Posted by Dr Michelle Wright
Welcome to your weekly check-in with the doctor on Health Matters – Dr Michelle Wright with you as usual – today, asparagus is on the menu.
We’re coming to the end of asparagus season here in Switzerland, but we had it for dinner last night and it stimulated the conversation I often have with family or friends – can you tell when you’ve eaten it?
Why does asparagus make your urine smell odd?
Ever noticed that you eat asparagus, and maybe an hour later, your urine smells odd. Kind of sulphuric – a bit like overcooked cabbage. What’s going on?
Well, asparagus contains a compound called asparagusic acid, which is broken down into sulphur-containing byproducts during digestion.
These byproducts are volatile – meaning they evaporate easily – and they exit the body through urine, becoming volatile when you pee, and releasing that distinct odour.
Can everyone smell it?
But here’s the twist: not everyone can smell it.
Scientists used to think that only some people produced these sulphur compounds – but newer studies suggest that most people produce the compounds, yet only between 25-50% of people actually carry the gene that allows them to detect the smell. So, it turns out, this is a case of genetic variability – not in how your body processes asparagus, but in how your nose perceives the outcome.
What makes asparagus so good for you?
But beyond this ‘smell it or not’ biology, asparagus is a fascinating vegetable with some unique effects on the human body.
Firstly, it’s incredibly nutrient-dense. Just one cup of cooked asparagus gives you nearly 70% of your daily vitamin K (needed for blood clotting), over 100% of your folate needs, and it’s also rich in antioxidants like vitamin E and glutathione.
What are antioxidants, and why do they matter?
Antioxidants are chemicals that are thought to help prevent, or slow down, cell damage in the body. They help to neutralise other chemicals called free radicals that can attack cells. Free radical damage has been linked with various diseases including heart disease, stroke, diabetes, Alzheimer’s disease and cancers.
What else can asparagus do for your health?
The other good news is that it’s low in calories, high in fibre, and so supports a healthy digestion. It even has a decent amount of protein for a veggie.
Just coming back to folate because that’s particularly important. Folate is essential for DNA synthesis and repair – so it’s vital during periods of rapid growth, like pregnancy. In fact, I always recommend folate-rich foods like asparagus to expectant mothers.
Asparagus is also a natural diuretic, which means it encourages the body to excrete excess salt and fluid – good news if you’re managing high blood pressure or bloating. However, if you’re on certain medications like lithium or diuretics, just be mindful – too much asparagus might amplify those effects.
It also contains prebiotics – these are substances that feed the good bacteria in your gut, helping with everything from digestion to immune function – so asparagus is often praised in gut health circles.
And a final health note: asparagus is high in purines, which break down into uric acid. If you have a history of gout, you don’t necessarily need to avoid asparagus, but moderation is key. As always, speak with your healthcare provider about your individual situation.
So, to sum it up – next time you see those green stalks at the market or in the supermarket, don’t pass them by. They’re a nutritional powerhouse with some curious side effects.
