Organic food quality and impact on human health
Chair of Organic Foodstuffs, Faculty of Human Nutrition and Consumer Sciences,
Nowoursynowska 159c, 02-776 Warszawa, Poland, phone: 48 22 5937038, fax: 48 22 5937036;
Abstract. and safety has drastically
decreased, mainly due to several food scandals and growing ecological awareness. Consumers
have started to look for safer foods, produced in environmentally friendly, authentic and local
systems. Organically produced foods are believed to satisfy these demands.
Organic crops contain less nitrates and pesticide residues, but more dry matter, vitamin C,
phenolic compounds, essential amino acids and sugars than conventional ones. Organically
produced milk contains usually more dry matter, fat, calcium, selected vitamins and beneficial
conjugated linoleic acids (CLA) compared to conventional milk from high input systems. Meat
from organically raised cattle, pigs and sheep was found to contain less total fats and saturated
fatty acids but higher content of unsaturated fatty acids and better n-6/n-3 fatty acid ratio.
The health effects of organic vs. conventional foods have been investigated in several
studies. In vitro analyses indicated better repair of bacterial DNA and decrease of cancer cells
proliferation on organic vs. conventional plant materials. Animal studies indicated better
fertility indexes and increased immune parameters in organically fed animals. The effects of
organic foods on human health are still not well known. However, according to PARSIFAL
study children representing antrophosophic lifestyle, including biodynamic and organic food,
had less allergies and lower body weight, while KOALA study associated consumption of
organic dairy products with lower eczema risk in children.
The overall number of studies analyzing the quality and safety of organic foods and
investigating the health effects of organic food consumption is growing. However, the results
are still insufficient to formulate the explicit conclusions.
Key words: organic food, food quality, health
During the last decades and safety has drastically
decreased, mainly due to several food scandals and growing ecological awareness.
Consumers have started to look for safer and better controlled foods, produced in more
environmentally friendly, authentic and local systems. Organically produced foods are
widely believed to satisfy the above demands.
The overall number of studies analyzing the quality and safety of organic vs.
conventional foods is growing rapidly. This paper presents the literature review of the
organic food quality and the health effects of organic food consumption.
Agronomy Research 7(Special issue II), 719727, 2009
Quality of organic plant products
Since the beginning of the 1980s until the end of 2007 nearly 100 studies comparing
the nutrient content of organic vs. conventional plant foods have been published.
The content of plant secondary metabolites beneficial for human health was the
topic of great interest in recent years. 72% of studies (Benbrook et al., 2008) indicated
higher level of total polyphenols in organically produced plant foods in comparison
with conventionally produced ones (e.g. Carbonaro et al. 2002; Young et al., 2005;
Abu-Zahra et al., 2007). Polyphenols represent a large class of plant secondary
metabolites with potential antioxidative properties. Moreover, there is a large number
of studies reporting the neuroprotective, cardioprotective and chemopreventive actions
of these substances (Frei & Higdon, 2003; Carlson et al., 2007; Kampa et al., 2007;
Ortuno et al., 2007). The important group of polyphenols identified in higher contents
in organic plants are flavonols (Caris-Veynard et al., 2004;
2005), which were found to diminish the incidence of heart disease, cancer,
gastrointestinal, neurological and liver diseases, atherosclerosis, obesity and allergies
(Frei & Higdon, 2003; Fresco et al., 2006; Ramos, 2007; Shankar et al., 2007).
According to Ren et al. (2001) juices from organic spinach, welsh onion and
chinese cabbage had 50120% higher antioxidant activity than juices from
conventionally produced vegetables. Antioxidant activity of currants grown organically
was also 30% higher according to Kazimierczak et al. (2008). These results were
confirmed by 88% of all the previously published studies describing higher antioxidant
capacity of organically produced plant foods (Benbrook et al., 2008).
According to the meta-analysis made by Benbrook et al. (2008) organic crops,
compared to conventional ones, contain also more beneficial substances, such as
quercetin (acc. to 87% of studies), kaempferol (55%), vitamin C (63%), vitamin E
(62%) and phosphorus (63%). They are also known to contain more sugars (Stertz,
2005; Hallmann &
sensory quality of organic produce.
85% of published papers (Benbrook et al., 2008) indicated lower protein content
in organic vs. conventional plant foods. On the other hand, Magkos et al. (2003)
described the quality of proteins (measured as essential amino acid content) in some
organic cereal crops and vegetables as higher than in conventionally produced ones.
Harmful substances, such as nitrates, are found in lower contents in organic crops
comparing to conventional ones according to 83% of previously published studies (e.g.
Abu-Zahra et al., 2007). Organic crops contain also significantly lower residues of
pesticides (Baker et al., 2002) which are known to exert carcinogenic, mutagenic,
neuro-destructive, endocrine and allergenic effects.
To assume, organic plant-based foods present on average higher nutritional
quality and safety in terms of compounds which have been previously measured.
Quality of organic animal products
The impact of organic farming methods and organic feed on the nutritional
quality of animal products has been investigated in several studies. There is strong
evidence that poultry and livestock that consume animal feeds and pastures grown
using organic methods produce meat, milk, and eggs that has modestly higher levels of
protein, more of some vitamins and minerals, and elevated levels of heart-healthy n-3
fatty acids and CLA (Benbrook et al., 2008).
Milk is one of the most important nutritional sources, especially in the nutrition of
children. It is reported that the composition of organic milk compared to conventional
milk from high input systems can be very different, especially while comparing the
antioxidant and the fatty acid profile. Organic milk has a higher content of CLA, n-3
fatty acids and a better n-6/n-3 fatty acids ratio (Kusche & Baars, 2007; Butler et al,
2008). Dietary intake of certain unsaturated fatty acids, in particular CLA and n-3 fatty
acids, has been linked to potential health benefits (Connor, 2000; Parodi, 2003). CLA
and n-3 fatty acids have been shown to counteract the negative physiological effects of
saturated fatty acids, and CLA has also been linked to anticancer properties, reduced
risk of type 2 diabetes and enhanced immune function (Pariza, 2003; Lock & Bauman,
2004; Wahle et al., 2004).
Factors for a beneficial milk fatty acids composition are outdoor grazing, high
biodiverity in pastures, low levels of concentrates and no silage feeding (except red
clover) (Kusche, 2009). Apart from polyunsaturated fatty acids, -linolenic acid (the
main n-3 fatty acid in milk), and CLA, dairy products from certified organic dairy
production systems have been reported to contain higher concentrations of fat-soluble
antioxidants (e.g., α-tocopherol, carotenoids) than those from high-input conventional
production (Butler et al., 2008). Moreover, organically produced milk compared to
conventionally produced one was found to contain more dry matter, calcium, vitamin
C, less somatic cells, but more coliform bacteria (what indicates worse hygiene regime
during milking) (Lund & Algers 2003).
Meat (beef, pork and lamb) from the organically raised animals is generally
characterized by lower content of total fat (Hansson et al., 2000). At the same time
organic pork and lamb were found to present higher intramuscular fat content (Fisher
et al., 2000; Sundrum et al., 2000). Organic meat contains usually more unsaturated
and less saturated fatty acids. Moreover, n-6/n-3 fatty acid ratio in organic beef was
reported to be much lower comparing to the conventional beef (Pastushenko et al.,
2000). Higher weight of breast and thigh muscles in poultry carcasses (Castellini et al.,
2002), and sirloin and ham in pork carcasses (Sather et al., 1997) were found in the
organically raised animals. Organic meat has also better sensory quality in most cases
(Hansson et al. 2000, Pastuschenko et al. 2000, Olsson et al. 2003). Organic lamb was
found to present better eating quality than conventional lamb in terms of juiciness
(attributed to the higher intramuscular fat content) and flavour (attributed to the higher
level of linolenic acid and total n
With regard to food safety, organic meat production scores as equally well as
conventional production. However, droppings from organic pigs and broilers showed,
as a positive, a much lower incidence of antibiotic resistant bacteria comparing to
conventionally raised animals (Hoogenboom et al., 2008).
Impact of the organic feeds on laboratory animals
As it was previously described, there is a number of scientific results supporting
health, due to higher contents of beneficial substances and lower levels of
contaminants in comparison to conventionally produced food products. Moreover,
some results of in vitro studies indicated better repair of bacterial DNA and decrease of
cancer cells proliferation on organic vs. conventional plant materials (Ren et al., 2001;
Olsson et al., 2006).
During the last fifty years several animal dietary intervention studies have been
conducted to investigate the health effects of organic vs. conventional food
consumption. Most of these studies confirmed beneficial impact of organic feeds on
development rate and reproductive abilities of rats, mice, rabbits and hens
(Gottschewski, 1975; McSheehy, 1977; Aehnelt & Hahn, 1978; Edelmuller, 1984;
Staiger, 1986; Plochberger, 1989; Velimirov et al., 1992). Study conducted by Staiger
(1986), including three generations of rabbits, showed stable fertility rate of
organically fed animals and at the same time decreasing fertility in subsequent
generations of rabbits fed conventional feed. Velimirov et al. (1992) indicated higher
percent of young born alive and superior body weight gain during and after lactation
period in organically fed female rats. Another research, concerning reproductive
abilities of male rats, was a Danish experiment (Jensen, 2004). In the above-mentioned
study no statistically significant differences were found between groups fed on organic
and conventional feed in relation to: epididymis weight, number of degenerative
changes in testicles and sperm de
qualitative analysis of rat sperm, which may be of great significance in determining
fertility of the studied rats as the number of non-deformed spermatozoa is the main
factor determine the ability to insemination.
Animal studies published in recent years indicated increased immune parameters
in organically fed lab animals. Finamore (2004) in a dietary study with protein shortage
indicated higher stimulated lymphocyte proliferation in a group of rats fed organic vs.
conventional feed. Lauridsen et al. (2005) showed a higher level of IgG in blood serum
of organically fed rats, demonstrating a higher immune system reactivity of these
animals. A pilot experiment of Bar et al. (2007) showed higher splenocyte
proliferation in male rats fed organically. According to a recent study in the
Netherlands (Huber, 2007) chickens on organic diet had a lower body weight, a higher
immune reactivity and significantly better catch-up growth after a challenge.
At the same time several studies have proven the negative influence of a few
pesticides used in conventional farming on the fertility rates of laboratory animals.
Examples of the above-mentioned studies are experiments estimating a genotoxic
effect of pyrethroid in mice (Bhunya et al., 1988) and a toxic effect of cypermethrin
pesticide on the fertility parameters in rats (Elbetieha et al., 2001). These results were
obtained with a significantly higher amount of chemical agents than permissible
concentrations of single pesticide residues in fruits and vegetables. However, very little
is known about the consequences of long-term dietary exposure to various mixtures of
pesticide residues present in foods (Carpy et al., 2000; Reffstrup, 2002). It cannot be
excluded that pesticides even in small, officially permitted doses disturb the hormonal
balance in the body, which has a great impact on its proper development and functions,
including fertility (Howard, 2005).
Studies presented above on the health effects of organic vs. conventional feeds are
sparse, moreover there is a lack of systematic and long-term investigations in this
scope. Therefore only preliminary conclusions can be formulated. There is a noticeable
tendency of better fertility indexes, survival rate of the young and better functioning of
the immune system. However, further, well-planned experiments are necessary in order
to evaluate overall health status of laboratory animals fed on feeds from different
agricultural production systems.
Impact of the organic food on human health
The effects of organic foods on human health are still not very well known. In the
psychological parameters was found among seventeen nuns eating biodynamic foods
for one month. Nuns on biodynamic diet had lower blood pressure and better immune
status. They also evaluated their physical fitness, intellectual acuity and overall well-
being much better in this period. Moreover, they declared less headaches and presented
better ability to handle stress. However, this was not a blinded study.
According to PARSIFAL study (14,000 children, 5 European countries) children
representing antrophosophic lifestyle, including biodynamic and organic food, were
found to have less allergies and lower body weight in comparison to group consuming
market, conventionally produced foods (Alfven et al., 2006). At the same time the
results of the KOALA Birth Cohort Study in the Netherlands (3,000 mothers and
children) associated the consumption of organic dairy products with lower eczema risk
in children (Kummeling et al., 2008). Organic dairy consumption resulted at the same
According to one of studies evaluating different aspects of organic and
( consumers of
organic foods assessed their health state significantly better than other consumers.
However, apart from organic diet, it was connected with differences between several
aspects of consumers lifestyle (e.g. nutritional pattern, living conditions, physical
activity, ways to manage stress). Therefore, it can be concluded that promotion of
overall ecological lifestyle, including organic food consumption, can influence
positively the nutritional pattern and the self-assessed health state of consumers.
As it was previously described, pesticide residues belong to dangerous food
contaminants, known to exert carcinogenic, genotoxic, neuro-destructive, endocrine
and allergenic effects and found usually in higher contents in conventionally produced
plant foods. There is scientific evidence that dietary exposure of children to
organophosphorus pesticides, measured on the basis of the level of pesticide
metabolites in urine samples, is much lower on organic than on conventional diet. It
can be concluded that consumption of organic foods provides a protective effect
against exposure to organophosphorus pesticides commonly used in agricultural
production (Curl et al., 2003; Lu et al., 2006).
To conclude, the overall number of studies comparing the quality and safety of
organic vs. conventional foods is growing rapidly. It is also possible to observe
increasing interest in investigating the health effects of organic food consumption.
Results indicating higher nutritional quality and safety of organic foods in terms of
many measured compounds, as well as the results of in vitro and animal dietary
intervention studies, showing the positive impact of organic foods on reproductive and
immune status of animals, are promising. The first experiments investigating health
impact of organic foods on humans brought also promising overview. However, the
results are still insufficient to formulate the explicit conclusions. Therefore, several
important problems still need to be investigated in the coming years: environmental,
bacterial and fungal contamination of the organic crops, and the most essential problem
the impact of the organic food consumption on human health.
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