Green asparagus

Grows above ground, so it stays green – spicier and nuttier than white. Peel the bottom third at most, then fry, grill or roast. German season: April–June.

What is green asparagus? The greener sibling

Every late spring, restaurants across Europe celebrate white asparagus season almost like a cult – often thick spears cooked until soft. Plenty of biohackers and nutrition doctors find white asparagus watery and less interesting by comparison. Their favourite is green asparagus (Asparagus officinalis). The only real difference is how it’s grown: white asparagus is deliberately grown under tall mounds of dark soil, away from sunlight, to keep it pale. Green asparagus pushes right up out of the ground into full sunlight and fills its cells with chlorophyll and polyphenols – the plant’s own sunscreen. It tastes nuttier, crunchier and more savoury.

The macros: almost no fat, plenty of folate

Green asparagus has very few calories (a little over 20 kcal per 100g), but it comes with a solid range of vitamins:

• Folate (vitamin B9): Just five large cooked spears cover more than 60 % of your daily folate needs. Folate matters especially in pregnancy, because low folate levels are linked to neural tube defects in the baby.
• Vitamin K1: Your body needs it for normal blood clotting. Green asparagus almost matches dark green broccoli here.
• Inulin: Like artichokes, the spears contain inulin fibre, which reaches the large intestine undigested and is fermented there by bifidobacteria.

What researchers look at: glutathione

Glutathione in green asparagus

Glutathione is a molecule your body makes itself – it’s often called the ‘master antioxidant’. It plays a central role in how cells deal with oxidative stress and in how the liver processes substances such as mercury. Glutathione taken as a supplement is often unstable in stomach acid. Green asparagus is known for containing comparatively large amounts of free glutathione that holds up well to heat. Whether eating it raises glutathione levels in your cells hasn’t been shown.

Asparagine and the kidneys

Asparagus lends its name to the amino acid asparagine, and it contains large amounts of it. Asparagus has a long reputation as a diuretic – something that makes you pass more urine – and asparagine is often named as the reason. Claims that it drains fluid from swollen feet or clears uric acid out of your muscles go beyond what has been shown. If you have swollen feet or ankles, talk to your GP.

Important: how to cook it (the griddle trick)

Never boil this pricey green veg in a huge pan of salted water like white asparagus: water-soluble folate and other B vitamins leach into the water and go down the drain. The better way: just snap off the dry, woody last 2 cm of each spear with your fingers – no peeling needed. Lay the raw spears side by side in a smoking-hot cast-iron griddle pan. Sear them uncovered for 6-8 minutes, turning, until browned in places but still crisp and green. When serving, finish with a drizzle of cold olive oil and a pinch of chilli flakes.