The key, as that vitamin D study suggests, is how you take your vitamins. You want to make sure that they’re as bioavailable and open to absorption as possible. Some vitamins, for example, are best taken with meals.

Supplements to eat with meals

Fat-soluble vitamins like A, D, E and K require fat for your body to absorb them, so you’re best off taking them alongside a fatty breakfast (yoghurt and fruit, avocado on toast, eggs, protein shake bowls). “Sometimes probiotics are also better with food to help reach the gut alive and not be destroyed by stomach acid,” O’Shaughnessy says.

Supplements to take without food

But others are best off taken on an empty stomach. “Usually it can depend on the supplement being better absorbed if taken on an empty stomach or with food. An example would be glutathione (which helps with tissue repair), which is better on an empty stomach.”

How long does it take for supplements to work? We ask the experts