In a world where food access has improved considerably in recent decades, micronutrient deficiencies remain a major global public health problem. A recent global analysis published in The Lancet Global Health has revealed an alarming reality: more than 5 billion individuals worldwide do not consume the necessary amounts of essential micronutrients such as iodine, vitamin E and calcium, leading to serious health consequences.
These deficiencies, which affect 68% of the world’s population, are added to the insufficiency of other micronutrients such as iron, riboflavin (vitamin B2), folic acid and vitamin C, which affect more than 4 billion people, putting their health at risk.
This study by researchers at the Harvard T.H. Chan School of Public Health, the University of California, Santa Barbara (UCSB), and the Global Alliance for Improved Nutrition (GAIN) is a pioneer in estimating the global prevalence of inadequate intake of 15 essential micronutrients (calcium, iodine, iron, riboflavin, folate, zinc, magnesium, selenium, thiamin, niacin, and vitamins A, B6, B12, C, and E), using dietary consumption data from 31 countries and applying a novel modeling approach that includes age- and sex-specific distributions, analyzing 34 age and sex groups in 185 countries, covering 99.3% of the world’s population. It is a reproducible and accessible methodology that highlights the scale of this nutritional crisis. The results are compelling: the majority of the world’s population has an insufficient intake of micronutrients, with particularly severe consequences for women.
Specifically, deficiencies were particularly significant for calcium (72% of the world’s population), iodine (68%), vitamin E (67%) and iron (65%). More than half of the study population consumed inadequate levels of riboflavin, folate and vitamins C and B6. Niacin intake was closest to sufficient, with 22% of the world’s population consuming inadequate levels, followed by thiamine (30%) and selenium (37%).
“These results are alarming,” said Ty Beal, Senior Technical Specialist at GAIN. “The majority of people—even more than previously thought, across all regions and countries at all income levels—do not consume sufficient amounts of multiple essential micronutrients. These gaps compromise health outcomes and limit human potential on a global scale.”
Inequality in nutrient intake
The study not only reveals the severity of nutritional deficiencies, but also highlights significant gender inequalities. Women, in particular, have a higher prevalence of inadequate intake of iodine, vitamin B12, iron, selenium, calcium, riboflavin and folate, compared to men. These differences may be related to factors such as nutritional requirements and specific dietary patterns.
On the other hand, men show a higher prevalence of insufficiency in micronutrients such as magnesium, vitamin B6, zinc, vitamin C, vitamin A, thiamine and niacin.
Women have a higher prevalence of inadequate intake of iodine, vitamin B12, iron, selenium, calcium, riboflavin and folate, compared to men
These disparities are not only observed between sexes, but also between different geographic regions. For example, countries in South Asia, sub-Saharan Africa and East Asia have the highest rates of inadequate calcium intake, while in North America, Central Asia and Europe deficiencies of this nutrient are considerably lower. In the case of iodine, its deficiency is less common in Europe and Canada, while the Pacific Islands are one of the few regions with a low prevalence of vitamin E deficiency.
Some countries also show specific patterns in their deficiencies. India, for example, has alarmingly high levels of inadequate intake of riboflavin, folate, vitamin B6 and B12. In Madagascar and the Democratic Republic of the Congo, niacin deficiency is particularly common, while Russia, Mongolia and Kazakhstan stand out for their high selenium deficiencies.
A global public health challenge
Micronutrient deficiency is a public health problem that has profound effects on physical and mental development, as well as on vulnerability to chronic diseases and the strength of the immune system, as well as poor development in children. Women of childbearing age are one of the most vulnerable groups due to the increased needs for certain micronutrients such as iron and folate, essential during pregnancy and lactation.
Despite efforts in some countries to implement food fortification and supplementation programmes, results indicate that many of these interventions are not sufficient or sufficiently widespread. For example, although 89% of the world’s population consumes iodized salt, which partially mitigates iodine deficiency, supplementation with other essential micronutrients, such as iron and vitamin A, remains limited in many developing countries.
The research therefore underscores the urgent need for interventions at local and global levels to address these deficiencies. While fortified foods and supplements are an effective tool in some contexts, the key lies in improving the quality of the overall diet. For many developing countries, where access to micronutrient-rich foods is limited, this will require coordinated efforts between governments, international organizations and the food industry to ensure that everyone has access to adequate nutrition.
Limitations of the study and areas for improvement
Although this study provides a clear picture of the scale of the problem, it also has limitations. The availability of individual dietary data, especially in low-income countries, remains scarce, affecting the accuracy of the estimates. Furthermore, the analysis does not take into account the effects of fortification and supplementation on nutrient intake, which could overestimate the risk in certain cases, such as with iodine.
Additionally, nutrient bioavailability and absorption were not included in this analysis, which could influence estimates of insufficient intake. Factors such as inflammation or the presence of disease also play a key role in nutrient absorption, but science has not yet advanced enough to accurately integrate these variables into calculations.
This study not only represents a significant advance in understanding global micronutrient inadequacy, but also opens the door to future research and concrete action. Public availability of the underlying code and data will allow other researchers to use and expand these results, fostering a better understanding of the global nutritional crisis.
The challenge now, the authors note, is to translate these findings into effective public health policies. They suggest that interventions such as crop biofortification, fortification of processed foods, and supplementation must be part of long-term solutions, particularly in the most affected regions. In addition, they note, it is critical to improve global dietary data collection to refine estimates and direct resources more effectively to the populations that need them most.
Ultimately, this analysis underlines the importance of addressing micronutrient deficiencies in an urgent and coordinated manner. In an increasingly globalised world, ensuring that all people have access to a balanced and nutrient-rich diet is not only a matter of health, but also of social justice.
Source: The Lancet
