Why a calcium-rich diet is crucial for your health

Telegraph

10-03-2025

There are few micronutrients more crucial to our wellbeing than calcium: it builds our bones and teeth, regulates our heartbeats and even allows our blood to clot up when we've had a scratch or scrape. But as we age, our bodies can do less and less with the calcium we consume through our diets. This can lead to osteoporosis, especially in postmenopausal women. Health authorities in plenty of other countries suggest that women in later life start to eat more calcium, but the NHS has no such advice, recommending 700mg a day for all of us regardless of age or sex – happily equating to a 6cm chunk of a hard cheese like cheddar or parmesan.
The latest science suggests that eating a much greater amount of calcium is better for us at any stage of life. A recent study published in the journal Jama Network Open found that consuming at least 1700mg of calcium per day can slash a person's risk of developing bowel cancer by 25 per cent. Other recent research suggests that those of us who consume an extra 300mg of calcium in excess of the NHS guideline amount, the same as a large glass of milk, have a 17 per cent lower risk of bowel cancer.
A diet low in dairy and in vegetables can lead to deficiencies, as leafy greens are a crucial source of calcium. So while older women are at risk of osteoporosis, younger women should be aware of a potential calcium deficiency, too. 'It's women in the UK aged between 20 to 29 in the UK have the lowest calcium intake,' says Rhian Stephenson, a nutritionist and founder of the supplement brand Artah. This is partially because women tend to avoid dairy products at a higher rate than men and partially because of the fact that people in that age bracket generally have a lower vegetable intake.
So how much calcium is really enough for the full range of its benefits – and how would you know that you're deficient?
Am I getting enough calcium?
'Calcium has tons of different uses in the body,' says Stephenson. 'It's one of the most abundant minerals, forming part of the structure of our bones and teeth as well as supporting nerve and muscle function and regulating cellular activity. If we aren't getting enough calcium in our diets, our bodies will take it out of our bones'.
All in all, 'most people in Britain are getting enough calcium in their diets, and pretty much exclusively through diet alone,' says Stephenson. Good data on the average calcium intake of a person in the UK is hard to come by, but American research suggests that the average woman in the US consumes 1,009mg of calcium per day, while men consume 1,156mg.
While dairy products are often the best source of calcium, 'it's entirely possible for someone on a vegetarian or vegan diet to get all the calcium they need, they only need to be more mindful,' Stephenson rules. Leafy vegetables such as kale, spinach and collard greens are all good sources of calcium. Younger people, who are both more likely to try out vegetarianism and be generally more veg-averse, 'might struggle here unless they were raised in a vegetarian or vegan household'.
Women who eat low-fat dairy products meanwhile, rather than avoiding dairy entirely, should also be in the clear. Products like zero-fat Greek yogurt 'tend to contain just as much calcium as the full-fat versions, sometimes even a little more,' says Stephenson.
The signs of calcium deficiency
The signs of calcium deficiency can be hard to spot, says Stephenson, as they are so easily confused with minor ailments or other conditions like arthritis. 'It's hard to measure whether the levels of calcium in your blood are healthy or not, because it will be taken from your bones to buoy up the levels if you aren't consuming enough in your diet,' she explains. 'The only way to know for sure is by scanning for bone density.'
Yet there are some warning signs that you could be calcium deficient. 'Aching bones, muscle soreness as well as cramps and spasms, low blood pressure and anxiety can all result from calcium deficiency, and might be used by a doctor along with an overview of your diet to assess whether you're consuming enough calcium,' Stephenson says.
Nails that 'are softer or break more easily' can also indicate calcium deficiency, 'but there are many things that could cause this, so that isn't definitive either,' Stephenson adds. White spots on a person's nails are often thought of as a telltale sign of calcium deficiency, but this is usually not the case – the spots, also known as leukonychia, are more easily caused by small injuries to your nails, often through nail biting.
The link between calcium and bowel cancer
Bowel cancer rates are on the rise in Britain and across much of the world. Research into the protective effects of calcium against bowel cancer is extremely promising, experts say.
It's thought that calcium works to ward off bowel cancer by 'binding to acids in the bowel and helping to sweep them out, so that they don't have as much of a chance to damage the bowel,' explains Megan Winter, a health information manager at Cancer Research UK.