Iron deficiency among Swedish military women doubles during training, study finds

10 Jul 2024 --- A collaborative study surveying conscripts at the Command and Control Regiment in Enköping, Sweden, observed the iron deficiency in female conscripts doubled from 25 to 55% during the five months of the evaluation. Conscripted men experienced roughly a 3% increase. Two of the study researchers give us a brief insight into the cause of the deficiency and potential nutrition and routine remedies.

“From this study, we cannot conclude that the diet itself is iron deficient. However, if the food available for the recruits, especially during longer field exercises, are not eaten due to lack of time to eat, fatigue, lack of time for recovery or that the recruits eat other foods with less iron content or other factors affecting food intake, then the iron intake can be limited,” Fabian Taube, medical research advisor, Swedish Armed Forces Center for Defense Medicine, lecturer at the University of Gothenburg and first author of the study, tells Nutrition Insight. 

The study aimed to assess variations in hemoglobin and ferritin concentrations in basic combat training (BCT) recruits. The secondary aim was to find predictors for missing training — a precursor for attrition, the decrease in strength from sustained attack — and overuse injuries during BCT.

The deficiency was detected before and after basic military training in Sweden. The study, published in the journal BMJ Military Health, is based on surveys of conscripts from a regiment that is a common resource in command and control for the Swedish Armed Forces.

Iron deposits
The study measured iron levels at baseline and after five months of basic military training. At the first measurement, 112 female and 148 male participants participated. Fifty-eight women and 104 men volunteered to take part in the second round of sampling and testing. 

According to the researchers, this study calls for increased attention and action to improve iron levels. The study shows that iron deficiency is as high in female conscripts as in the rest of the population for the given age group. The same applies to the proportion of women with anemia due to iron deficiency, with an incidence of 8%.

“Iron deficiency and especially iron deficiency anemia can, in general, cause fatigue, weakness, shortness of breath and decreased endurance, all of which can affect physical performance during military training, but more importantly, it might lead to an increased risk of overuse injury,”  Ingrid Larsson, associate professor of Clinical Nutrition at the University of Gothenburg and one of the co-authors, tells us.Swedish researchers have called for a heightened awareness of iron deficiencies during basic military training (Credit: Sverige Radio).

Larsson recommends early screening for iron deficiency before BCT and iron substitution when needed. The researcher also recommends increasing awareness of the benefits of a nutrient-dense diet on physical performance and health, especially during military training, and encouraging recruits to eat the food served during training.

“In terms of mental health, iron deficiency anemia can cause symptoms such as irritability, mood swings and decreased cognitive function.”

On average, the levels of hemoglobin increased during the study period. However, the levels of ferritin — a measure of iron deposits in the body — fell in the male and female participants. The decrease was significantly more significant for women than for men. 

Meanwhile, a retrospective cohort study of US veterans has found that higher doses of vitamin D supplementation reduced suicide attempts and intentional self-harm by up to 48%. Published in Plos One, the research identified the decreased risk as most significant in Black veterans with low blood serum levels.

Iron status related injuries
In gender-adjusted analyses, baseline ferritin was related to the risk of overuse injury. Still, neither baseline nor change in iron status was related to injuries or risk of missing training when controlling for confounders. 

Body mass increased significantly in both genders, but the researchers found no correlation between individual change in body mass and change in hemoglobin or ferritin. Body mass change was also unrelated to the risk of overuse injury or missing training.

“From this study alone, we cannot conclude specific reasons (for the iron reduction), except that there was a significant reduction of stored iron in the body during the five months of BCT, especially in women,” says Taube.

“One plausible reason though, could be the high levels of physical activity during BCT. From earlier studies on female and male adolescent athletes it has been shown that high levels of physical activity decrease the ability of the body to absorb and accumulate iron.”

Researchers from the Sahlgrenska Academy at the University of Gothenburg, Sahlgrenska University Hospital, the Swedish School of Sport and Health Sciences in Stockholm, the Swedish Armed Forces Center for Defense Medicine in Gothenburg and the Command and Control Regiment in Enköping, collaborated on the study.

Influenced by diet
Iron deficiency is often accompanied by fatigue, lethargy, attention deficit, dizziness and headaches. Iron levels are mainly influenced by the diet and blood loss during menstruation among women. 

“The results of the study highlight the importance of paying attention to iron levels and potential iron deficiency among conscripts and to discuss causes and measures that should be implemented,” says Taube. 

“Given the central role of iron in health, this is an important discussion that not only concerns the Armed Forces,” adds Larsson.

The study also found that high physical work capacity at the time of enlistment was related to a lower risk of having adapted service. Adapted service is when a soldier does not fully participate in intensive training sessions, often due to injury or illness. Adapted service can be seen as a risk factor for discontinuing training.

In addition, US-based food-tech company Nutrient Survival, which develops Special Ops Grade nutrition, shed light on the issue of food scarcity among military members in support of US Army Pacific Chaplains’ Operation Helping Hand to show appreciation to active duty military personnel for their service.

By Inga de Jong