A recent study from Harvard T.H. Chan School of Public Health, UC Santa Barbara (UCSB), and the Global Alliance for Improved Nutrition (GAIN) has found that more than half of the world’s population does not get enough essential micronutrients. These include calcium, iron, and vitamins C and E. Published in The Lancet Global Health on August 29, this research provides the first global estimates of inadequate intake for 15 critical micronutrients.
Micronutrient deficiencies are a major global health issue, leading to problems such as poor pregnancy outcomes, blindness, and higher vulnerability to infections. This study builds on previous research by assessing whether current micronutrient intakes meet health recommendations and by identifying gaps for different age and gender groups throughout their lives.
Study Highlights
Chris Free, a research professor at UCSB and co-lead author of the study, called the research a significant advancement. “Our study is the first to estimate inadequate micronutrient intakes for 34 age-sex groups across nearly every country. It also makes these methods and results accessible to researchers and practitioners,” he said.
The team used data from the Global Dietary Database, the World Bank, and dietary recall surveys from 31 countries. They analyzed nutritional needs versus actual intake across 185 countries, dividing the population into 17 age groups, from zero to 80 years old, and an additional 80+ group. The study covered 15 nutrients: calcium, iodine, iron, riboflavin, folate, zinc, magnesium, selenium, thiamin, niacin, and vitamins A, B6, B12, C, and E.
The study found significant deficiencies in nearly all the evaluated micronutrients. The most common inadequacies were for iodine (68% of the global population), vitamin E (67%), calcium (66%), and iron (65%). Over half of the population also had insufficient levels of riboflavin, folate, and vitamins C and B6. Niacin levels were the closest to adequate, with only 22% of people having insufficient intake, followed by thiamin at 30% and selenium at 37%.
Gender and Regional Disparities
The study also revealed gender disparities in micronutrient deficiencies. Women had higher rates of inadequate intake for iodine, vitamin B12, iron, and selenium compared to men. Conversely, men had more deficiencies in calcium, niacin, thiamin, zinc, magnesium, and vitamins A, C, and B6. The study identified that both men and women aged 10-30 were particularly prone to low calcium intake, with notable deficiencies in South and East Asia, sub-Saharan Africa, North America, Europe, and Central Asia.
Ty Beal, a senior technical specialist at GAIN, expressed concern over the findings. “These results are alarming. More people than previously thought, across all regions and income levels, are not getting enough essential micronutrients. This compromises health outcomes and limits global human potential.”
Senior author Christopher Golden, an associate professor of nutrition and planetary health at Harvard Chan School, emphasized the challenge ahead. “The public health challenge is immense, but practitioners and policymakers have the chance to implement effective dietary interventions targeted at those most in need.”
The researchers acknowledged that limited data on individual dietary intake worldwide may have constrained their findings.
