Limitations of a diet touted for glucose management in diabetes
Original article from MedPageToday
The low-carb ketogenic diet is gaining traction among people with diabetes, though whether it has a role in cardiovascular disease is not as well characterized.
“Ketogenic diet” is a term that actually refers to several different types of diets, all which try to get the body to generate ketones from burning fat and have been effective in rapid weight loss and improvements in glucose levels, said Anand Rohatgi, MD, of UT Southwestern Medical Center in Dallas.
“The key in a ketogenic diet is what protein source is replacing the carbs,” he added. “From epidemiologic studies, it seems that replacement with animal sources of protein may not be healthy and in fact could be harmful compared to plant-based sources of protein. So the devil is in the details.”
In one small randomized study, patients with type 2 diabetes lost more weight and experienced more significant drops in hemoglobin A1c (HbA1c) after 8 months on a ketogenic diet compared with peers assigned instead to a low-fat diet endorsed by the American Diabetic Association. Moreover, 55% of the ketogenic group achieved HbA1c levels below 6.5% by the end of the study, compared with none of the controls.
Children and adults with type 1 diabetes may also achieve good glycemic control (mean HbA1c of 5.67%) with this diet, according to an observational study of 316 individuals.
While 69% of those study participants reported symptomatic hypoglycemia in the past month, most of them experiencing one to five episodes per month, the incidence of hospitalizations for hypoglycemia was nevertheless a low 1%.
Low blood sugar has been thought to be a risk of the ketogenic diet, especially for those also taking insulin.
Unknown Safety in the Long Run
Another caveat is that research is limited regarding long-term use of the low-carb meal plan.
A ketogenic or low-carb diet may be recommended to those who want to jump-start weight loss, but not as a maintenance diet, according to Rohatgi. Ultimately, patients with diabetes and/or heart disease especially should seek guidance from a dietitian if they are considering this diet, he said.
Notably, diabetes and heart disease often go hand in hand: patients with diabetes have an increased risk of developing heart failure, for example, and those with heart failure have an increased risk of developing diabetes.
New diabetes drugs are currently required by the FDA to be tested in cardiovascular outcomes trials following the 2007 discovery that a glucose-lowering agent was tied to cardiovascular risks.
The safety and efficacy of the ketogenic diet therefore is more complicated for diabetic patients who have cardiovascular disease or risk factors for it.
“There is no substantial evidence on the safety of the ketogenic diet for people who have heart disease,” according to Nisa Maruthur, MD, MHS, of Johns Hopkins University in Baltimore, who said she wouldn’t recommend this diet to anyone in particular given the lack of long-term safety data.
“For patients who are really interested in this diet, who do not have concerning or unstable health conditions, I let them know that we don’t have a lot of good evidence but that it’s okay to try. We know from decades of obesity and weight loss research that the best diet for a given person for weight loss is the diet that they can maintain,” Maruthur said.
“People with heart disease should talk with their healthcare providers before starting a ketogenic diet,” she stressed.
Alternatives to the Ketogenic Diet
In terms of sustainability and effectiveness, the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) nutritional approaches may be best for long-term health, according to Rohatgi.
A typical Mediterranean diet emphasizes vegetables, fruits, whole grains, beans, nut and seeds, and olive oil. Meat and dairy play less of a role. Studies have found this kind of diet to be protective against cardiovascular disease and perhaps even diabetes.
Similarly, the DASH diet prioritizes vegetables and fruits along with low-fat dairy, whole grains, fish, poultry, and nuts. Followers of the DASH diet adhere to sodium-restricted meals, however, which are currently recommended by the American hypertension guidelines.
A lower-sodium version of the DASH diet limits intake to 1,500 mg of sodium per day. An intervention that consisted of sending pre-made low-sodium DASH meals to heart failure patients failed in the first randomized trial evaluating the diet’s effects on outcomes.
Moreover, the whole concept of sodium restriction for heart health is being questioned by some researchers.
Yet the fact remains that people with diabetes often have high blood pressure. Certain behavioral and social risk factors — such as smoking and less education — have been associated with the onset of both conditions.
