🌱 This winter, I sowed rocket seeds which developed into eight healthy plants, yielding a substantial crop within three months! Set amongst lettuces and spinach, in a semi-shaded spot given rocket’s preferences for cool fertile soil, I wasn’t sure if the plants would receive enough sunlight but the plants have since flowered and completed their natural cycle. The appearance of flowers typically signifies the end of a productive crop. By successive planting you can get a year-round crop as it can tolerate brief freezing spells. Needless to say, with my current commitments (encompassing full-time employment and academic study), I haven’t been too diligent in that respect; consequently, I am rather hoping that they self-seed instead!

🌱 Eruca vesicaria, commonly known as rocket or arugula, is now a common edible salad leaf. Native to the mediterranean region, it has a pungent, pepper-mustard-like flavour. A fast growing annual reaching 50cm in height, having pinnately shaped leaves with 4-10 lobes. A member of the Brassicaceae (Cruciferous) family, that of Brussels sprouts, kale, cauliflower, broccoli, it has a typical four-petalled flower which are also edible and look lovely in salads.

🌱 Notable nutrient values for rocket are displayed in the infographic above. The highest value is vitamin K, a fat-soluble family of vitamins. Composed of K1 (phylloquinone) and K2 (menaquinones). K1 is mainly found in green leafy foods. K2 members (derivatives with varying isoprenoid chemical groups, designated as MK2 through to MK13, the number referring to the amount of chains) are found in foods such as poultry and eggs or made by bacteria, with high amounts in natto (fermented soybeans).

🌱 The absorption rate of vitamin K from food is low at around 5-20%. The UK has an Adequate Intake (AI) set to 1 mcg per kg of body weight while some countries still use RDAs of 90mcg for women and 120 mcg for men. The body can only store small amounts which become rapidly depleted without regular dietary intake. It makes sense that our body has developed an efficient way to recycle vitamin K in the aptly named Vitamin K Cycle, otherwise our AI would be much higher.

🌱 Kale fits the number one spot with around 330mcg of vitamin K per cup (30g). To actually absorb 90mcg, we would need to be eating closer to two cups. While rocket, spinach, chard, and collard greens contain less vitamin K, enjoying some fermented foods and eating a varied diet can help you to reach your recommended 1mcg per kg of BW each day. Vitamin K is fat-soluble and therefore combining it with oily foods can increase absorption. Olive oil on your rocket salad, anyone? Why not check out this week's recipe for rocket salad with oily fish with fennel, orange, and mustard with an olive oil dressing?

The Vitamin K Cycle and Blood Clotting

🌱 Perhaps best known in relation to blood clotting, as many people on warfarin are told to reduce their green leafy veggies because K1 can be antagonistic to the drug's effect by activating blood clotting proteins. If you cut yourself and a scab forms, you can thank vitamin K...

🌱 Vitamin K is efficiently recycled in the body through the aptly named vitamin K cycle. We absorb vitamin K from food in its inactive form, called quinone. The inactive quinone is activated by gaining electrons (a process called reduction) to become hydroquinone thanks to the enzyme Vitamin K Epoxide Reductase (VKOR). The hydroquinone can then work with gamma-glutamyl carboxylase (GGCX) as its cofactor to activate coagulation proteins (Factor II, VII, IX, X). During this activation process, the hydroquinone loses electrons (a process called oxidation) and which is recycled back to quinone, ensuring efficient recycling of vitamin K. GGCX binds to glutamic acid residues which are found on the coagulation proteins. The addition of an extra acid group turns the glutamic acid proteins into gammacarboxy-glutamic acid, which we can thankfully refer to as Gla proteins! These Gla proteins bind to calcium ions, which help localise clotting factors to the site of injury. Calcium and vitamin K is also involved in bone formation, but more on that another time!