“The Mediterranean diet is rich in foods that support overall health and help protect against diseases, including cancer,” says the lead study author, Inmaculada Aguilera-Buenosvinos, PhD, a researcher in preventive medicine and public health at the University of Navarra in Pamplona, Spain.
“While obesity is a known risk factor for many types of cancer, our study found that even without significant weight loss, people who follow a Mediterranean diet have a lower risk of developing obesity-related cancers,” Dr. Aguilera-Buenosvinos says.
Mediterranean Diet Improves Health Even if Weight Doesn’t Change
For the study, researchers examined data on about 450,000 adults who were 51 years old on average and had no history of cancer. At the start of the study, participants provided detailed information about their eating habits, lifestyle, and medical history, and had measurements taken for their height, weight, and waist circumference.
During a follow-up period of about 15 years, 4.9 percent of the study participants developed obesity-related cancers, according to findings published in JAMA Network Open. Those cancers included certain tumors that grow in the esophagus, breast, colon or rectum, uterus, gallbladder, stomach, kidneys, liver, bile ducts, ovaries, pancreas, thyroid, brain, and blood cells.
People who most closely followed a Mediterranean diet were 6 percent less likely to develop obesity-related cancers, the study found. Participants’ BMI and waist size didn’t appear to influence how much their eating habits impacted cancer risk, the study also found.
The Mediterranean Diet Is Rich in Antioxidants and Anti-Inflammatory Foods
While the study wasn’t designed to prove whether or how a Mediterranean diet might directly prevent cancer, this way of eating includes lots of anti-inflammatory and antioxidant-rich foods that might have a protective effect, Aguilera-Buenosvinos says. These foods include:
- Fruits and vegetables, which provide fiber, vitamins, and antioxidants that help reduce damage to cells.
- Legumes and whole grains, which support healthy digestion and help control blood sugar levels.
- Olive oil, which is rich in healthy fats that reduce inflammation.
- Fish and nuts, sources of omega-3 fatty acids, which may protect against chronic diseases.
At the same time, the Mediterranean diet limits processed foods, red and processed meats, and added sugars, which have been linked to increased cancer risk, Aguilera-Buenosvinos says.
“This combination of nutrient-rich foods and the reduction of harmful ones creates an environment in the body that is less favorable for cancer to develop,” Aguilera-Buenosvinos says.
Because obesity can lead to inflammation throughout the body that increases the risk of some cancers, the ability of the Mediterranean diet to reduce inflammation might reduce cancer risk even when people remain overweight or obese, says Kerry St. Pierre, a licensed nutritionist in New York City and the secretary of the cancer interest group at the American College of Lifestyle Medicine.
“Consuming an abundance of foods rich in antioxidants and anti-inflammatory nutrients such as those emphasized in the Mediterranean diet is especially important if obesity-related chronic inflammation is present, as it is likely these foods mitigate the damaging effects of low-grade systemic inflammation,” says St. Pierre, who wasn’t involved in the new study.
Other Lifestyle Factors May Have Influenced Lower Risk
One limitation of the study is that it relied on participants to accurately recall and report on what they ate. Another drawback is that there may have been too few participants who were overweight or had obesity to properly assess whether the Mediterranean diet helps prevent cancer by causing reductions in body weight or waist size.
It’s also possible that other aspects of participants’ lifestyles that weren’t measured by the study helped explain their reduced cancer risk, says Dawn Hershman, MD, the deputy director of the Herbert Irving Comprehensive Cancer Center at Columbia University in New York City.
“Mediterranean diet adherence is likely associated with many health behaviors that may reduce the risk of cancer,” says Dr. Hershman, who wasn’t involved in the new study. “While some were corrected for in this analysis, not all health behaviors may have been assessed.”
Even so, there are many health benefits to following a Mediterranean diet, including its potential to reduce cancer risk, says Graham Colditz, MD, DrPH, a professor and the associate director of prevention and control at the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine in St. Louis.
“Overall, the approach to eating focuses on a collection of foods and nutrients that could help lower cancer risk beyond the impact of weight control by itself,” says Dr. Colditz, who wasn’t involved in the new study.
How to Ease Into a Mediterranean Diet
A Mediterranean diet can make a difference even when you don’t eat this way for every single meal, Colditz adds.
“It’s great to start with small changes and build slowly from there,” Colditz says.
You might, for example, try adding more fruits, vegetables, and whole grains to one or two meals a week, or consider replacing red and processed meats with chicken, fish, or beans, Colditz suggests. You might also use olive oil instead of butter or other saturated fats for cooking.
When it comes to cancer prevention, however, there’s one piece of the Mediterranean diet that you may want to go without — the alcohol.
“While moderate drinking can be a traditional part of the Mediterranean diet, we know that zero alcohol is actually the best option when it comes to cancer risk,” Colditz says. “So cutting back on alcohol by choosing water or other low-calorie, low-sugar options can be a healthy change to work toward as well.”