Bio 28: Nutrition Instructor: Paul Nagami Laney College Carbohydrates, pt. 1 Jan. 28, 2014 Bio 28: Nutrition Instructor: Paul Nagami Laney College

Today’s Agenda Reminders What Are Carbohydrates? Simple and Complex Sugars Sources of Carbohydrates Wrap-Up, Add Codes

What Are Trees Made Of? Every year, the General Sherman sequoia adds on over a cubic meter of wood – enough to make a new 15-meter (50-foot) tall tree! Where does all of this dry mass come from?

Take a guess: Most of the General Sherman tree’s dry mass is derived from…. A) Water and minerals from the soil. B) Organic matter from the soil. C) Energy from the sun. D) Gas from the air.

All Our Energy Ultimately Comes from the Sun. Our Carbon Comes from CO2

Monomers and dimers Dimer Monomer Many biological molecules, such as proteins and complex carbohydrates, are made of repeating pieces. Each piece is a monomer. Sticking two monomers together makes a dimer. Dimer Monomer two + pieces one + piece Glucose

Monosaccharides (Simple Sugars) Simple sugars are made out of one sugar “piece” (monomer.) They are not chains of sugar. * These are the three most common monosaccharides (name means “one sugar”) : Glucose is “blood sugar.” It’s the main circulating energy storage molecule in the body. Fructose is “fruit sugar.” It’s found in fruits, vegetables, and honey. Galactose is part of milk sugar, and is also found in fruits and vegetables. What do these names (glucose, fructose, galactose) have in common?

Disaccharides (Simple Sugars with Two Parts) Disaccharides (“two sugars”) are made out of two parts. Most of the sugar we eat that is not starch is in the form of disaccharides. Sucrose = “table sugar” Lactose = “milk sugar” Maltose = “malt sugar”

Sources Sources of mono- and disaccharides …and now are closer to 55% fructose/45% glucose. Is that a problem in itself? Natural sources of fructose: fruits, vegetables. Syrup sweeteners used to contain more glucose… Milk contains lactose, made of glucose and galactose Starch is made out of simple sugars

The HFCS (High Fructose Corn Syrup) Controversy Agree or disagree? “High fructose corn syrup is worse for the body than table sugar.”

Fructose: 16% of American Calorie intake. Quick poll: How much soda have you drank in the last 24 hours? 20 oz. soda: 65 g of sugar (16 teaspoons!) 12 oz soda: 39 g of sugar

Lactose Intolerance Disaccharide Monosaccharide

Lactose-Intolerant Diets Regardless of myplate.gov’s recommendations, dairy is not necessary for a healthy diet (though nonfat milk is quite healthy), provided calcium sources are available. Some people can tolerate low-lactose dairy products, such as cultured yogurt (where the bacteria break down the lactose), yet have trouble with other dairy products. If you drink soy milk or almond milk, be sure to get fortified products that add back the missing nutrients.

Polymers Organisms can chain together smaller monomers to make polymers! Examples of polymers include proteins and starch. The polymers can then be broken down later into their parts to recycle them or harvest chemical energy.

Polysaccharides Starch Glycogen Cellulose

Dietary Fiber Dietary fiber is (mostly) carbohydrates that are not starch – ones that your body can’t break down (unless you’re a termite!) There are two categories of dietary fiber: soluble and insoluble dietary fiber. Insoluble dietary fiber: Cellulose, lignin, etc. Soluble dietary fiber: Pectins and mucilage Sources: Oats, some fruits, legumes, potatoes Sources: Seeds, beans, wheat bran, etc. Lowers blood cholesterol by getting rid of bile! Helps digestion; lowers colon cancer risk.

Benefits of Fiber Lowers cholesterol Reduces “transit time” through intestines (though that varies normally!) Increases satiety (because it holds water, fiber makes you feel more “full.”) Softens stool and reduces constipation. Displaces calories. Reduces risk of colon polyps

Whole Wheat vs. White Bread Outer layer: Bran High in fiber, with some B vitamins. Not present in white bread, only whole grain. Developing embryo: Germ Rich in vitamins, minerals, and oil. Not easy to store/preserve. Energy source for embryo: Endosperm. Most of white flour. High in starch, not in other nutrients.

What About Low-Carb Diets? Recommended calories from carbs: 50-60% of diet Low-carb diets can result in weight loss, but at least some of this is due to the removal of empty calories from the diet. (Foods like sugar that aren’t very nutrient dense). Low-carb diets can also result in shortages of fiber, and can cause the body to break down muscle for energy. However, for some people, a well-balanced low-carb diet, set up with a nutritionist’s advice, can be beneficial, especially for controlling blood sugar in diabetics!