Why Fibre Is So Important In Diabetes Prevention

By Sheila Walker, RD, CDE, M.Ed posted in Healthy Eating Professionals & Educators
Updated

chickpeasThe majority of Canadians do not consume enough fibre. The recommendation for fibre has been increased to 25-50 grams in the CDA 2008 Clinical Practice Guidelines.

This article will explore why fibre is so important and some practical ways of helping our clients increase their fibre intake.

What is fibre?

Fibre is the part of our diet that one cannot digest. Fibre is also referred to as either bulk or roughage and can be either soluble or insoluble.

Soluble fibre is a sticky type of fibre that dissolves in water to form a paste. Examples are oat bran, barley and All Bran Buds with psyllium. This fibre can help in lowering cholesterol and blood sugars after a meal.

Insoluble fibre increases stool weight and helps prevent constipation. Examples are wheat bran, Fibre 1 cereal and whole grain breads.

Benefits of fibre

  1. Prevents constipation. Constipation is a very common problem in clients with diabetes. The prevalence can be up to 60% and the use of laxatives is much higher than those without diabetes (1).
  2. Lowers risk of diverticular disease, haemorrhoids and irritable bowel syndrome.
  3. Lowers cholesterol. Soluble fibre helps to lower LDL cholesterol. Research has suggested the addition of 10-20 grams of soluble fibre per day to a low fat diet. See Table 1 for sources of soluble fibre. Dr. David Jenkins (2) has used 20 grams of soluble fibre in his “portfolio” approach to cholesterol reduction.
  4. Controls blood sugar levels. Soluble fibre helps slow the rise in blood sugar after a meal.
  5. Aids in weight loss. A high fibre diet can add to a greater feeling of satiety and help one to stay full longer.

Table 1: Sources of Soluble Fibre

Sources of soluble fibre
Soluble fibre (g)
Bran buds with psyllium – 1/3 cup
3.0
Kellogg’s Guardian – 1 cup
3.0
Oat bran – 1/3 cup raw
2.0
Kidney beans – 1/2 cup from can
2.0
Oatmal – 1/3 cup raw
1.4
Orange – 1 fresh medium size
1.1
Apple – 1 fresh medium size
1.0
Barley – 2 tbsp raw
0.9
Brussel sprouts – 1/2 cup cooked
1.4
Broccoli – 1/2 cup cooked
1.0

 

Diabetes prevention

Including a high fibre breakfast cereal appears to be an important strategy for those at risk of type 2 diabetes. One study which compared a high fibre breakfast cereal (Fibre 1) to one low in fibre (Cornflakes) found that the high fibre cereal reduced both glucose and insulin responses in hyperinsulinemic subjects (3). The high fibre breakfast cereal contained 36.7g of dietary fibre while the low fibre cereal contained only 0.8g of fibre. Other studies have suggested that diets high in insoluble fibre and whole grains may reduce the risk of type 2 diabetes. The reason for this risk reduction is somewhat unclear but may relate to a reduction in inflammatory markers and other unknown hormonal and molecular markers (4).

The debate about 50 grams of fibre

The 50 gram fibre recommendation appears to be controversial. The ADA recommends an intake of 25-30 grams per day (5). One study (6) compared an ADA diet of 25 grams of fibre (8g soluble and 16g insoluble) to a high fibre diet of 50 grams of fibre (25g soluble and 25g insoluble) in patients with type 2 diabetes. The mean plasma glucose levels were lower by 8.9 percent on the high fibre diet. The high fibre diet included unfortified foods such as cantaloupe, lima beans, okra, sweet potato, winter squash, zucchini, granola, oat bran and oatmeal. The high fibre diet reduced total cholesterol by 6.7 percent and this was felt to be due to the soluble fibre content of 25 grams.

Anderson et al. (7) have recommended 25-50 grams/day for individuals with diabetes based on the evidence and recommendations from the international diabetes community.

Prebiotic fibre

Prebiotic breads have inulin added to boost their fibre content. They are called prebiotic because good bacteria in the digestive tract multiply when they gobble up the inulin (8). It is unclear whether this type of fibre offers the same benefit as that found in whole grains or bran products.

Tips for increasing fibre intake

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  • Start the day with a high fibre cereal (All Bran, All Bran Buds with psyllium, Fibre 1, Fibre First). These cereals with add 12-18 grams of fibre per ½ cup serving and make it easier to reach the 25-50 gram total. Bran Buds is now available in 28g portion packs which make a handy snack when combined with some of the 5 gram carbohydrate yoghurts (= 1 carbohydrate choice).
  • Add wheat bran to your hot cereal. One serving of oatmeal has only 3 grams of fibre and this can be increased to 11 grams by mixing in 4 tbsp to the hot cereal. Wheat bran can also be added to meatloaf, meat balls, muffins, soups, salads, rice and pasta. It should be noted however that one study (7) has suggested care in the use of wheat bran as the evidence is not strong that non-viscous fibre benefits glycemic control.
  • Choose whole grain products more often. Whole grain products include the bran, endosperm and seed of the grain product. Make your own pizza on whole grain pita and add lots of vegetables. There are now many whole grain crackers with 3-7 grams of fibre per serving (egg., Finn Crisp).
  • Enjoy beans more often in place of meat at a meal. Fibre content ranges from 4 to 10 grams per cup cooked. See Recipes.
  • Snack on fresh fruits or raw vegetables. Add extra vegetables to your sandwich. Eat ½ plate or more of vegetables at meals.
  • Enjoy popcorn as a snack in place of chips (8.5 cups = 31g carbohydrate – 7g fibre).

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Summary

So, how feasible is it to increase one’s fibre intake to 25-50 grams per day. See sample menu which shows that it can be done.

We need to promote food fibre as a great aid to diabetes control, satiety and cholesterol control. Many of our patients rely on fibre supplements while their diet is less than 10 grams of fibre per day.

A good starting point is an accurate assessment of current fibre intake. If the present diet is less than 10 grams then of course 15 or 20 grams would be a worthy goal. We can introduce 1 or 2 foods at a time to boost fibre intake. Our patients are spending lots of money on supplements and we need to encourage the value of real fibre in food.

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And of course, we need to introduce fibre gradually and encourage lots of water along with some activity. Many of my clients report that they have never felt so full on a high fibre diet and yet are still losing weight.

SAMPLE MENU

Breakfast
½ cup All Bran Buds with psyllium – 18g fibre or ¾ cup Fibre 1 – 21g fibre
½ cup blueberries – 2g fibre
1 cup skim milk

AM Snack
1 oat bran muffin – 4g fibre

Lunch
Salad (cucumbers, peppers, tomatoes) – 4g fibre
1 cup chickpeas – 10g fibre
1 apple – 4g fibre

PM Snack
4 Finn Crisp Crackers – 4g fibre
1-2 tbsp hummus
1 no fat yoghurt

Supper
3 ounces salmon/dill/garlic/mustard
1 medium sweet potato – 4g fibre
1 cup green beans – 4g fibre
1 cup skim milk

Evening snack
3 plain cookies

Total = over 50 grams of fibre

Recipes

Oat Bran Muffins

2 cups oat bran
¼ cup Splenda
2 tsp baking powder
1 cup skim milk
½ cup blueberries
1 beaten egg
1 tbsp canola oil (can add more oil if weight is not a concern)Mix dry ingredients with wet ingredients. You may need to extra ¼ cup of water to make the mixture liquid enough.Bake at 375 degrees for 15-20 minutes

Makes 8 muffins

1 muffin = 1 carbohydrate choice, 4 g fibre

Vegetarian Chilli

1 chopped onion
3-5 cloves chopped garlic
1-2 zucchini chopped
3-4 cups other chopped vegetables (celery, peppers, carrots etc.)
1 can no salt added diced tomatoes (796ml)
1 tbsp canola oil
1-2 tbsp chilli powder
1 can rinsed and drained kidney beans (540 ml)Stir fry onion and garlic in oil until soft. Add other vegetables along with can of diced tomatoes, and rinsed kidney beans. Bring to a boil and gently simmer for 20-30 minutes. Add more water as necessary. Freezes well.Makes 10 servings

1 serving = 1 carbohydrate choice, 3g fibre, approximately 1 cup

Curried Chickpeas

1 onion chopped
3-5 cloves of chopped garlic
4-5 plum tomatoes
1 can rinsed and drained chick peas ((398 ml)
1 tsp canola oil
1-2 tbsp curry powder
½ cup chopped corianderStir fry onion and garlic in 1 tsp of oil until soft. Add chopped plum tomatoes, and can chick peas. Add curry powder and chopped coriander. Continue to coat chick peas in mixture on low heat. Serve hot or cold.Makes 6 servings

1 serving = 1 carbohydrate choice, 3 g fibre, approximately 2/3 cup serving

References

  1. Ganguli S, Tougas G. Diabetes and the Gastrointestinal Tract (p545-567) in Gerstein H, Haynes R, editors in Evidence-Based Diabetes Care.2001
  2. Jenkins,D et al.A Dietary Portfolio Approach to Cholesterol Reduction:Combined Effects of Plant Sterols, Vegetable Proteins and Viscous Fibers in Hypercholesterolemia.Metab.51:1596-1604,2002.
  3. Wolever T, et al. High –Fiber Cereal Reduces Postprandial Insulin Responses in Hyperinsulinemic but not Normoinsulinemic Subjects.Diabetes Care 27:1281-1286,2004
  4. Weickert MO, et al.Metabolic Effects of Dietary Fiber Consumption and Prevention of Diabetes.The Journal of Nutrition 138:439-442, 2008
  5. ADA website-www.diabetes.org
  6. Chandalia M, et al.Beneficial effects of high dietary fiber intake in patients with type 2 diabetes.The New Eng. Journal of Med.342:1392-1399, 2000
  7. Anderson JW et al.Carbohydrate and Fiber Recommendations for Individuals with Diabetes:A Qualitative Assessment and Meta-Analysis of the Evidence.Am Coll of Nutr.23:5-17, 2004
  8. Hurley J, Liebman.Finding the Best Sliced Bread.Nutriton Action Health Letter35:13-15, 2008
About the Author

Sheila Walker RD, CDE, M.Ed is a dietitian at Sunnybrook Health Sciences Centre in Toronto and counsels clients with Type 2 diabetes and those at risk of diabetes. She has also had type 1 diabetes for 41 years and is a strong believer in the benefits of a high fibre diet.