Dietary intake during a Royal Navy submarine deployment

Abstract

Royal Navy (RN) submarines present a unique occupational setting that exposes individuals to confined space, a lack of natural light, disruptive working patterns, and limited opportunities for physical exercise. Restricted storage space and prolonged submersion also limits access to a variety of fresh food, which imposes a challenge to achieving an adequate total energy intake, and a nutritionally balanced intake to maintain health. Information on the dietary habits of operationally deployed submariners is limited, therefore this study aimed to monitor the dietary intake of RN submariners whilst deployed.Two cohorts of male submariners on separate operational deployments (SUB1: n = 36; SUB2: n = 60) completed a 4-day food diary early in the deployment (DIET 1) and within 2 weeks prior to the end of deployment (DIET 2). The deployment period at sea was 3 months, during which food provision was not replenished. Dietary intake data were analysed using a dietary assessment software package (DietPlan 6). The study was approved by the Ministry of Defence Research Ethics Committee (Ref: 0903/228) and volunteers provided informed consent. Data were tested for normality (Shapiro-Wilk test) before differences between early and late stage intakes were assessed using a paired sample t-test.There were no significant differences in the mean intakes of total energy and macronutrients across the deployment for either submarine cohort (Table 1).In conclusion, dietary intake of RN submariners was not different during the early and late stages of a 3-month submarine deployment. Whilst total energy intake was maintained, despite potential limitations from a provision perspective, it was lower than public health guidelines.1 Nevertheless, data are consistent with some 2 but not all 3 previously reported literature in submariner cohorts. Importantly, the energy requirement of the submariner occupational role has not been defined, therefore future work is required to determine energy expenditure to better inform dietary provision.

Global overview of dietary outcomes and dietary intake assessment methods in maritime settings: a systematic review

“…Of included studies -in the period of 1970 to 2019-the US researchers conducted the most studies [26][27][28][29][30][31]. Other countries according to the number of studies were as follow: UK [32][33][34][35], Germany [10,36,37], Denmark [8,38], Iran [39,40], India [41,42], China [43], Croatia [44], Italy [45], Brazil [46], Philippines [47], Lithuania [48], and Poland [6]. However, it appears that some of these studies from Germany [10,36,37], Denmark [8,38], Iran [39,40] and the US [27,29] are sub-projects conducted within the framework of a larger and more comprehensive program.…”

“…The following quantitative tools were used for dietary assessment: [6,10,42], 24 h dietary recalls [10,26], food diaries/ diet records (1, 4, 7 or 8 days) [27,[33][34][35], dietary habits questionnaire (even one or two questions) [8, 28, 30-32, 38, 40, 44, 45, 48], and food stores and food waste of the ship [35,41]. Additionally, health parameters related to nutrition such as anthropometric measurements [26,27], bioelectrical impedance analysis (BIA) [42], blood samples and the 24-h urine collections [27,29] were used.…”