Guest post by Kara Moore, dietetic intern, Georgia State University's Coordinated Program for Dietetics
If you're not convinced that eating more plant-based foods may help to reduce your risk of breast cancer from parts one and two of our three-part series on plant-based eating for breast breast, then keep reading. Part three, how plant-specific nutrients may help reduce breast cancer risk, takes a deeper dive into why adding more plant-based foods to your plate may mitigate the risk of breast cancer.
Phytonutrients, nutrients specific to only plants, are beneficial to human health, in part due to their antioxidant properties. Antioxidants prevent cellular damage, which may reduce the risk of cancer, heart disease, stroke, Alzheimer’s disease, and Parkinson’s disease. Because phytonutrients are exclusive to plants, the best way to include them is through colorful vegetables and fruits, whole grain products, nuts and seeds, legumes, tea, and dark chocolate.
Recent research has evaluated the anti-carcinogenic effects of the bioactive compounds in phytonutrients. Some of the bioactive compounds that have been researched include curcumin (found in turmeric), myricetin (found in berries, nuts, herbs), geraniin (found in berries, pomegranates, walnuts), and tocotrienols (found in rice bran, barley, whole grains), just to name a few.
Curcumin
You may have heard of curcumin, the powerful phytonutrient in turmeric. Curcumin has shown much promise for its anticancer effects through mechanisms that prevent cancer cell growth and promote cancer cell death. Include ground turmeric in stir fries, homemade veggie burgers, or take a curcumin supplement for additional support.
Myricetin
Myricetin is commonly found in plant-based food sources such as vegetables, tea, berries, nuts, and herbs. It has been studied due to its anti-carcinogen and chemopreventive affect in several cancers, including breast cancer. It was recently discovered that it may prevent metastasis (the process by which cancer cells spread to other parts of the body) of breast cancer cells.
What is chemoprevention?
Plant nutrients that have been shown to suppress cancer cell proliferation, inhibit growth factor signaling pathways, induce apoptosis (death of cancer cells), inhibit cancer cell activation pathways, and inhibit growth of new cancer cells, and, therefore, may have therapeutic value.
Geraniin
Geraniin is found in berries, pomegranates, walnuts. Geraniin has been shown to have antioxidant, antibacterial, anti-hyperglycemic, antiviral and anticancer properties. In regard to breast cancer, geraniin isolated from amla, a fruit native to south Asia, may prevent growth of breast cancer cells.
Tocotrienol
Tocotrienols are a class of fat-soluble antioxidants that are members of the vitamin E family and found in plant oils. Tocotrienols can act as antioxidants, improve blood flow, and support brain, heart and immune health. Studies have shown that they may encompass anti-tumor properties as they can inhibit the reproduction of cancer cells, including breast cancer. Foods with tocotrienols include cereal grains, rice bran, and barley.
Other notable phytonutrients that have shown protection against cancer include genistein (found in fava beans and soybeans), resveratrol (found in grapes, pistachios, dark chocolate), allicin (found in garlic), capsaicin (found in hot peppers), lycopene (found in tomatoes), ellagic acid (found in berries and walnuts), gingerol (found in ginger), silymarin (found in artichokes), and catechins (found in green tea and dark chocolate).
Vitamins
Additionally, research has studied the role of certain vitamins, specifically folate, vitamin D3, vitamin B6, and vitamin A, in relation to their effects on breast cancer chemoprevention and breast cancer recurrence.
Folate
Studies have shown that consumption of folate through whole foods (not supplements) may be associated with a decrease in the risk of developing hormone receptor-negative (HRneg) breast cancer, an aggressive subtype of breast cancer that accounts for 30–40 percent of all newly diagnosed breast malignancies. Increased folate intake in increments of 100 mg per day has been shown to correlate with a 10 percent decreased risk among women. Naturally occurring folate is found in leafy greens, oranges, strawberries, nuts, peas, and beans.
Vitamin D
Vitamin D has two primary forms, vitamin D2 and D3. Vitamin D2 (ergocalciferol) is derived from fortified and plant sourced foods, while vitamin D3 (cholecalciferol) is primarily derived from animal sourced foods, lichen (a combination of algae and fungus), and exposure to sunlight. Vitamin D3 has been shown to deliver two main benefits to breast cancer cells — suppressing cell growth and encouraging natural breast cancer cell death. More recent studies showed that vitamin D deficiency was directly related to breast cancer risk and the total amount of vitamin D in the blood had protective effects. Before supplementing with vitamin D, ask your healthcare provide to check your vitamin D levels to determine the amount you may need to supplement. Look for lichen-sourced vitamin D3 for plant-based origin D3 supplements. Getting 20-30 minutes of sunshine each day can help your body naturally produce vitamin D (bonus that it's also an instant mood-booster!).
Vitamin B6
Among postmenopausal women, adequate levels of pyridoxal 5′-phosphate (PLP), the active form of vitamin B6, were shown to be associated with a 20 percent reduction in breast cancer risk. Additionally, adequate intake of vitamin B6 through diet was significantly associated with 22 percent reduction in risk of all cancers. Plant-based sources of vitamin B6 include nutritional yeast, nuts, starchy vegetables, quinoa, oranges, tahini and sunflower seeds.
Vitamin A (from plant-based foods)
Prospective studies found high serum levels of beta carotene, the precursor to vitamin A production in the body, was associated with a 17 percent decreased risk of breast cancer. Also, intake of beta-carotene through whole foods was significantly associated with breast cancer survival and 30 percent decrease in odds of dying from cancer. Beta carotene can be found in leafy greens, carrots, butternut squash, sweet potatoes, and orange or red bell peppers.
Eat the Rainbow
As you can see, from the promising studies mentioned above, phytonutrients and certain vitamins may offer healing effects when we consume them. The best way to consume them (you may have guessed!) is by eating a colorful array of plant-based foods like brightly colored vegetables and fruits, whole grain products, nuts and seeds, legumes, tea and coffee, and dark chocolate.
It’s estimated 9 out of 10 Americans aren’t eating the daily recommended 5 servings of fruits and vegetables in their diet (some experts recommend up to 10 servings a day!). This means that most Americans also aren’t obtaining enough phytonutrients in their diet. If you feel you could use more powerful plant nutrients in your diet, see below for tips on how to include them.
Red
Rich in the carotenoid lycopene which is a powerful antioxidant that has been found to protect against some types of cancer as well as heart and lung disease.
Best sources: bright red fruits such as strawberries, cranberries, raspberries, cherries, apples, red grapes and vegetables such as tomatoes, beets, red peppers, red onions.
Green
Rich in chemicals such as sulforaphane, isocyanate, and indoles that inhibit the action of cancer-causing compounds called carcinogens.
Best sources: green tea, green herbs such as mint, rosemary, sage, thyme basil, green vegetables such as spinach, kale, asparagus, avocado, broccoli, Brussels sprouts, collard greens and fruit such as kiwis.
Yellow/orange
Rich in beta cryptothanxin and beta carotene, which help cells in the body communicate and may help prevent heart disease.
Best sources: bright orange and yellow vegetables such carrots, sweet potatoes, winter squash, pumpkin, yellow peppers, corn and fruits such as oranges, bananas, pineapple, tangerines, mango, apricots, and peaches.
Purple/blue
Contain powerful antioxidants called anthocyanins that may prevent cardiovascular disease, cancer and boost cognitive function.
Best sources: lavender, fruits such as blueberries, elderberries, concord grapes, raisins, plums, figs, prunes and vegetables such as eggplant and purple cabbage.
White/Tan
Contains allicin that has anti-tumor properties and flavonoids such as quercetin and kaempferol, known for their anti-inflammatory and antioxidant properties that prevent chronic diseases.
Best sources: garlic, onions, cauliflower, leeks, parsnips, daikon radish, and mushrooms.
How to easily incorporate more colorful veggies onto your plate
Include at least one (or two or three!) colorful vegetables or fruits in each meal.
Incorporate more veggies as snacks. Instead of reaching for chips or a store-bought granola bar when hungry between meals, try having sliced vegetables or fruit ready to go.
Pro tip: pair veggies with a source of protein for a hunger crushing combo! (for example, carrots and hummus or apples and peanut butter)
When grocery shopping, try to get at least one fruit/vegetable in each different color. Frozen fruits and veggies are great options too!
Blend vegetables into smoothies. This is a great option if you find it challenging to get enough vegetables throughout the day or have a low appetite. If you have produce that is on its last leg, place it in the freezer, in a freezer-safe container, until you are ready to use it in a smoothie. This practice packs a big nutrition punch and prevents food waste!
Replace your afternoon coffee with green tea. Green tea is chock-full of antioxidants. It also contains caffeine that has been shown to improve brain function for that afternoon boost. If you're sensitive to caffeine, time your green tea sipping accordingly.
Comment below if you have questions or share your favorite way to include a rainbow of colors to your plate!
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Hi! My name is Kara and I'm a student in Georgia State University's Coordinated Program for Dietetics. As a former D1 cross country & track athlete, I've seen firsthand the important role that nutrition can play in one's wellbeing. I'm so excited to be pursuing my passion and learning a lot on the way! When I'm not studying or working, you can find me rock climbing with my husband, hanging out with our two dogs, or running on some fun trails.
References:
Eslami-S, Z., et al. (2020). "Microbiome and Breast Cancer: New Role for an Ancient Population." Frontiers in Oncology 10(120).
UnlockFood.ca. Phytonutrients - Nature’s Natural Defense. Updated January 3, 2019. https://www.unlockfood.ca/en/Articles/Vitamins-and-Minerals/Phytonutrients-%E2%80%
https://pubmed.ncbi.nlm.nih.gov/15488631/
Mokbel K, Mokbel K. Chemoprevention of Breast Cancer With Vitamins and Micronutrients: A Concise Review. In Vivo. 2019 Jul-Aug;33(4):983-997.
Yau C, Esserman L, Moore DH, Waldman F, Sninsky J, Benz CC. A multigene predictor of metastatic outcome in early stage hormone receptor-negative and triple-negative breast cancer. Breast Cancer Res. 2010;12(5):R85.
Lee-Kwan SH, Moore LV, Blanck HM, Harris DM, Galuska D. Disparities in State-Specific Adult Fruit and Vegetable Consumption — United States, 2015. MMWR Morb Mortal Wkly Rep 2017;66:1241–1247.
McManus, KD. Harvard Health Blog. Phytonutrients: Paint your plate with the colors of the rainbow. April 19, 2019. https://www.health.harvard.edu/blog/phytonutrients-paint-your-plate-with-the-colors-of-the-rainbow-2019042516501