According to recent alarming findings by researchers, more than half of the global population consumes inadequate levels of several micronutrients essential to health, including calcium, iron and vitamins C and E.
The study, by a team from Harvard TH Chan School of Public Health, UC Santa Barbara (UCSB), and the Global Alliance for Improved Nutrition (GAIN), is the first to provide global estimates of inadequate consumption of 15 micronutrients critical to human health.
In the findings, published in The Lancet Global Health, the researchers explain that micronutrient deficiencies are one of the most common forms of malnutrition globally, that each deficiency carries its own health consequences, from adverse pregnancy outcomes, to blindness, to increased susceptibility to infectious diseases.
Previous research has estimated the amounts of micronutrients available to and consumed by people; this study evaluates whether these intakes meet requirements recommended for human health and looks at the inadequacies specifically facing males and females across their lifespans.
“This is a big step forward,” said co-lead author Chris Free, research professor at UCSB. “Not only because it is the first to estimate inadequate micronutrient intakes for 34 age-sex groups in nearly 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 requirements with nutritional intake among the populations of 185 countries.
They divided populations into males and females belonging to 17 age groups: zero to 80 in five-year spans, as well as an 80+ group. The assessment studied 15 vitamins and minerals: calcium, iodine, iron, riboflavin, folate, zinc, magnesium, selenium, thiamin, niacin, and vitamins A, B6, B12, C, and E.
The study found significant intake inadequacies for nearly all of the evaluated micronutrients, excluding fortification as a potential source of additional nutrients.
Inadequate intake was especially prevalent for iodine (68% of the global population), vitamin E (67%), calcium (66%), and iron (65%).
More than half of people consumed inadequate levels of riboflavin, folate and vitamins C and B6. Intake of niacin was closest to sufficient, with 22% of the global population consuming inadequate levels, followed by thiamin (30%) and selenium (37%).
Estimated inadequate intakes were higher for women than men for iodine, vitamin B12, iron, and selenium within the same country and age groups. Conversely, more men consumed inadequate levels of calcium, niacin, thiamin, zinc, magnesium, and vitamins A, C, and B6 compared with women.
While patterns of micronutrient inadequacy emerged more clearly on the basis of sex, the researchers also observed that males and females aged 10-30 were most prone to low levels of calcium intake, especially in South and East Asia and sub-Saharan Africa. Calcium intake was also low across 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, across all regions and countries of all incomes – are not consuming enough multiple essential micronutrients. These gaps compromise health outcomes and limit human potential on a global scale.”
“The public health challenge facing us is immense, but practitioners and policymakers have the opportunity to identify the most effective dietary interventions and target them to the populations most in need,” added 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.
Study details
Global estimation of dietary micronutrient inadequacies: a modelling analysis
Simone Passarelli, Christopher M Free, Alon Shepon, Ty Beal, Carolina Batis, Christopher D Golden.
Published in The Lancet Global Health on 2024
Summary
Background
Inadequate micronutrient intakes and related deficiencies are a major challenge to global public health. Analyses over the past 10 years have assessed global micronutrient deficiencies and inadequate nutrient supplies, but there have been no global estimates of inadequate micronutrient intakes. We aimed to estimate the global prevalence of inadequate micronutrient intakes for 15 essential micronutrients and to identify dietary nutrient gaps in specific demographic groups and countries.
Methods
In this modelling analysis, we adopted a novel approach to estimating micronutrient intake, which accounts for the shape of a population's nutrient intake distribution and is based on dietary intake data from 31 countries. Using a globally harmonised set of age-specific and sex-specific nutrient requirements, we then applied these distributions to publicly available data from the Global Dietary Database on modelled median intakes of 15 micronutrients for 34 age-sex groups from 185 countries, to estimate the prevalence of inadequate nutrient intakes for 99·3% of the global population.
Findings
On the basis of estimates of nutrient intake from food (excluding fortification and supplementation), more than 5 billion people do not consume enough iodine (68% of the global population), vitamin E (67%), and calcium (66%). More than 4 billion people do not consume enough iron (65%), riboflavin (55%), folate (54%), and vitamin C (53%). Within the same country and age groups, estimated inadequate intakes were higher for women than for men for iodine, vitamin B12, iron, and selenium and higher for men than for women for magnesium, vitamin B6, zinc, vitamin C, vitamin A, thiamin, and niacin.
Interpretation
To our knowledge, this analysis provides the first global estimates of inadequate micronutrient intakes using dietary intake data, highlighting highly prevalent gaps across nutrients and variability by sex. These results can be used by public health practitioners to target populations in need of intervention.
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