Olive oil benefits, side effects
November 22, 2011   
Introduction
The high intake of olive oil in the Mediterranean diet among populations in Southern Europe is associated with low
incidences of coronary heart disease, inflammatory and autoimmune diseases. [1,2] Olive oil is a rich source of
phenolic compounds. The phenolic compounds in olive oil can be divided into three groups: simple phenols
(
hydroxytyrosol, tyrosol); secoiridoids (oleuropein, the aglycone of ligstroside, and their respective decarboxylated
dialdehyde derivatives); and the lignans [(+)-1-acetoxypinoresinol and pinoresinol]. Phenolics in these three groups
have potent antioxidant properties. [5] Olive oil is also a good source of monounsaturated fatty acids, squalene, and
alpha-tocopherol. [6]

Olive oil is divided into three types- extra virgin olive oil, virgin olive oil and ordinarily olive oil, dependent to its free oleic
acid content. The limit of free oleic acid for extra virgin olive oil is 1%, virgin olive 2% and ordinary olive oil 3.3%. THe
type of unrefined olive oil with free oleic acid more than 3.3% can not be used for human consumption.
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Olive oil benefits and olive oil uses

Oxidation
Several studies have demonstrated that olive oil phenolics are powerful antioxidants, both in vitro and in vivo [4]
Recently, a study shows that olive oil phenolic extract and its active ingredient gallic acid act as powerful antioxidants
against oxidative stress and exert anti-apoptotic effects. (in HeLa cells, a model for human epithelial cells) [14]

Immunology and Inflammation
Studies have shown that olive oil modulates immune function, particularly the inflammatory processes. Its high content
of oleic acid combined with its high content of antioxidants, such as oleuropein, hydroxytyrosol, and tyrosol, contribute
to olive oilÂ’s antioxidant effects and thus its anti-inflammatory activities. [8]

Researchers discovered a chemical called oleocanthal having effects similar to that of the non-steroidal anti-
inflammatory compound in the commercial pain-killer. This discovery is important because olive oil is known to have
benefits on a variety of chronic diseases like stroke, heart disease, and breast and lung cancer. [11]

Arthritis
Oleuropein aglycone is an olive oil compound. Treatment with oleuropein aglycone starting at the onset of arthritis
ameliorated the clinical signs at days 26 to 35 and improved histological status in the joint and paw. The degree of
oxidative and nitrosative damage was also significantly reduced in oleuropein aglycone-treated mice. Plasma levels of
the proinflammatory cytokines were also significantly reduced by oleuropein aglycone. [18]

Cardiovascular diseases
Researchers found that polyphenolic compounds [especially hydroxytyrosol and oleuropein] in olive oil may contribute
to the lower incidence of coronary heart disease in the Mediterranean area. [3,4]

Phenols have been shown in laboratory studies to have antioxidant, anti-inflammatory and blood clot preventing
powers. A recent study has shown a benefit for phenol-rich olive oils on blood vessel function.

Dr. Francisco Perez Jimenez and his team at Hospital Universitario Reina Sofia in Cordoba Spain compared the effect
of consuming phenol-rich olive oil or olive oil with most of its phenol content removed in a group of 21 volunteers with
high cholesterol. They found that blood vessel response and function was improved for the first four hours after the
high-phenol olive oil meal. Blood vessels have been shown to function poorly after a high-fat meal.

They concluded that a meal containing high-phenolic virgin olive oil improves ischemic reactive hyperemia during the
postprandial state. And, this phenomenon might be mediated via reduction in oxidative stress and the increase of nitric
oxide metabolites. [12]

Cancer activities
A systematic review and a meta-analysis of 13,800 patients found olive oil consumption was associated with lower odds
of developing breast cancer and a cancer of the digestive system, compared with the lowest intake. The strength and
consistency of the findings states a hypothesis about the protective role of olive oil intake on cancer risk. [24]

Olive oil has anti-cancer activities because of its high content of antioxidants (such as hydroxytyrosol, tyrosol,
secoiridoids and lignans) and compounds deemed to be anticancer agents (such as squalene and terpenoids). [9] The
oleic acid of olive oil could sharply cut levels of a gene called Her-2/neu thought to trigger the breast cancer. Oleic acid
might also boost the effectiveness of herceptin.  [10]

Diabetes
Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in placental development and function, although
related to the pro-inflammatory environment when produced in excess. Previous studies have identified MMP-2 and
MMP-9 overactivities in the placenta from diabetic rats. Olive and safflower oil-supplemented diets were found to be
able to prevent MMPs overactivities in the placenta from diabetic rats, and that these beneficial effects are reflected in
rat sera. [13] Thus, intake of olive oil may benefits diabetic patients indirectly.

Hair
There is no study on how olive oil affects the hair growth. However, there are some shampoos, conditioners contain
olive oil.

Huntington's disease
Free radicals contribute to altered neuronal functions in neurodegenerative diseases and brain aging, by producing
lipid- and other molecule-dependent modifications. The Mediterranean diet has been associated with a reduced risk of
neurodegenerative disease. In a study of rats, extra virgin olive oil and hydroxytyrosol reduces lipid peroxidation
product levels and blocks the glutathione depletion prompted by 3-nitropropionic acid in both striatum and rest of the
brain. In addition, extra virgin olive oil blocks and reverses the effect of 3-nitropropionic acid on succinate
dehydrogenase activity. In brief, the data obtained indicate that extra virgin olive oil and HT act as a powerful brain
antioxidant.[25]

Oliver Oil Skin
Oral and/or topical administration of olive oil extracts show benefits on patients with atopic dermatitis or psoriasis, it may
be a result of alteration of the serum levels of two cytokines and HDL cholesterol in the patients.  [20]

Atopic dermatitis skin is dry and readily colonized by Staphylococcus aureus. Coconut and olive oils are traditionally
used to moisturize and treat skin infections. [19]

A double-blind controlled trial in two outpatient dermatology (skin) clinics with adult atopic dermatitis patients suggests
that virgin olive oil may be useful in the proactive treatment of atopic dermatitis colonization. [21]

Twelve infants suffering from diaper dermatitis (a skin inflammatory condition) were treated four times daily for 7 days
with a mixture containing honey, olive oil and beeswax. This topical treatment was found to be safe and well-tolerated,
and demonstrated clinical and mycological benefits in the treatment of diaper dermatitis. [22]

Skin lesions
Chronic pruritic skin lesions are among the common late complications of sulfur mustard intoxication. A study shows A.
vera/olive oil cream was at least as effective as betamethasone 0.1% in the treatment of sulfur mustard-induced chronic
skin complications and might serve as a promising therapeutic option for the alleviation of symptoms in mustard gas-
exposed patients. [17]

Most of the studies were conducted in animals. Clinical studies are needed to confirm olive oil health
benefit claims.
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Extra Virgin Olive Oil
The Mediterranean diet is associated with a lower incidence of chronic degenerative diseases and higher life
expectancy. These health benefits have been partially attributed to the dietary consumption of extra virgin olive oil by
Mediterranean populations, and more specifically the phenolic compounds naturally present in extra virgin olive oil.
Studies involving humans and animals (in vivo and in vitro) have demonstrated that olive oil phenolic compounds have
potentially beneficial biological effects resulting from their antimicrobial, antioxidant and anti-inflammatory activities. [15]

Polyphenols are potent antioxidants found in extra virgin olive oil; antioxidants have been shown to reverse age- and
disease-related learning and memory deficits. A study of mice suggests extra virgin olive oil has benefits on learning
and memory deficits found in aging and diseases, such as those related to the overproduction of amyloid-β protein, by
reversing oxidative damage in the brain, effects that are augmented with increasing concentrations of polyphenols in
extra virgin olive oil. [16]

Chronic colitis
Recent epidemiological studies have shown that habitual consumption of extra virgin olive oil (EVOO), the characteristic
culinary fat of the Mediterranean area, is effective in the prevention of diverse types of digestive disorders such as
inflammatory bowel disease. Many of these benefits are, in addition to its high proportion of oleic acid, due to the high
content of phenolic compounds. Extra virgin olive oil diets exerted a noteworthy beneficial effect in chronic DSS-induced
colitis by cytokine modulation and COX-2 and iNOS reduction via downregulation of p38 MAPK. In addition to the
beneficial effect by EVOO, supplementation of the diet with hydroxytyrosol may improve chronic colitis through iNOS
downregulation plus its antioxidant capacity. [23]
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Olive Oil Side Effect
Olive Oil side effects include skin allergy, high doses of olive oil intake may lead to side effect of diarrhea.

Olive Oil Dosages
According to DRUGS.COM, the daily olive oil dosage can be ranged from 25 mL to 40 mL and 8 g to 70 g without
reported side effects. Olive oil at dosages of 30 mL is usually used as a laxative.
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BIOAVAILABILITY OF OLIVE OIL PHENOLS
Bioavailability studies in humans show that the absorption of olive oil phenols is about or larger than 55-66% [7]
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REFERENCES
[1] Sanders TA Olive oil and the Mediterranean diet. Int J Vitam Nutr Res. 2001 May;71(3):179-84. [2] Alarcon de la Lastra C et al,
Mediterranean diet and health: biological importance of olive oil. Curr Pharm Des. 2001 Jul;7(10):933-50. [3] Visioli F et al, The
effect of minor constituents of olive oil on cardiovascular disease: new findings. Nutr Rev. 1998 May;56(5 Pt 1):142-7. [4] Visioli F et
al Antiatherogenic components of olive oil. Curr Atheroscler Rep. 2001 Jan;3(1):64-7. [5] Owen RW et al, Olive-oil consumption and
health: the possible role of antioxidants. Lancet Oncol. 2000 Oct;1:107-12. [6] Stark AH et al, Olive oil as a functional food:
epidemiology and nutritional approaches. Nutr Rev. 2002 Jun;60(6):170-6. [7] Vissers MN et al Bioavailability and antioxidant effects
of olive oil phenols in humans: a review. Eur J Clin Nutr. 2004 Jun;58(6):955-65.  [8] Wahle KW et al Olive oil and modulation of cell
signaling in disease prevention. Lipids. 2004 Dec;39(12):1223-31. [9] Owen RW Olives and olive oil in cancer prevention. Eur J
Cancer Prev. 2004 Aug;13(4):319-26. [10] Olive oil acid 'cuts cancer risk'  BBC Online Publication 2005/01/10. [11] Beauchamp, G.
Nature, Sept. 1, 2005; vol 437: pp 45-46. News release, Monell Chemical Senses Center, University of Pennsylvania. [12] Phenolic
content of virgin olive oil improves ischemic reactive hyperemia in hypercholesterolemic patients. J Am Coll Cardiol. 2005 Nov 15;46
(10):1864-8. Epub 2005 Oct 24 [13] Martinez N et al, Dietary treatments enriched in olive and safflower oils regulate seric and
placental matrix metalloproteinases in maternal diabetes. Placenta. 2011 Nov 16. [14] Erol-Dayi O et al, Protective effects of olive oil
phenolics and gallic acid on hydrogen peroxide-induced apoptosis. Eur J Nutr. 2011 Nov 16 [15] Cicerale S et al Antimicrobial,
antioxidant and anti-inflammatory phenolic activities in extra virgin olive oil. Curr Opin Biotechnol. 2011 Oct 13 [16] Farr SA, et al,
Extra Virgin Olive Oil Improves Learning and Memory in SAMP8 Mice. J Alzheimers Dis. 2011 Sep 28. [17] Panahi Y, et al, Efficacy of
Aloe vera/olive oil cream versus betamethasone cream for chronic skin lesions following sulfur mustard exposure: a randomized
double-blind clinical trial. Cutan Ocul Toxicol. 2011 Oct 12. [18] Impellizzeri D, et al, Oleuropein Aglycone, an Olive Oil Compound,
Ameliorates Development of Arthritis Caused by Injection of Collagen Type II in Mice. J Pharmacol Exp Ther. 2011 Dec;339(3):859-
69. [19]
Dermatitis. 2008 Nov-Dec;19(6):308-15. [20] Actas Dermosifiliogr. 2010 Sep;101(7):585-99.] [21]Dermatitis.
2008 Nov-Dec;19(6):308-15.] [22] Clin Microbiol Infect. 2005 Feb;11(2):160-3.] [23] Sánchez-Fidalgo S, et al, Influence
of extra virgin olive oil diet enriched with hydroxytyrosol in a chronic DSS colitis model. Eur J Nutr. 2011 Aug 27. [24]
Psaltopoulou T, et al, Olive oil intake is inversely related to cancer prevalence: a systematic review and a meta-analysis
of 13,800 patients and 23,340 controls in 19 observational studies. Lipids Health Dis. 2011 Jul 30;10:127. [25]Tasset I,
et al, Olive oil reduces oxidative damage in a 3-nitropropionic acid-induced Huntington's disease-like rat model. Nutr
Neurosci. 2011 May;14(3):106-11.
Different people may experience different side effects and benefits of olive oil. You are encouraged to report
adverse side effects to FDA, its website is
www.fda.gov., or report the adverse side effects to the manufacturer, you
should be able to find the contact information on the label.

There are always new information. Please, send me an email (
zhion@zhion.com) to correct my mistake(s).
Reasonable care has been taken in preparing this document and the information provided herein is believed to be
accurate. The information is not intended to be a substitute for professional medical advice. It is important to seek
the advice of a physician about any medical condition or symptom or the benefits and side effects of olive oil. Finally,
please, do not transfer the article to other website. Thank you. ALL RIGHTS RESERVED.