Millions of people around the world may be at risk of osteoporosis, an interactive map about global calcium intake intake has revealed.
The mineral, found in milk, cheese and yoghurt, is essential for bone health and a deficiency can lead to the agonising condition.
However, global data shows just 21 countries - mostly in Europe - are getting the recommended daily levels of calcium in their diet.
The two most populated countries in the world, China and India, had intake levels at less than half of what health chiefs advise. The UK and US had recommended intakes of calcium.
Nepal in Asia was found to be the worst offender - having an intake of calcium seven times lower than the amount in Iceland.
Every country sets its own medical guidelines on how much calcium people should incorporate into their diet each day.
The International Osteoporosis Foundation, who made the new map, recommend a daily intake of between 800 and 1,000mg a day.
In Britain, health chiefs urge people to consume 700mg daily while in the US the amount is as much as 1,000mg a day.
The IOF's map, which presents data from 74 countries, reflects the findings of the agency's recent study into estimated calcium intakes.
Professor Bess Dawson-Hughes, chair of the IOF Calcium Steering Committee, said: 'Increasing calcium intake throughout the lifespan is an important strategy to improve bone health.
'We encourage people of all ages to meet their calcium intake requirements by consuming a variety of calcium-rich foods.
'For people who may not be able to get enough calcium through their diets, calcium supplementation may be needed to reach the intake requirement of 800 to 1,000 mg/day.
'This is particularly important for older adults who do not consume enough calcium-rich foods.
The lowest calcium intake was shown to be Nepal (175mg/day), while the highest was in Iceland (1,233mg/day).
Ireland, Germany, Switzerland, the Netherlands and Finland were the only other countries to have calcium intakes of more than 1,000mg.
Consumption sits at around 994mg/day in the UK, which was found to be the next highest amount recorded in Europe.
The US consumes 934mg of calcium each day, if estimates are true - the highest across all of North, South and Central America.
Jamaica and Mexico both also consume more than Canada, which was listed as a yellow on the map for its intake of 787mg/day.
None of the 13 African countries met the recommended intakes - and four consumed less than 400mg/day, Burkina Faso, Uganda, Cape Verde and Gambia.
In Asia, just Iran and Jordan showed up on the map in green, which signals they have an intake of at least 800mg each day.
However, six countries, including China, which has a population of nearly 1.4 billion, consume less than 400mg of calcium each day.
Professor Wei-bo Xia, president of the Chinese Society of Osteoporosis and Bone Mineral Research, was concerned about the low levels of calcium intake in China.
He said: 'Hip fractures are the most serious, costly, and life-threatening fractures due to osteoporosis.
He also noted that high phytate intake in relation to low calcium intake is an additional aspect of concern in China.
Phytates, found in certain plant foods such as rice, beans and legumes, inhibit the absorption of calcium and other nutrients.
The map was shown at a symposium today at the World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases in Krakow, Poland.