Am J Clin Nutr 2003;78(suppl):657S–9S. Printed in USA. © 2003 American Society for Clinical Nutrition 657S

Nutrition ecology: the contribution of vegetarian diets1–3

Claus Leitzmann

ABSTRACT Nutrition ecology is an interdisciplinary sci-
entific discipline that encompasses the entire nutrition system,
with special consideration of the effects of nutrition on health,
the environment, society, and the economy. Nutrition ecology
involves all components of the food chain, including production,
harvesting, preservation, storage, transport, processing, packag-
ing, trade, distribution, preparation, composition, and consump-
tion of food, as well as disposal of waste materials. Nutrition
ecology has numerous origins, some of which go back to antiq-
uity. The introduction of industrialized agriculture and mass ani-
mal production gave rise to various negative influences on the
environment and health. Food quality is determined in part by the
quality of the environment. The environment, in turn, is influ-
enced by food consumption habits. Research shows that vegetar-
ian diets are well suited to protect the environment, to reduce pol-
lution, and to minimize global climate changes. To maximize the
ecologic and health benefits of vegetarian diets, food should be
regionally produced, seasonally consumed, and organically
grown. Vegetarian diets built on these conditions are scientifically
based, socially acceptable, economically feasible, culturally
desired, sufficiently practicable, and quite sustainable. Am J
Clin Nutr 2003;78(suppl):657S–9S.

KEY WORDS Nutrition ecology, vegetarian diets, nutrition
system, health, environment, sustainability

INTRODUCTION

Nutrition ecology is an interdisciplinary scientific discipline
that incorporates the entire food chain as well as its interactions
with health, the environment, society, and the economy. The food
chain includes production, harvesting, preservation, storage, trans-
port, processing, packaging, trade, distribution, preparation, com-
position, and consumption of food, as well as disposal of all waste
materials along the food path.

Nutrition ecology has many roots, some of which go back to
antiquity. The introduction of systematic agriculture (slash and
burn cultivation) and domestication of animals (food rivals) has
markedly affected our environment. One early example of the con-
sequences of systematic agriculture is the Greek invasions of other
countries as a consequence of their increasing meat consumption,
which required them to acquire more farmland for fodder pro-
duction. Another example is the deforestation for farmland and
for building purposes, which began thousands of years ago and
has continued to this day. Both the Torah and the Bible mention
environmental issues numerous times. The impact of systematic
agriculture on the environment was discussed by Thomas Aquinas

1 From the Institute of Nutrition, University of Giessen, Giessen, Germany.
2 Presented at the Fourth International Congress on Vegetarian Nutrition,

held in Loma Linda, CA, April 8–11, 2002. Published proceedings edited by
Joan Sabaté and Sujatha Rajaram, Loma Linda University, Loma Linda, CA.

3 Address reprint requests to C Leitzmann, Institute of Nutrition, University
of Giessen, Wilhelmstrasse 20, 35392 Giessen, Germany. E-mail: claus.leitz-
mann@ernaehrung.uni-giessen.de.

(1224–1274), Jean-Jacques Rousseau (1712–1778), and Henry
David Thoreau (1817–1862). At the end of the 19th century, Jacob
von Uexkuell (1864–1944) founded the science of ecology.

Industrialized agriculture was introduced in the 19th century
and rapidly took command of all aspects of life, with striking
social, economic, and environmental consequences. Reactions to
these developments led to the formation of the Sierra Club in
North America and to the Reform Movement in Central Europe in
the second half of the 19th century. People migrated from urban
to rural areas to dwell in unpolluted regions and to grow their own
food. Economic and social reforms were proposed and practiced.
Some of these included a vegetarian lifestyle. Another reaction to
industrialized agriculture was organic farming, which was initi-
ated by the anthroposophists in 1924 and started to flourish in the
1970s. At that time, a number of organizations were established
that raised concerns about the environment and food quality [eg,
the Club of Rome (1968), Greenpeace (1971), World Watch Insti-
tute (1975), the Green Party (1980)]. At the same time, literature
on the negative influence of industrialized agriculture appeared
by Rachel Carson (1), Frances Moore-Lappé (2), Dennis Mead-
ows (3), Joan Gussow (4), and Ralph Nader (5). These authors dis-
cussed the dramatic effects of industrialization and industrialized
agriculture on the environment, health, society, and the economy.

NUTRITION ECOLOGY

The term nutrition ecology was coined in 1986 by a group of
nutritionists at the University of Giessen, Germany (6). Nutrition
ecology as an interdisciplinary scientific discipline is a holistic
concept that considers all links in the nutrition system, with the
aim of sustainability. Thus, nutrition ecology describes a new field
of nutrition sciences that deals with the local and global conse-
quences of food production, processing, trade, and consumption.
Nutrition ecology goes beyond econutrition, which is limited to
the interactions of nutrition and environment. Nutrition ecology
goes further than the older concept of ecology of food and nutri-
tion, which is limited to the eating patterns of indigenous and abo-
riginal populations.

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658S LEITZMANN

At present, nutrition sciences are dominated by health aspects
of food and, in part, by food quality. Recommendations are based
primarily on physiologic and toxicologic considerations (7). The
implications of our current nutrition system are more complex and
go beyond nutrient content and contamination with pathogens and
contaminants. To avoid ecologic damage caused by the nutrition
system and to attain nutrition security for the world population,
additional aspects need to be incorporated (8–10). The necessity
of taking a more holistic view for a sustainable development is
underlined by the current crises in the nutrition system, as dis-
cussed at the World Food Summit in June 2002 (11).

Dimensions of nutrition ecology

As is typical for an interdisciplinary discipline, nutrition ecol-
ogy deals with a wide range of issues, including research, teach-
ing, and public actions. A broad view of the entire nutrition sys-
tem covers subject matters such as total food quality, ecologic
balances, and life cycle assessments; the influences of nutrition
systems on climate, world nutrition, and food prices; and a com-
parison of different diets and agricultural, environmental, and con-
sumer policies. Basically, there are 4 dimensions of nutrition ecol-
ogy: health, the environment, society, and the economy.

To maintain or retain good health, the consumption of an indi-
vidually optimal diet is recommended. The term preventative diet
has been used recently to underline the possibility of avoiding
nutrition-based diseases (12, 13). The aggregate of most studies
suggests that the consumption of plant-derived foods (grains, veg-
etables, fruits, legumes, nuts) should be increased and that the
intake of animal-derived foods (meat products, dairy products, and
eggs) should be reduced. This principle applies particularly to
sedentary individuals. Plant foods should be consumed when they
are as fresh as possible, should be minimally processed, and
should be eaten partly as raw food (14–16).

The nutrition system influences the environment (17), which in
turn determines the quality of food. The environmental impact of
food production is determined by the agricultural method used.
Conventional farming methods rely on extensive use of natural
resources and result in higher levels of food contamination. In
contrast, the environmental impact of organic farming is lower.
Organic farming practices include controlling pests naturally,
rotating crops, and applying legume plants as manure, in contrast
to the use of synthetic pesticides and fertilizers in conventional
farming. In integrated farming, organic and conventional methods
are combined, resulting in an intermediate environmental impact
(18, 19). To reduce the environmental impact of the nutrition sys-
tem, organic farming needs to be supported globally. In addition,
foods should be minimally processed, packaged, and transported.

The nutrition system is closely related to society, including the
responsibility for food purchasing and meal preparation, as well
as the social implications of the family meal. Furthermore, the
interactions between food consumption habits and lifestyle, as
well as the social conditions and the wages of people working in
the nutrition system, need to be considered. Additional social
aspects include the import and export of agricultural and other
products and the influence of this trade on people in developing
countries (20).

On a worldwide basis, the major factor driving food con-
sumption patterns is the financial situation of countries, differ-
ent population groups, and influential individuals. Transporta-
tion and processing of food are carried out under the premise
that money can be earned. In private households, the food budget

is a determining factor in the choice of foods. From a holistic
point of view, the food price should include all costs caused by
the nutrition system, especially environmental damage (internal-
ization of external costs) (9).

These 4 dimensions of nutrition ecology are of equal impor-
tance for achieving a sustainable nutrition system. On this basis,
the various aspects of food and nutrition are taken into account.
What eating pattern best serves the holistic and sustainable aspects
of nutrition ecology? From all we know, a vegetarian diet comes
closest to fulfilling the demands and to minimizing damage to the
4 dimensions.

Contribution of vegetarian diets

Vegetarians have many reasons not to eat the flesh of animals.
In addition to religious beliefs, there are health-based, ecologic,
ethical, and philosophical reasons (14, 21–23). When the ecologic
damage caused by industrial animal production is examined (24),
certain aspects need to be considered. On average, land require-
ments for meat-protein production are 10 times greater than for
plant-protein production. About 40% of the world’s grain harvest
is fed to animals. Half of this grain would be more than enough
to feed all hungry people of our planet. Animal manure, which is
produced in huge amounts by industrial agriculture, causes high
levels of potentially carcinogenic nitrates in drinking water and
vegetables. Animal production requires considerable energy and
water resources and leads to deforestation, overgrazing, and over-
fishing (8, 25–27).

One solution to the problems caused by industrial animal pro-
duction is a vegetarian lifestyle (23, 28–32). The positive ecologic
effects achieved by vegetarianism can be enhanced by avoiding
processed and packaged foods and by choosing seasonally avail-
able and locally produced organic foods. In this way, support is
given to subsistence and family farming, the securing of employ-
ment, and global food security. In addition to these socioeconomic
benefits, the caging of animals as well as their transportation over
long distances and finally slaughtering them can be avoided, thus
fulfilling ethical concerns.

Sustainability

The 4 dimensions of nutrition ecology are the basis for sus-
tainable nutrition behavior (6). The term sustainability was intro-
duced in the 17th century by forestry experts in Germany to call
attention to the fact that only the amount of trees that would grow
back in a given time should be harvested. Presently, sustainabil-
ity describes development that fulfills current global needs with-
out diminishing the possibility of future generations to meet their
own needs (33).

From a nutritional point of view, sustainability also deals with
the fair distribution of food through ecologic and preventive eat-
ing behavior. To achieve sustainability, a comprehensive rethink-
ing of common values is needed to attain a new understanding of
the quality of life. The question as to the adequate amount of food
needs to be addressed at all social levels with the goal of achiev-
ing nutrition security for all. To fulfill the demands concerning
ecologic, economic, social, and health compatibility, the follow-
ing 7 principles have been formulated: 1) food should be pre-
dominantly plant derived, 2) food should originate from organic
farming, 3) food should be produced regionally and seasonally, 4)
food should be minimally processed, 5) food should be ecologi-
cally packaged, 6) food trade should be fair, and 7) food should be
tastefully prepared. These principles have been derived from

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NUTRITION ECOLOGY AND VEGETARIANISM 659S

guidelines of wholesome nutrition described elsewhere (34). A
diet based on these principles has a scientific basis, is socially
acceptable, is economically feasible, is culturally desired, is prac-
ticable, and has a high degree of sustainability.

There are only a limited number of long-term trials on sustain-
ability. In one project, 3 apple production systems—organic farm-
ing, integrated farming, and conventional farming—were com-
pared (19). The yields were nearly equal, but the organic
production system showed not only the best apple quality but also
the best soil quality and the least detrimental environmental
impact. Therefore, the organic production system had the best
environmental sustainability. The economic sustainability is given,
since the market price was highest for the organic apples. The
authors of this report question the sustainability of conventional
farming systems because of escalating production costs, heavy
reliance on nonrenewable resources, reduced biodiversity, water
contamination, soil erosion, and health risks to farmworkers
caused by pesticide use.

Another study carried out over 21 y showed that although the
crop yield was 20% lower in the organic systems, the input of
fertilizer and energy was reduced by 34–53% and the pesticide
input by 97%. Enhanced soil fertility and higher biodiversity
found in organic plots were due to compost- and legume-based
crop rotations (35).

Biodiversity is also the basis of food variety. Apart from the pro-
motion of breast-feeding, the recommendation to eat a variety of foods
is the most internationally agreed-upon dietary guideline. Biodiver-
sity also protects against climate and pestilence disasters. In addition,
biodiversity serves increasingly as the basis for new pharmaceuticals.

CONCLUSIONS

Nutrition ecology has the goal of attaining sustainability of
food and nutrition security worldwide. To achieve this goal, pro-
fessionals involved in the nutrition system must inform the pub-
lic about the principles of nutrition ecology. In this manner, peo-
ple can be motivated to practice sustainable eating behavior (36).

Nutrition ecology is also a question of personal priorities. Inter-
ested and well-informed consumers will be able to weigh the argu-
ments and make the necessary decisions. The vision of a sustainable
future depends upon individuals who feel responsible for the envi-
ronment and health. One of the most effective ways to achieve the
goals of nutrition ecology, including healthy and sustainable food
choices, is a vegetarian lifestyle (37).

The author had no conflicts of interest.

REFERENCES
1. Carson R. Silent spring. Greenwich, CT: Fawsett, 1959.
2. Moore-Lappé F. Diet for a small planet. New York: Ballantine

Books, 1971.
3. Meadows D. The limits of growth. New York: Universe Books, 1972.
4. Gussow J. The feeding web. Palo Alto, CA: Bull Publishing, 1978.
5. Nader R. Eating clean: food safety and the chemical harvest. Wash-

ington, DC: Center for Study of Responsive Law, 1982.
6. Spitzmüller E-M, Schönfelder-Pflug K, Leitzmann C. Ernährungsökolo-

gie: Essen zwischen Genuss und Verantwortung. (Nutrition ecology:
eating between relish and responsibility.) Heidelberg, Germany:
Haug, 1993 (in German).

7. German Nutrition Society. Reference values for nutrient intake.
Frankfurt, Germany: Umschau Braus, 2002.

8. Pimentel D, Pimentel M. Population growth, environmental resources
and global food. J Sustain Forestr 1999;9:35–44.

9. Pimentel D, Pimentel M. To improve nutrition for the world’s popu-
lation. Science 2000;288:1966–7.

10. Hopfenberg R, Pimentel D. Human population numbers as a function
of food supply. Environ Dev Sustain 2001;3:1–15.

11. Food and Agriculture Organisation. Report of the World Food Sum-
mit 2002. Rome: Food and Agriculture Organisation, 2002.

12. World Cancer Research Fund, American Institute of Cancer Research.
Food, nutrition and the prevention of cancer: a global perspective.
Washington, DC: American Institute of Cancer Research, 1997.

13. Krauss RM, Eckel RH, Howard B, et al. AHA dietary guidelines, revision
2000: a statement for healthcare professionals from the Nutrition Com-
mittee of the American Heart Association. Circulation 2000;102:2284–99.

14. Leitzmann C, Hahn A. Vegetarische Ernährung. (Vegetarian nutri-
tion.) Stuttgart, Germany: Ulmer, 1996 (in German).

15. Watzl B, Leitzmann C. Bioaktive Substanzen in Lebensmitteln.
(Bioactive substances in foods.) 2nd ed, rev. Stuttgart, Germany: Hip-
pokrates, 1999 (in German).

16. Leitzmann C, Keller M, Hahn A. Alternative Kostformen. (Alternative
dietary regimens.) Stuttgart, Germany: Hippokrates, 1999 (in German).

17. Carlson-Kanyama A. Climate change and dietary choices—how can
emissions of greenhouse gases from food consumption be reduced?
Food Policy 1998;23:277–93.

18. Reganold J. Farming’s organic future. New Sci 1989;122:49–52.
19. Reganold JP, Glover JD, Andrews PK, Hinman HR. Sustainability of

three apple production systems. Nature 2001;410:926–30.
20. Strahm RH. Warum Sie so arm sind. (Why they are so poor.) Wup-

pertal, Germany: Hammer, 1995 (in German).
21. Messina VK, Burke KI. Position of the American Dietetic Associa-

tion: vegetarian diets. J Am Diet Assoc 1997;11:1317–21.
22. Key TJ, Davey GK, Appleby PN. Health benefits of a vegetarian diet.

Proc Nutr Soc 1999;58:271–5.
23. Rajaram S, Sabaté J. Health benefits of a vegetarian diet. Nutrition

2000;16:531–3.
24. Giehl D. Vegetarianism. New York: Harper & Row, 1981.
25. Pimentel D, Pimentel M. The future of American agriculture. In: Knorr D,

ed. Sustainable food systems. Westport, CT: AVI Publishing, 1983:3–27.
26. Pimentel D. Environmental and economic benefits of sustainable agri-

culture. In: Kihn J, Gowdy J, Hinterberger F, van der Straaten J, eds.
Sustainability in question. Cheltenham, United Kingdom: Edward
Elgar Publishing, 1999:153–70.

27. Pinstrup-Andersen P, Pandya-Lorch R. Food security and sustainable
use of natural resources: a 2020 vision. Ecol Econ 1998;26:1–10.

28. Gussow JD. Ecology and vegetarian considerations: does environ-
mental responsibility demand the elimination of livestock? Am J Clin
Nutr 1994;59(suppl):1110S–6S.

29. Fox MA. The contribution of vegetarianism to ecosystem health.
Ecosys Health 1999;5:70–4.

30. Hahn NI. Growing a healthy food system. J Am Diet Assoc 1997;97:
949–50.

31. Gussow JD, Clancy KL. Dietary guidelines for sustainability. J Nutr
Educ 1986;18:1–5.

32. Gussow JD. Mediterranean diets: are they environmentally responsi-
ble? Am J Clin Nutr 1995;61(suppl):1383S–9S.

33. United Nations, ed. The global partnership for environment and
development: a guide to Agenda 21/post Rio Edition. 2nd ed. Wash-
ington, DC: United Nations Press, 1993.

34. Koerber KV, Männle T, Leitzmann C. Vollwert-Ernährung. Konzep-
tion einer zeitgemäßen Ernährungsweise. (Wholesome nutrition: con-
cept of a contemporary diet.) 9th ed, rev. Heidelberg, Germany: Haug,
1999 (in German).

35. Maeder P, Fliessbach A, Dubois D, Gunst L, Fried P, Niggli U. Soil
fertility and biodiversity in organic farming. Science 2002;296:1694–7.

36. Gee H. Food and the future. Nature 2002;418:667.
37. Sabaté J, ed. Vegetarian nutrition. Boca Raton, FL: CRC Press, 2001.

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