A groundbreaking study led by Harvard T.H. Chan School of Public Health, UC Santa Barbara, and the Global Alliance for Improved Nutrition (GAIN) has uncovered a significant global health issue: more than half of the world’s population suffers from inadequate intake of essential micronutrients such as calcium, iron, and vitamins C and E. The study, published in The Lancet Global Health on August 29, 2024, provides unprecedented global estimates of micronutrient deficiencies and underscores the urgent need for targeted interventions.
The comprehensive study is the first of its kind to estimate global inadequacies in 15 critical micronutrients across 34 age-sex groups in nearly every country. It highlights alarming deficiencies in essential nutrients that have profound implications for health, including increased risks of adverse pregnancy outcomes, blindness, and susceptibility to infectious diseases.
Key Findings
The research team utilized data from the Global Dietary Database, the World Bank, and dietary recall surveys in 31 countries to assess nutritional intake across 185 countries. By analyzing these data, the researchers divided populations into 17 age groups, ranging from zero to 80 years and beyond. They evaluated the intake of 15 vitamins and minerals, including calcium, iodine, iron, riboflavin, folate, zinc, magnesium, selenium, thiamin, niacin, and vitamins A, B6, B12, C, and E.
The study revealed severe inadequacies in micronutrient intake, particularly for iodine (68% of the global population), vitamin E (67%), calcium (66%), and iron (65%). Additionally, over half of the global population had insufficient levels of riboflavin, folate, and vitamins C and B6. Niacin levels were closest to adequate, with only 22% of the global population falling short, followed by thiamin (30%) and selenium (37%).
Gender and Regional Disparities
The study also identified notable gender disparities in micronutrient deficiencies. Women were found to have higher inadequacies in iodine, vitamin B12, iron, and selenium compared to men. Conversely, men had higher rates of inadequacies in calcium, niacin, thiamin, zinc, magnesium, and vitamins A, C, and B6. The research highlighted that individuals aged 10-30, particularly in South and East Asia and sub-Saharan Africa, are most vulnerable to low calcium intake. Low calcium levels were also observed across North America, Europe, and Central Asia.
Public Health Implications
Senior technical specialist at GAIN, Ty Beal, expressed concern over the study’s findings, stating, “The results are alarming. The data reveals that more people than previously thought, across all regions and income levels, are not consuming enough essential micronutrients. These deficiencies pose significant risks to global health outcomes and human potential.”
Christopher Golden, senior author and associate professor of nutrition and planetary health at Harvard Chan School, emphasized the urgency of the situation: “The public health challenge is immense. However, this study provides an opportunity for practitioners and policymakers to identify and implement effective dietary interventions targeted at the populations most in need.”
The researchers acknowledged that limited data on individual dietary intake may have constrained their findings. Nonetheless, the study’s comprehensive analysis offers crucial insights for addressing micronutrient deficiencies on a global scale.