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Nutrients like iron and calcium are crucial to blood and bone health. But more than half of the world’s population doesn’t eat enough of these and five other nutrients that are also crucial to human health, according to a new study.
More than 5 billion people don’t consume enough iodine, vitamin E or calcium, the study published Aug. 29 in the journal The Lancet Global Health found. And more than 4 billion people have inadequate intakes of iron, riboflavin, folate and vitamin C.
“Our study is a major step forward,” said study co-lead author Dr. Christopher Free, an assistant research scientist in the Marine Science Institute and the Bren School of Environmental Science and Management at the University of California, Santa Barbara, in a press release. Free also specializes in human nutrition.
That’s “not only because it is the first to estimate micronutrient deficiencies for 34 age groups in almost every country,” Free added, “but also because it makes these methods and results easily accessible to researchers and practitioners.”
Previous studies have shown that there are micronutrient deficiencies or inadequate supplies of foods containing these nutrients worldwide. However, the most recent research shows that there are no global estimates of the intakes that are considered inadequate based on nutritional needs.
For these reasons, the research team estimated the prevalence of inadequate intakes of 15 micronutrients across 185 countries, or 99.3% of the population. They did this through modelling, applying a “globally harmonised set of age- and sex-specific dietary requirements” to data from the 2018 Global Dietary Database, which provides intake estimates based on data from individual-level surveys, household surveys, and national food inventories.
The authors also found differences between women and men. Women were more likely than men to not get enough iodine, vitamin B12, iron and selenium. However, men did not get enough magnesium, zinc, thiamine, niacin and vitamins A, B6 and C.
There were also geographical patterns. In India, inadequate intakes of riboflavin, folate, and vitamins B6 and B12 were particularly high, while poor calcium intake was highest in South and East Asia, sub-Saharan Africa, and the Pacific.
“These results are alarming,” study co-author Ty Beal, a senior technical specialist at the Switzerland-based Global Alliance for Improved Nutrition, said in the press release. “Most people — even more than previously thought, in all regions and countries of all incomes — are not consuming enough of multiple essential micronutrients. These gaps are jeopardizing health outcomes and limiting human potential on a global scale.”
While the findings are unique, they are consistent with what other, smaller, country-specific studies have found over the years, Dr. Lauren Sastre, assistant professor of nutritional sciences and director of the Farm to Clinic Program at East Carolina University in North Carolina, said via email.
“This is a valuable study,” added Sastre, who was not involved in the research.
The study has several important limitations. First, since the study did not include consumption of supplements and fortified foods, some of the deficiencies found in the study may not be as severe in real life if some people consume supplements and fortified foods that would theoretically increase their intake of certain nutrients, the authors said. However, supplementation and fortification with many of the other nutrients studied is uncommon worldwide, the authors said.
But 89 percent of people worldwide consume iodized salt, according to UNICEF. “Therefore, iodine may be the only nutrient whose inadequate dietary intake is largely overestimated,” the authors said, citing their findings.
“My only criticism is that they left out potassium, because there are no standards,” Sastre said. “We certainly have (a recommended daily allowance of) potassium in the U.S., and most people don’t consume nearly enough of it. And it has to be balanced with sodium. We have people who consume far too much sodium, and not nearly enough potassium, which is critical for blood pressure (and) heart health.”
In addition, there is a scarcity of more complete information on global individual dietary intake, particularly datasets that are nationally representative or contain more than two days of intake, the researchers said. This scarcity limits researchers’ ability to validate their modeled estimates.
Although the team found that inadequate intakes were present, they did not have data on whether these led to deficiencies that would need to be determined by a doctor or dietitian based on blood tests and/or symptoms.
Dietitians and doctors can help you determine whether you are getting enough of certain vitamins or minerals or whether you have deficiencies that have been detected by a blood test.
“Micronutrients play a critical role in cellular function, immunity (and) metabolism,” Sastre said. “However, we are not consuming fruits, vegetables, nuts, seeds, whole grains — where they are. We need to follow the American Heart Association’s recommendation to ‘eat the rainbow.'”
Below is a list of reasons why the seven nutrients with the lowest global intakes are important and some foods rich in them:
1. Calcium
● Important for strong bones and overall health
● Found in dairy products and fortified soy, almond or rice alternatives; dark green leafy vegetables; tofu; sardines; salmon; tahini; and fortified orange or grapefruit juice
2. Folic acid
● Important for red blood cell formation and cell growth and function, especially during pregnancy
● Found in dark green vegetables, beans, peas, lentils and fortified grains such as bread, pasta, rice and breakfast cereals
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 the oxygen supply to the body and for growth and development
● Found in oysters, duck, beef, sardines, crab, lamb, fortified cereals, spinach, artichokes, beans, lentils, dark leafy greens and potatoes
5. Magnesium
● Important for muscle and nerve function, blood sugar levels, blood pressure and the production of proteins, bones and DNA
● Found in legumes, nuts, seeds, whole grains, leafy greens and fortified cereals
6. Niacin
● Important for the nervous system and digestive system
● Found in beef, chicken, marinara sauce, turkey, brown rice, pumpkin seeds, salmon, and fortified cereals
7. Riboflavin
● Important for the metabolism of food for energy, the immune system and healthy skin and hair
● Found in eggs, dairy products, meat, grains and green vegetables