2nd Clinical Trial- NKUA: Effect of Daily Consumption of Kalamon Table Olives on the Lipidemic Profile of Patients with Hyperlipidemia

2nd clinical study Kalamon Kalamata olives cholesterol LDL HDL total lipid profile reduction NKUA

The beneficial properties of Kalamata table olives for health, mainly in the lipid profile of volunteers and in particular in the LDL/HDL cholesterol ratio as well as in the protection of the cardiovascular system, result from clinical studies and research carried out from 2014 until today, in healthy volunteers and patients, under the auspices of the Department of Pharmacy of the National and Kapodistrian University of Athens (NKUA).

For the specific studies, the Kalamata organic table olives with a high phenolic content by the Sakellaropoulos Organic Farms from Sparta were selected exclusively, among 150 different types and qualities of table olives, after their phenol content and especially hydroxytyrosol and tyrosol content was examined.

These are organically grown olives, without pasteurization, produced by the process of natural fermentation, without chemical additives or preservatives and possess superior organoleptic and quality characteristics that are confirmed by the awards they have received in the largest taste and quality competitions around the world.

The first study was conducted on healthy volunteers from 2014 to 2016 and was the first study internationally to show the beneficial effect of table olives on the lipid profile of the participants. The results were presented at the international conference of the Oleocanthal International Society, 2-3 June 2016 at the International Olympic Academy, at Olympia (read more here).

Based on the positive results of the 1st study, a 2nd study was carried out in a larger group of patients with hyperlipidemia, lasting five years, from 2017 to 2022 and entitled “The effect of daily consumption of Kalamata table olives on the lipidemic profile of patients with hyperlipidemia”. The study and its impressive results, as published in the annual edition of the World Olive Center for Health, follows:

The Effect of Daily Consumption of Kalamon Table Olives on the Lipidemic Profile of Patients with Hyperlipidemia

Christos Papanikolaou1*, Martha-Spyridoula Katsarou2*, Elias Makrodimitris2, Vassiliki Mouzioura2, Stamatina Kontokosta2, Annia Tsolakou1, Eleni Melliou1, Dimitrios Konstantinidis3, Vassiliki Liggounou4, Konstantinos Liaskonis4, Prokopios Magiatis1 and Nikolaos Drakoulis2

1Laboratory of Pharmacognosy and Natural Products Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens
2Laboratory of Pharmacogenomics, Department of Pharmacy, National and Kapodistrian University of Athens
3Hypertensive Unit, 1st Cardiology Department, Hippocration Hospital, Athens
4 Biopathology Laboratory, 401 General Military Hospital, Athens

Cardiovascular diseases are the leading cause of death worldwide and coronary heart disease, accounts for 2/3 of deaths from heart disease. Risk factors for cardiovascular disease are divided into three major categories: environmental factors, metabolic factors and the social-economic factors. The metabolic risk factors include hypertension, diabetes, hyperlipidemia, and obesity. This set of risk factors is characterized as metabolic syndrome, according to the World Health Organization.

The Mediterranean diet is rich in natural antioxidants, vitamins and monounsaturated fats, and the main source of fat is extra virgin olive oil. The extra virgin olive oil (EVOO) has a central position in the Mediterranean diet, as it has been shown that its consumption has a health protective role. This effect has been correlated with ingredients contained in extra virgin olive oil, which are active phenolic compounds, which have attracted the attention of researchers, as responsible for the low mortality and morbidity from cardiovascular diseases.

Phenols are not only found in EVOO but are also contained in table olives. The table olive is defined as "the healthy fruit of certain varieties of the cultivated olive tree which is harvested at the appropriate stage of maturity". World production of table olives amounts to 1.4 million tons, of which, approximately 80% is produced in the Mediterranean and the Middle East. In addition to lipid ingredients, the composition of table olive fruits is characterized by a number of phenolic compounds, which are not present in any other edible fruit, and which have been correlated with the beneficial role on health. Among other phenolic compounds, hydroxytyrosol-4-O-glucoside, hydroxytyrosol, chlorogenic acid, rutin, verbascocide, luteolin-7-O-glycoside, coumaric acid, oleuropein, aglycon of oleuropein and aglycon of ligstroside are ingredients included in table olives.

In the current study we initially performed a screening of 150 different types and qualities of table olives found in the Greek market concerning their phenolic content and especially the hydroxytyrosol and tyrosol content. After selecting the appropriate type of table olives we performed a clinical trial regarding the effect of daily consumption of high-phenolic table olives on the Lipidemic Profile of Patients with Hyperlipidemia.

Study Design and Procedure

Inclusion/exclusion criteria for the study are the following:
 1. Patients with total cholesterol levels 200-290.
 2. Ages 18-75.
 3. Patients with LDL more than 140.
 4. Patients that agreed on results publications of their biochemical markers.
 5. Patients that comply with the study protocol.
 6. Patients that do not receive statins.

At the initial clinical visit at the Hypertensive Unit (1st Cardiology Department, Hippocration Hospital and Biopathology Laboratory, 401 General Military Hospital, Athens), a cardiologist interviewed and all participants and ordered specific laboratory tests. Following participants’ eligibility, according to the inclusion and exclusion criteria, all patients were informed about the study aim. The study objectives were explained and patients provided informed consent for their participation in the study. Figure 1 illustrates the study design as well as the evaluation methods.

2nd clinical study Kalamon Kalamata olives cholesterol LDL HDL total lipid profile reduction NKUA


Table olives selection

The average values of hydroxytyrosol and tyrosol in commercial olive samples that were included in this study, from harvest period 2017-2018, until harvest period 2021-2022 were 800 and 420 μg/g respectively.

The finally selected type of olives for the clinical trial was the Valsamikes Kalamata olives (Sakellaropoulos Organic Farms, Sparta) which contained hydroxytyrosol 1300 μg/g and tyrosol 560 μg/g. Daily consumption of 5 olives afforded 25 mg of hydroxytyrosol and 10 mg tyrosol.

Clinical trial

A total of 94 patients participated in the study. From those, 23 patients did not complete the study or did not fulfill the inclusion criteria. In total, 71 patients completed the study. The mean age was 54 years (± 8 years). Women participats were 63%. Mean age of female was 60 years and of male was 49 years.

Statistically significant results were found at cholesterol and LDL levels of the 71 patients (p<0.05), while no significant change observed at HDL and TG levels. Cholesterol showed a profound 9.01 units decrease, and LDL levels showed 10.98 units decrease after 30 days of olive consumption. Cholesterol average levels before olives consumption were 238.51 mg/dL and after 30 days were 229.49 mg/dL. At day 0, the female population of the study had a cholesterol average of 240.29 mg/dL, and after 30 days the cholesterol average showed a significant decrease of 8.85 units (231.44 mg/dL), (p<0.05). Men had cholesterol levels, at day 0, 235.42 mg/dL and at day 30 they had 226.12 mg/dL, which is 9.32 units average decrease (p<0.05). LDL levels showed also statistical significance results after analysis of data (p<0.05). Average LDL levels of patients were 158.20 mg/dL at baseline, and after 30 days of olive consumption the average levels were 147.82 mg/dL. This means that daily olive consumption lead LDL levels to an average decrease of 10.38 units within 30 days (p<0.05). The average female participant LDL levels at baseline were 159.00 mg/dL and after 30 days of olive consumption it was 149.27 mg/dL, showing an average decrease of 9.73 units (p<0.05). The average LDL level the male participants was 156.81 mg/dL at baseline and after 30 days it showed an average 11.50 units decrease (145.31 mg/dL) (p<0.05). HDL and TGs levels between day 0 and day 30 showed no statistically important changes within the participant group.

Other biochemical analyses, including Glucose, CPK, K, Na, Ca, ALP, γGT Urea and Uric Acid showed no statistically significant changes. Further, hepatic enzymes SGOT and SGTP showed no statistically significant changes throughout the trial as well, indicating absence of any toxic effects. No adverse effects were observed throughout the study. Thirty days after patients refrained of olive consumption (day 90) no statistically significant changes of any biochemical analysis was observed, indicating prolonged olive consumption effects.


Daily consumption of Kalamata type olives may favorably affect the lipidemic profile and probably contribute to reduce cardiovascular risk. The positive effect on lipidemic profile achieved without any further contribution on behalf of patients.

It is necessary to perform future randomized studies with larger sample size and more biomarkers to obtain stronger evidence on the role of table olives on hyperlipidemia. Our next steps are to continue with more participants and for a longer duration to see if these results remain or will be even better, but also to use more biological markers for better follow up.