BC prof: calorie-restricted diet can fight against cancer
Published: Thursday, October 4, 2007
Updated: Wednesday, January 9, 2013 18:01
We've all heard it before: A calorie-restricted diet is the key to good health. But Boston College biologist Dr. Thomas Seyfried is taking the old adage a step further and applying it to brain cancer.
He argues that a calorie-restricted diet with an emphasis on ketones (i.e., fat) is the way to prevent tumor mutations and growth. The science behind it is simple: normal cells can derive energy from both glucose and ketones, whereas mutated cancer cells are inefficient and only able to metabolize fuel from glucose.
Because glucose is the predominant energy source, both the liver and the kidneys are able to convert excessive fat, carbohydrates, and protein into glucose. But by cutting both the overall amount of calories as well as glucose, you can starve the cancer and provide nutrition for the rest of your body.
Furthermore, while on an unrestricted diet, tumor cells have superior receptors relative to normal cells for glucose absorption. On a restricted or ketogenic diet, however, the situation becomes increasingly competitive for the tumor cells. When glucose is restricted, the normal cell receptors become equally receptive and both types of cells are vying for the diminished supply.
Seyfried's theory stems from the junction of metabolic control theory and evolutionary biology. The former asserts the flexibility of normal healthy cells in transitioning between glucose and ketones for energy; the latter posits that human evolution is embedded in our genomes. This human ability to adapt to change has allowed us to survive the harsh climates by transitioning between energy sources. Cancer cells, however, are genetically unstable and remarkably inconsistent across individuals. These mutations prevent the cancer cells from adapting to ketone-derived sustenance.
He applied this theory to brain cancer in mice and found that those on the ketogenic diet were 12-15 percent lighter than mice on an unrestricted diet, and thus had a 60-80 percent reduction in tumor size (versus those on an unrestricted diet).
Researchers at the Wurzburg Hospital in Germany have applied Seyfried's diet to terminal human brain cancer patients and have found promising results. The patients who stuck with the ketogenic diet survived and their tumors slowed, stopped growing, or shrunk.
Seyfried argues that the current medical model of providing marijuana to cancer patients post-chemotherapy to induce hunger is actually hindering the patient's recovery. The subsequent gorging of food ultimately becomes glucose, thus feeding the tumor and speeding its growth. As he puts it, "the proof [of the efficacy of the current methods] is in the obituaries." He believes the only reason current methods work is because the nausea-inducing treatments reduce overall caloric intake, thus Seyfried says that alternatives to traditional cancer treatments exist. "We have a choice," he says, "we just don't know it."
Instead, he proposes use of the ketogenic diet to starve and minimize the tumors before beginning the poisonous chemo and radiation therapies. This outlook actually aids the pharmaceutical industry in that drugs that have failed initial clinical trials may find new life in a post ketogenic-diet testing.
A key point here is the cutting of calories (with the majority of intake being ketones), a vast difference from Atkins' "eat endless amount of fat and lose the weight" strategy that reached popularity in 2002. The remarkable ability of the liver and kidneys to convert any and all excessive intake to glucose hinders Atkins' theory.
Seyfried is not the first person to examine ketones; the diet was originally developed in the 1920s for epilepsy treatment. It was found that fasting decreased incidences of seizures.
We now realize that fasting decreases glucose levels and increases ketone levels, thus supporting Seyfried's hypotheses. The diet's popularity was renewed in the 1990s when a movie producer's son was diagnosed with severe epilepsy. His son's treatment was so exceptional that it inspired him to produce a movie in 1997 regarding their experience, First Do No Harm, starring Meryl Streep.