Alimentación, movimiento y sueño

Calcium and vitamin D

Revisado: 4 de octubre de 2026

Solo en inglés por ahora

Calcium and vitamin D work together to keep your bones strong. Here is why they matter at every age, where to find them, and who may need more.

Why your bones need them

Almost all the calcium in your body is stored in your bones and teeth, where it makes them hard and strong. Your muscles and nerves need calcium too. Vitamin D helps your body absorb calcium from food, so the two work as a team. Vitamin D also helps your muscles, nerves and immune system work well. Without enough of them over time, bones can become weak and fragile (osteoporosis), which raises the risk of breaks.

Bones, hormones and your cycle

Hormones matter for bones as well as food. Oestrogen helps keep bones strong. Low oestrogen, poor nutrition and too little calcium or vitamin D can all lead to bone loss. This is one reason periods that stop because of under-eating or very heavy training are worth getting checked. After menopause, oestrogen levels fall and bones can lose strength quickly. The body also absorbs and holds on to less calcium. This makes calcium and vitamin D even more important in later life.

Where to find calcium

Milk, yoghurt and cheese are rich in calcium. Other sources include tinned sardines and salmon eaten with their soft bones, and green vegetables such as kale, broccoli and pak choi. Many plant-based drinks, such as soy and almond drinks, and some fruit juices have calcium added. If you avoid dairy, for example because you are vegan or lactose intolerant, it can be harder to get enough, so look for fortified foods.

Getting enough vitamin D

Sunlight on your skin helps your body make vitamin D. Glass blocks this, so sitting by a window does not help. You make less on cloudy or smoggy days, as you get older, and if you have darker skin. The best natural food sources are fish such as salmon, trout, mackerel and tuna. Egg yolks, cheese and mushrooms have small amounts. In some countries, milk and other foods have vitamin D added.

How much you need

Advice differs between countries and changes with age, so check your local guidance. As one example, the US National Institutes of Health advises 1,000 mg of calcium a day for adults aged 19 to 50, rising to 1,200 mg for women aged 51 to 70. Children and teens aged 9 to 18 need more, 1,300 mg a day. The same body advises 15 micrograms (600 IU) of vitamin D a day for most people aged 1 to 70.

Supplements and advice

Too much calcium or vitamin D from supplements can cause problems, such as feeling sick, constipation and kidney stones. Some people may need a supplement, for example if you avoid dairy, have darker skin, are pregnant or breastfeeding, or are past menopause. Ask a doctor, nurse or pharmacist before you start one. Breast milk alone does not give babies enough vitamin D, so ask about this if you are breastfeeding.

This is general information. Advice on calcium and vitamin D differs by country, so check with a doctor, nurse or pharmacist.