Calcium is essential for bone health. Yet 16 percent of 11–18 year olds and 9 percent of 16–49 year olds consume less than the Lowest Reference Nutrient Intake (LRNI) of calcium through food, according to the National Diet and Nutrition (NDNS) survey, putting them at risk of weak bones later in life.
“About one in two women and one in five men over 50 will break a bone because of osteoporosis, so it is important to keep your bones healthy”, advises Age UK. But what is the role of calcium in preventing this disease, and how can you make sure you and your family are getting enough of the mineral?
What are the dangers of eating too little calcium?
Calcium is the most abundant mineral in the body. It helps build strong bones and teeth, and plays a part in regulating muscle contractions, including your heart, and blood clotting.
A lack of calcium could lead to weak bone disorders, including rickets in children, osteomalacia in adults, and osteoporosis in later life. “In recent years, there’s been an increase in cases of rickets in the UK”, according to the NHS, although “the number of… cases is still relatively small”.
Osteoporosis affects over 3 million people in the UK, more than 500,000 of whom receive hospital treatment for fragility fractures (bones that break after falling from standing height or less) every year. Factors other than diet, such as family history, gender, ethnicity, smoking and excessive alcohol, as well as lack of exercise, also play a part in determining your risk of osteoporosis.
It’s important to get enough calcium when you’re young, in order to obtain strong bones. “Bone mass reaches its ‘peak’ in our late 20s, but the level of bone mass reached varies from person to person”, according to the British Nutrition Foundation. “The higher the peak bone mass we can get in young adulthood and the slower the loss of bone mass in later adulthood, the better.” Therefore, it’s vital to get enough calcium at any age.
The group most likely to eat below the calcium recommendation is 11–18-year-old females, of whom 22 percent were found to eat less than the LRNI (the amount of a nutrient that is enough for only the 2.5 percent of people who have the lowest requirements) by the NDNS. 11 percent of males in the same age group were also found to eat levels of the mineral below the LRNI. Between the ages of 11–18, males need 1000mg of calcium per day, females 800mg.
Adults over 19 are recommended to have 700mg of calcium daily (and women who are breastfeeding need an extra 550mg a day). According to the British Dietetic Association, this increases to 1200mg for post-menopausal females and males over 55, as bone density loss starts to increase.
Calcium can be stored by the body, so it is not essential to consume the recommended amount every day, although it is important to average the daily nutrient intake over time.
You should be able to get all the calcium you need by eating a varied, balanced diet.
Dairy, such as milk, cheese and yoghurt, is a good source of calcium: a 125g pot of plain yoghurt typically contains 250mg of calcium, and a 200ml glass of milk or 30g of a hard cheese such as Cheddar 240mg.
Tofu can contain from 100–500mg of calcium per 100g. This wide range is because calcium is used as a coagulant, which makes the tofu firm, so firmer tofu may have more calcium per serving. Fish bones contain calcium, making sardines, tinned salmon, whitebait and pilchards good sources: 80g of whitebait provides 688mg of calcium. Some foods are fortified with calcium, including many soya and oat drinks, breads, and cereals – check the label.
Some green vegetables, including broccoli, okra and kale, are good sources of calcium: 60g of curly kale provides 90mg. Spinach is naturally high in calcium, but it also contains oxalic acid, which reduces calcium’s absorption, so it is not considered a good source.
Salt causes the body to lose calcium. More than two-thirds of adults in England are estimated to eat too much salt, according the NDNS 2020 study. You can read more about reducing salt in your diet on BBC Food.
Get a list of calcium-rich food sources and advice on what to limit from the NHS.
Vitamin D is vital for your body to absorb calcium properly. If you are low in vitamin D, as 29 percent of adults and 37 percent of 11–18-year-olds are between the months of January and March every year, your body may not be able to maintain sufficient levels of calcium.
Your body produces vitamin D when exposed to sunlight, and it’s difficult to get the recommended 10 micrograms a day from the UK sun between October and March. The NHS recommends everyone over the age of five considers taking a daily supplement of 10 micrograms of vitamin D during these months, or all-year-round if your exposure to sunlight is limited. Keep an eye on how much you take, because too much vitamin D could lead to toxicity.
Should you take a calcium supplement?
We can get the calcium we need from a healthy diet, but if you’re over 65 and feel you’re not getting enough from your diet, the NHS suggests considering taking a dietary supplement containing both calcium and vitamin D. But taking too much calcium supplement could be harmful. If you’re taking medication, ask your GP before supplementing. For an otherwise healthy adult, 1,500mg or less a day is unlikely to cause any harm, advises the NHS.