Effects of Meal Composition on the Postprandial Blood Pressure, Catecholamine and Insulin Changes in Elderly Subjects

Abstract

1. The effects of four meals of similar energy, but different nutritional, composition on postprandial blood pressure, heart rate, autonomic function, catecholamines, insulin and packed cell volume levels were studied in seven fit elderly subjects. 2. The high carbohydrate and high protein meals led to a significant overall fall in supine systolic and diastolic blood pressure compared either with no change or a rise after the normal (i.e. mixed) and high fat meals. Similar between-meal differences were seen with erect diastolic but not erect systolic blood pressure. No significant postural blood pressure fall occurred after any of the meals. Supine heart rate was unaffected by meal type or by time, and although erect heart rate showed a small increase during the study there was no between-meal difference. 3. Parasympathetic function was unaffected by meal type. Plasma noradrenaline rose after the high carbohydrate and mixed meals only, remaining elevated for 120 min after meal consumption. This increase was not related to the changes in blood pressure or plasma insulin levels. 4. Plasma insulin and glucose rose after the high carbohydrate and mixed meals, but were unchanged after the high protein and high fat meals. Packed cell volume showed a small decrease towards the end of the study, although there was no between-meal variation. 5. The differences in the cardiovascular changes after the different meals could not be ascribed to alterations in autonomic function, insulin release or fall in plasma volume. We propose that the postprandial changes in blood pressure are due to the nutrient composition of the meal rather than the actual energy load.

The Influence of Food Ingestion on Blood Pressure in Stroke Patients

“…High carbohydrate meals may result in a greater reduction in BP than meals with high protein, high fat or mixed content [15]. Carbohydrate is thought to increase insulin and glucose, which can alter baroreceptor sensitivity [15]. Although encouraging patients to eat meals with a lower carbohydrate content may attenuate postprandial hypotension [16], it may be at the expense of reducing alveolar ventilation and thereby arterial oxygen tension during meals [17].…”

“…High carbohydrate meals may result in a greater reduction in BP than meals with high protein, high fat or mixed content [15]. Carbohydrate is thought to increase insulin and glucose, which can alter baroreceptor sensitivity [15].…”

“…Nutritional content, time or size of the meal may play an important part in postprandial BP changes in elderly subjects [15, 16]. High carbohydrate meals may result in a greater reduction in BP than meals with high protein, high fat or mixed content [15].…”

Carbohydrate as a nutrient in adults: range of acceptable intakes

“…The coordination of these vascular responses to food is dependent on normal functioning of the autonomic (especially the sympathetic) nervous system, and disruption of this can produce substantial reductions in blood pressure after a meal. Such an effect is particularly noticeable with elderly subjects consuming a high CHO meal, where postprandial hypotension can occur (Potter et al, 1989). This fall in blood pressure in the elderly is due to an inadequate cardiac output response, and a failure of vasoconstriction in the limbs, after a high CHO meal (Sidery et al, 1993).…”

Postprandial hypotension in older adults: Can it be prevented by drinking water before the meal?

“…The most common symptoms of postprandial hypotension are dizziness, nausea, weakness and light-headedness [1] but more severe consequences such as syncope have also been reported. Meal composition appears to play a role in postprandial hypotension because carbohydrates, particularly glucose, have the greatest blood pressure lowering effect [2]. Even older adult individuals with no history or symptoms of postprandial hypotension tend to show some degree of blood pressure reduction after ingesting a carbohydrate meal [3].…”