The Mediterranean Diet – More Than Just a Sum of its Parts

A new study has uncovered a synergistic, blood pressure-lowering effect between certain vegetables and olive oil, which are essential components of the Mediterranean way of eating. Not only should this help olive oil sales recover after a fraught period of recessionary pressure, but it could also boost the health and wellness standing of lettuce, one of the most unappreciated vegetables, long belittled as a mere “bulking agent”.

It’s all About Team Work, Even for Nutrients

The Mediterranean diet, although highly varied across the extent of the geographical region where it is consumed, is generally based on abundant quantities of fruits, vegetables, whole grains, pulses and olive oil, supplemented by plenty of fish, seafood, nuts and seeds.

But what is it, exactly, about the Mediterranean diet that makes it so healthy? This question has been asked for well over 60 years, ever since Ancel Keys’ seminal study on the island of Crete first established a tangible link between the Mediterranean way of eating and a strikingly low incidence of heart disease.

Over the years, a raft of studies have centred on isolating supposedly health-promoting components, such as specific fatty acids and polyphenols, although there has always been a sense that the sum of the Mediterranean diet was much greater than its constituent parts.

Despite this common sense recognition, comparatively little research has so far been carried out on how the different components of the Mediterranean diet may interact with each other to produce a number of positive health outcomes that just cannot seem to be achieved by consuming nutrients in isolation, for example via dietary supplements.

In May 2014, an intriguing piece of research appeared in a journal published by the Proceedings of the National Academy of Sciences (PNAS). The paper shed some light on how two groups of food ubiquitous in the Mediterranean diet work together to lower blood pressure, namely nitrite and nitrate-rich vegetables and olive oil.

Researchers from King’s College London and the University of California found that olive oil’s unsaturated fatty acids reacted with vegetables’ nitrogen compounds, forming nitro fatty acids, which, through their interaction with an enzyme produced by the body, resulted in lowering blood pressure. Although the study was carried out on mice, the researchers are confident that the human body features the same enzymatic pathways and hence that their conclusions are transferrable to the human cardiovascular health realm.

Switch to Olive Oil Not a Fad

Although the precise mechanisms are still in the process of being deciphered, the recognition that olive oil plays a major role in the longevity of Mediterranean people has elevated it to the most desirable of culinary oils globally, even in regions where it was virtually unknown only a few decades ago. Our data show that in India, for example, retail volume consumption tripled over the 2008-2013 review period, reaching 6,500 tonnes in the latter year, while Japan registered a 150% increase to 30,300 tonnes.

Olive oil’s growth potential remains strong. Western European average retail per capita consumption stood at 2.4kg in 2013, Australasia’s at 1.2kg and North America’s at a mere 0.3kg, compared to Spain’s 9.8kg and Portugal’s 4.3kg.

The premium price tag, especially of extra virgin olive oil, dampened the category’s growth slightly during the early part of the review period when the grip of the global recession was at its tightest, but now sales are recovering. In 2008, global olive oil retail value sales posted a marginal decline, while in 2013 they boasted double-digit growth.

The fact that organic olive oil delivered a buoyant performance throughout the review period, driven by unrelentingly high demand in Western Europe and North America, demonstrates just how dedicated health and wellness consumers can become when it comes to what they consider to be their everyday dietary “essentials”. For many, the switch to olive oil is not a fad but a long-term commitment to health and quality-conscious eating.

Lettuce a Health Food?

Besides the expected positive impact on olive oil sales, the new research may also help to boost sales of vegetables naturally rich in nitrogen compounds. Among these are beetroot, carrots, celery, celeriac, radishes, green beans, spinach and salad greens in general, including (who’d have thought it!) the humble lettuce.

Although lettuce is generally regarded as healthy by mainstream consumers, it has always been looked down upon as the lightweight option by the more serious breed of nutritionists. Light green leaves and iceberg lettuce, in particular, barely register on the dedicated health foodist’s nutritional Richter scale, being considered “filler material” at best. Denser vegetables, such as broccoli, fennel, kale and asparagus, are much preferred as these deliver substantial quantities of vitamins, minerals and fibre.

And while standard lettuce may not be awarded the “superfoods” badge anytime soon, this new research holds at least some degree of promise to help release undervalued leafy greens from their perceived “mainly water and little substance” handicap.