analytical factors. Nutritionally, these small differences are unlikely to have a major impact on the population’s nutritional status, although efforts to improve fruit and vegetable consumption are encouraged to meet recommendations.

CONCURRENT IRON OVERLOAD AND NEOPLASIA IN LESCHENAULT'S ROUSETTES (ROUSETTUS LESCHENAULTII): A CASE SERIES

Article

Mar 2024

This case series investigates a cluster of deaths in a captive colony of Leschenault's rousettes (Rousettus leschenaultii). Six of seven bats that died between March and September 2021 were diagnosed postmortem with both iron overload (IO) and neoplasia, neither of which have previously been reported in this species. Iron status was assessed via hepatic histopathological grading, hepatic iron concentration, and, in two cases, serum iron concentration. On histopathological grading, all cases had hemochromatosis except one, which had hemosiderosis. Hepatic iron concentrations did not correlate with histopathological grading. Neoplasms in these six bats included hepatocellular carcinoma (HCC; 4), bronchioloalveolar adenocarcinoma (1), pancreatic adenocarcinoma (1), and sarcoma of the spleen and stomach (1). One bat had two neoplasms (HCC and sarcoma of the spleen and stomach). One additional case of HCC in 2018 was identified on retrospective case review. Etiology was investigated to the extent possible in a clinical setting. Nutritional analysis and drinking water testing found oral iron intake within acceptable bounds; however, dietary vitamin C was potentially excessive and may have contributed to IO. Panhepadnavirus PCR testing of liver tissue was negative for all bats. A species-associated susceptibility to IO, as seen in Egyptian fruit bats (Rousettus aegyptiacus), is possible. The high incidence of HCC is suspected to be related to IO; other differentials include viral infection. Causes or contributing factors were not definitively identified for the other neoplasms seen but could include age, inherited risk (given a high level of inbreeding), or an oncogenic virus. Pending further research in this species, it is recommended that keepers of Leschenault's rousettes offer conservative amounts of vitamin C and iron (as for Egyptian fruit bats), submit for postmortem examination any euthanized or found dead, and share records of similar cases.

Effects of Agricultural Intensification on Mediterranean Diets: A Narrative Review

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Oct 2023

Introduction: Mediterranean diets (MedDiets) are linked to substantial health benefits. However, there is also growing evidence that the intensification of food production over the last 60 years has resulted in nutritionally relevant changes in the composition of foods that may augment the health benefits of MedDiets. Objective: To synthesize, summarize, and critically evaluate the currently available evidence for changes in food composition resulting from agricultural intensification practices and their potential impact on the health benefits of MedDiets. Methods: We summarized/synthesized information from (i) systematic literature reviews/meta-analyses and more recently published articles on composition differences between conventional and organic foods, (ii) desk studies which compared food composition data from before and after agricultural intensification, (iii) recent retail and farm surveys and/or factorial field experiments that identified specific agronomic practices responsible for nutritionally relevant changes in food composition, and (iv) a recent systematic literature review and a small number of subsequently published observational and dietary intervention studies that investigated the potential health impacts of changes in food composition resulting from agricultural intensification. Results and discussion: There has been growing evidence that the intensification of food production has resulted in (i) lower concentrations of nutritionally desirable compounds (e.g., phenolics, certain vitamins, mineral micronutrients including Se, Zn, and omega-3 fatty acids, α-tocopherol) and/or (ii) higher concentrations of nutritionally undesirable or toxic compounds (pesticide residues, cadmium, omega-6 fatty acids) in many of the foods (including wholegrain cereals, fruit and vegetables, olive oil, dairy products and meat from small ruminants, and fish) that are thought to contribute to the health benefits associated with MedDiets. The evidence for negative health impacts of consuming foods from intensified conventional production systems has also increased but is still limited and based primarily on evidence from observational studies. Limitations and gaps in the current evidence base are discussed. Conclusions: There is now substantial evidence that the intensification of agricultural food production has resulted in a decline in the nutritional quality of many of the foods that are recognized to contribute to the positive health impacts associated with adhering to traditional MedDiets. Further research is needed to quantify to what extent this decline augments the positive health impacts of adhering to a traditional MedDiet.

Validation of Low-cost Reflectometer to Identify Phytochemical Accumulation in Food Crops

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Sep 2023

Diets consisting of greater quantity/diversity of phytochemicals are correlated with reduced risk of disease. This understanding guides policy development increasing awareness of the importance of consuming fruits, grains, and vegetables. Enacted policies presume uniform concentrations of phytochemicals across crop varieties regardless of production/harvesting methods. A growing body of research suggests that concentrations of phytochemicals can fluctuate within crop varieties. Improved awareness of how cropping practices influence phytochemical concentrations are required, guiding policy development improving human health. Reliable, inexpensive laboratory equipment represents one of several barriers limiting further study of the complex interactions influencing crop phytochemical accumulation. Addressing this limitation our study validated the capacity of a low-cost Reflectometer ($500) to measure phytochemical content in selected crops, against a commercial grade laboratory spectrophotometer. Our results suggest the Reflectometer provides an accurate accounting of phytochemical content within evaluated crops. Additionally, we confirmed large variation in phytochemical content within specific crop varieties, suggesting that cultivar is but one of multiple drivers of phytochemical accumulation. Our findings indicate dramatic nutrient variations could exist across the food supply, a point whose implications are not well understood. Future studies should investigate the interactions between crop phytochemical accumulation and farm management practices that influence specific soil characteristics.

Changes in Nutrient Content in Indian Food Over Thirty Years

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