New global analysis highlights micronutrient shortages

By Pooja Toshniwal PahariaReviewed by Danielle Ellis, B.Sc.Sep 4 2024

Most people around the world don't get enough of at least one essential vitamin or mineral.

In a recent study published in The Lancet Global Health, researchers modeled the global prevalence of insufficient micronutrient intakes for 15 crucial micronutrients to identify dietary nutrient gaps by demographics.

Background

Micronutrient deficiency is a serious health concern globally. It impacts vital nutrients such as zinc, iron, folate, vitamin A, and iodine and increases morbidity and mortality. However, due to a lack of data, the extent and demographic specificities of this issue remain unclear.

Vitamin D is critical for calcium absorption in the body, which is essential for building and maintaining strong bones and teeth. Deficiency can lead to conditions like rickets in children and osteomalacia or osteoporosis in adults.

Studies have investigated micronutrient deficits and insufficient nutrient supply; however, limited research exists on global estimations of micronutrient intake inadequacy.

Clinical nutritional biomarkers assess the worldwide prevalence of micronutrient deficiencies; however, data gaps exist for different micronutrients, demographic categories, and geographies. Previous estimates of micronutrient adequacy do not account for home food wastes, food service wastes, small-scale production, and wild harvest, resulting in erroneous estimations.

About the study

In the present study, researchers present worldwide estimates of insufficient dietary micronutrient intakes, stratified by age and gender.

The researchers examined dietary intake information from 31 nations, including individual- and nutrient-level data, at least two days of dietary consumption, and data from 24-hour recalls, diet records, or food diaries for over 200 inhabitants.

They used globally harmonized gender- and age-specific nutritional information provided by the Global Dietary Database (GDD), applied to the predicted median consumption of micronutrients for different age-gender categories from 185 nations.
The researchers created subnational nutrient consumption distributions by estimating distribution size (i.e., median intake) from the Global Dietary Database (GDD) and the shape of the distribution (i.e., intake variabilities) using nutriR data. According to 2018 GDD projections, they projected nutritional deficiency for 7.6 billion individuals or 99% of the world population.

The researchers used probability methods to calculate the prevalence of intake inadequacy by comparing estimated micronutrient intakes to the nutritional requirement distributions. They used World Bank human population estimates to assess nutritional inadequacies among 17 age groups: 0 to 80 years old in five-year groups and a group of individuals aged ≥80 years, including men and females. Researchers matched every subnational group to the shape characteristics of the most comparable subnational group based on data.

The researchers eliminated two micronutrients from the study: potassium, which has no established average need levels, and D vitamin, whose distribution is very regionally varied since the mean requirement can be satisfied by sun exposure instead of food consumption. To account for the nutrient supply in drinking water, they assumed that everyone drinks an acceptable amount of water daily (containing 16 mg magnesium and 46 mg calcium per liter).

Results

According to dietary nutrient intake estimates (excluding supplementation and fortification), nearly five billion individuals (68%) consume insufficient amounts of iodine, calcium (66%), and E vitamin (67%).

Over four billion individuals consume inadequate quantities of iron (65%), folate (54%), ascorbic acid (53%), and riboflavin (55%). Within a particular nation and age category, females had higher estimated insufficient intakes of vitamin B12, iodine, selenium, and iron than men. In contrast, males had higher estimates of vitamin B6, magnesium, vitamin C, zinc, vitamin A, niacin, and thiamin.

A few nations reported anticipated intake shortfalls that deviated from the overall pattern. For example, the estimated insufficient intakes of folate, riboflavin, and vitamins B6 and B12 were very high in India; the Democratic Republic of the Congo (DRC) and Madagascar had extremely insufficient intakes of niacin; and Mongolia, Kazakhstan, and Russia had highly insufficient selenium intakes.

Calcium intake deficiency was most prevalent in Southeast Asia, the Pacific, and Sub-Saharan parts of Africa, particularly among those aged 10 to 30. Only Central Asia, Europe, and North America have consistently low rates of insufficient calcium consumption. Only Canada and Europe had a low rate of poor iodine consumption, whereas vitamin E was mostly found among Pacific Island nations. Only South Asian and African nations have high rates of poor vitamin B12 and riboflavin consumption.

Implications

The study identifies major worldwide nutritional deficits, notably in vitamin E, iodine, iron, calcium, folate, and riboflavin. Most individuals do not consume enough micronutrients. Understanding these patterns can help determine where nutritional interventions, such as dietary modifications, biofortification, and supplementation, are required.

Correlating nutritional intake deficiencies can increase intervention delivery efficiency. The study findings might help public health practitioners create focused dietary programs and policies. Further research into the origins and severity of deficiencies is required before implementing fortification, supplementation, and dietary intervention strategies in specific regions.