Breast Health Challenge Tip #9

Use 45 grams of fiber daily to regulate estrogen and insulin. Include 2 Tbsp flaxseed, 2 Tbsp chia seed, 1 Tbsp psyllium and 1-2 cups legumes.


Did you know that the more bowel movements you have, the more estrogen you eliminate? And that premenopausal women who consume higher amounts of fiber reduce their risk of breast cancers driven by estrogen?

Fiber, such as oatbran or psyllium taken with a meal also help to lower insulin. High insulin levels increase breast cancer risk.


We need both soluble and insoluble fiber in our diets. Both types of fiber help to decrease appetite, potentially making weight loss easier. Insoluble fiber adds more bulk to the stools, while soluble fiber increases bowel frequency. Many foods contain both soluble and insoluble fiber, with one form dominating.

Soluble Fiber

Soluble fiber absorbs water, becoming gel-like, and slows digestion. It adds bulk to your stools. Soluble fiber lowers estrogen and insulin, and is found in psyllium, oat bran, oatmeal, barley, nuts, chia seed, flax and other seeds, beans (black beans, lima beans, kidney beans, navy beans, pinto beans, lentils etc), peas, apples, blueberries and many vegetables, including potatoes, okra and beets. It lowers cholesterol and reduces high blood sugar, helping to prevent diabetes. Consume plenty of water when you eat soluble fiber to ensure regular bowel movements.

Insoluble Fiber

Insoluble fiber does not dissolve in water and cannot be absorbed by the intestines. It passes quickly through the digestive system in comparison to soluble fiber, so may help with constipation. It is found in wheat bran, vegetables, the seeds and skins of fruit, nuts, brown rice, bulgur and other whole grains, zucchini, celery, broccoli, cabbage, onions, tomatoes, carrots, cucumbers, green beans, dark leafy vegetables, raisins, grapes, fruit, and root vegetable skins.

All fiber improves elimination, decreases a tendency to constipation, helps to eliminate toxins through the bowel, maintains the health of the intestinal flora and decreases cancer risk. One study showed that wheat bran and psyllium, when used together, provided protection from breast cancer by lowering estrogen levels.[i]

Fermentable Fiber

Some insoluble and soluble fibers can be included in another fiber category, known as fermentable dietary fiber. Beneficial bacteria in the small and large intestine flourish in the presence of fermentable dietary fiber. One pilot study of postmenopausal women with breast cancer found that they had an altered composition and low diversity of their bowel flora compared to women without breast cancer.[iii]

Healthy gut bacteria can produce protective anti-cancer substances and help to decrease inflammation. One of these protective substances is a short-chain fatty acid called n-butyrate or butyric acid, which is produced during the fermentation of fiber by beneficial intestinal bacteria. We can encourage increased numbers of butyrate-producing bacteria with the intake of specific types of fiber. Fibers that sustain butyrate-producing bacteria are called prebiotics.

A prebiotic has the following characteristics:

  1. It resists stomach acid, digestive enzymes, and absorption in the upper gastrointestinal tract
  2. It is fermented by the intestinal bacteria
  3. It selectively stimulates the growth and/or activity of intestinal bacteria associated with health and well-being

Fermentable Dietary Fiber and Butyrate

Below is a chart of fermentable dietary fiber, and the foods that contain them:[iv]

Fermentable Dietary Fiber Foods Containing Fermentable Fiber
Beta glucans oats, barley, germinated barley foodstuff
pectin apples, peaches, citrus peels, plums, apricot, gooseberry, carrots, tomato, potato, peas, legumes[v]
guar gum guar gum
psyllium psyllium
wheat bran wheat bran[vi]
resistant starch potato starch, potatoes (roasted and cooled), yam, corn starch, mung bean starch, cassava starch, green banana, plaintain or green banana flour, legumes at room temperature, cooked white beans, red lentils, red beans, red kidney beans, black beans, split peas, hummus, rice (cooked and cooled i.e. sushi, stuffed grape leaves), uncooked rolled oats, cashews, peanuts, pumpernickle bread[vii]
inulin and oligofructose Jerusalem artichoke, chicory root, asparagus, garlic, leek, onion, dandelion greens, banana, wheat
oligosaccharides Fructo-oligisaccharides (FOS), a dietary supplement


Each of the foods in the above chart will increase butyrate production by promoting the growth of beneficial bacteria in the large intestine. If you are sensitive to gluten, avoid wheat. The intake of fish oil also increases butyrate production.[viii] Butyric acid inhibits cancer cell growth and promotes normalization of cancer cells.[ix]

Functions of Butyrate

  1. Heals leaky gut, and therefore improves food intolerances
  2. Prevents colon cancer
  3. Reduces inflammation in the bowel
  4. Acts as an energy source for colon cells
  5. Stabilizes blood sugar responses, even to carbohydrates
  6. Lessens hunger and helps weight loss
  7. Stimulates bowel movements
  8. Helps damaged nerve cells to function again
  9. Inhibits cancer – inhibits NFkB activation and histone deacetylation (which regulates gene expression), induces cell death and decreases proliferation of cancer, increases differentiation towards normalize cells[x]

Evaluate the Fiber Content of Your Diet

Aim to eat at least 45 grams or just over 1 ½ ounces of fiber each day for optimal health.

This is equivalent to the combination of 1 cup of beans, 2 tbsp ground flaxseed, 1 tbsp psyllium, 6 servings of fruits and vegetables and 2 servings of whole grain.

Using the following chart, estimate what your daily fiber intake has been each day over the last three days.

How close do you come to 45 grams or 1 ½ ounces?

Grams / Oz Fiber Food Item
15 g / .53 oz 1 cup kidney beans
10 g / .35 oz


½ cup wheat or oat bran

2 ½ tbsp psyllium

2 tbsp chia seeds

1 cup split peas

1 ¼ cup lentils

¾ cup navy beans

¼ cup ground flaxseed

5 g / .18 oz ½ cup cooked dried beans, peas or lentils

1 serving of a high fiber wheat bran cereal

2 g / .07 oz.


1 serving of a fruit or vegetable

1 serving of any whole grain food

1 cup oatmeal

1 slice of whole grain bread

½ cup whole grain pasta

½ whole grain bagel

1 slice rye crisp cracker

½ cup cooked brown rice

1 g / .035 oz.


1 serving of refined grain

10 almonds

20 filberts


BreastFest Cereal

Here’s a great recipe for a fiber-filled breakfast.

Let us know how you do with increasing your fiber intake. And invest in a good plunger!



[i] Cohen LA, Zhao Z et al. Wheat bran and psyllium diets: effects on N-methylnitrosourea-induced mammary tumorigenesis in F344 rats. J Ntl Cancer Inst. 1996 Jul 3;88(13):899-907.

Dietary fiber intake and risk of breast cancer by menopausal and estrogen receptor status.

[i] Erdman SE, Poutahidis T. Gut bacteria and cancer. Biochem Biophys Acta. 2015 Aug;1856(1):86-90

[ii] Lakritz JR, Poutahidis T, Miriabai S, Varian BJ et al. Gut bacteria require neutrophils to promote mammary tumorigenesis. Oncotarget. 2015 Apr 20;6(11):99387-96.

[iii] Goedert JJ, Jones G, Hua X et al. Investigation of the association between the fecal microbiota and breast cancer in postmenopausal women: a population-based case-control pilot study. J Natl Cancer Inst. 2015 Jun 1;107(8)


[v] Srivastava P, Malviya R. Sources of pectin, extraction and its application in pharmaceutical industry – An overview. Ind Jour Nat Prod and Resour. Vol. 2(1), March 2011, 10-118.

[vi] Duncan SH, Russell WR, Quartieri A, et al. Wheat bran promotes enrichment within the human colonic microbiota of butyrate-producing bacteria tht release ferulic acid. Environ Microbiol. 2015 Dec 4. doi: 10.111/1462-2920.13158


[viii] Ostan R, Lanzarini C, Pini E, et al. Inflammaging and cancer: a challenge for the Mediterranean diet. Nutrients. 2015 Apr; 7(4): 2589-2621.

[ix] Chopin V, Toillon RA, Jouy N, Le Bourhis XL. Sodium butyrate induces P53-independent, Fas-mediated apoptosis in MCF-7 human breast cancer cells. Br J Pharmacol. 2002 Jan; 135(1): 79-86.

[x] Hamer HM, Jonkers D, Venema K et al. Review article: the role of butyrate on colonic function. Alim Pharmac and Therap. 2008; 27(2):104-119

[xi] Kumar A, Alrefai WA, Borthakur A, Dudeja PK. Lactobacillus acidophilus counteracts enteropathogenic E. coli inducced inhibition of butyrate uptake in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol. 2015 Oct 1;309(7)

[xii] Nowak A, Slizewska K, Otlewska A. Antigenotoxic activity of lactic acid bacteria, prebiotics, and products of their fermentation against selected mutagens. Regul Toxicol Pharmacol. 2015 Dec;73(3):938-46

Take the Breast Health Challenge!

Use 45 grams of fiber daily and take a photo or make a video of you doing it, and post on your Facebook page, Youtube or Instagram with the hashtag #breasthealthchallenge between Oct 1-31.

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Tell us about how you get your fiber in the comments section below. Let’s share what works!

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