Have you had your BLT today? Part 2: Lettuce

Functional Food

By Janet Colston, PhD

Bell pepper, Leafy greens and Tomato

These are the most common salad items added to our weekly shopping basket and they supplement our food plates adding nutrients to our diets. We want to delve deeper into their additional phytonutrients, this week we discuss healthy leafy greens.

Leafy Greens

Traditionally we think about leafy greens being the lettuce common in our supermarkets, but there is a very wide range of leafy greens, all vying for unique taste, crunch and flavour. 

Microgreens are all the rage but what exactly are they? Generally they are the young seedlings of their more mature parents and are harvested within weeks rather than months making them much more accessible and easy to grow. They are packed full of vitamins and research suggests they contain more antioxidants than mature plants [1]. In a 2011 study, almost all of the microgreens tested had four to six times more ascorbic acid (vitamin C), tocopherols (vitamin E), phylloquinone (vitamin K), and beta-carotene (Vitamin A precursor)  than the mature leaves of the same plant [2]. 

Some leafy greens like spinach and arugula are very high in vitamin K and this can be a problem for people on blood thinners or those prone to kidney stones who may want to avoid large quantities [3].

Some of the most interesting scientific research looking at phytochemical properties in leafy greens has been done by The Watercress Company examining the potential benefits of watercress to human health. Their studies show significant anti-cancer, anti-inflammatory and cardiovascular protective effects in people that consume Watercress daily [4]. More research is underway by The Watercress Research Company examining the biochemical mechanism of urease, an enzyme found in Watercress implicated in a range of pathological states in humans [5].

Cultivating leafy vegetables in a plant factory can help people suffering from very specific conditions. For instance, spinach can be cultivated with a low potassium content to help patients undergoing dialysis [6]. Environmental factors influence the growth of plant metabolites and manipulating these can help elucidate the perfect consistency of medicinal components. The quality and biomass of these plants can also be controlled using light intensity and spectrum. Varying the ratio of red to blue light can increase anthocyanin and ascorbic acid content in lettuce [6]. 

Growing Leafy Greens

Most of the world’s Vertical Farms grow leafy greens of one type or another. Most greens are easy to grow and optimized techniques using CEA have aided large scale commercialization in America’s largest facilities including Aerofarms, Plenty, Square Roots and Bowery. Hort Americas has a useful resource to help beginners grow microgreens and a master class on controlled environment technology can help beginners successfully grow micro herbs.  Hort Americas also recommends Farmer Tyler’s comprehensive road map on growing leafy greens.

Remember!
The CDC recommends the following measures in regard to COVID-19.
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Disclaimer: We are not doctors and do not prescribe this blog as a medicinal alternative to bona fide medical advice should you contract seasonal flu or Coronavirus.


Janet Colston PhD is pharmacologist with an interest in growing ‘functional’ foods that have additional phytonutrients and display medicinal qualities that are beneficial to human health. She grows these using a range of techniques including plant tissue micropropagation and controlled environmental agriculture to ensure the highest quality control.

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