Rocket

Why it matters

When people talk about nitrate-rich foods, they usually mean beetroot. Yet rocket often contains even more nitrate than beetroot, weight for weight. It is so consistently high that UK and EU food law set a separate maximum nitrate level for rocket, higher than the one for lettuce.

That sounds alarming but is the reverse. Nitrate from vegetables is the raw material your body uses to make nitric oxide, which helps blood vessels relax.

What's inside

The standout is dietary nitrate. Rocket also provides vitamin K, folate, calcium, vitamin C and beta-carotene, for very few calories.

Rocket belongs to the same plant family as broccoli, cabbage and watercress, so it also contains glucosinolates, the compounds behind that peppery taste.

For men

Bacteria on your tongue convert nitrate to nitrite, and your body converts nitrite to nitric oxide. Nitric oxide widens blood vessels, which is the same pathway that matters for erections, although erectile dysfunction medicines act further along it and far more powerfully.

Diets rich in nitrate vegetables have reasonable evidence for modest falls in blood pressure. Whether they improve erections is plausible but not proven. What is clear is that healthy blood vessels underpin both. See low testosterone and erectile dysfunction.

Nitrate has also been studied for exercise performance, mostly as concentrated beetroot juice, with mixed but sometimes positive results.

For women

Blood pressure tends to rise after menopause, and heart disease becomes one of the leading causes of death for women. A daily handful of nitrate-rich leaves is a simple, food-first habit that fits that stage of life. See menopause and heart health.

Rocket also adds calcium and vitamin K, both involved in bone health, and folate, which matters for anyone planning a pregnancy, alongside the recommended supplement.

How to eat it

Raw is best: as a bed for steak or fish, tossed through warm grains, or piled onto pizza after it comes out of the oven. Try the steak, rocket and Parmesan salad or the halloumi, lentil and roasted vegetable salad.

It wilts quickly, so add it at the last moment and use bagged rocket within a day or two of opening.

Worth knowing

Antibacterial mouthwash kills the tongue bacteria that start the nitrate to nitric oxide conversion, and studies show it blunts the effect. Something to bear in mind if you use it several times a day.

Warfarin. Rocket is high in vitamin K, so if you take warfarin, keep your intake consistent rather than suddenly eating much more or less, and speak to your pharmacist.

Nitrate from vegetables comes packaged with vitamin C and polyphenols that limit the formation of harmful nitrosamines, which is one reason it behaves differently from the nitrites added to processed meat. Eating leafy vegetables is linked with better health, not worse.

Bottom line

Rocket is one of the most nitrate-rich foods you can buy, so a daily handful is a cheap, peppery way to support healthy blood flow; eat it raw and skip the mouthwash chaser.

Related reading: Can low testosterone cause erectile dysfunction?, what foods increase testosterone? and the best diet for menopause. Browse the full food library.