NUTRITIONAL INTAKE AND CARBOHYDRATE SUPPLEMENTATION AT HIGH-ALTITUDE

A high carbohydrate (CHO) diet has previously been shown to lessen the severity of the symptoms of Acute Mountain Sickness (AMS). The aims o f this study were to ascertain whether selected military field rations provided adequate nutritional support, and assess the effectiveness o f a high CHO food supplement in reducing the severity of the symptoms of AMS at high altitude. An experimental group (n = 32) received field rations plus a CHO food supplement and a control group (n = 35) only received field rations. Food intakes for 15 consecutive days were reco rded using a visual estimation technique and 24-h dietary log. Food ac ceptability was assessed with a 9-point hedonic scale. Daily urine sam ples and body weights were obtained from all subjects and a 24-h urine sample obtained from a subsample of the combined groups (n - 30) for the first and last two days of the study. Results show that energy int ake decreased for the first three days at altitude, improved on day fo ur and leveled out thereafter. Mean daily energy intakes were 2265 kca l for the supplemented group and 2140 kcal for the control group; body weight losses were 1.71 kg and 1.68 kg. Mean CHO intake was 271 and 2 44 g per day; 48 and 46% of energy intake. Ration acceptability was ge nerally good and did not decline over time. It was concluded that rati ons used at sea level could also be satisfactorily used at altitude, b ut given an ad libitum dietary regimen and a CHO food supplement, CHO intake was not automatically increased. Supplementation via a beverage component, rather than a food supplement, may therefore be more effec tive in increasing CHO intake.