Lecture 4b-4 Oct. 2010 FIBRE

Overview of lecture 4b FIBRE FIBRE STRUCTURE AND CLASSIFICATION AND EFFECTS DAT OF FIBRES FIBRES IN HEALTH AND DISEASE HOW TO GET HIGHER FIBRE IN THE DIET    

OVERVIEW OF LECTURE 4B CONTINUED RECOMMENDATIONS FOR FIBRE INTAKE TOO MUCH FIBRE IN THE DIET FIBRES AS FOOD ADDITIVES WHAT IS NEW IN FIBRE RESEARCH CHOOSING CARBOHYDRATES WISELY NEXT LECTURE DAY (LECTURES 5A-6C INCLUSIVE)- 18 October 2010 LIPIDS-STRUCTURE -FUNCTION -DAT

Fibre structure and classification and effects Insoluble Cellulose-bran,vegetables Hemicellulose-bran, whole grains Lignins-fruits, mature vegetables, flax Generally-accelerate gi transit, increase fecal weight(promotes bowel movements), slow starch digestion, delay glucose absorption But can be exceptions

Fibre structure and classification and effects continued Soluble Pectins-apples, carrots gums and mucilages- oats, legumes Generally-delay gi transit, delay glucose absorption, lower blood cholesterol But can be exceptions

OTHER FIBRE FUNCTIONS (classifications) - water holding capacity viscosity cation exchange capacity bile binding capacity fermentability

Fibre digestion, absorption and transport not digested by small intestine enzymes-why? bacteria-make short chain fatty acids water, gas short chain fatty acids absorbed at large intestine and transported by blood used for energy

Fibre in health weight control bulk-less appetite SOLUBLE AND INSOLUBLE FIBRES heart disease soluble fibres lower cholesterol (bile issue) fibre may displace fat in diet

FIBRE IN HEALTH CONTINUED Cancer lower colon cancer-maybe by diluting and binding and more rapid excretion of carcinogens SOLUBLE AND INSOLUBLE FIBRE Breast cancer lignans (not fibre per se but lignans are part of the fibre fraction of some plants – e.g. flaxseed contains lignans) -secoisolariciresinol diglucoside (SDG)(an estrogen-like compound that is a lignan) is a found in flaxseed -metabolites of SDG are produced by bacteria in the large intestine- made reduce breast tumour growth

FIBRE IN HEALTH CONTINUED Diabetes control weight-diabetes slow glucose absorption-glucose surge and rebound associated with diabetes onset SOLUBLE FIBRES

FIBRE IN HEALTH CONTINUED gastrointestinal health enhance health of gi tract-healthy intestine easier to block absorption of unwanted constituents INSOLUBLE FIBRES

How to get higher fibre in the diet Fibre content High Medium Low Breads cereal 5g 2 g 0.5 g Rice Group Breads Whole wheat white 1 slice bread bread Cereal All shredded rice ½ cup bran wheat krispies Pasta Whole macaroni ½ cup wheat pasta

How to get higher fibre in the diet continued Fibre content High Medium Low 4 g 2 g 1 g Fruit group 1 MEDIUM OR ½ CUP berries apple melon

How to get higher fibre in the diet continued Fibre content High Medium Low 4 g 2 g 1 g Vegetable group peas green asparagus ½ CUP beans

REMEMBER THAT: FIBRE FROM NATURAL SOURCES RATHER THAN COMMERCIALLY PREPARED FIBRE IS BETTER BECAUSE FOODS CONTAIN VITAMINS AND MINERALS AS WELL AS THE FIBRE

DRI RECOMMENDATION FOR FIBRE INTAKE FOLLOW DRI RECOMMENDATIONS FOR CARBOHYDRATE INTAKE AND THIS WILL PROVIDE SUFFICIENT FIBRE DRI - 14 GRAMS FIBRE/1000 KCAL (NO DISTINCTION BETWEEN SOLUBLE AND INSOLUBLE BUT VARIETY IS THE KEY TO BALANCE)

TOO MUCH FIBRE IN THE DIET FLATULENCE OBSTRUCT GI TRACT IF GREATER THAN 50 G FIBRE /DAY TOP RECOMMENDATION IS 40 G/D FOR ADULTS (WHO)

TOO MUCH FIBRE IN THE DIET CONTINUED INSOLUBLE FIBRE HAS PHYTATES THAT CAN BIND MINERALS- EG CALCIUM, IRON, ZINC AND MAGNESIUM PREVENT ENZYME CONTACT

TOO MUCH FIBRE IN THE DIET CONTINUED INCREASES VOLUME OF FOOD REQUIRED TO MEET ENERGY REQUIREMENTS SATIETY BEFORE ADEQUATE NUTRITION-GENERALLY ONLY A PROBLEM IF DIET LOW IN MICRONUTRIENTS OR IN SMALL CHILDREN (SMALL STOMACHS)

TOO MUCH FIBRE IN THE DIET CONTINUED IMPORTANT TO INCREASE WATER INTAKE WITH INCREASES IN DIETARY FIBRE -OTHERWISE CONSTIPATION BUT IF HAVE ENOUGH WATER CAN GET DIARRHEA (BACTERIAL BREAKDOWN OF FIBRE)

FIBRES AS FOOD ADDITIVES PECTIN -COMMON IN FRUITS AND VEGETABLES -FORMS GEL WHEN SUGAR AND ACID ADDED -COMMERCIALLY FROM CITRUS PEELS AND APPLES -THICKENING AGENT IN JAMS, JELLIES TOMATO PASTE

FIBRES AS FOOD ADDITIVES CONTINUED CARBOHYDRATE GUMS- USED AND THICKENERS AND STABILIZERS BECAUSE THEY COMBINE WITH WATER TO KEEP SOLUTIONS FROM SEPARATING USED IN GRAVIES, PIE FILLINGS, JELLIES AND PUDDINGS

FIBRES AS FOOD ADDITIVES CONTINUED GUMS DERIVED FROM GUM ARABIC, GUM KARAYA, GUAR GUM, LOCUST BEAN GUM, XANTHAN GUM AND GUM TRAGACANTH GUMS EXTRACTED FROM SHRUBS, TREES AND SEED PODS

FIBRES AS FOOD ADDITIVES CONTINUED PECTINS AND GUMS ARE USED IN REDUCED FAT PRODUCTS TO MIMIC THE TEXTURE AND VISCOSITY OF FAT

FIBRES AS FOOD ADDITIVES CONTINUED OTHER THICKENING AGENTS AND STABILIZERS ARE FROM SEAWEEDS ( E.G. AGAR, CARRAGEEN AND ALGINATES)

Whats new in fibre research Khan et al, 2007. Canadian Journal of Cardiology 23: 539-550 Emphasise fibre in diet to help manage hypertension

How to choose carbohydrates wisely 1)increase intakes of whole grains 2)use whole grain products such as oatmeal, brown rice and whole wheat bread 3)increase consumption of legumes such as kidney, black and pinto beans)if fresh fruits not available, choose frozen or canned fruits without added sugar

How to choose carbohydrates wisely continued 4)use whole grain flour for ¼ to ½ the amount of flour in the recipe 5)use less sugar in baking 6)use less added sugars in foods 7)eat fewer high sugar foods 8)use food labels to guides one’s choices