The Search for the Perfect Cancer-Fighting Superfoods
Article originally written by Karen Collins, MS, RDN, CDN, FAND and Nutrition Advisor for the AICR.
Sometimes it seems like we're witnessing a battle of superfoods, as we alternately hear that grapes, blueberries, broccoli or kale is the ultimate top choice. But I find myself confused about how to answer when I am asked, "Which are the best cancer-fighting fruits or vegetables?"
It's like the question of whether it's the all-star player or a strong team that's the key to victory.
"A food doesn't need to be a rockstar source of one of the nutrients or compounds that may protect against cancer. A healthy diet is made up of strong players and ultimately it is the overall eating pattern that wins the day."
The Quest for the Best Superfood
When people hear about the powerful role diet can play in reducing risk of cancer, it's not surprising that they wonder about the "best" foods to provide protection. And you hear claims touting a wide range of foods as "superfoods" - supposedly providing the ultimate amounts and combinations of nutrients and natural plant compounds for antioxidant, cancer-fighting power.
In that search, it's easy to overlook some key points.
A superfood is defined in the eye of the beholder. In some cases, that can be from the perspective of a brand or retailer with food to sell, or an author or editor with publications or Internet "clicks" to sell. Sometimes it's a carry-over from cultural traditions or ideas passed down within families.
Foods can offer scores of nutrients and protective compounds, but none "does it all". Early research on diet and cancer prevention focused on a few antioxidant nutrients. New studies show a wide range of nutrients, several kinds of fiber, and thousands of phytochemicals that offer the potential for protection through gene expression, cell signaling, anti-inflammatory support and more. No single food - and not even a top 10 list of "superfoods" - can provide all of them.
The AICR Food Facts library has a section called Foods that Fight Cancer. Here you can learn about a number of foods and what evidence from laboratory studies and from human studies shows so far about their potential to protect against cancer. This is far from a complete list of foods that contribute to a diet to lower cancer risk. But it's a starting point in understanding how a variety of foods contribute in different ways.
Lots of foods, like those listed in the Food Facts library, are good choices, but none is essential. If there's a food you don't like or have reasons to avoid, that's fine. There's no need to push it. On the other hand, maybe you realize that your typical food choices provide little variety. Not only can that make healthy eating seem boring, it also limits the range of nutrients and compounds in your diet. So if the lists and recipes on the AICR website prompt you to step outside the box and expand your choices, that's great.
Foods' cancer-fighting power doesn't happen overnight. So a food that's "super" for you also needs to fit your budget, health conditions, cultural traditions and flavor preferences. That said, just because you tried a healthful food before and didn't like it, don't disregard it too quickly. A different flavoring, preparation method, or companion foods could make it one of your new favorites!
A food doesn't need to be a rockstar source of one of the nutrients or compounds that may protect against cancer development and spread. Some foods are team players that add moderate amounts of healthful compounds and play well with other foods to create a meal - and overall eating habits - that promote good health and lower cancer risk.
Misunderstandings Over Dietary Patterns
The consistent conclusion from current research about diet to reduce risk of cancer is that protection doesn't come from massive amounts of superfoods. It is overall eating habits that show the strongest potential.
There are lots of ways to create a plant-focused diet. Research often uses the term "plant-based diet" when referring to an eating pattern that makes plant foods like vegetables, fruits, whole grains, and pulses the largest part of the plate. Some individuals or groups use "plant-based diet" to refer to a plants-only diet. But that's just one way to create a plant-focused eating pattern.
A plant-forward eating style is a clear winner over Western-style eating habits. Research on various types of eating patterns is generally not comparing one plant-focused diet to another. Studies typically compare some version of a mainly plant-based diet to a Western diet. A Western diet is high in red and processed meats, refined grains and sweets, and sugar-sweetened beverages; and low in vegetables, fruits and whole grains. It's sometimes called the SAD (Standard American Diet) because it is, unfortunately, very common.
Typical American eating habits (aka a "Western diet") are strongly linked to weight gain, overweight and obesity, according to the AICR Continuous Update Project analysis. And although more research is needed, studies suggest that eating habits that fit the characteristics of this Western diet tend to be less able to support a health-promoting gut microbiome, and to be linked with greater risk of colorectal cancer (including the early-onset type that is on the rise) and potentially with worse outcome after at least some types of cancer. If that's not enough to prompt concern, research also ties a Western-style diet to increased risk of heart disease and type 2 diabetes.
No single type of plant-forward eating style is best. The AICR Third Expert Report concluded that strong evidence links a "Mediterranean-style" dietary pattern with lower risk of weight gain, overweight and obesity. This is important, because there is strong evidence that excess body fat increases the risk of at least 12 different cancers. More limited research suggests links to lower risk of several types of cancer even after accounting for overweight. But there are lots of ways to put together a plant-focused eating pattern. A DASH-style diet (originally developed to prevent or control high blood pressure), a pescatarian diet (including fish in a vegetarian diet), a vegan (plants-only) diet and more can all meet the AICR Recommendations for Cancer Prevention. In fact, AICR's New American Plate can represent all of these and more.
A diet that lowers cancer risk can work through, and beyond, helping you reach and maintain a weight and body composition that's healthy for you. Evidence is so strong about the benefit of avoiding weight gain that leads to excess body fat, that this has to be part of what makes a dietary pattern cancer-protective. But studies on diet's role in cancer prevention look at links after adjusting for risk factors like this. Studies that separate healthy plant-focused diets from plant-based diets that are built around low-nutrient, highly-processed foods show that diet quality matters.
There's no need to force your eating habits to fit into a single mold. You can use dietary patterns like those outlined in the Appendix of the Dietary Guidelines for Americans or USDA's MyPlate as a way of "trying on" a different proportion of foods on your plate. But the ultimate goal is to create an eating pattern that fits you. So instead of forcing your habits into a specific pattern, you can simply start where you are now and take one step at a time to get closer and closer to the AICR Recommendations.
The Winner: Eating Habits Trump Superfoods
Overall dietary pattern is where we see the strongest links to lower cancer risk and overall health. Of course, a dietary pattern is made of which foods you choose - and in what size portions - and which you leave for occasional use. Long-term eating habits are the key for reducing risk of a chronic disease like cancer, so find the line between what is comfortable, enjoyable and sustainable long-term, while allowing for habit change and learning new approaches to eating habits.
Link to original article by the American Institute for Cancer Research