The Influence of Agriculture on Mineral Nutrition and Health

 

Third Edition 2000:

Jointly published by:

Eastleigh Research

Greenfield Close, Joys Green, Lydbrook, Glos, England, GL17 9QIJ

and

The Good Gardeners’ Association

4 Lisle Place, Wotton-under-Edge, Glos, GL12 7AZ. Telephone: (01453) 520322

 

 

This introduction is an extract from an in depth review of worldwide research and the Fastleigh trials.

A full copy is available from the Publishers for £12.00 (including p & p for the U.K. and Europe).

 

INTRODUCTION

I would like to start with just one cautionary tale from history. There was, in the Ohio River valley, a nation of first Americans who vanished around 1500 AD. These people are known to the archaeologists as the mound builders, for they left many intriguing earth works. They also left a cemetery which had been in use for 1500 years. In early times this nation had been hunter gatherers. Skeletons from this period showed no consistent health disorders. Skeletons from later times, after they had become farmers, indicate the extensive presence of juvenile anaemia, arthritis, tuberculosis and bone demineralisatjon (osteoporosis).

What Had Changed?

Early man, with a low population density and as hunter gatherers, drew for their source of food on a wider variety of plants than do farmers. Furthermore the wild food was not subject to the degradation of the soil ecology associated with agricultural activity.

The low population density also allowed people to move away from areas of mineral deficiency that can cause health disorders.

Clearly we cannot return to the hunter gatherer state but we can learn from the differences in the soil environment between the wild and agricultural states.

These differences occur principally in the effect of agriculture on the beneficial soil bacteria and fungi.

Since the development of agriculture there have been many theories as to what makes plants grow. From the simple idea that all that was needed was air and water to the idea that plants depended on the organic waste from other plants and animals. In the early 1800s research into the effects of soil chemistry on plant growth was undertaken. A principal researcher of that time was the German chemist Justus von Liebig, who in 1843 published the theory that plant growth was limited by the most limited available mineral in the soil. Unfortunately, only a few of the essential minerals were known at that time, and nothing was known of the beneficial soil micro-organisms. Liebig's 150 year old theory has led to the modern use of chemical fertiliser.

Since the time of Liebig much research has been done into the beneficial influence of many soil bacteria and fungi on plant growth and food chain nutrition. It is this much neglected aspect of the food chain that I want to consider.

Many people. used to thinking of bacteria and fungi as the cause of disease, may find it strange that many of these organisms can be, and are beneficial, not only in the soil but also in the digestive systems of animals and man.

Of the beneficial soil micro-organisms, one group, the Mycorrhizal Forming Fungi (mycorrhiza) plays a vital and irreplaceable role in the plant soil connection, in the support of other soil organisms functioning in an elegant network of plant support and in the health and growth of plants and the food chain.

It is a diverse group of symbiotic fungi growing in, or on the roots, of most plants. Mycorrhiza draws its energy directly from the host plant and, by acting as a root extension, increases the plant uptake of many minerals. Over time mycorrhiza has developed to colonise the roots of plants in environments as diverse as tropical rain forest and Arctic tundra. The fossil record shows that mycorrhiza has colonised plant roots for more than 300 million years. Its role in increasing plant mineral content has influenced the development and the mineral requirement of all land life.

 

The Effect Of Agriculture On Mycorrhiza.

Changes in the plants growing in the soil have a seriously adverse effect on mycorrhiza: the most extreme case being the clearance of forest for agriculture.

Soil disturbance, as occurs in arable cropping, also reduces the level of mycorrhizal root colonisation, thus reducing plant mineral content. By the time of Liebig's research most arable crops would have had only poor levels of mycorrhiza. No wonder then that he found that plants with fertiliser grew better than those without. Without knowledge of trace elements, nor of the beneficial effect of micro-organisms, chemically-aided plant growth bore little resemblance to the influence of mycorrhiza on plant growth and health.

This partial knowledge that has led to the extensive use of chemical fertiliser has further damaged mycorrhiza, even to extinction. The following table shows the loss of minerals

(1) As a result of cultivation

  1. As a result of fertiliser use.

Percentage nutrient loss

From cultivation

From cultivation and chemical fertiliser use

More than 30%

 

Boron Selenium

Cobalt Vanadium

Copper Zinc

Iron

25-30%

Boron Selenium
Cobalt Vanadium
Copper Zinc

Iodine

Magnesium

Nickel

15-25%

Chromium Magnesium
Iron Nickel
Manganese

Potassium

5-15%

Calcium Potassium
Iodine
Phosphorus

Calcium Molybdenum
Chromium Phosphorus
Manganese

 

Why Do Living Organisms Need Minerals?

All living organisms from bacteria to man need minerals in two principal ways: structural and enzymatic. Minerals are needed structurally, as in the case of nitrogen and sulphur for muscle-building in man and animals. Calcium, phosphorus and magnesium are the principal (but by no means the only) minerals in bone.

These five minerals, together with more than twenty others, are involved in enzyme function.

What are enzymes? The best description perhaps comes from a "Textbook of Biochemistry edited by T. M. Devlin.

"Enzymes are proteins evolved by the cells of living organisms for the specific function of catalysing chemical reactions. Enzymes increase the rate at which reactions approach equilibrium."

Clearly then, any diminution of minerals in the environment, below levels that are normally required. can lead to decreased enzyme activity and to problems of activity and health in living organisms.

The Influence Of Mycorrhiza And Mineral Loss On Other Soil Micro-Organisms.

Soil bacteria capable of fixing nitrogen from the air are either fully symbiotic, as in the case of rhizobium, drawing their nutrients from the host legume, or are closely associated with other plants where they depend on nutrients exuded from the plant root or particles detached from the root. In either ease, if the plant is mineral-deficient, the bacteria will be less active and will fix less nitrogen. This means less nitrogen is available to the plant for growth.

Organic Matter.

There are many species of bacteria and fungi which are involved in the breakdown of organic matter. The bacteria, and to a lesser extent fungi, require much the same range and quantity of minerals as do man and animals. When the original plant material is mineral-deficient, the micro-organisms are the first to draw on the deficient mineral, potentially creating greater deficiencies in subsequent crops.

Some bacteria create B vitamins which are then available in the soil for other soil micro-organisms and plants.

Mycorrhiza, nitrogen-fixing bacteria and organisms involved in the breakdown of organic matter, create plant hormones which aid and control plant growth. They also create antibiotic-type substances which help plants to resist disease, and in some cases, pests.

Mycorrhiza clearly play a vital and irreplaceable role in total soil fertility and in the health and growth of soil micro-organisms, plants, animals and man.

Since the start of settled agriculture we have been on a downward slide of nutrition. A fellow independent researcher, Anne-Marie Mayer, has reviewed data published over the past 50 years by the British Ministry of Agriculture, Fisheries and Food, a period which corresponds with the intensification of agriculture.

The data below are the averages of 20 raw vegetables and 20 raw fruits. The numbers are the percentages of minerals in modern food, as compared to that of 50 years ago.

e.g. calcium in vegetables is approximately one fifth lower now than it was 50 years ago.

Ca Calcium, Mg = Magnesium, Fe = Iron, Cu = Copper, Na = Sodium, K = Potassium, P = Phosphorus.

 

Ca

Mg

Fe

Cu

Na

K

P

Zn

Vegetables

80.1

83.1

94.6

80.6

49.9

101.3

103.3

108.5

Fruit

88.9

80.3

77.5

72.6

81.9

80.8

80.8

83.3

 

I am often asked ‘Can the world feed itself without fertiliser?" I believe the answer is "Yes’. It would require a change in current agricultural practice. For example, much of the world grain production is fed to ruminant animals. The crop involves soil disturbance and produces a feed frequently deficient in minerals. Pasture feeding, however, requires no soil cultivation and has historically been beneficial to mycorrhiza. Where crop production is essential, we need to develop new techniques to retain mycorrhiza.

Data which compares yield using mycorrhiza or fertiliser are sparse. That which does exist indicates the following:-Yield with mycorrhiza is at its maximum when soil available phosphorus is close to 30 parts per million. At higher levels mycorrhizal root colonisation falls rapidly. Yields increase as available soil phosphorus increases when phosphorus fertiliser is applied. As the yield from phosphorus fertiliser approaches the mycorrhizal maximum the data show great variation, probably due to the result of increasing deficiencies of other minerals. In both mycorrhizal and fertiliser crops, many minerals fall as soil phosphorus increases. We see then that maximum yield with near-optimum minerals occurs only in mycorrhizal crops.

What Can Be Done?

It is better to remedy a problem at the point of production than at the point of consumption.

Food producers must consider not only crop yield but also the nutritional value of their product. By recognising the natural systems which supported life on land for many millions of years, we can achieve improved nutrition and health and a sustainable agriculture with less chemical pollution. The medical establishment must recognise the vast volume of research already available on mineral nutrition (the internet has 30,000 references on zinc nutrition alone).

As many of the endemic health disorders of modern man are caused or aggravated by mineral deficiency, a full understanding of the importance of minerals in the diet could cut illness and rescue the National Health Service from its present financial crisis.

Impact on Health of a National Diet improved to meet lowest level RDA

Health Problem Potential saving

Cancer

20% reduction in incidence and death

Heart and vascular conditions

25% reduction of disease and death

Respiratory and infectious diseases

20% reduction in incidence

Infant deaths

50% reduction

Maternal deaths

50% reduction

Congenital birth defects

20% reduction

Arthritis

50% reduction

Osteoporosis

75% reduction

Muscular disorders

10% reduction in general cases

Diabetes and carbohydrate disorders

50% of cases avoided or improved

Obesity

80% reduction in incidence

Mental health

10% fewer disabilities

Improved mental ability

Raise IQ by 10 points for persons with IQ of 70 to 80

Alcoholism

33% reduction in incidence and death

Eyesight

20% fewer people blind or with corrective lenses

Allergies

20% relieved

Digestive problems

25% fewer acute conditions

Kidney and urinary problems

20% reduction in death and acute conditions

Dental health

50% reduction in incidence, severity and cost

 

This data first presented by C Welt in Benefits from Human Nutrition Research USDA 1992 indicates the potential impact of improving the US national diet to encourage people to achieve the lowest level Recommended Daily Allowance of energy, carbohydrate, vitamins and minerals. An estimated 500,000 lives could be saved annually, along with millions of dollars of public sector income.