Billions worldwide are not consuming adequate amounts of micronutrients crucial to human health, a new study shows

More than half of the world’s population consumes inadequate levels of several micronutrients essential for health, including calcium, iron and vitamins C and E, according to a new study by researchers at Harvard TH Chan School of Public Health, UC Santa Barbara ( UCSB) and the Global Alliance for Improved Nutrition (GAIN). It is the first study to provide global estimates of inadequate consumption of 15 micronutrients critical to human health.

The research was published in The Lancet Global Health magazine.

Micronutrient deficiencies are one of the most common forms of malnutrition worldwide, and each deficiency has its own health consequences, from adverse pregnancy outcomes to blindness and increased susceptibility to infectious diseases. Previous research has estimated the amounts of micronutrients available to and consumed by humans; this study evaluates whether these intakes meet recommended requirements for human health and looks at the deficiencies that men and women specifically face throughout their lives.

“Our study is a major step forward,” said co-lead author Chris Free, a research professor at UCSB. “Not only because it is the first to estimate inadequate micronutrient intake for 34 age groups in almost every country, but also because it makes these methods and results easily accessible to researchers and practitioners.”

The researchers used data from the Global Dietary Database, the World Bank and dietary recall surveys in 31 countries to compare nutritional needs with nutritional intake among the populations of 185 countries. (They created this data, as well as code for analysis, freely available.) They divided the population into men and women belonging to 17 age groups: zero to 80 in five-year periods, as well as a group of 80+. The assessment looked at fifteen vitamins and minerals: calcium, iodine, iron, riboflavin, folic acid, zinc, magnesium, selenium, thiamin, niacin and vitamins A, B6, B12, C and E.

The study found significant deficiencies in intake of almost all micronutrients evaluated, with the exception of fortification as a potential source of additional nutrients. Inadequate intake mainly occurred with iodine (68% of the world population), vitamin E (67%), calcium (66%) and iron (65%). More than half of people consumed insufficient amounts of riboflavin, folic acid and vitamins C and B6. Niacin intake was closest to adequate, with 22% of the world’s population consuming inadequate amounts, followed by thiamin (30%) and selenium (37%).

Estimated inadequate intakes of iodine, vitamin B12, iron and selenium were higher for women than for men within the same country and age groups. Conversely, more men did not consume enough calcium, niacin, thiamin, zinc, magnesium and vitamins A, C and B6 compared to women.

Although patterns of micronutrient deficiencies emerged more clearly by gender, the researchers also noted that men and women between the ages of 10 and 30 were most susceptible to low calcium intake, especially in South and East Asia and Sub-Saharan Africa. Calcium intake was also low in North America, Europe and Central Asia.

“These results are alarming,” said Ty Beal, senior technical specialist at GAIN. “Most people – even more than previously thought, in all regions and countries of all incomes – are not consuming enough of several essential micronutrients. These gaps are jeopardizing health outcomes and limiting human potential on a global scale.”

“The public health challenge we face is enormous, but practitioners and policymakers have the opportunity to identify the most effective nutritional interventions and target them to the populations that need them most,” said senior author Christopher Golden , associate professor of nutrition and planetary health at Harvard. Chan School.

The researchers noted that a lack of available data, especially on individual dietary intake worldwide, may have limited their findings.

Simone Passarelli, a former doctoral candidate and postdoctoral researcher in the Department of Nutrition at Harvard Chan School, was co-lead author.