Written by Kristen Fischer on October 5, 2018
Researchers investigate if the keto diet might help women with ovarian cancer.
The trendy and sometimes controversial keto diet has become popular with many hoping to shed weight while eating foods like bacon and eggs.
Initially, the diet, which is high in protein and low in carbs, was developed to help epilepsy patients in the 1920s. Now, nearly a century later, researchers are looking to see if the diet can have other medical purposes, like helping improve the health of cancer patients.
Researchers from the University of Alabama at Birmingham are investigating if the diet can help women with ovarian or endometrial cancer lose more body fat and reduce their insulin levels.
What did the study find?
Researchers examined 45 overweight or obese women with ovarian or endometrial cancer. They were randomly assigned to either the ketogenic diet or the American Cancer Society-recommended diet, which is a moderate- to high-carbohydrate, high-fiber and low-fat diet.
Compared to those who followed a low-fat diet recommended by the American Cancer Society (ACS), women with cancer who stayed on the keto plan for 12 weeks shed more body fat and had lower insulin levels. The researchTrusted Source was published in Journal of Nutrition.
But the experts caution that positive weight loss in cancer patients doesn’t mean that the diet is a treatment for the disease.
How can keto help?
The keto diet limits carbs, which are known to increase glucose and insulin. It forces the body to burn fat as fuel. Some of the fat is converted to ketones, which are used by the brain and many other tissues as another type of fuel.
“Because cancer cells prefer to use glucose, diets that limit glucose may be beneficial,” Barbara Gower, PhD, senior author and professor in the Department of Nutrition Sciences, said in a statement. “Because they limit glucose and several growth factors, ketogenic diets will limit the ability of cancer to grow, which gives the patient’s immune system time to respond.”
Previous studies have shown that the keto diet can have positive impacts on the development and outcomes related to cancer.
“First, it lowered insulin, which is a growth factor,” Gower explained. “High-glucose diets result in high insulin, which stimulates cancer cell growth. Second, this ketogenic diet resulted in selected loss of visceral fat.”
Gower explained that visceral fat is the “bad fat” that resides in the abdomen. Having this visceral fat is associated with elevated risk for cancer and diabetes.
Gower said the team also “noted that patients with higher ketones had lower levels of IGF-1. IGF-1 is also a growth factor that stimulates cancer cells.”
The study authors want to continue the research to see if the keto diet has impacts on cancer treatments.
Cancer-fighting keto? Not so fast
Carolyn Lammersfeld, RD, vice president of integrative medicine for the Cancer Treatment Centers of America, said that the research on using the keto diet to help cancer patients does not suggest that the keto diet should be routinely recommended outside of a clinical trial setting for any type of cancer or treatment.
“This study did not evaluate the impact of the diet on cancer outcomes,” she warned.
As for why the one group lost more weight, Lammersfeld said it is possible that the ketogenic diet resulted in lower calorie intake than the ACS diet due to the elimination of a significant number of foods. It is also possible that the metabolic effects of the ketogenic diet contributed to greater fat loss, Lammersfeld noted.
Leigh Tracy, RD, a dietitian and certified diabetes educator at The Center for Endocrinology at Mercy Medical Center in Baltimore, also advised people to remember that the study did not focus on whether or not the keto diet prevented or inhibited cancer growth — only on changes to the body including the fact that the diet reduced that patients’ central body fat, improved insulin levels, and improved lean body mass.
While it’s possible that adhering to the keto diet on a short term may lower body fat, more research is needed to look at the long-term effects of following the ketogenic diet.
Dr. J. Michael Gonzalez-Campoy, medical director and CEO of the Minnesota Center for Obesity, Metabolism, and Endocrinology, said that long-term nutritional eating plans — not diets — are better suited to help patients.
Though he admits weight loss can help people with estrogen-sensitive cancers, he said that the keto diet only offers temporary weight loss results. A 2010 case studyTrusted Source found that a post-surgical cancer patient on keto experienced slowed tumor progression, but progression returned when the patient went off the keto diet.
“For me, the focus is on optimizing nutrition, and on nutritional interventions as part of the therapy for chronic diseases,” he said. “Depriving the body of access to any major macronutrient changes metabolism and invariably has a negative impact on health. The best nutritional intervention for weight loss is a caloric-restricted, portion-controlled, well-balanced meal plan.”
A report on the Dana Farber Cancer Institute’s website states that benefits to following keto for cancer patients are not evident, and there are potential risks.
“It may be difficult for keto-dieters to meet their energy and protein needs, and the diet may cause long-term issues, including kidney damage, higher cholesterol levels, unintentional weight loss, bone loss, and certain vitamin and mineral deficiencies,” the article says. They say a more moderated approach to the diet may be advised, and cite evidenceTrusted Source that reducing refined carbohydrates and increasing the amount of healthy fats consumed can be beneficial to one’s overall health.
