Olive oil is good for you—in more ways than one

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Olive oil is a key component of the Mediterranean diet and is considered by many to be a natural health-food product. Until recently, the known protective effects of olive oil against oxidative stress-associated diseases, such as cardiovascular, cancer, or neurodegenerative diseases, had been attributed to its high monounsaturated fat content.

29 aug 2013--The EU-funded project EUROLIVE ('The effect of olive oil consumption on oxidative damage in European populations') investigated whether there might be other chemical factors contributing to the documented beneficial health effects of olive oil.

In particular, project partners, led by researchers at the Mar Institute of Medical Research in Barcelona, wanted to know if olive oil rich in phenolic compounds, such as virgin olive oil, would have particular health benefits beyond those already established for olive oil in general.

The researchers did six clinical trials in which 200 healthy volunteers were given 25 millilitres per day of three similar olive oils for three weeks. The olive oils had different polyphenol content. The dose was similar to the amount typically ingested daily in Mediterranean countries.

The results showed that the higher the polyphenolic content of the olive oil consumed, the higher the increase in HDL cholesterol levels (so-called good cholesterol).

Positive effects were also recorded for the atherogenic index - the total cholesterol/HDL cholesterol, and the oxidative damage of lipids decreased in a linear manner with olive oil polyphenolic content. Lipid oxidation is considered a high risk factor for the development of coronary heart disease.

Finally, the results of the EUROLIVE project demonstrated that consuming 25 millilitres of olive oil per day, in place of other fats, did not lead to participants gaining weight.

For many, these results put an end to the debate over the antioxidant properties of olive oil polyphenols when consumed, and confirm the added value of virgin olive oil as opposed to other oils in protecting against cardiovascular disease and other risk factors.

EUROLIVE received EUR 1.9 million in EU funding. The researchers completed their work in December 2004.

More information: cordis.europa.eu/projects/rcn/64505_en.html

Provided by CORDIS

Food fried in olive or sunflower oil is not linked to heart disease

Eating food fried in olive or sunflower oil is not linked to heart disease or premature death, finds a paper published in the British Medical Journal today.

29 jan 2012--The authors stress, however, that their study took place in Spain, a Mediterranean country where olive or sunflower oil is used for frying and their results would probably not be the same in another country where solid and re-used oils were used for frying.

In Western countries, frying is one of the most common methods of cooking. When food is fried it becomes more calorific because the food absorbs the fat of the oils.

While eating lots of fried food can increase some heart disease risk factors such as high blood pressure, high cholesterol and obesity, a link between fried food and heart disease has not been fully investigated.

So the authors, led by Professor Pilar Guallar-Castillón from Autonomous University of Madrid, surveyed the cooking methods of 40,757 adults aged 29 to 69 over an 11-year period. None of the participants had heart disease when the study began.

Trained interviewers asked participants about their diet and cooking methods. Fried food was defined as food for which frying was the only cooking method used. Questions were also asked about whether food was fried, battered, crumbed or sautéed.

The participants' diet was divided into ranges of fried food consumption, the first quartile related to the lowest amount of fried food consumed and the fourth indicated the highest amount.

During the follow-up there were 606 events linked to heart disease and 1,134 deaths.

The authors conclude: "In a Mediterranean country where olive and sunflower oils are the most commonly used fats for frying, and where large amounts of fried foods are consumed both at and away from home, no association was observed between fried food consumption and the risk of coronary heart disease or death."

In an accompanying editorial, Professor Michael Leitzmann from the University of Regensburg in Germany, says the study explodes the myth that "frying food is generally bad for the heart" but stresses that this "does not mean that frequent meals of fish and chips will have no health consequences." He adds that specific aspects of frying food are relevant, such as the type of oil used.

Provided by British Medical Journal

Oleocanthal may help prevent, treat Alzheimer's

Natural compound in extra-virgin olive oil targets toxic beta-amyloid proteins

PHILADELPHIA, 30 sept 2009-- Oleocanthal, a naturally-occurring compound found in extra-virgin olive oil, alters the structure of neurotoxic proteins believed to contribute to the debilitating effects of Alzheimer's disease. This structural change impedes the proteins' ability to damage brain nerve cells.

"The findings may help identify effective preventative measures and lead to improved therapeutics in the fight against Alzheimer's disease," said study co-leader Paul A.S. Breslin, PhD, a sensory psychobiologist at the Monell Center.

Known as ADDLs, these highly toxic proteins bind within the neural synapses of the brains of Alzheimer's patients and are believed to directly disrupt nerve cell function, eventually leading to memory loss, cell death, and global disruption of brain function. Synapses are specialized junctions that allow one nerve cell to send information another.

"Binding of ADDLs to nerve cell synapses is thought to be a crucial first step in the initiation of Alzheimer's disease. Oleocanthal alters ADDL structure in a way that deters their binding to synapses," said William L. Klein, PhD, who co-led the research with Breslin. "Translational studies are needed to link these laboratory findings to clinical interventions." Klein is Professor of Neurobiology & Physiology, and a member of the Cognitive Neurology and Alzheimer's Disease Center, at Northwestern University.

Klein and his colleagues identified ADDLs in 1998, leading to a major shift in thinking about the causes, progression and treatment of Alzheimer's disease. Also known as beta-amyloid oligomers, ADDLs are structurally different from the amyloid plaques that accumulate in brains of Alzheimer's patients.

Reporting on a series of in vitro studies, the team of Monell and Northwestern researchers found that incubation with oleocanthal changed the structure of ADDLs by increasing the protein's size.

Knowing that oleocanthal changed ADDL size, the researchers next examined whether oleocanthal affected the ability of ADDLs to bind to synapses of cultured hippocampal neurons. The hippocampus, a part of the brain intimately involved in learning and memory, is one of the first areas affected by Alzheimer's disease.

Measuring ADDL binding with and without oleocanthal, they discovered that small amounts of oleocanthal effectively reduced binding of ADDLs to hippocampal synapses. Additional studies revealed that oleocanthal can protect synapses from structural damage caused by ADDLs.

An unexpected finding was that oleocanthal makes ADDLs into stronger targets for antibodies. This action establishes an opportunity for creating more effective immunotherapy treatments, which use antibodies to bind to and attack ADDLs.

Breslin commented on the implications of the findings. "If antibody treatment of Alzheimer's is enhanced by oleocanthal, the collective anti-toxic and immunological effects of this compound may lead to a successful treatment for an incurable disease. Only clinical trials will tell for sure."

In earlier work at Monell, Breslin and co-workers used the sensory properties of extra virgin olive oil to identify oleocanthal based on a similar oral irritation quality to ibuprofen. Oleocanthal and ibuprofen also have similar anti-inflammatory properties, and ibuprofen – like extra virgin olive oils presumably rich in oleocanthal – is associated with a decreased risk of Alzheimer's when used regularly.

Future studies to identify more precisely how oleocanthal changes ADDL structure may increase understanding of the pharmacological actions of oleocanthal, ibuprofen, and structurally related plant compounds. Such pharmacological insights could provide discovery pathways related to disease prevention and treatment.

The findings are reported in the October 15 issue of Toxicology and Applied Pharmacology.

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First author Jason Pitt, a graduate student in Klein's lab, conducted the studies. Also contributing to the work were chemist Amos B. Smith, III, of Monell and the University of Pennsylvania, who supplied the oleocanthal; William Roth, Pascale Lacor and Pauline Velasco from Northwestern; Matthew Blankenship from Western Illinois University; and Fernanda De Felice from the Universidade Federal do Rio de Janeiro. In addition to his faculty appointment at Monell, Breslin is Professor of Nutritional Sciences in the School of Environmental and Biological Sciences at Rutgers University.

The National Institute on Aging funded the research; Dr. Breslin is funded by the National Institute on Deafness and Other Communication Disorders.