Assessment of dietary intakes of cadets at the US Military Academy at West Point

Dietary Intakes From Ad Libitum Consumption of Canadian Armed Forces Field Rations Compared With Usual Home Dietary Intakes and Military Dietary Reference Intakes

INTRODUCTION

Diet has an impact on weight status, health, and physical performance. Assessing the usual at-home dietary intakes of military personnel can help ascertain their nutritional status before field training or operations. Preference for foods consumed on a routine basis can also impact the military's preference for and consumption of field rations. Military personnel are limited by the inherent nature of the field rations and availability of calories and food types; and despite previous studies indicating a high acceptability of the field rations, it is unknown whether military personnel self-select the same number of calories when faced with a restricted list of field ration options as they would from their usual foods. Although field rations are intended to be nutritionally sufficient for standard military operations, there are limited data on the ad libitum intake of nutrients of Canadian Armed Forces (CAF) personnel from field rations in comparison to the military dietary reference intake (MDRI) recommendations, which establishes standards intended to meet the nutritional requirements of military personnel on duty. Thus, assessing the adequacy of their usual diets at home and longer-term sustenance on field rations in relation to MDRIs can provide insight on CAF personnel's operational readiness. The objectives of this study were to describe and compare, in a convenience sample of CAF, their ad libitum nutrient intakes from the consumption of self-selected field rations at home with their usual home intakes and to compare both with MDRI recommendations.

MATERIALS AND METHODS

Eighteen CAF participants weighed and recorded their dietary intake from the ad libitum consumption of field rations at home and their usual at-home diets. Both MDRIs and the Institute of Medicine's dietary reference intake recommendations were used to assess the adequacy of intakes for each individual. Paired Student's t-test or Wilcoxon-matched paired tests were used to compare nutrient intake levels between usual at-home diets and field rations consumed at home.

RESULTS

Mean daily energy intakes were similar between ad libitum intakes from field rations (2,688 ± 619 kcal) and usual home diets (2,657 ± 580 kcal), although participants had significantly higher intakes of protein and fat from their home diets and higher intakes of carbohydrates from the field rations (P ≤ 0.05). Participants had less than the recommended intakes of some micronutrients (vitamins A and D, folate, calcium, magnesium, and potassium), from both their home diets and field rations, but adequate intakes of vitamin C and iron.

CONCLUSIONS

The results of this study showed no difference in energy intake between the consumption of field rations and home diets, with levels consistent with recommendations for individuals with average physical activity levels. The results also demonstrated less than the recommended intakes (in comparison with MDRIs) of some nutrients from both home diets and self-selected consumption of field rations, warranting further research into nutritional adequacy for operational readiness.

Negative energy balance during military training: The role of contextual limitations

During multiday training exercises, soldiers almost systematically face a moderate-to-large energy deficit, affecting their body mass and composition and potentially their physical and cognitive performance. Such energy deficits are explained by their inability to increase their energy intake during these highly demanding periods. With the exception of certain scenarios in which rations are voluntarily undersized to maximize the constraints, the energy content of the rations are often sufficient to maintain a neutral energy balance, suggesting that other limitations are responsible for such voluntary and/or spontaneous underconsumption. In this review, the overall aim was to present an overview of the impact of military training on energy balance, a context that stands out by its summation of specific limitations that interfere with energy intake. We first explore the impact of military training on the various components of energy balance (intake and expenditure) and body mass loss. Then, the role of the dimensioning of the rations (total energy content above or below energy expenditure) on energy deficits are addressed. Finally, the potential limitations inherent to military training (training characteristics, food characteristics, timing and context of eating, and the soldiers' attitude) are discussed to identify potential strategies to spontaneously increase energy intake and thus limit the energy deficit.

Dietary Assessment Methods in Military and Veteran Populations: A Scoping Review

Optimal dietary intake is important for the health and physical performance of military personnel. For military veterans, the complex nature of transition into civilian life and sub-optimal dietary intake is a leading contributor to the increased burden of disease. A scoping review was undertaken to determine what is known about the assessment and reporting of dietary intakes within both military and veteran populations. In addition, this review determines if studies reporting on the dietary intake of military personnel or veterans include comparisons with dietary guidelines. Six databases were searched to identify papers published from the database inception to April 2019. Observational and intervention studies were searched to identify if they assessed and reported whole dietary intake data, reported data exclusively for a military or veteran population, and included only healthy populations. A total of 89 studies were included. The majority of studies used one dietary assessment method (n = 76, 85%) with fewer using multiple methods (n = 13, 15%). The most frequent methodology used was food frequency questionnaires (FFQ) (n = 40, 45%) followed by 24-hour recalls (n = 8, 9%) and food records (n = 8, 9%). The main dietary outcomes reported were macronutrients: carbohydrate, protein, fat, and alcohol (n = 66, 74%) with total energy intake reported in n = 59 (66%). Fifty four (61%) studies reported a comparison with country-specific dietary guidelines and 14 (16%) reported a comparison with the country-specific military guidelines. In conclusion, dietary intake in military settings is most commonly assessed via FFQs and 24-hour recalls. Dietary intake reporting is mainly focused around intakes of energy and macronutrients. Most studies compare against dietary guidelines, however, comparison to specific military dietary guidelines is minimal.

A systematic review and meta-analysis on the prevalence of dietary supplement use by military personnel

Background

Although a number of studies have been conducted on the prevalence of dietary supplement (DS) use in military personnel, these investigations have not been previously summarized. This article provides a systematic literature review of this topic.

Methods

Literature databases, reference lists, and other sources were searched to find studies that quantitatively examined the prevalence of DS use in uniformed military groups. Prevalence data were summarized by gender and military service. Where there were at least two investigations, meta-analysis was performed using a random model and homogeneity of the prevalence values was assessed.

Results

The prevalence of any DS use for Army, Navy, Air Force, and Marine Corps men was 55%, 60%, 60%, and 61%, respectively; for women corresponding values were 65%, 71%, 76%, and 71%, respectively. Prevalence of multivitamin and/or multimineral (MVM) use for Army, Navy, Air Force, and Marine Corps men was 32%, 46%, 47%, and 41%, respectively; for women corresponding values were 40%, 55%, 63%, and 53%, respectively. Use prevalence of any individual vitamin or mineral supplement for Army, Navy, Air Force, and Marine Corps men was 18%, 27%, 25%, and 24%, respectively; for women corresponding values were 29%, 36%, 40%, and 33%, respectively. Men in elite military groups (Navy Special Operations, Army Rangers, and Army Special Forces) had a use prevalence of 76% for any DS and 37% for MVM, although individual studies were not homogenous. Among Army men, Army women, and elite military men, use prevalence of Vitamin C was 15% for all three groups; for Vitamin E, use prevalence was 8%, 7%, and 9%, respectively; for sport drinks, use prevalence was 22%, 25% and 39%, respectively. Use prevalence of herbal supplements was generally low compared to vitamins, minerals, and sport drinks, ≤5% in most investigations.

Conclusions

Compared to men, military women had a higher use prevalence of any DS and MVM. Army men and women tended to use DSs and MVM less than other service members. Elite military men appeared to use DSs and sport drinks more than other service members.

Nutrition consumption of female combat recruits in army basic training

PURPOSE

The Karakal is an existing light infantry unit consisting of both female and male fighters (predominantly female). This was the first Israel Defense Forces study to assess and to evaluate the dietary intake among male and female recruit fighters in comparison to nonfighters from preinduction through Army Basic Training (ABT).

METHODS

One company of Karakal recruits plus a control group of female medics were assessed for dietary intake at three time points: day of recruitment, 2 months into ABT, and at the end of 4 months ABT, using validated Food Frequency Questionnaires. Means of dietary intake were presented and compared with the Military Dietary Reference Intakes (MDRI).

RESULTS

This study included 92 Karakal females (KF), 33 Karakal males (KM), and 48 control females (CF) aged 18-19 yr. Mean energy and calcium intakes at preinduction for KF were 90% and 71% of MDRI, respectively. These values were significantly lower than CF values (108% and 88%). Both groups of females consumed 57% of vitamin D. The KM intakes were similarly deficient. At preinduction, deficiencies were greater among recruits who first volunteered for 1 yr of national service (NS). During ABT, average dietary intakes decreased in all groups. Values for KF and CF were as follows: energy intake = 80% and 71%, respectively; Ca = 61% and 49%, respectively; Zn = 71% and 57%, respectively; and vitamin D = 34% and 24%, respectively. The diet of all groups met the MDRI requirements for protein, vitamin B6, and vitamin B12.

CONCLUSIONS

Karakal fighters' food consumption during ABT did not meet most MDRI nutrient requirements. Females entering the army directly from a home environment began with a nutritional status that met MDRI requirements, unlike those inducted after 1 yr of NS away from home. Deficiencies need further investigation as they may have a negative impact on soldiers' health and physical performance.