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[SANET-MG] organic foods enhance human health
April 12, 2006
Prof. Joe Cummins
Organic Foods Enhance Human Health
The following review focuses on scientific studies that have been
published after 2000. The review will focus on information related to
the health consequences of consuming organic food and will not deal with
the many reports on people’s preferences and beliefs about organic
foods. However, the growth in demand for organic food is driven by
people’s beliefs about the benefits of organic food and the fact that
organic foods generally taste better than conventional foods. The
general reviews comparing organic and conventional foods focus on
comparisons of gross composition of organic foods as compared to the
gross composition of conventional foods. Those studies show that organic
foods contain low to undetectable levels of pesticides, lower level of
nitrates and levels of microbial toxins about the same as conventional
foods. However, those reviews have not yet dealt with comprehensive data
on the health of those consuming organic foods in comparison to those
consuming conventional food. The current review will deal with evidence
that organic foods are richer in cancer fighting secondary metabolites,
on evidence that lower pesticide levels are beneficial and on evidence
that microbial toxins are not substantially elevated in organic food as
has been claimed by those opposing organic food. New studies showing
that organic strawberry extracts inhibit growth of cancer cells are a
landmark in scientific research, showing that organic food provides a
defense against cancer.
Two recent reviews from Harokopio Universty, Athens Greece have been
skeptical of about the value of organic food in comparison to
conventional food. The most consistent difference was the low level of
nitrate and elevated vitamin C levels in organic as compared to
conventional food. Numerous other measurements such as mycotoxin level
or environmental pollutants were not different in the two types of food.
Even though pesticide levels were much higher in convetional foods than
in organic food those elevated pesticide levels were deemed acceptable
(1,2) Christine Williams of Reading University,UK pointed out that there
are no studies in the literature of controlled intervention studies of
humans subjects and comparison of people habitually consuming organic as
compared to conventional diets are flawed by confounding factors. Older
animal studies are poorly designed and give conflicting results (3).
The above reviews failed to consider the importance of health promoting
secondary metabolites that accumulate once synthetic plant protection
agents are eliminated. Bengt Lundegardh and Anna Martensson of the
University of Agricultural Sciences , Uppsala , Sweden stressed the
benefits of organic culture in (a) an activation of the plant defence
mechanisms by excluding synthetic plant protection agents, (b) an active
soil life where plants and microbes interact, exchanging certain
metabolic compounds and (c) a balanced mineral nutrient uptake where
excesses of easily available nutrients are avoided (4).
Bioactive compounds in foods, especially the plant phenolic
antioxidants, are well known to prevent cancer and cardiovascular
disease.(5).Of course, phenolics are present in many crops ,
particularly fruits, but it has grown very clear that organic foods are
richer in cancer fighting antoxidants (6,7).
Strawberries have been studied extensively for their cancer fighting
ability and those berries have also been used to emphasize the cancer
preventing advantages of organic fruit cultivation. Extracts of five
organic and conventional cultivars were compared for their ability to
inhibit proliferation of human colon and breast cancer cells. The
anti-cancer extracts were rich in vitamin C and plant phenolics , the
extracts from organically grown strawberries had a higher
antipropiferative activity than the conventionally grown berries for
both breast and coloncancer cells (8). Compost as a soil supplement
increases the level of antioxidant compounds in strawberries (9).
Strawberry extracts were found to interfered with mitogen-activated
protein kinase (MAPK) signaling cascade and to suppress cancer cell
proliferation and transformation (10).Organic yellow plums were found to
were found to be richer in phenolic acids when grown on natural meadow
or with a ground cover of clover than conventional plums (11). Plum and
clover extracts induced apoptosis and contributed to reduced cell
viability in human liver cancer cells (12).
Rats fed conventionally grown wheat had a higher risk for lymphocyte
function than did organically grown wheat. Lymphocyte proliferation
represented an animals response to toxicity (13,14).
A number of recent studies show that there is solid scientific basis for
the theory that organic culture practices produce crops that prevent
cancer and modulate toxic responses.
Along with the benefits of organic culture in providing secondary
metabolites that are beneficial to humans the absence of pesticide
residues in food and feed provides a tangible benefit from organic food.
The “green revolution” has provided a high level of food production in
developing countries through the deployment of high levels of pesticide
and fertilizers. Investigators with the Centre for Rural Development and
Technology , Dehli, India studied residues of organochlorine,
organophosphorous, carbamate and pyrethroid pesticides in conventionally
grown wheat and rice and found that organic wheat and rice and little or
no detectable pesticide. Wheat and rice production under conventional
system was higher than organic but this higher production is at the cost
of health risk and also poses other hazards to flora and fauna(15).
Dietary exposure intake is the major source of pesticide exposure for
infants and children in the United States, this exposure may account for
increased pesticide related health risks in children compared to adults.
Direct controlled experiments showed that children consuming an organic
diet provided dramatic and immediate protective effect against
organophosphorous pesticide exposure (16). In Denmark a 1999 study on
human sperm and semen quality in relation to dietary pesticide exposure
and organic diet was published. A group consuming mainly organic food
were estimated to have a reduced pesticide intake based on the pestide
levels measured in their food. The authors of the article concluded
pesticide intake in the diet did not entail a risk of impaired semen
quality (17). However, the article reported that the group of men
without organic food intake had a significantly lower proportion of
morphologically normal sperm. Abnormal sperm is normally considered
predictive of pregnancy outcome representing DNA damaged or defectively
packaged DNA in the abnormal sperm (18,19). It is not clear why the
significantly damaged sperm did not impair semen quality in the opinion
of the Danish investigators.
Mycotoxins are toxic metabolites produced by fungi. Mycotoxin poisoning
has been known since the beginning of agriculture and has taken a large
toll on humans and farm animals consuming contaminated crops. Mycotoxins
cause immunological effects, specific organ damage, cancer, and in some
cases, death. Agricultural workers may also suffer from skin and
respiratory exposure during crop harvest and storage. Mycotoxin
poisoning is a worldwide problem associated with maize, rice, tree nuts
and peanuts along with fresh fruits and vegetables. Recently, pro-GM
scientists in academia and biotech corporations have been claiming that
organic food and feed is more heavily contaminated with mycotoxins than
conventional and genetically modified foods, on grounds that organic
production does not use chemical fungicides, and are hence more likely
to be infected. But the United Nations Food and Agriculture Organization
(FAO) states that, "studies have not shown that consuming organic
products leads to a greater risk of mycotoxin contamination." Peer
reviewed publications showed that organic foods are not more hazardous
sources of mycotoxin than conventional foods (20).
Recently the terms nutrigenomics and nutrigenetics have been coined to
probe the relationship between genes and diet. With that approach the
diet will be personalized (21). Presently, in organic agriculture ,
nutrigenomics and nutrigenetics are probably not as valuable to farmer
as would a couple of tones of horse manure compost. Nevertheless, the
breakthroughs associated with the discovery that organic strawberry
extracts inhibit cancer cell growth through identifiable pathways show
that organic agriculture provides science based health benefits.
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