Effects of Cyclic and Continuous Total Enteral Nutrition on Circadian Cortisol Rhythm

Abstract

To clarify relationships between the pattern of diet intake and the circadian adrenocortical rhythm, we measured plasma cortisol levels at circadian intervals in two groups of patients who had been receiving total enteral nutrition (TEN) for about 11 days: one group was given a liquid diet intraduodenally and continuously (continuous TEN), whereas the other received their nutrition discontinuously from 0700-2300 h every day (cyclic TEN). In patients with cyclic TEN there was a clear cortisol rhythm with a peak at 0700 h, which pattern is quite similar to the well-established cortisol rhythm seen in normal subjects. However, patients with continuous TEN did not show any consistent circadian cortisol rhythm, although the 24-h mean cortisol level was nearly the same as that in the case of cyclic TEN. Plasma glucose levels showed circadian fluctuations in the cyclic TEN group, but remained fairly constant in the continuous TEN group. These results indicate that the periodicity of nutrient intake is essential for the maintenance of the circadian cortisol rhythm and suggest the importance of the timing of diet intake as a synchronizer (zeitgeber) of the rhythm in man, as proposed in laboratory animals.

Effects of Cyclic and Continuous Total Enteral Nutrition on 24-h Rhythms of Body Temperature and Urinary Excretions.

“…Our previous results (2,3) clearly showed that the phase of the cortisol rhythm was shifted by changing the daily pattern of diet infusion, suggesting a synchronizing effect of food intake on the adrenocortical rhythm in man as well as in laboratory animals. To extend this view and to confirm the relationship between diet intake and circadian rhythm of other physiological activities in man, in this study we examined 24-h patterns of body temperature and urinary excretions in the same patients as in the previous study (3): that is, they were kept under a schedule of either continuous or cyclic TEN.…”