Nutrients such as iron and calcium are critical for blood and bone health, respectively. But more than half the global population isn’t eating enough of these and five other nutrients also crucial for human health, according to a new study.
More than 5 billion people don’t consume enough iodine, vitamin E or calcium, found the study published August 29 in the journal The Lancet Global Health. And more than 4 billion people have insufficient intake of iron, riboflavin, folate and vitamin C.
“Our study is a big step forward,” said co-lead study author Dr. Christopher Free, assistant researcher at the Marine Science Institute and the Bren School of Environmental Science and Management at the University of California, Santa Barbara, in a news release. Free also specializes in human nutrition.
That’s “not only because it is the first to estimate inadequate micronutrient intakes for 34 age-sex groups in nearly every country,” Free added, “but also because it makes these methods and results easily accessible to researchers and practitioners.”
Past studies have assessed worldwide deficiencies in micronutrients or insufficient supplies of foods containing them, but there haven’t been any global estimates of intake considered inadequate based on nutritional requirements, according to the latest study.
For these reasons, the research team estimated the prevalence of inadequate intakes of 15 micronutrients among 185 countries, or 99.3% of the population. They did so via modeling — applying a “globally harmonised set of age-specific and sex-specific nutrient requirements” to data from the 2018 Global Dietary Database, which provides intake estimates based on data from individual surveys, household surveys and national food supplies.
The authors also found differences among women and men. Women were more likely than men to not consume enough iodine, vitamin B12, iron and selenium. Men, however, didn’t get enough magnesium, zinc, thiamin, niacin and vitamins A, B6 and C.
There were geographic patterns, too. In India, insufficient intakes of riboflavin, folate and vitamins B6 and B12 were especially high, while poor calcium intake was highest in south and east Asia, sub-Saharan Africa and the Pacific.
“These results are alarming,” said study coauthor Ty Beal, a senior technical specialist at the Swiss-based Global Alliance for Improved Nutrition, in the news release. “Most people — even more than previously thought, across all regions and countries of all incomes — are not consuming enough of multiple essential micronutrients. These gaps compromise health outcomes and limit human potential on a global scale.”
While the findings are unique, they align with what other smaller country-specific studies have found for years, said Dr. Lauren Sastre, assistant professor of nutrition science and director of the Farm to Clinic Program at East Carolina University in North Carolina, via email.
“This is a valuable study,” added Sastre, who wasn’t involved in the research.
The problems with evaluating diets worldwide
The study has several important limitations. For one, since the research doesn’t include consumption of supplements and fortified foods, some of the inadequacies found in the study may not be as bad in real life if some people are consuming supplements and fortified foods that would theoretically increase their intakes of certain nutrients, the authors said.
However, supplementation and fortification with many of the other studied nutrients is uncommon globally, the authors said.
But 89% of people worldwide do consume iodized salt, according to UNICEF. “Therefore, iodine might be the only nutrient for which inadequate intake from food is largely overestimated,” the authors said, referring to their findings.
“My only critique is they left out potassium, citing that there aren’t standards,” Sastre said. “We certainly have (a recommended daily amount) of potassium in the US, and most folks are not consuming nearly enough. And it needs to be balanced with sodium. We have folks consuming way too much sodium, and not nearly enough potassium which is essential for blood pressure (and) heart health.”
Additionally, more complete information on worldwide individual dietary intake is scarce, especially datasets that are nationally representative or contain more than two days of intake, the researchers said. This scarcity limits the ability of researchers to validate their modeled estimates.
And though the team measured inadequate intakes, it didn’t have data on whether those led to deficiencies that must be diagnosed by a doctor or dietitian based on blood tests and/or symptoms.
A more nourishing diet
Dietitians and physicians can help you determine whether you’re getting enough of certain vitamins or minerals or if you have deficiencies proven by a blood test.
“Micronutrients have critical roles in cellular function, immunity (and) metabolism,” Sastre said. “However, we are not consuming fruits, vegetables, nuts, seeds, whole grains — where they are found. We need to follow the American Heart Association’s recommendation to ‘eat the rainbow.’”
Here’s a list of why the seven nutrients with the lowest global intake are important and some of the foods they’re rich in:
1. Calcium
● Important for strong bones and overall health
● Found in dairy products and fortified soy-, almond- or rice-based alternatives; dark leafy greens; tofu; sardines; salmon; tahini; and fortified orange or grapefruit juice
2. Folate
● Important for red blood cell formation and cell growth and function, especially during pregnancy
● Found in dark green vegetables, beans, peas, lentils and enriched grains such as bread, pasta, rice and cereal
3. Iodine
● Important for thyroid function and bone and brain development
● Found in fish, seaweed, shrimp, dairy products, eggs and iodized salt
4. Iron
● Important for delivery of oxygen to the body as well as growth and development
● Found in oysters, duck, beef, sardines, crab, lamb, fortified grains, spinach, artichokes, beans, lentils, dark leafy greens and potatoes
5. Magnesium
● Important for muscle and nerve function, blood sugar, blood pressure, and the making of protein, bone and DNA
● Found in legumes, nuts, seeds, whole grains, green leafy vegetables and fortified cereals
6. Niacin
● Important for nervous and digestive systems
● Found in beef, chicken, marinara sauce, turkey, brown rice, pumpkin seeds, salmon and fortified grains
7. Riboflavin
● Important for metabolism of food for energy, the immune system and healthy skin and hair
● Found in eggs, dairy products, meats, grains and green vegetables