Ground flaxseeds offer nutrients that may lower your risk of breast cancer.
Reviewed by Dietitian Madeline Peck, RDN, CDN
Key Points
- Ground flaxseed is rich in omega-3s, lignans and fiber, which may help lower breast cancer risk.
- The nutrients in ground flaxseed may support hormone balance, insulin sensitivity and gut health.
- Store ground flaxseed in the fridge to keep it fresh, and try mixing it into oatmeal.
While there’s no single food that can prevent breast cancer, incorporating certain foods into an overall healthy dietary pattern may influence your risk. Flaxseeds are a nutrient-dense ingredient that could support a lower risk of breast cancer. They are rich in nutrients such as fiber, omega-3 fatty acids and phytoestrogens called lignans that may lower your risk when included in an overall balanced diet.
Adjustments to your diet can make a big difference in breast cancer risk. “In 2023, an estimated 28.3% of the global breast cancer burden (measured in disability-adjusted life-years) was attributable to modifiable risk factors, with dietary risks being the leading contributor,” notes Lisa Reale, MD. Making small adjustments, like adding ground flaxseed to your diet, can help improve your eating patterns to support a lower cancer risk.
Below, oncologists share why ground flaxseeds are a great choice for lowering your risk of breast cancer.
It’s a Rich Source of Plant-Based Omega-3s
Ground flaxseed contains the plant-based omega-3 alpha-linolenic acid (ALA), which is an important part of an anti-inflammatory dietary pattern, shares Amar Rewari, MD, MBA. The Adequate Intake for ALA ranges from 1.1 to 1.6 grams per day, and a 15-gram serving (about 1 ½ to 2 tablespoons) provides nearly 3 grams of ALA. Some studies suggest that a higher intake of omega-3 fatty acids is associated with a lower risk of breast cancer, and adding ground flaxseed to your routine is an easy way to boost your omega-3 intake.
It Contains Lignans
Ground flaxseed is a potent source of lignans, plant compounds that act as antioxidants and phytoestrogens in the body. Phytoestrogens, such as lignans, are plant compounds that structurally resemble estrogen and exert weak estrogen-like effects in the body. Although more research is needed to definitively show that lignans reduce breast cancer risk by binding to estrogen receptors, they are thought to support overall hormone balance, explains Deena Graham, MD.
Preliminary research suggests that gut bacteria convert lignans into active compounds such as enterolactone and enterodiol, notes Graham. These compounds can influence estrogen signaling. Some research suggests that higher circulating levels of enterolactone are associated with better breast cancer survival rates in postmenopausal women.
Lignans provide the raw material for enterolactone production, but how much gets converted depends on the bacteria present in your gut. Preclinical research suggests that bacterial conversion of flaxseed lignans may reduce tumor size and spread and may contribute to cancer-cell death. However, Graham adds that additional research in humans is necessary to better understand the impact of lignans on cancer risk.
It’s High in Fiber
Ground flaxseeds provide 3.5 grams of fiber per 15-gram serving (about 1.5 to 2 tablespoons). “Higher fiber intake has been associated with a lower risk of breast cancer,” shares Reale. Insoluble fiber from ground flaxseed binds to excess circulating estrogens and bile acids in the digestive tract, sweeping them out of the body through bowel movements, preventing reabsorption and lowering estrogen levels, explains Graham.
Fiber in ground flaxseed may also support weight management, which can influence cancer risk. “Soluble fiber absorbs water, slowing down digestion and triggering satiety hormones that keep you full longer,” shares Graham. Additionally, a higher fiber intake may improve insulin sensitivity, which may influence hormonal and growth-signaling pathways that can impact breast cancer risk.
Tips for Enjoying Ground Flaxseed
- Choose ground flaxseed. “Ground flaxseed is preferable to whole flaxseed because grinding makes many of these compounds [ALA, lignans and fiber] easier for the body to absorb,” explains Rewari. You can grind whole flaxseeds yourself or buy ground flaxseed to add more easily to your meals.
- Keep it refrigerated. Rewari recommends keeping ground flaxseed in the refrigerator or freezer in an airtight container, as it can become rancid quickly at room temperature.
- Add ground flaxseed to your breakfast. Ground flaxseed has a nutty flavor that works well with several breakfast foods. Try stirring ground flaxseed into oatmeal, yogurt or cold cereal, or blending it into smoothies for a thicker beverage.
- Mix it into a crust for proteins. Combine ground flaxseed with breadcrumbs or panko to coat proteins such as chicken, fish or tofu. Then bake for a delicious crunchy crust.
Our Expert Take
Breast cancer risk reflects a combination of genetics, age and lifestyle. While you can’t control every factor, certain lifestyle changes—such as following a healthy dietary pattern—may help lower your risk. Ground flaxseed is one simple way to add more lignans, plant-based omega-3s and fiber to your meals, although more research is needed to understand its specific effects on breast cancer risk. Stir ground flaxseed into oatmeal, blend it into smoothies or sprinkle it over yogurt. Talk to your health care professional about which dietary interventions would be best to support your overall health and help lower your cancer risk.