Another Of The Wonderful Polyphenols Found In Our Extra Virgin Olive Oil
Updated May 23rd 2023
- Lignans are polyphenolic compounds found in plants.
- Lignan precursors are found in a wide variety of plant-based foods, including seeds, whole grains, legumes, fruit, and vegetables.
- When consumed, lignan precursors may be converted to enterolignans, enterodiol and enterolactone, by bacteria that normally colonize the human intestine.
- Enterodiol and enterolactone have weak estrogenic activity but may also exert biological effects through non-estrogenic mechanisms.
- Lignan-rich foods like extra virgin olive oil are part of a healthy diet.
- Health Benefits Of Lignans In Extra Virgin Olive Oil
- What Are Lignans?
- Lignans: A Major Polyphenol Found In Extra Virgin Olive Oil
- New Research : Polyphenols In Extra Virgin Olive Oil And Reductions In Breast Cancer Risk.
- Extra Virgin Olive Oil, Lignans & Cardiovascular Disease
Health Benefits Of Lignans In Extra Virgin Olive Oil
In recent years, the discussion on the health benefits of extra virgin olive oil has gained immense popularity. Arguably, it is the best olive oil to ingest, credited with numerous health benefits. Among the numerous components of olive oil, polyphenols have been identified as having the highest antioxidant properties.
Recent studies have shown that the polyphenol lignans can play a significant role in preventing breast cancer and providing cardiovascular protection. In particular, its ability to protect against DNA damage has attracted attention in the medical community. Incorporating extra virgin olive oil into your diet is a delicious and simple way to take advantage of these health benefits.
What Are Lignans?
Lignans are polyphenolic compounds found in plants. The enterolignans, enterodiol and enterolactone are formed by the action of intestinal bacteria on lignan precursors found in plants. Because enterodiol and enterolactone can mimic some of the effects of estrogens, their plant-derived precursors are classified as phytoestrogens.
Lignan precursors that have been identified in the human diet include pinoresinol, lariciresinol, secoisolariciresinol, matairesinol, and others. Secoisolariciresinol and matairesinol were among the first lignan precursors identified in the human diet and are therefore the most extensively studied.
Lignan precursors are found in a wide variety of foods, including flaxseeds, sesame seeds, legumes, whole grains, fruit, vegetables and olive oil. While most research on phytoestrogen-rich diets has focused on soy isoflavones, lignans are the principal source of dietary phytoestrogens in the typical Western diet.
When plant lignans are ingested, they can be metabolized by intestinal bacteria to the enterolignans, enterodiol and enterolactone, in the intestinal lumen and then absorbed into the bloodstream. Enterodiol can also be converted to enterolactone by intestinal bacteria. Thus, enterolactone levels measured in blood and urine reflect the activity of intestinal bacteria in addition to dietary intake of plant lignans.
Because data on the lignan content of foods are limited, blood and urinary enterolactone levels are sometimes used as markers of dietary lignan intake.
A pharmacokinetic study that measured plasma and urinary levels of enterodiol and enterolactone after a single dose (0.9 mg/kg of body weight) of secoisolariciresinol, (the principal lignan in flaxseed), found that at least 40% was available to the body as enterodiol and enterolactone. Plasma enterodiol concentrations peaked at 73 nanomoles/liter (nmol/L) an average of 15 hours after ingestion of secoisolariciresinol, and plasma enterolactone concentrations peaked at 56 nmol/L an average of 20 hours after ingestion. Thus, substantial amounts of ingested plant lignans are available to humans in the form of enterodiol and enterolactone.
Lignans: A Major Polyphenol Found In Extra Virgin Olive Oil
Because extra virgin olive oil is an important component of the Mediterranean diet, increasing levels of research has been carried out to determine the source of the health benefits associated with extra virgin olive oil, in particular the major antioxidant polyphenols it contains. Structural analysis includes spectroscopic techniques, including mass spectrometry and nuclear magnetic resonance (NMR) testing.
The resulting data shows that lignans (+)-1-acetoxypinoresinol and (+)-pinoresinol are major components of the polyphenols found in extra virgin olive oil. Lignans are polyphenols that accumulate in the woody tissues, seeds and roots of many plants including olives. These molecules are thought to be directly involved in the defence mechanisms of plants and now have been found to be useful for humans. Foods containing high amounts of lignan precursors have been found to be protective against breast, colon, and prostate cancer.
These lignans, which are potent antioxidants, are absent in seed oils and virtually absent in refined virgin oils. As with other polyphenols, there is considerable variation in lignan concentrations in different varieties of olive.
Source: PubMed (nih.gov)
New Research: Polyphenols In Extra Virgin Olive Oil And Reductions In Breast Cancer Risk.
Javier Menendez from the Catalan Institute of Oncology and Antonio Segura-Carretero from the University of Granada in Spain led a team of researchers who set out to investigate which parts of olive oil were most active against cancer.
Menendez said, “Our findings reveal for the first time that all the major complex phenols present in extra-virgin olive oil drastically suppress overexpression of the cancer gene HER2 in human breast cancer cells”.
Extra virgin olive oil is the oil that results from pressing olives without the use of heat or chemical treatments. It contains phytochemicals that are otherwise lost in the refining process. Menendez and colleagues separated the oil into fractions and tested these against breast cancer cells in lab experiments. All the fractions containing the major extra virgin phytochemical polyphenols (lignans and secoiridoids) were found to effectively inhibit HER2.
Although these findings provide new insights on the mechanisms by which good quality extra virgin olive oil rich in polyphenols might contribute to a lowering of breast cancer risk in a HER2-dependent manner, extreme caution must be applied when applying the lab results to the human situation. As the authors point out, “The active phytochemicals (i.e. lignans and secoiridoids) exhibited tumoricidal effects against cultured breast cancer cells at concentrations that are unlikely to be achieved in real life by consuming olive oil”.
Nevertheless, and according to the authors:
These findings, together with the fact that that humans have safely been ingesting significant amounts of lignans and secoiridoids as long as they have been consuming olives and extra-virgin oil, strongly suggest that these polyphenols might provide an excellent and safe platform for the design of new anti breast-cancer drugs”.Javier Menendez/Antonio Segura-Carretero
Extra Virgin Olive Oil, Lignans & Cardiovascular Disease
Diets rich in foods containing plant lignans such as whole grains, nuts and seeds, legumes, and fruit and vegetables have been consistently associated with reductions in risk of cardiovascular disease. However, it is likely that numerous nutrients and phytochemicals found in these foods contribute to their cardioprotection.
A large prospective cohort study conducted within Spain’s PREDIMED trial – a trial evaluating the effects of a Mediterranean diet on cardiovascular disease outcomes followed 7,172 older adults at high risk of cardiovascular disease for a mean of 4.3 years. In this study, the highest quintile of dietary lignan intake (mean intake, 0.94 mg/day), measured by a food frequency questionnaire at baseline, was associated with a 49% lower risk of incident cardiovascular disease compared to the lowest quintile (mean intake, 0.44 mg/day of lignans). The primary dietary source of lignans in this cohort was extra virgin olive oil, which itself is known to be cardioprotective.
This continues our series of articles about the polyphenol content of our new harvest extra virgin olive oil and what they can do to improve our health. As we have reported, this year’s harvest has produced a low acidity level of 0.2% together with the highest level of polyphenols yet seen in our extra virgin olive oil of 644 mg/kg