Photosynthesis & Fiber Module 3.3 Photosynthesis & Fiber By Jennifer Turley and Joan Thompson © 2013 Cengage

Presentation Overview Photosynthesis Carbohydrate structures: sugar, starch, fiber Fiber categories & recommendations Fiber benefits & actions Negative effects of too much fiber Food sources

Photosynthesis Process by which plants make carbohydrate structures Photosynthesis requires chlorophyll CO2 + H20 + sunlight  carbohydrate in plants sugars starch fiber

Fiber Content in Food Dietary fiber- The residue after “in vivo” treatment. Animal tested Functional Fiber- Indigestible carbohydrate isolated from natural sources or synthetic indigestible carbohydrate. Has beneficial physiological effects in humans An example of indigestible carbohydrate isolated from a natural source is cellulose gel added to a processed food

Fiber Content in Food Total Fiber- The combination of dietary & functional fiber Is reflected as the fiber content value on food package labels in the Nutrient Facts Panel

Categories of Fiber Solubility Fiber Sources Food Sources Soluble: Solubility Fiber Sources Food Sources Softens & Gels in water. Does attract water Pectins Gums Mucilages Fruits (like apple pectin), vegetable, legumes, and oats

Categories of Fiber Solubility Fiber Sources Food Sources Insoluble: Solubility Fiber Sources Food Sources Does not soften or gel in water. Does attract water Cellulose Hemi-cellulose Lignins Whole grain foods, Celery strings Apple peels

Fiber Recommendations DRI for total fiber intake: Adult males= 38g Adult females= 25g Personalized DRI is 1.4g total fiber per 100 Calories consumed Example: a person eating 4200 Calories/ day should consume 59g of fiber

High Fiber Intake & Food Sources High fiber intake is well above 2g/ 100 Calories consumed High fiber foods provide >2g fiber per serving How you assess high fiber: Compare total grams of fiber to total Calories per serving

Fiber Food Sources Grains Cereals Legumes Fruits & Vegetables Most American’s under consume these types of foods, and thus fiber. Average American intake is 11-13g fiber/ day

Fiber in Foods

Food Sources Food Group Very High >4gm High 2-4gm Good 1-2gm Low Grains ½ C Bran Flakes 1 C Shredded whole wheat or whole multigrain cereal 1 C Oatmeal or puffed brown rice cereal 1 Slice Whole Wheat Bread 1 Slice Rye Bread ½ C Brown or Wild Rice 1 Corn Tortilla 1 C Cornflakes ½ C White Rice ½ C Pasta

Food Sources Food Group Very High >4gm High 2-4gm Good 1-2gm Low Vegetable ½ C Legumes (dried beans) ½ C Broccoli, Cauliflower, Corn, Beans, Cabbage 1oz Nuts & Seeds ½ C Carrots, Green pepper, Celery, Onion, Lettuce 1 C Some Vegetable Juices

Food Sources Food Group Very High >4gm High 2-4gm Good 1-2gm Low Fruit N/A 1 Apple, Banana Orange, Peach, 1 C Berries 2 Prunes ½ C WatermelonHoneydew melon, Cantaloupe 1 C Fruit Juice

Benefits/ Actions of Fiber: Bulk Increases the volume of food in the diet without adding calories… decreases caloric density of food Bulks the volume of stool BOTH soluble & insoluble fiber provide bulk

Benefits/ Actions of Fiber: Stool Softener Complex carbohydrate chemical structures are hydrophillic (i.e. water-loving)  binds/attracts water  creating a softer stool that is easier to move along the G.I. tract. Relieves constipation, hemorrhoids & diverticulosis

Benefits/ Actions of Fiber: Stool Softener Complex carbohydrate chemical structures are hydrophillic (i.e. water-loving)  binds/attracts water  creating a softer stool that is easier to move along the G.I. tract. Relieves constipation, hemorrhoids & diverticulosis BOTH soluble & insoluble fiber act as a softener

Benefits/ Actions of Fiber: Decreases transit time Food, the bolus, chyme and feces move through the GI tract faster  thus the transit time is reduced Decreases time in the colon Reduces exposure time to potential carcinogens thus reduces colon cancer BOTH soluble & insoluble fiber provide these benefits

Benefits/ Actions of Fiber: Improves GI tract muscle tone The larger volume of bulk and the softer mass moving through the “tube” allows the GI tract muscles to exercise efficiently BOTH soluble & insoluble fiber provide this benefit

Benefits/ Actions of Fiber: Heart Health Reduces heart disease risk by binding cholesterol-rich bile in the GI tract Normally, bile is reabsorbed Bile binds tightly to soluble fiber & cannot be reabsorbed Thus, a large source of cholesterol can be excreted in the feces ONLY Soluble fiber provides this benefit

Benefits/ Actions of Fiber: Bile binds tightly to soluble fiber & cannot be reabsorbed

Benefits/ Actions of Fiber: Slows gastric emptying time It takes a longer time for the chyme to leave the stomach The rate of glucose absorption is slowed This is beneficial with diabetes & reactive hypoglycemia ONLY soluble fiber provides this benefit

Benefits/ Actions of Fiber: This is beneficial with diabetes & reactive hypoglycemia

Too Much Fiber: Negative Effects Causes gas & bloating (due to decomposition of fiber by gastrointestinal microbes) Too large & frequent bowel movements Binds positively charged minerals Binds beta-carotene Decreases caloric value Can cause GI tract blockages without adequate water intake Too much soluble OR insoluble fiber can cause negative effects

Whole Grain Processing Refined wheat kernels  removes the husk, bran & germ The endosperm (containing mostly starch & protein) remains Iron, thiamin, riboflavin, niacin, folate, vitamin B6, magnesium, zinc, & fiber are lost

Whole Grain Processing Some nutrients are added back into refined grain products as a result of the Enrichment Act of 1942 Enriched-nutrients that were lost are added back in Fortified-nutrients that are not naturally occurring in that food are added in

% Nutrients in whole grain, enriched white & un-enriched white breads

Summary Plants make carbohydrates via photosynthesis Fiber is non-caloric Categories are soluble & insoluble Total fiber = functional & dietary fiber The DRI is 1.4 gm/100 Calories eaten There are health benefits for adequate fiber intake There are negative effects from too much fiber Whole foods provide the best source of fiber and nutrients. References for this presentation are the same as those for this topic found in module 3 of the textbook