Benefits of Fiber for PCOS

fiber and pcos

Fiber plays an important role in managing PCOS. But it tends to be a neglected nutrient! Most women with PCOS think more about cutting down on carbs versus increasing fiber. Fiber has numerous health benefits in the body, including improving insulin resistance, lowering cholesterol and blood sugar, keeping you feeling full longer and aiding weight management. And it plays a major role in the hottest area of research right now – improving the gut microbiome. These are all really important issues for women with PCOS. It’s important that you understand more about the different types of fiber and learn how to increase your intake.

What is fiber?

Also known as “roughage”, fiber is the indigestible part of plant foods that passes through our digestive system. On its way throughout the digestive tract, it does a lot of good things. It’s naturally found in many foods including beans, whole grains, fruits, and vegetables. It’s also added to foods to increase the fiber or nutritional content.

Types of fiber

Fiber is a complicated topic!  Years ago, it was just known as “fiber”. But we now know there are many different types of fiber with unique health benefits, including cellulose, dextrins, inulin, lignin, chitins, pectins, beta-glucans, waxes and oligosaccharides. To simply things, I’ll categorize them into 2 main types: Insoluble and soluble. All types of fiber are needed every day for the body to function well.

  • Insoluble fiber increases the movement of material through your digestive tract and increases your stool bulk. Sources of insoluble fiber are whole grains, bran, nuts, seeds, and the skin of some fruits and vegetables.
  • Soluble fiber (includes viscous, fermentable and resistant starch) All types of soluble fibers slow digestion, so it takes longer for your body to absorb sugar from the foods you eat. This helps prevent quick spikes in your blood sugar and insulin levels.  Soluble fibers also  lower LDL (bad cholesterol levels) by binding with fatty acids and flushing them out of the body. There are different types of soluble fiber that have different health benefits. Sources of soluble fiber are oats, legumes (beans, peas, and soybeans), apples, berries, barely, some vegetables,psyllium, chia and flaxseeds. Resistant starches is a type of soluble fiber that resists digestion until they reach the large intestine. Because they are not digested, neither blood glucose or insulin spike after consumption nor do they provide significant calories. In the large intestine resistant starches cause bacteria to produce fatty acids. The fatty acids provide several health benefits – including lowering glucose after eating, decreasing inflammation and increasing metabolism. Foods that contain large amounts of resistant starch are: legumes; cooked and cooled potatoes, pasta and rice; oatmeal as well as plantain flour, green banana flour, unmodified potato starch and hi-maize corn starch.

Different types of fiber chart from WebMD

How much fiber should you eat a day?

The average American woman consumes 13 grams a day and men 18 grams a day. It’s recommended that women consume 21-29 grams/day and men 30-38 grams a day. Reference

Health concerns in PCOS

PCOS is a genetic, reproductive, metabolic condition affecting up to 20% of women. There are numerous health concerns associated with PCOS, including:

-Insulin resistance
-Increased risk of diabetes
-Increased risk of heart disease
-Elevated lipid levels
-Increased carb cravings
-Higher rates of obesity and difficulty losing weight
-Carb cravings and increased hunger
-Constipation caused by low carb low fiber diets

10 benefits of fiber for PCOS

There aren’t many studies done specifically on fiber and PCOS. But from what we know about the health benefits of fiber, it would make sense for women with PCOS to increase their intake! Here are 10 benefits of increasing your fiber intake.

  1. Improves gut heath. This one is so important! We have “good” and “bad” bacteria in our gut. Studies are showing the types and amount of bacteria we have play major roles in our health –  including weight, blood sugar control, inflammation, heart health, immune function and even brain function. And what do these good bacteria like to eat – plant foods! Certain kinds of fiber (especially fermentable soluble fiber)  optimize the function of the friendly bacteria in the gut.  Reference
  2. Improves insulin sensitivity. Studies have shown that intakes of 28- 36 g fiber/day, consisting of both soluble and insoluble fiber, improve insulin sensitivity and reduces circulating insulin in adults. It’s also been shown that resistant starch can improve insulin sensitivity. Researchers are suggesting that fermentation in the large intestine may be contributing to this benefit, as the short-chain fatty acids (SCFAs) produced by the fermentation of certain fibers triggers the production of hormones related to insulin sensitivity and elicits shifts in metabolism within the intestinal tract by up-regulating the production of hormones important to lipid and carbohydrate metabolism.  Reference 
  3. Improves glucose control. Fiber, especially soluble fiber, helps to slow the rise and fall of blood sugar and insulin after a meal. Studies have also shown hi-maize resistant starch have shown lower post-meal glucose and insulin levels, increased satiety, and decreased hunger post food and meal consumption.
  4. Decreased risk of heart disease. High intake of dietary fiber has been linked to a lower risk of heart disease in numerous studies. In one Harvard study of over 40,000 male health professionals, researchers found that a high total dietary fiber intake was linked to a 40 percent lower risk of coronary heart disease, compared to a low fiber intake. Soluble fiber lowers risk of heart disease by decreasing serum total and low-density lipoprotein cholesterol concentrations and improves insulin resistance.
  5. Decreasing cholesterol levels. Soluble fiber can reduce the absorption of cholesterol in your intestines by binding with bile (which contains cholesterol) and dietary cholesterol so that the body excretes it. *5 to 10 grams of soluble fiber a day decreases LDL cholesterol by about 5%. It is most likely that water-soluble fibers lower the (re)absorption of in particular bile acids. As a result hepatic conversion of cholesterol into bile acids increases, which will ultimately lead to increased LDL uptake by the liver. Read more about how the Portfolio diet (which is high in soluble fiber)  can lower your cholesterol.
  6. Lower blood pressure
  7. May aid in weight loss by several mechanismsFiber gets digested more slowly which can make you feel full longer. It causes a slower rise of blood sugar (and insulin) so you don’t get insulin spikes. As we know, insulin spikes can contribute to fat storage. This can help curb carb cravings as well. Fiber also as a positive effect on the gut microbiome, which may aid in weight loss.
  8. Reduce constipation and promote colon health. Some types help reduce constipation whereas others help with diarrhea. I find many women on low carb diets experience constipation. Increasing your fiber intake may help with this.
  9. May decrease risk for certain kinds of cancer
  10. May lower androgens. This one is not conclusive, but is worth discussing as many women with PCOS have elevated levels of androgens. This study showed: “dietary components, specifically low fiber, low magnesium, low vitamin A and high glycemic load, may contribute to IR/HI and obesity. In addition, low fiber intake may contribute to hyperandrogenemia. Future randomized controlled trials are required to determine the benefit of high‐fiber, low‐glycemic diets in improving glucose tolerance, and preventing metabolic complications in women with PCOS.”

Recommendations to increase fiber intake

The key is to eat a variety of fiber to obtain all the health benefits. Rather than driving yourself nuts thinking about soluble, insoluble, resistant, viscous … just think variety!  Here are some tips to get you started.

  1. Eat more whole grains found in whole grain bread, brown rice, quinoa, whole grain crackers. Since some women choose to go gluten free, check out my previous post on Gluten and PCOS to get the list of GF whole grains.
  2. Add chia or ground flaxseeds to yogurt, oatmeal, smoothies and salads. See my previous post on Flax, Chia and Hemp Seeds
  3. Eat at least 2 servings of fruit a day
  4. Increase portion size of vegetables at meals
  5. Include more beans in your diet. Add them to soups, salads, vegetable or grain dishes, make chili with lean beef, ground turkey breast or just vegetarian
  6. Have oatmeal for breakfast. Overnights is even better as it contains more resistant starch
  7. Increase your intake of resistant starch found in underripe bananas, uncooked rolled oats (found in overnight oats), cooked white beans and lentils. Other sources include:
    -Bob’s Red Mill Unmodified Potato Starch (NOT potato flour) is one of the best sources of RS with approximately eight grams of RS in one tablespoon.  Potato starch is generally well tolerated even by those who react adversely to nightshades.
    -Plantain flour and green banana flour are also excellent sources of RS, and there may be benefit to including all three of these sources (specifically alternating your source of RS rather than relying on a single one).| These are relatively bland in flavor and can be added to cold or room temperature water, almond milk, or mixed into smoothies.  But to maintain the benefits of RS, these should not be heated above 130 degrees.

Word of caution

When it comes to fiber, more is not better … at first. If your current diet is low in fiber, increase your fiber intake slowly otherwise you may initially feel bloated or gassy. Your body will likely get used to the fiber. Make sure you are drinking adequate amounts of fluid as you increase your fiber intake.  If you have any gastro-intestinal issues, make sure you check with your doctor before increasing your fiber intake. Large amounts of fiber in food or supplements may NOT be well tolerated in some people. This is especially true for women who have IBS. Check out my previous post on IBS.


Bottom line

Fiber has so many health benefits for women with PCOS.  The average women consumes 13 grams of fiber a day. It’s common to see women with PCOS consume even less than this due to being on low carb diets. Keep in mind that not all women with PCOS need to be on low carb diets. But if you find a lower carb diet works best for you,  just make sure you are doing your best to increase your fiber intake using my tips above.

Do you think about fiber when planning your diet?



Why fiber is good for you




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