Animals like elephants, giraffes, rhinos, gorillas don’t need to drink milk to get the calcium they need. They get it from green leafy vegetables. Should humans do the same?

It is obvious that humans look very different to these animals on the outside but our physiology is also quite different to them on the inside. The human digestive system is omnivore, whereas these animals are herbivores, which means our ability to consume and digest various foods is not the same. There are several differences but the main one is that humans principally digest food using enzymes and herbivores principally digest food using fermentation. Our nutritional requirements and ability to absorb nutrients is therefore quite different, so naturally our diets should be different too.

Gorillas, for example, have a much greater capacity to break down plant materials compared to humans, because their colon is proportionately much bigger and better at microbial fermentation, which helps to break down the cellulose and organic compounds in plants. Elephants must spend most of their day eating to acquire the amount of calcium they need. They also have a large caecum, which helps to break down a large volume of fibrous foliage that would be too course and indigestible for humans.

It is very important for us to include green leafy vegetables in our diet but it is quite challenging for humans to get all the calcium they need from plants alone. Some healthy plant foods also contain substances which reduce calcium absorption, for example phytic acid in foods such as wholegrains or beans and and oxalic acid in spinach or rhubarb. To get the same amount of calcium that is in a 250 ml glass of milk, a person would need to eat either 63 Brussels sprouts, 550 g of cabbage or 900 g of spinach! Several leading health organisation recognise dairy as one of the best sources of dietary calcium and that is why it is included in dietary recommendations across the world.