Critically low intake was found in certain Asian, African and Latin American countries - while studies showed nearly double the intake in many European countries and in the USA.
The research, led by an International Osteoporosis Foundation (IOF) research committee, pointed out that calcium is a major building block of bone, accounting for about 30-35% of its mass and much of its strength.
The impact of calcium intake is most significant during adolescence, when the skeleton gains bone mass, and during later life when bone loss occurs at a rate of about 1% per year, resulting in calcium loss of approximately 15 g per year.
A major concern is that in countries with sub-optimal dietary calcium intake the population may be putting itself at increased risk of osteoporosis and related fractures.
Data from 74 countries was assessed, revealing average national dietary calcium intake ranges from 175 to 1233 mg/day. Southern and Eastern Asia had world's lowest average calcium intakes, often at less than 400mg a day.
Countries in South America and Africa mostly had average intakes in the mid-range, between about 400 and 700 mg a day. Only Northern European countries registered calcium intakes greater than 1,000 mg a day.
Average calcium intake is generally lower in women than in men, but there are no clear patterns across countries regarding relative calcium intake by age, sex, or socioeconomic status.
The study's lead author Ethan Balk, associate professor at the Center for Evidence Synthesis in Health, Brown University School of Public Health, said: "In many parts of the world there is lower intake than there should be for good bone health. While consumption is highest among adults in North America and Europe, it is alarmingly low in Asia and in some of the world's most populous countries, including in China, India and Indonesia."
IOF hopes that the data will motivate action to promote increased calcium consumption, particularly in the Asia-Pacific region and in places where calcium consumption hasn't been documented.
An interactive online global map representing the study findings will be launched by IOF at the World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases in April 2018.
Source: Osteoporosis International
“Global dietary calcium intake among adults: a systematic review”
Authors: E.M Balk, et al.