3.1 Nutritional Importance of Polyphenols
47
more than 5 mg of hydroxytyrosol. The decision to approve such claim was based
on the results of such a study carried on with 200 healthy volunteers.
Eligible participants were from six locations in the EU:
(a) 32 men from Barcelona, Spain
(b) 33 men from Copenhagen, Denmark
(c) 30 men from Kuopio, Finland
(d) 31 men from Bologna, Italy
(e) 40 men from Potsdam, Germany
(f) and 34 men from Berlin, Germany.
Women were excluded from the study because estrogens are potential antioxidant
and an interference could be possible. Three samples of olive oil were used in the
study and consisted of 25 mL (22 g) samples of three olive oils. In detail, used olive
oils exhibited:
(1) A low quantity in polyphenols (2.7 mg/kg of olive oil)
(2) A medium concentration in polyphenols (164 mg/kg)
(3) And a relevant amount in polyphenols (366 mg/kg).
It is noteworthy, that the sample with a low phenolic content was produced by
refining the olive oil with a high level of polyphenols, in order to keep the same
fatty acid composition and an identic micronutrient profile (highlighting the effect
of refining steps in reducing phytonutrients in oils). The medium-range polyphenols
sample was prepared by a blend between refined olive oil and a virgin olive oil
(VOO) with high phenolic levels. Vitamin E was adjusted around 8 mg. Samples
were prepared in order to keep all the macro- and micronutrients as constant as
possible, modifying only the phenolic content.
The results of the study highlighted an independent effect of phenolic compounds
in olive oil: the increase of high-density lipoprotein (HDL) cholesterol was significantly detected. Oxidative lipid damage decreased linearly with the phenolic content
of olive oil, particularly in markers directly associated with low-density lipoprotein
(HDL) cholesterol oxidation. Authors have summarized their research by this conclusion: ‘our study shows that olive oil is more than a monounsaturated fat. The
polyphenol content of an olive oil can account for further benefits on HDL cholesterol levels and oxidative damage in addition to those from its monounsaturated fatty
acid content. Our study provides evidence to recommend the use of polyphenol-rich
olive oil, that is, virgin olive oil, as a source of fat to achieve additional benefits
against cardiovascular risk factors’ (Castañer et al. 2011).
According to the findings of the above-described EUROLIVE study, the European
Food Safety Authority (EFSA) admitted the claim, by stating: ‘On the basis of the
data presented, the Panel concludes that a cause and effect relationship has been
established between the consumption of olive oil polyphenols (…) and protection of
LDL particles from oxidative damage (…)’ (Castañer et al. 2011).
The European Commission (EC) authorized the above-mentioned labelling claim
applicable to certain types of olive oil. Besides hydroxytyrosol and derivatives (e.g.
47
more than 5 mg of hydroxytyrosol. The decision to approve such claim was based
on the results of such a study carried on with 200 healthy volunteers.
Eligible participants were from six locations in the EU:
(a) 32 men from Barcelona, Spain
(b) 33 men from Copenhagen, Denmark
(c) 30 men from Kuopio, Finland
(d) 31 men from Bologna, Italy
(e) 40 men from Potsdam, Germany
(f) and 34 men from Berlin, Germany.
Women were excluded from the study because estrogens are potential antioxidant
and an interference could be possible. Three samples of olive oil were used in the
study and consisted of 25 mL (22 g) samples of three olive oils. In detail, used olive
oils exhibited:
(1) A low quantity in polyphenols (2.7 mg/kg of olive oil)
(2) A medium concentration in polyphenols (164 mg/kg)
(3) And a relevant amount in polyphenols (366 mg/kg).
It is noteworthy, that the sample with a low phenolic content was produced by
refining the olive oil with a high level of polyphenols, in order to keep the same
fatty acid composition and an identic micronutrient profile (highlighting the effect
of refining steps in reducing phytonutrients in oils). The medium-range polyphenols
sample was prepared by a blend between refined olive oil and a virgin olive oil
(VOO) with high phenolic levels. Vitamin E was adjusted around 8 mg. Samples
were prepared in order to keep all the macro- and micronutrients as constant as
possible, modifying only the phenolic content.
The results of the study highlighted an independent effect of phenolic compounds
in olive oil: the increase of high-density lipoprotein (HDL) cholesterol was significantly detected. Oxidative lipid damage decreased linearly with the phenolic content
of olive oil, particularly in markers directly associated with low-density lipoprotein
(HDL) cholesterol oxidation. Authors have summarized their research by this conclusion: ‘our study shows that olive oil is more than a monounsaturated fat. The
polyphenol content of an olive oil can account for further benefits on HDL cholesterol levels and oxidative damage in addition to those from its monounsaturated fatty
acid content. Our study provides evidence to recommend the use of polyphenol-rich
olive oil, that is, virgin olive oil, as a source of fat to achieve additional benefits
against cardiovascular risk factors’ (Castañer et al. 2011).
According to the findings of the above-described EUROLIVE study, the European
Food Safety Authority (EFSA) admitted the claim, by stating: ‘On the basis of the
data presented, the Panel concludes that a cause and effect relationship has been
established between the consumption of olive oil polyphenols (…) and protection of
LDL particles from oxidative damage (…)’ (Castañer et al. 2011).
The European Commission (EC) authorized the above-mentioned labelling claim
applicable to certain types of olive oil. Besides hydroxytyrosol and derivatives (e.g.