The entire selling point of smoothies is that you can throw together a number of vegetables, herbs and fruits for a quick-and-easy meal that packs extra nutrients into your daily diet.

But before blending everything together, think twice, the German Consumer Advice Centre says. Rhubarb and elderberry, for example, must be heated before they are suitable for consumption.

Other ingredients might be hard to digest, meaning that you’ll end up with a stomach ache.

Another concern: high levels of nitrates in leafy greens such as spinach, field greens and rocket. To avoid going overboard with these greens, the centre advises leaving the stalks, ribs and outer leaves out of your smoothies.

Otherwise, all the vegetables and herbs you usually eat raw or uncooked, such as parsley, chervil, dill, radish leaves, celery and sorrel, are great to add into a smoothie.

However, if you’re thinking of using wild herbs in your smoothie, the centre advises using only those collected with a plant expert. This reduces the risk of accidentally picking and using a toxic species. – dpa