Calcium supplements: how much you need and which form

Do you need a calcium supplement?

Probably not, if you eat dairy. The UK reference intake is 700 milligrams a day, and milk, yoghurt and cheese make that easy to reach without counting. A calcium supplement earns its place when your diet leaves a gap, and the clearest case is a dairy-free or plant-based diet, where the everyday sources are missing. So the honest order is to look at your diet first, and reach for a supplement to fill what food does not cover, rather than adding calcium on top of a diet that already has enough.

What does calcium do?

Most people think of calcium as the bone mineral, and it is, but the authorised descriptions cover more than that. Calcium contributes to the maintenance of normal bones and teeth, to normal muscle function, to normal blood clotting, to normal neurotransmission, to normal energy-yielding metabolism and to the normal function of digestive enzymes. Bones hold most of the body's calcium, which is why it is talked about the way it is, but it has these other roles too.

How much, and getting it from food first

The UK reference intake is 700 milligrams a day for adults. Calcium is a food-first nutrient, and for most people dairy supplies most of it: milk, yoghurt and cheese are rich, everyday sources. If you eat those, you are probably getting close without counting. Food first is the right order here, because it is easy to reach 700 milligrams from a normal diet that includes some dairy or fortified alternatives.

The plant-based problem

Without dairy, it gets harder. If you do not eat dairy, calcium becomes a nutrient you have to plan for. Plant sources exist, but they are less concentrated: fortified plant milks and yoghurts, calcium-set tofu, some leafy greens like kale, and tahini. The trap is the plant milk that is not fortified, which gives almost no calcium. So a plant-based diet can meet its calcium needs, but only on purpose, by choosing fortified products or a supplement to fill the gap.

Which form of calcium?

Calcium supplements come in a few forms. The common mineral forms are calcium carbonate, which carries a lot of calcium by weight and is best taken with food, and calcium citrate, which is gentler to take on an empty stomach. For a plant-based routine there is also calcium drawn from marine algae rather than from mined minerals, which is the form our own calcium uses, covered next. All of them raise your calcium intake; the right one is the one that suits your diet and sits comfortably for you.

Calcium from marine algae

For a plant-based supplement, one option is calcium drawn from marine algae rather than from rock-mined minerals. Aquamin is a source of this kind, made from a calcified red seaweed that takes up calcium and other minerals from seawater as it grows, leaving a plant-derived, multi-mineral calcium. It is the source used in our Bone Strength formula. It suits a plant-based routine and comes with the trace minerals that occur naturally alongside it.

Building bone support

Calcium rarely works alone on a bone-support label. Vitamin D helps your body absorb calcium, and vitamin K2 contributes to the maintenance of normal bones, which is why bone formulas tend to combine the three. Our Bone Strength provides 600 mg of calcium (75% of the daily reference intake), from Aquamin marine algae, brought together with magnesium, vitamin D3 and K2 in one formula. Calcium is needed for the maintenance of normal bones and teeth. If you want the detail on the partners, the vitamin K2 guide and the vitamin D3 guide cover each in turn.