Is Organic Food Healthier?

Is Organic Food Healthier?

Townsend Letter for Doctors and Patients
October 1, 2001

Is Organically Grown Food More Nutritious?
BY: Virginia Worthington

This article is a summary of a review article entitled "Effect of
Agricultural Methods on Nutritional Quality: A Comparison of Organic with
Conventional Crops" by Dr Worthington which appeared in Alternative
Therapies, Volume 4, 1998, pages 58- 69.

Since the 1920s when chemical fertilizers were first used commercially on a
large scale, there have been claims that agricultural chemicals produce less
healthful and less nutritious food crops. By the 1940s, the organic farming
movement had begun, in part due to this belief that food grown using more
traditional, chemical-free methods was more healthful. Foods grown by these
methods came to be known as "organic." Today, this notion has continued in
the alternate health arena, and some alternative treatments, such as the
Gerson cancer therapy, rely on food grown organically. But the question
remains: is organically grown food more nutritious? There are several
reasons why there has not been a solid answer to this question. The first is
that the difference in terms of health effects is not large enough to be
readily apparent. In other words, if people stayed well on an organic diet
but got violently ill as a result of consuming food grown with chemical
fertilizers and pesticides, then the difference would be perfectly obvious;
however, this is not the case, and a more subtle difference, such as an 8%
increase in the incidence of allergies, for example, is much more difficult
to detect and easier to overlook.

A second reason is that it is difficult to conduct and interpret
agricultural research investigating nutrient content. Factors such as
sunlight, temperature and rainfall, which influence the nutrient content of
plants, vary from year to year. Additional changes in the nutrient content
of a crop can occur during storage and shipping. For these reasons, it is
difficult both to plan effective studies and to make sense of the results.
Furthermore, these considerations often make it difficult to compare the
results of different studies.

Finally, many of the studies that have been done are relatively old and not
performed according to modern standards. In particular, the older studies do
not include a rigorous statistical analysis. This factor alone can make
these studies difficult to evaluate. As a result, they have been dismissed
by some as valueless.

What is the evidence? There are more than 30 studies comparing the nutrient
content of organic crops and those produced conventionally with chemical
fertilizers and pesticides. In these studies, various individual nutrients
in individual crops were compared, such as zinc in organic versus
conventional carrots, or vitamin C in organic versus conventional broccoli.
In the more than 300 comparisons performed in these studies, organic crops
had a higher nutrient content about 40% of the time, and conventional crops
had a higher nutrient content only about 15% of the time. Overall, organic
crops had an equal or higher nutrient content about 85% of the time. These
results suggest that, on average, organic crops have a higher nutrient

While the overall outlook is favorable for organic crops, there is too
little data for most individual nutrients to say anything at all. But for
three individual nutrients - vitamin C, nitrates and protein quality - there
is enough evidence to suggest that organic crops are superior to
conventional ones. Compared to crops grown with chemical fertilizers and
pesticides, organically grown crops generally have a higher vitamin C
content, a lower content of carcinogenic nitrates and better protein
quality. Further work is needed on other nutrients before any definitive
conclusions can be drawn.

While this nutrient content data is interesting, it does not tell us
anything about the health of people and animals that consume these crops.
The most relevant studies then, are not those that simply assess nutrient
content, but are those that feed organic or conventional feed to animals and
then look at how healthy they are. There are 14 such animal studies that
have been performed over the last 70 years. In ten of these, the organically
fed animals fared better; in one, the animals fed organic feed came in
second among several chemically fertilized feeds; and 3 studies showed no
difference, possibly due to weaknesses in the study designs.

The ten positive studies are summarized in Table 1. Again, these results
support the notion that organically produced crops may be more conducive to
good health and hence more nutritious. The positive effects are most
striking in sick or otherwise vulnerable animals such as newborns and in
sensitive areas of reproduction such as sperm motility. It is particularly
interesting to see that the fertility of animals fed fodder grown with
chemical fertilizers and pesticides declined over several generations. This
recalls the progressive decline in health that Dr. Pottenger saw in each
succeeding generation of cats fed a less than optimal diet.

In summary, from the research that has been done, it appears that
organically grown crops may have, on average, a higher nutrient content than
crops grown with chemical fertilizers and pesticides. In addition, animal
evidence supports the thesis that organically produced foodstuff can produce
a better health outcome over the long term, particularly in the area of
reproduction. These studies support a return to traditional, organic farming

Table 1
Summary of Results from 10 Animal Studies: Comparisons of Organic with
Conventional Feed

Females: Higher ovum production in rabbits (6 versus 3 eggs per dam) &
chickens (192 versus 150 eggs per hen).
Males: Testes in better condition in mice; sperm motility greater in bulls.
Young: Fewer perinatal deaths & other deaths prior to weaning in rabbits
(mortality rate of 27% versus 51%) in mice (mortality rate of 9% versus 17%)
and rats.
Overall: Fertility rate of rabbits remained constant over 3 generations in
organically fed rabbits and declined in rabbits fed conventionally produced

Weight Maintenance & Growth
* Lower percentage weight loss (22.4% versus 37.4%) & longer survival (50
versus 33 days) in birds with polyneuritis.
* Better weight maintenance in lactating female rats
* Higher percentage weight gain in young rats (77% versus 51.4%) and in
* Better weight gain after coccidial illness and fewer incidents of illness
in chickens.

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