By Marcello Cherchi, MD PhD
For patients
Some people feel lightheaded during or after eating. This sometimes happens because during or after a meal your blood pressure or blood sugar (or both) drop too much. Your general medicine doctor may be able to figure this out, or may suggest that you talk with a cardiologist or endocrinologist.
For clinicians
Overview
Some individuals experience disequilibrium (usually manifesting as lightheadedness) postprandially. Potential proximal causes include postprandial hypotension and postprandial hypoglycemia. The underlying mechanisms of these problems have not been fully elucidated. Postprandial hypotension may be captured on ambulatory blood pressure monitoring. Postprandial hypoglycemia may be captured on ambulatory glucose monitoring.
Introduction
Some individuals experience disequilibrium during or after eating. The main mechanisms implicated in postprandial disequilibrium include postprandial hypotension and postprandial hypoglycemia.
Pathophysiological mechanism of disease
Postprandial hypotension can occur in otherwise healthy individuals, but appears more common in the elderly (Trahair, Horowitz, Jones 2014) and in the context of various neurological diseases (Pavelic et al. 2017). The mechanism of postprandial hypotension is unclear; proposals have included impaired sympathetic baroreflex function, release of vasodilatory peptides, gastric distension and splanchnic blood pooling (Jansen and Lipsitz 1995; Madden, Feldman, Meneilly 2021; O’Mara and Lyons 2002; Trahair, Horowitz, Jones 2014). Postprandial hypotension appears to be a different clinical entity than orthostatic hypotension (Jansen and Lipsitz 1995). It is probably best assessed by ambulatory blood pressure monitoring before a meal, and during or after a meal when the patient is symptomatic (Luciano, Brennan, Rothberg 2010; Nakajima et al. 1992).
In non-diabetic patients there has been debate about how common postprandial hypoglycemia is (Hofeldt, Adler, Herman 1975). Although the usual method for assessing postprandial hypoglycemia would be a glucose tolerance test, this appears relatively insensitive to the phenomenon (Brun, Fedou, Mercier 2000; Lefebvre et al. 1988), and some researchers suggest that measurement of blood glucose during a postprandial episode by ambulatory glucose monitoring (rather than merely in a laboratory setting) is more likely to secure the diagnosis (Palardy et al. 1989).
Testing
Practically, in a patient who experiences postprandial disequilibrium (usually manifesting as lightheadedness) fairly consistently, their internist may suggest ambulatory glucose monitoring and/or ambulatory blood pressure monitoring. Depending on those results, referral to cardiology or endocrinology may be appropriate.
Treatment
The materials distributed to patients with postprandial hypotension suggest generous hydration before a meal, eating smaller meals, reducing intake of rapidly digested carbohydrates, and simply being aware that the nadir of blood pressure tends to occur 30 – 60 minutes after a meal ([No authors] 2010).
There are relatively few treatment trials for idiopathic postprandial hypoglycemia (Galati and Rayfield 2014). Some studies of idiopathic postprandial hypoglycemia suggest that treatment with acarbose (taken with each meal) may be helpful (Peter 2003).
References
[No authors] (2010) Eating can cause low blood pressure. Postprandial hypotension can show up as dizziness or falling after a meal. Harv Heart Lett 20: 2.
Brun JF, Fedou C, Mercier J (2000) Postprandial reactive hypoglycemia. Diabetes Metab 26: 337-51.
Galati SJ, Rayfield EJ (2014) Approach to the patient with postprandial hypoglycemia. Endocr Pract 20: 331-40. doi: 10.4158/EP13132.RA
Hofeldt FD, Adler RA, Herman RH (1975) Postprandial hypoglycemia. Fact or fiction? JAMA 233: 1309.
Jansen RW, Lipsitz LA (1995) Postprandial hypotension: epidemiology, pathophysiology, and clinical management. Ann Intern Med 122: 286-95. doi: 10.7326/0003-4819-122-4-199502150-00009
Lefebvre PJ, Andreani D, Marks V, Creutzfeldt W (1988) Statement on postprandial hypoglycemia. Diabetes Care 11: 439-40. doi: 10.2337/diacare.11.5.439b
Luciano GL, Brennan MJ, Rothberg MB (2010) Postprandial hypotension. Am J Med 123: 281 e1-6. doi: 10.1016/j.amjmed.2009.06.026
Madden KM, Feldman B, Meneilly GS (2021) Baroreflex function and postprandial hypotension in older adults. Clin Auton Res 31: 273-280. doi: 10.1007/s10286-020-00671-8
Nakajima S, Otsuka K, Yamanaka T, Omori K, Kubo Y, Toyoshima T, Watanabe Y, Watanabe H (1992) Ambulatory blood pressure and postprandial hypotension. Am Heart J 124: 1669-71. doi: 10.1016/0002-8703(92)90118-f
O’Mara G, Lyons D (2002) Postprandial hypotension. Clin Geriatr Med 18: 307-21. doi: 10.1016/s0749-0690(02)00012-5
Palardy J, Havrankova J, Lepage R, Matte R, Belanger R, D’Amour P, Ste-Marie LG (1989) Blood glucose measurements during symptomatic episodes in patients with suspected postprandial hypoglycemia. N Engl J Med 321: 1421-5. doi: 10.1056/NEJM198911233212101
Pavelic A, Krbot Skoric M, Crnosija L, Habek M (2017) Postprandial hypotension in neurological disorders: systematic review and meta-analysis. Clin Auton Res 27: 263-271. doi: 10.1007/s10286-017-0440-8
Peter S (2003) Acarbose and idiopathic reactive hypoglycemia. Horm Res 60: 166-7. doi: 10.1159/000073227
Trahair LG, Horowitz M, Jones KL (2014) Postprandial hypotension: a systematic review. J Am Med Dir Assoc 15: 394-409. doi: 10.1016/j.jamda.2014.01.011
