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Boosting fibre intake offers health benefits

wheat2Dietary fibre is essential to good health and disease prevention.

Research shows that a diet high in fibre can reduce the risk of developing type 2 diabetes, coronary heart disease, bowel and breast cancer, gallstones, diverticular disease and weight gain1-6. It also seems that some fibres are better at doing this than others.

What is dietary fibre?

Dietary fibre is the structural part of plants and plant tissue forming the skeleton and cell walls. It is more abundant on the outside of plants and thus is often removed during milling and food processing. While there are many kinds of dietary fibres the one thing that they share in common is that they are not digested or absorbed as they pass through the gut.

Types of fibre

Soluble fibre

This provides nutrients for colonic bacteria that increase microbial growth and help produce volatile fatty acids; such as butyrates, which are protective of colonic mucosa. Soluble fibre is greater in whole fruit (as opposed to fruit juices or peeled fruit) and is also found in vegetables, legumes, nuts, oats and barley.

Insoluble fibre

This increases stool bulk through the absorption of water into its structure. This helps the stools to soften and decrease their transit times through the gut. It also binds fat soluble carcinogens and removes them from the body. Insoluble fibre is found in cereals e.g. wheat, rice and bran and cereal products such as bread, breakfast cereals and pasta.

The main role of dietary fibre

The natural properties of fibre improve digestion and help to reduce the risk of developing many diseases that affect our long-term health.

  • Faecal bulking which helps to prevent constipation
  • Increases satiety i.e. it is filling so aids weight reduction
  • Aids blood sugar control by slowing the rate of absorption of sugar from the gut into the blood stream, thereby releasing glucose into the blood more slowly This improves blood sugar control and providing energy for a longer period of time. This is particularly important to those with Diabetes and weight control issues.
  • Fibre absorbs water in the gut and helps prevent diarrhoea
  • It reduces fat absorption because fibre absorbs and removes bile acids and salts from the body, this not only reduces fat absorption aiding weight control but also improves cholesterol control
  • It helps bowel regularity. Maintaining a diet high in fibre speeds up the transit time of food through the bowel, reducing the risk of haemorrhoids, diverticular disease and colon cancer.
  • Fibre reduces mortality– Cereal fibre has been shown to reduce total mortality and mortality rates of cancer and coronary heart disease by around 20%.5
  • It reduces the risk of developing type 2 diabetes by 28-37% when cereal fibre is increased. 6
  • Fibre reduces the risk of colorectal cancer by up to 10% with each 10gm increase in cereal fibre intake.7Constipation can also be reduced when fibre increases because it  increases faecal bulk making stools softer and easier to pass.
  • A reduced risk of developing coronary heart disease can be achieved by an estimated 14% with each 10gm increase in dietary fibre.8 It has been found that the soluble fibre in oats and barley lower total and LDL-cholesterol by around 5% when just 6g/day is added to the diet.9,10
  • Weight loss is easier to maintain. The Nurse’s Health study, which tracked the diets of 74,000 healthy women over 12yrs, found those with a higher fibre intake gained less body weight. A 12gm increase in total dietary fibre intake was associated with 3.5kg less weight gain over 12years.11
  • A similar study The Health Professional Follow-up study found a 20gm increase in total dietary fibre intake was associated with 5.5kg less weight gain over 8 years.12
  • Waist circumference can be reduced when total fibre from cereals, fruits and vegetables increase. 13

How much do we need?

The national recommendation is for the following:

Children            Age +5g (e.g. 5yr old requires 10g)
Adult women    25g
Adult men         30g

However currently the levels for women are 17.5g/day and 22.1g/day for men. So we all need to work a lot harder at improving our fibre intake.

A word of caution

A moderate increase in dietary fibre to the levels outlined for age will certainly benefit health however more is not better. Excessive levels of dietary fibre can lead to the leaching of key minerals such as calcium, iron and zinc. Athletes or those consuming large volumes of carbohydrate rich foods need to be particularly careful not to eat in excess of guidelines as it can lead to diarrhoea, flatulence and bloated feelings.

Care should also be taken with young children(particularly if they are underweight) as fibre is filling and can suppress appetite for protein rich foods that are important for growth and development.

How much dietary fibre is in foods?

Choosing foods highest in fibre and lowest in energy can help guide you to better weight control.

Food

Fibre  

Energy

 

Food

Fibre

Energy
Bread med slice

g

kcal/kJ

 Cereals    1/2 cup

g

kcal/kJ
White

0.79

68/287

 San   Bran®

10.9

79/334
Wholemeal

1.6

53/224

 All   Bran®

7.3

79/333
Whole grain

0.72

54/226

 Porridge

1

62/262
Fibre   white®

1.12

71/300

 Muesli

5.7

161/674
Burgen   ®

2.05

82/342

 Weetbix®   x2

5

105/441
Molenburg®

2

68/285
Cream   cracker x2

0.28

77/323

 Vegetables   100g
Crispbread   x2

1.18

45/188

 Tomato

1.2

16/68
Coleslaw

1.5

94/397
Legumes   100g Carrot   boiled

3.2

26/112
Lentils

1.9

88/370

 Pumpkin

1.1

44/188
Lima   beans

5.2

94/396

 Green   peas

4.5

51/216
Kidney   beans

5.9

100/422

 Green   beans

1.95

18/79
Chick   peas

3.2

102/429

 Broad   beans

6.7

57/242
Mix   bean salad

5.2

83/350

 Cauliflower

2

20/84
Baked   beans

5.7

83/351

 Brocoli

3.2

26/113
Haricot   beans

6.1

90/380

 Potato

1.7

81/347
Soy   bean sprouts

2.5

140/587

 Spinach

2.1

21/92
Fruit   each Nuts 50g
Apple

1.9

 75/314 Brazil

2.1

338/1415
Pear

3

 76/321 Almonds

3.6

304/1275
Banana

1.8

 131/551 Walnuts

2.5

349/1465
Orange

1.3

 51/215 Hazil

3.6

312/1310
Kiwi

1.6

 45/190 Pistachio

2.9

311/1305
Tamarillo

1.9

 18/78
Feijoa

1

 11/46 Seeds   2Tb
Pineapple 1 slice

1.3

 53/222 Sunflower

1.3

139/582
Watermelon 1 slice

0.4

 49/208 Pumpkin

2

221/928
Flaxseed

10

311/1305

Ref: Food works 2009

(For practical purposes single servings have been used where possible).

Dietary tips to improve your fibre intake

Becoming more aware of the practical ways you can boost your fibre intake each day can greatly improve your long-term health.

  • Eat a high fibre cereal at breakfast. Just ½ cup bran/day can give up to 10gm fibre
  • Choose whole grain breads, rice and pasta rather than white varieties
  • Avoid reducing the natural fibre content by peeling or juicing fruits and vegetables
  • Use vegetables to replace fat by adding more of the things you eat e.g add vegetables to casseroles and reduce the meat; reduce the cheese in pizza, quiches, toasted sandwiches, Panini etc by adding more tomato, onion, corn, spinach or leftover vegetables.
  • Legumes and cereals contribute the most fibre per serving however fibre is accumulative so while bread may only be 2-3 gms per slice eating 3-4 slices the fibre will soon add up.
  • For people who are gluten or wheat intolerant, but still keen to boost their fibre intake, rice bran is a suitable alternative to wheat or oat bran.
  • As beans, peas and lentils also contain protein these can be used to replace meat meals 2-3 times per week. This can benefit heart health by reducing saturated fat. For serving ideas the Heart Foundation is offering free down loads of its recent Full O’ Beans Cook book

http://www.heartfoundation.org.nz/blog-stories/blog/full-o-beans-free-cookbook-launched

For an assessment of your dietary fibre intake and advice on things you may need to change for better health contact us today.

References

  1. Dong J, He K, Wang P and Qin L. Dietary fibre intake and risk of breast cancer: a meta-analysis of prospective cohort studies. Am J Clin doi: 10.3945/ajcn.111.015578
  2. Mendez-Sanchez N, Zamora-Valdes D, Chavez-Tapia NC, Uribe M. Role of diet in cholesterol gallstone formation. Clin Chim Acta. 2007 Feb:376 (1-2): 1-8.
  3. Strate LL. Lifestyle factors and the course of diverticular disease. Dig Dis. 2012;30 (1):35-45.
  4. Liu S, Willet WC, Manson JE, Hu FB, Rosner B, Colditz G. Relation between changes in intakes of fibre and grain products and changes in weight and development of obesity among middle-aged women. Am J Clin Nutr 2003;78(5)920-27
  5. Park Y, Subar AF, Hollenbeck A, Schatzkin A. Dietary fibre intake and mortality in the NIH-AARP diet and health study. Arch Intern Med. 2011 Jun 27; 171 (12):1061-8 Epub 2011 Feb 14.
  6. Priebe MG, van Binsbergen JJ, de Vos R, Vonk RJ. Whole grain foods for the prevention of type 2 diabetes mellitus. Cochrane Database Syst Rev 2008 (1): CD006061
  7. Norat T, Kampman E, Greenwood D, Vieira R, Lau R, Chan D, Aune D. Dietary fibre, whole grains and risk of colorectal cancer systematic review and dose response meta-analysis of prospective studies. BMJ 2011; 343:d6617.
  8. Pereira MA, O’Reilly E, Augustsson K, Fraser GE, Goldbourt U, HeitmannBL,et al. Dietary fiber and risk of coronary heart disease: a pooled analysis of cohort studies. Arch Intern Med 2004:164 (4):370-6.
  9. Truswell A Cereal grain and coronary heart disease. Eur J Clin Nutr 2002;56(1):30-42.
  10. Brown L, Rosner B, Willett WW, Sacks FM Cholesterol lowering effects of dietary fiber: a meta-analysis Am J Clin Nutr 1999;69 (1):30-42.
  11. Liu S, Willett WC, Manson JE, HU FB, Rosner B, Colditz G. Relation between changes in intakes of dietary fibre and grain products and changes in weight and development of obesity among middle aged women. Am J Clin Nutr 2003:78 (5):920-27.
  12. Koh-Banerjee P, Franz M, Sampson L, Liu S, Jacobs DR, Jr, Spiegelman D et al. Changes in wholegrain, bran, cereal fibre consumption in relation to 8 year weight gain among men. Am J Clin Nutr 2004;80 (5):1237-45.
  13. Du H et al. Dietary fibre and subsequent changes in body weight and waist circumference in European  men and women. Am J Clin Nutr 2010:91: 329-36.

 

 

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Lea Stening

Lea is one of New Zealand’s leading paediatric dietitians and also specialises in Sports Nutrition. She has specialised in Paediatric Nutrition for 31 years and in 1985 was the first paediatric dietitian to enter private practice in New Zealand. Lea helps families through her private consultations, public lectures, newspaper and magazine articles as well as television and radio interviews. Read more »

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