Some olive oils are extracted with solvents that are felt to evaporate
afterwards.
"montygram" <[email hidden]> wrote in message
news:[email hidden]...
Scientists are supposed to start with a hypothesis, which can then be
tested. When it comes to the food that people eat, there are so many
components hitting the body at the same time it is difficult to
determine the "cause." What I have pointed out on this newsgroup many
times is that "olive oil" is not one thing. Some olive oils are highly
refined and very dangerous to the body due to the probability of excess
lipid peroxidation. Fresh, high-quality, uncooked olive oil is on the
other end of the health sprectrum. The other problem is using terms or
phrases in an unscientific way, for example, blaming "cholesterol" for
the effects of oxysterols. Then there is the classfication problem,
calling lard and coconut oil "saturated fats," when doing so makes no
sense whatsoever, and contradicts the only hypothesis that does make
sense at this point, whether one calls it the "free radical theory of
aging" or whatever. There are much more interesting
studies/experiments involving olive oil (MMu has pointed out why this
study is rather strange), for example:
© 2004 The American Society for Nutritional Sciences J. Nutr.
134:2314-2321, September 2004
Human Nutrition and Metabolism
Olive Oils High in Phenolic Compounds Modulate Oxidative/Antioxidative
Status in Men1
Tanja Weinbrenner*, Montserrat Fitó*, Rafael de la Torre,, Guillermo
T. Saez, Philip Rijken, Carmen Tormos, Stefan Coolen, Magí Farré
Albaladejo,**, Sergio Abanades**, Helmut Schroder*, Jaume Marrugat*,**
and Maria-Isabel Covas*,2
2To whom correspondence should be addressed. E-mail: [email hidden].
The aim of the present study was to evaluate whether olive oils high in
phenolic compounds influence the oxidative/antioxidative status in
humans. Healthy men (n = 12) participated in a double-blind,
randomized, crossover study in which 3 olive oils with low (LPC),
moderate (MPC), and high (HPC) phenolic content were given as raw doses
(25 mL/d) for 4 consecutive days preceded by 10-d washout periods.
Volunteers followed a strict very low-antioxidant diet the 3 d before
and during the intervention periods. Short-term consumption of olive
oils decreased plasma oxidized LDL (oxLDL), 8-oxo-dG in mitochondrial
DNA and urine, malondialdehyde in urine (P < 0.05 for linear trend),
and increased HDL cholesterol and glutathione peroxidase activity (P <
0.05 for linear trend), in a dose-dependent manner with the phenolic
content of the olive oil administered. At d 4, oxLDL after MPC and HPC,
and 8-oxo-dG after HPC administration (25 mL, respectively), were
reduced when the men were in the postprandial state (P < 0.05).
Phenolic compounds in plasma increased dose dependently during this
stage with the phenolic content of the olive oils at 1, 2, 4, and 6 h,
respectively (P < 0.01). Their concentrations increased in plasma and
urine samples in a dose-dependent manner after short-term consumption
of the olive oils (P < 0.01). In conclusion, the olive oil phenolic
content modulated the oxidative/antioxidative status of healthy men who
consumed a very low-antioxidant diet.
http://www.nutrition.org/cgi/content/abstract/134/9/2314
© 2004 The American Society for Nutritional Sciences J. Nutr.
134:2133S-2140S, August 2004
Supplement: WALTHAM International Science Symposium: Nature, Nurture,
and the Case for Nutrition
Application of the Comet Assay for Investigation of Oxidative DNA
Damage in Equine Peripheral Blood Mononuclear Cells1,2
David J. Marlin3, Lucy Johnson, Demelza A. Kingston, Nicola C. Smith,
Chris M. Deaton, Sarah Mann, Paul Heaton, Fenneke Van Vugt, Kelly
Saunders*, Julia Kydd* and Pat A. Harris
Centers for Equine Studies and * Preventive Medicine, Animal Health
Trust, Kentford, Newmarket, Suffolk, CB8 7UU, UK and Equine Studies
Group, WALTHAM Centre for Pet Nutrition, Waltham-on-the-Wolds,
Leicestershire LE14 4RT, UK
3 To whom correspondence should be addressed. E-mail:
[email hidden].
Oxidative stress occurs when antioxidant defense mechanisms are
overwhelmed by free radicals and may lead to DNA damage, which has been
implicated in processes such as aging and diseases such as cancer. The
two main techniques presently used to quantify DNA damage are
measurement of 8-hydroxydeoxyguanosine and the Comet assay (also known
as single-cell gel electrophoresis). The aim of this study was to apply
the comet assay to equine peripheral blood mononuclear cells (PBMCs)
and identify two conditions in which we hypothesized that oxidative DNA
damage would be increased in PBMCs: aging and equine recurrent airway
obstruction (RAO, a condition similar to human asthma). The images
obtained were similar to those previously published for humans, cats,
and dogs. The optimum concentration of H2O2 to estimate susceptibility
to exogenous damage was 50 µM. Mean intraassay coefficients of
variation were 4.7 and 9.7% for endogenous and exogenous tail-DNA
quantities, respectively, and 7.3 and 8.3%, respectively, for
interassay coefficients. There was no significant difference in either
endogenous or exogenous percentages of tail DNA for samples collected
from six ponies on three consecutive days. There was no significant
difference in endogenous, exogenous, or exogenous (corrected for
endogenous) oxidative DNA damage between mature and aged ponies.
However, young pony foals had significantly less endogenous DNA damage
than mature or aged ponies (P < 0.05). RAO-affected horses without
airway inflammation (i.e., in clinical remission) had significantly
greater endogenous damage compared with non-RAO-affected control
animals (P = 0.009). There was a significant correlation between
endogenous percentage of tail DNA in PBMCs and red blood cell
hemolysate glutathione concentration (r = 0.720; P < 0.001). In
conclusion, the comet assay appears to be suitable for investigating
DNA damage in equine PBMCs.
http://www.nutrition.org/cgi/content/abstract/134/8/2133S
The study below suggests that free radical amount is more important
than antioxidant amount:
Cancer Epidemiology Biomarkers & Prevention Vol. 12, 1016-1022, October
2003
© 2003 American Association for Cancer Research
No Effect of 600 Grams Fruit and Vegetables Per Day on Oxidative DNA
Damage and Repair in Healthy Nonsmokers1
Peter Møller2, Ulla Vogel, Anette Pedersen, Lars O. Dragsted,
Brittmarie Sandström3 and Steffen Loft
Institute of Public Health, University of Copenhagen, DK-2200
Copenhagen N, Denmark [P. M., S. L.]; National Institute of
Occupational Health, Denmark [U. V.]; Research Department of Human
Nutrition, Royal Veterinary and Agricultural University, Frederiksberg,
Denmark [A. P., B. S.]; and Institute of Food Safety and Nutrition,
Danish Veterinary and Food Administration, Søborg, Denmark [L. O. D.]
In several epidemiological studies, high intakes of fruits and
vegetables have been associated with a lower incidence of cancer.
Theoretically, intake of antioxidants by consumption of fruits and
vegetables should protect against reactive oxygen species and decrease
the formation of oxidative DNA damage. We set up a parallel 24-day
dietary placebo-controlled intervention study in which 43 subjects were
randomized into three groups receiving an antioxidant-free basal diet
and 600 g of fruits and vegetables, or a supplement containing the
corresponding amounts of vitamins and minerals, or placebo. Blood and
urine samples were collected before, once a week, and 4 weeks after the
intervention period. The level of strand breaks, endonuclease III
sites, formamidopyrimidine sites, and sensitivity to hydrogen peroxide
was assessed in mononuclear blood cells by the comet assay. Excretion
of 7-hydro-8-oxo-2'-deoxyguanine was measured in urine. The expressions
of oxoguanine glycosylase 1 and excision repair cross complementing 1
DNA repair genes, determined by real-time reverse transcription-PCR of
mRNAs, were investigated in leukocytes. Consumption of fruits and
vegetables or vitamins and minerals had no effect on oxidative DNA
damage measured in mononuclear cell DNA or urine. Hydrogen peroxide
sensitivity, detected by the comet assay, did not differ between the
groups. Expression of excision repair cross complementing 1 and
oxoguanine glycosylase 1 in leukocytes was not related to the diet
consumed. Our results show that after 24 days of complete depletion of
fruits and vegetables, or daily ingestion of 600 g of fruit and
vegetables, or the corresponding amount of vitamins and minerals, the
level of oxidative DNA damage was unchanged. This suggests that the
inherent antioxidant defense mechanisms are sufficient to protect
circulating mononuclear blood cells from reactive oxygen species.
http://cebp.aacrjournals.org/cgi/content/abstract/12/10/1016
