Findings of a study on the relationship between a high-fat diet and cancer was published in the August 12, 2017 edition of the Journal of the Academy of Nutrition and Dietetics.
Lead researcher was Cynthia Thompson, a professor at the University of Arizona’s Zuckerman College of Public Health.
Not involved in the study but welcomed onboard to interpret unexpected test results was Marji McCullough, strategic director of nutritional epidemiology for the American Cancer Society.
Chips and Candy Bars
Test participants numbered more than 92,000 and were women between the ages of 50 and 79 at the start of the study. The research project was initiated by the women providing detailed information on their eating habits. From this information, Thompson’s team calculated the calorie-density of each woman’s typical diet.
Calorie-dense foods are relatively low in nutrients and are recognized as generally being processed foods (chips, crackers, and prepared dressings), fast foods (cheeseburgers and pizza) and candy bars. Such foods were described in the context of a person ending up eating a whole bowl of them before feeling satisfied, thus downing a lot of calories with little nutritional value.
The study was conducted over a 15-year period and was based on statistics that obesity is linked to malignancies of the breast, colon, kidneys, ovaries and to endometrial cancer.
Study results demonstrated that those who favored high-calorie, low-nutrient foods had a 10% higher risk linked to obesity than their counterparts.
During the 15 years, just under 9,600 women developed cancers that have been tied to obesity—most commonly of the breasts and colon.
While the study only found an association, the odds of developing cancer were slightly higher in general among the women who favored calorie-laden foods.
Those who ate the most calorie-dense foods (enough to land them in the top 40%) were 12-18 % more likely to develop an obesity-related cancer, versus the women who ate relatively few of those foods. And that was with other factors considered, to include age, overall health, smoking, drinking, and exercise habits.
Another study, published in the July 6th issue of Stem Cell, reports “how a research team showed in pre-clinical trials that cancer stem cell growth was enhanced by a high-fat Western diet. Cancer stem cells are a subset of resilient, aggressive malignant cells that are believed to be partially responsible for spread and recurrence of cancer.”
“Furthermore, when the researchers blocked a cellular signaling pathway known to promote tumor growth, the spike in cancer stem cell growth caused by the high-fat diet declined.”
“This study provides more insight into how the … pathway is linked to diet-related cancer. Pinpointing the exact mechanism can help researchers develop therapeutics to counteract the negative effects of a Western diet.”
As the data was shaken down, it became apparent there was a confusing outcome: The group of women demonstrating increased incidences of cancer were those of normal weight.
But, if dietary quality mattered, why was there no link among heavier women?
“Metabolic dysregulation” might partly explain the higher cancer risk seen in this study, Thompson and her colleagues speculated.
Metabolic dysregulation is also referred to as metabolic syndrome. It’s a diet-induced state involving insulin resistance, obesity, hypertension and is a known cancer risk. Calorie-dense foods pack a lot of calories relative to their weight.
McCullough pointed to another possibility: People who eat lots of calorie-laden foods tend to eat few “plant-based” foods, including fruits, vegetables, beans and whole grains. That means they’ll be low on fiber, vitamins, and other nutrients that may help curb the risk of certain cancers.
Another possibility she posed was that the effects of a person’s excess weight “overwhelmed” any impact of the foods taken in.
Thompson pointed to another possibility: Normal-weight women who ate a lot of calorie-dense foods may have had a more dramatic weight gain later in life. While the researchers had some information relative to weight gain, they did not have data for the entire study period. And so, this input was conjectural.
Staying Thin Is Not Enough to Stay Healthy
Therefore, staying thin, alone, is not enough to curb the risk of these cancers. Being thin doesn’t translate into being “metabolically healthy”, with normal blood sugar, cholesterol and triglycerides, for instance.
“The bottom line is fairly simple,” according to McCullough. “Eat more plant-based foods.”
Alice Smith, contributor to the Pharma & Healthcare site, tells us that “science has shown that what we eat is linked to everything from diabetes to dementia to cancer.” A typical American diet is noted to be between 20% and 40% fat.
Noting today’s emphasis on avoiding fatty foods, she reminds us to eat them wisely and to not cut them out entirely as we do need fat to live.
Processed Sugars and Fats
She goes on to say that “if the no-fat craze of the 80s has taught us anything, it’s that processed sugars in excess are at least as bad for our health as diets high in fat.”
Alice leaves us with the information that “As a group, fats are not the culprits we once believed. But, like anything else in extreme amounts, fats can do damage to the body over time. So, moderation is (though we may not like to hear it) generally a good rule of thumb.”
Focus on Plant Foods
From Karen Collins, MS, RDN, the “Health Talk” blogger for the online American Institute for Cancer Research site, we learn additional directions for a healthy diet:
“Common guidelines are to limit fat from red meats (beef, pork and lamb) and especially from processed meats. And to make plant foods the focus of our diet by centering meals and snacks around vegetables, fruits, whole grains, and beans. These offer a wide range of nutrients, protective phytochemicals, and dietary fiber."
Beware of Fat Phobia
Also, she warns us “to not become ‘fat phobic’ as portions of fat, appropriate to overall caloric needs, will not derail weight management. And (they will) provide valuable nutrients while making healthy eating choices.”
And she admonishes us to remember that “removing fear of fat does not mean giving a green light to all high-fat foods. Focus on overall quality of foods you eat to promote health and reduce cancer risk.”
She additionally encourages us to “enjoy healthful oils to flavor foods while keeping total calories in check. With hunger-satisfying eating patterns that include abundant vegetables, modest amounts of oil we don’t need send total daily calories over the top.”
Enjoy Healthy Fats
A diet high in fat is also acknowledged as an indicator for obesity (which is a risk factor for cancer).