Ketogenic, low-carb diets require diabetes medication adjustments
HOUSTON — Health care providers must consider revising medication regimens when a person with diabetes adopts a ketogenic or other low-carbohydrate eating plan that can affect glucose levels and blood pressure, according to a speaker at the American Association of Diabetes Educators annual meeting.
People with diabetes should be encouraged to make healthy dietary changes, Diana Isaacs, PharmD, BCPS, BC-ADM, CDE, clinical pharmacy specialist and CGM program coordinator in the department of endocrinology, diabetes and metabolism at the Cleveland Clinic Diabetes Center, said during her presentation.
“People with diabetes should have their choice in what type of meal plan they want to follow,” Isaacs told Endocrine Today. “Many enjoy low-carbohydrate eating, and the diabetes care team should work to support the person to do it in a healthy and safe way.”
A very low-carbohydrate diet can cause diuresis and a reduction in blood glucose levels, so people with diabetes and their providers should be especially vigilant about avoiding dehydration and hypoglycemia, Isaacs said.
Isaacs outlined several medication adjustments for people adopting a ketogenic or very low-carbohydrate eating plan.
Discontinue, use caution with some drugs
For people with type 2 diabetes, Isaacs recommends stopping sulfonylureas, meglitinides and mealtime insulin to prevent hypoglycemia. Alpha glucosidase inhibitors, which prevent digestion of carbohydrates, should not be needed by someone consuming little carbohydrate, so those agents can be discontinued as well.
SGLT2 inhibitors have been associated with euglycemic diabetic ketoacidosis and should be continued with caution if not and usually discontinued for those also taking insulin, Isaacs said. Consider discontinuing thiazolidinediones as well, since these agents are associated with weight gain.
BP medication with a diuretic effect can be halved depending on current BP management, according to Isaacs, and BP should be monitored closely.
Insulin adjustments for type 2 diabetes
For people with type 2 diabetes, Isaacs recommends reducing basal insulin by 30% to 50% and U-500 insulin by 50%.
“If someone is really committed [to a very low-carbohydrate meal plan] — they’re serious and they’re going to do this — I would rather err on the side of 50%, and we can always go up on their insulin, but I don’t want a hypoglycemic event,” Isaacs said. “Other things that come into play are the baseline HbA1c, of course. If you have a person with a 10% HbA1c vs. a person with 7%, how you do that adjustment will be different, closer to the 30% or the 50%.”
Combination products with short- and long-acting insulins should be traded for a basal insulin, according to Isaacs.
“I generally also will give a patient a rapid-acting insulin as a correction factor to simply say, ‘If your blood sugar goes over 150 [mg/dL], you’ve got this tool in your toolbox that you can correct for a high sugar,’” Isaacs said. “Also, it gives flexibility if they decide ‘this keto thing’s not for me,’ they have that insulin ready and we can give them a plan to replace their former 70/30 [combination insulin].”
Insulin adjustments for type 1 diabetes
People with type 1 diabetes adopting a very low-carbohydrate diet will require very little mealtime insulin, Isaacs said. However, they may find they need to intensify their carbohydrate ratio or even dose extra for high protein and fat foods, which may affect glucose levels but to a much lesser extent than carbohydrates.
“It’s a lot of tweaking, especially for people on insulin pumps,” Isaacs said.
She recommends people using an FDA-approved hybrid closed-loop system keep it in manual mode to lessen variability and follow-up with their health care provider often.
Basal insulin should be reduced by about 20%, Isaacs said, and patients must monitor ketones.
“The person would have small ketones if they are in ketosis, but if there’s medium or large increase accompanied with sickness or certainly nausea or vomiting, it is very important to stop this plan right away,” Isaacs said.
Hypoglycemia should always be treated, Isaacs said.
“A question I usually get is, ‘What do you do about hypoglycemia? You’re not supposed to eat carbs, so you can’t eat a glucose tablet.’ That is a dead stop,” Isaacs said. “If a person is having hypoglycemia, you need to treat the low.”
A continuous glucose monitor can help a user anticipate and prevent low blood glucose by consuming some protein, she said.
Constipation may occur with a very low-carbohydrate diet, but can be avoided by drinking enough water, at least 2 L per day, according to Isaacs. However, drinking too much water may lead to electrolyte imbalance, such as low sodium or potassium, and so these should be measured regularly and increased from food sources and additional supplementation, if needed.
“What I really want to convey is that adopting a ketogenic diet should be done under medical supervision,” Isaacs said. “Very low-carbohydrate eating can be a healthy plan with the right guidance, and as diabetes care and education specialists, we can help support our patients in what they are interested in trying.” – by Jill Rollet
Isaacs D. S15B. Presented at: American Association of Diabetes Educators; Aug. 9-12, 2019; Houston.
Disclosure: Isaacs reports no relevant financial disclosures.