Experts Bust Breast Cancer Nutrition Myths

From fears about soy to misconceptions about dairy, nutrition myths about breast cancer can lead to restrictive eating patterns that may do more harm than good.

“I hear myths about nutrition and breast cancer often. Many patients feel pressure to overhaul their diets completely because they fear ‘feeding cancer,’” says Brannon Blount, M.S., RDN, LDN. “This can add unnecessary stress during treatment, when balanced, evidence-based nutrition would actually better support healing and overall well-being.” 

We asked the experts to put the top four breast cancer nutrition myths to rest and provide evidence-based ways to reduce your risk. 

Myth #1: Soy Increases Breast Cancer Risk

For years, soy has had a reputation for promoting hormone-related cancers like breast cancer, causing many women to cut tofu, soy milk and edamame from their diets. Thankfully, this myth has been busted by years of clinical research and population studies. 

The confusion stems from soy’s isoflavones, plant compounds that act as phytoestrogens. Lauren Manaker, M.S., RDN, LD, clarifies the science: “While these compounds can mimic estrogen to a small degree, they are much weaker than human estrogen and can actually block the effects of stronger, natural estrogen by binding to estrogen receptors. This may even reduce the risk of hormone-related cancers like breast cancer.”

That said, there is conflicting evidence of soy’s impact on anticancer therapy, so you should talk with your provider about any dietary limitations if you’re undergoing treatment.

Myth #2: Dairy Increases the Risk of Breast Cancer

Another persistent myth suggests that consuming milk, cheese and yogurt can increase your odds of breast cancer. This belief often leads people to unnecessarily eliminate an entire food group from their diets, potentially missing out on important nutrients like calcium and vitamin D, both of which are essential for bone health as we age, especially in women.

“The thought was that if one has a high intake of dairy, then most likely someone is also taking in larger amounts of dietary fat and saturated fat, which is a risk factor for developing breast cancer,” explains Jennifer L. Armendariz, RN, FNP-C, AOCNP. “However, according to recent research, consuming milk or milk products does not seem to contribute to developing breast cancer.” A systematic review of 18 studies found an inverse relationship between dairy consumption and breast cancer risk, most likely related to the high amount of beneficial nutrients, including calcium, vitamin D, linoleic acid and probiotics (the latter found primarily in fermented dairy products).

Myth #3: Fat Fuels Breast Cancer

The belief that fat can increase the risk of breast cancer promotes low-fat diets, which vastly misses the mark. Blount explains that it’s the type of fat and overall diet quality that impacts breast cancer risk.

“Diets high in saturated fat may increase your risk, while healthier fats do not show the same effect.” This distinction is key, as excessive saturated fat from sources like red meat and processed foods may increase risk, particularly in postmenopausal women. The greatest association was found between saturated fat intake and breast cancer, along with colon and prostate cancer., Meanwhile, unsaturated fats from foods including olive oil, avocados, nuts and fatty fish may actually be protective., 

Myth #4: “Superfoods” Can Prevent Breast Cancer

While there is no clear definition for what a “superfood” is, you’ll see this label slapped on everything from acai berries to spinach, turmeric and more. While these nutrient-dense and antioxidant-rich foods do have cancer-fighting properties, no single food can prevent breast cancer, or any type of cancer. 

Instead of focusing on one single food, research consistently shows us that overall patterns matter most when it comes to reducing the risk of breast cancer. Dietary patterns like the Mediterranean diet and others including plenty of fruit, vegetables, whole grains, fish, nuts, seeds and dairy have been shown to offer the most protection against breast cancer.

Believe These Facts Instead

• Alcohol increases your risk of breast cancer: “Even small amounts of alcohol raise breast cancer risk, and the risk increases the more you drink,” says Blount. In one study, women who drank more than one drink per day had double the odds of developing breast cancer as women who drank the lowest amount or none.
• A healthy body weight can reduce risk: Maintaining a healthy body weight, especially as you age, can help lower your risk of developing breast cancer. “After menopause, excess body fat raises breast cancer risk by fueling estrogen and inflammation that can drive cancer growth,” says Blount.
• A high-fiber, plant-forward diet can reduce your risk: A diet rich in fruits, vegetables and fiber may help lower breast cancer risk, explains Blount. The antioxidants and polyphenols found in many plant foods have anticarcinogenic properties, reduce inflammation, and reduce insulin resistance, all of which support overall health. One study even found that women who adhered to a Mediterranean-style diet before their diagnosis had improved long-term prognosis compared to those who did not.
• Limit red and processed meat: Eating red meat and processed meat is associated with a 10% to 18% increased risk of breast cancer. Instead, Armendariz recommends adding protein sources like fish and chicken alongside plant-based proteins. 

Our Expert Take

Fear-based food myths are anything but helpful when it comes to breast cancer prevention and treatment. “Many patients often blame themselves when they are diagnosed and often wonder or question what they did wrong,” says Armendariz. The truth is that no one food can cause breast cancer, and no one food can cure it. Eating a well-balanced diet that’s rich in fruits and vegetables while limiting red meat, processed meat and alcohol can help support your body before, during and after a breast cancer diagnosis.