ISIS Report 08/12/04
Are Organic Foods More Healthy?
Rhea Gala and Sam Burcher
report on new research showing that organic feed gives protection against
toxins under vulnerable conditions where conventional feed fails
Sources for this article
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Details here
It has been suggested that organic food contains higher amounts of
natural toxic compounds produced by fungi or plants (but see "Increased mycotoxins in organic
produce?" this series), whereas conventional food may contain more
synthetic toxins from pesticide residues which can also seriously damage human
health and the environment. So are there any real health benefits from organic
food?
Research reviewed in the Independent Science Panel Report,
The
Case for a GM-Free Sustainable World (www.indsp.org) has shown that
organic crops tend to have a higher nutrient content, and organic feed improves
the general health and disease resistance of farm animals. Organic farming
practices including the use of animal or green manure and long crop rotation
are also thought to reduce plant infection by pathogens. However, mycotoxins
(fungus derived toxins) called DON (deoxynivalenol) and OTA (ochratoxin A),
often contaminate wheat, whether grown organically or conventionally; they
cause cancer, damage genes, and are harmful to the kidneys and the immune
system. The levels of these toxins may be reduced by fungicides, or increased
by nitrogen fertilisers, and are also influenced by climate and improper
storage; for example being kept too hot or wet, a condition that may be
associated with organic production.
There have been a few studies showing that animals fed organically have
slight improvements over those fed conventionally in mortality rate, body and
organ weight, reproductive performance and fertility.
Scientists at the National Institute for Research into Food and
Nutrition in Rome have taken a new approach in comparing organic and
conventional food consumption, by looking at sensitive markers of cell function
in response to the toxins in animals under vulnerable conditions [5]. The
markers were the proliferative capacities of lymphocytes found in the intestine
and in the spleen, and the acute-phase reaction of the liver, both responding
to the presence of the toxins.
The intestinal mucosa (lining) is continuously exposed to millions of
food antigens and ingested toxic substances, so the intestinal immune system
and the spleen lymphocytes should mount a prompt defence against the insults.
The liver acute-phase reaction, responding to disturbances of cell homeostasis
(state of balance), will increase the synthesis of some blood plasma proteins
and decrease the synthesis of others.
The vulnerable conditions in which body defences can be less efficient
are during weaning, and under protein energy malnutrition (PEM). Several
studies have shown that PEM induces severe alterations in different organs and
tissues including the liver and the immune system, especially during
development, causing a predisposition to damage by food contaminants such as
DON and OTA.
Weaned rats were assigned to two groups and fed for 30 days on
conventional or organic wheat, both of which had been grown under carefully
controlled conditions. Both groups were then divided into two subgroups of
well-nourished or protein energy malnourished (PEM) rats.
For each rat, lymphocyte proliferation was assayed after stimulating
the cells with a mitogen (substance that causes cells to divide) in a culture
medium containing either fetal calf serum (FCS) or the rat’s own serum
(RS) to mimic the in vivo proliferative response. The acute phase
proteins - albumin, transthyretin, transferring, ceruloplasmin, retinal-binding
protein – were measured in the rat’s plasma.
The proliferative response of lymphocytes cultured with FCS, and acute
phase proteins showed no difference in organically and conventionally fed rats,
under either well-fed or PEM condition; despite the fact that the organic wheat
contained higher amounts of mycotoxins, though still lower than that reported
to affect immune response.
The proliferative capacity of lymphocytes cultured with the rat’s
own serum, however, was inhibited in PEM rats on conventional feed compared
with those fed organically. This effect was thought to be due to contaminants
other than mycotoxins in the conventionally grown wheat.
Thus, conventionally grown wheat represented a higher risk for
lymphocyte function than the organically grown wheat, at least, in animals
under vulnerable conditions.
In other words, the conventional wheat appeared to compromise the
ability of the vulnerable animals to mount an immune response.
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