Carbs will be out, fats will be in, if a ketogenic diet proves to be a tool in the battle to fight cancer.
A ketogenic diet starves cancer cells of glucose, thereby stunting the disease’s growth and compelling the body to burn fats, which trigger the production of compounds called ketones that, scientists hypothesize, cancer cells can’t use for fuel. The effectiveness of the diet, which should only be used in consultation with a doctor, is in the pilot-study phase of human research.
The diet may work for other reasons: Like a campfire burning wood, cells burning glucose for energy undergo incomplete combustion, thus creating free radicals of oxygen that can damage DNA. In addition, scientists are increasingly studying the insulin the pancreas produces in response to glucose. It appears to trigger a cascade of actions that may stimulate cancer’s growth. Close to a century ago, German scientist Otto Warburg first suggested that glucose may play a role and in 1931 won a Nobel Prize for identifying cancer as a sugar feeder.
Recently, two American scientists collected a smaller prize for their pilot study. Dr. Eugene Fine, a physician and professor at Yeshiva University’s Albert Einstein School of Medicine in the Bronx, N.Y., and his colleague, Richard Feinman, professor of cell biology at State University of New York’s Downstate Medical Center took 10 patients with advanced cancers who had failed or refused standard chemotherapy and put them on ketogenic diets for 28 days, then looked at tumors on PET scans. Patients with the least ketosis (which they defined as least insulin inhibition) showed progressive disease whereas higher levels of ketosis were accompanied by stable disease or partial remission, they reported.
“We think what’s important is that we may have opened a door, long overdue, to studying dietary change as a component of cancer therapy,” Fine said, cautioning against reading too much into a small study.
Ultimately these scientists hope to identify which cancers might best respond to carbohydrate restriction. “For sure, they all won’t,” Fine said. The common slow-growing form of prostate cancer, he said, feeds on fats as well as glucose and glutamate, a protein that’s been implicated in a few cancers. “Even within a single individual with a primary cancer and metastases, the cancer’s behavior … can vary from one cell to the next.”
Ketogenic diet research takes off
Ketogenic diets are actually ancient. That’s how cave dwellers ate, Fine explained, and today’s paleo movement and the similar Atkins approach are bringing them back.
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Johns Hopkins Medicine in Baltimore has been using forms of a ketogenic diet since the 1920s to control epileptic seizures.
But in the cancer field, clinical trials of ketogenic diets are just sprouting up. Among the scientists touting the “fat as fuel” approach is Dr. Craig Thompson, the president and CEO of Memorial Sloan-Kettering Cancer Center in New York City. Thompson founded a private company that’s helping develop drugs to lower glucose and glutamine.
In his recent book, Boston College biology professor Thomas Seyfried takes the ketogenic diet one big step further. He advocates that patients fast periodically. There’s nothing more powerful than calorie restriction in reducing a tumor’s ability to grow blood vessels and spread, he said.
The diet he proposes includes 70% of calories from fat, 12% to 15% from protein, and the rest from carbs. How low carb is that? According to Fine, you need to eat 50 grams of carbs or less a day to get your body into a state of ketosis, where it produces ketones as a result of utilizing fat as its main energy source. The typical U.S. diet provides 250 to 400 grams daily.
Do the types of fat matter? Like the answers to most questions, it depends on whom you ask. Many versions of the ketogenic diet may include bacon and butter, albeit not on toast, but why consume saturated animal fats that are known to promote inflammation and disease? Unsaturated fats, such as those found in avocado and nuts, are good for your heart and may help control insulin. Omega 3 fats, abundant in fatty fish and flaxseed, fight inflammation.
And coconut fats contain medium-chain triglycerides, a type of fat that promotes the production of ketones. How about low-calorie vegetables immersed in high-fat coconut milk? One day that might be just what the doctor orders.
Top photo: A ketogenic diet of fats such as avocados, nuts and seeds is the focus of cancer research. Credit: Harriet Sugar Miller