Nutrition

The Process of Digestion and Absorption

1. Conceptual Overview

   • The body does not use food in its original form.

   • Two main processes are involved: digestion and absorption.

2. Digestion

   • Food is broken down into smaller pieces.

   • Occurs in various locations along the alimentary canal.

3. Absorption

   • Moves small food molecules into the bloodstream.

   • Takes place in the small intestine, just after the stomach.

4. Physical vs. Chemical Digestion

   • Physical Digestion: Involves processes like chewing.

   • Chemical Digestion: Enzymes break down large molecules (lipids, proteins, carbohydrates) into smaller, absorbable molecules.

Enzyme Specificity and the Alimentary Canal

1. Carbohydrates

   • Composition: Complex carbohydrates (like starch) consist of long chains of simple sugars.

   • Digestive Enzyme: Carbohydrases, specifically amylase.

   • Amylase Mechanism: Breaks starch into smaller molecules, ultimately into glucose.

   • Locations: Amylase is found in saliva and released into the small intestine from the pancreas.

2. Proteins

   • Composition: Composed of amino acids.

   • Digestive Enzyme: Proteases.

   • Pepsin: Works in the stomach at an acidic pH of about 2.

   • Trypsin: Released from the pancreas into the small intestine, continues protein digestion at a higher pH (~8).

3. Lipids

   • Digestive Enzyme: Lipases.

   • End Products: Break down into glycerol and fatty acids.

   • Emulsification: Necessary for efficient lipid digestion.

The MyPlate Nutritional Guide

1. Purpose

   • Helps simplify food choices and visualize healthy proportions to prevent nutrition-related health risks.

2. Historical Context

   • Replaced the confusing Food Guide Pyramid from 1992.

3. Visual Proportions

   • Half of the plate: Fruits and vegetables.

   • One-quarter: Grains.

   • One-quarter: Protein.

   • Include a portion of dairy.

4. Ten Tips for a Great Plate

   1. Balance calories.

   2. Enjoy food but eat less.

   3. Avoid oversized portions.

   4. Eat fruits, vegetables, and whole grains often.

   5. Make half your plate fruits and vegetables.

   6. Switch to fat-free or low-fat milk.

   7. Make half your grains whole grains.

   8. Reduce solid fats, sugar, and salt intake.

   9. Compare sodium in foods.

   10. Drink water instead of sugary drinks.

Detailed Food Group Breakdown

1. Vegetables

   • Organized into five groups by vitamin and mineral content.

   • Subgroups:

     • Dark Green: Broccoli, spinach.

     • Red and Orange: Carrots, red peppers.

     • Beans and Peas: Black beans, lentils.

     • Starchy: Corn, potatoes.

     • Other: Artichokes, cucumbers.

2. Fruits

   • Can be fresh, canned, frozen, or dried.

   • Categories:

     • Berries: Strawberries, blueberries.

     • Melons: Watermelon, cantaloupe.

     • Common Fruits: Apples, bananas.

3. Grains

   • Foods made from wheat, rice, oats, etc.

   • Whole Grains: Include the whole grain kernel (e.g., brown rice).

   • Refined Grains: Processed, losing fiber and nutrients (e.g., white rice).

4. Dairy

   • Major nutrients: Calcium, Vitamin D.

   • Recommended: Fat-free or low-fat dairy.

   • Alternatives for lactose intolerance available.

5. Protein

   • Recommended portion: 3 to 4 ounces cooked.

   • Includes meat, beans, eggs, nuts.

   • High sodium warning for processed meats.

Calorie Management and Physical Activity

1. Empty Calories

   • From solid fats and added sugars.

   • Common sources: Sweets, fast food.

2. Hydration

   • Importance of drinking enough water (8 servings of 8 ounces daily).

3. Physical Activity Levels

   • Sedentary: 30 minutes or less daily.

   • Moderately Active: 30 to 60 minutes daily.

   • Active: Over 60 minutes daily.

4. Intensity Definitions

   • Light: Casual activities.

   • Moderate: Elevates heart rate (e.g., brisk walking).

   • Vigorous: More intense, like running.

5. Recommendations

   • Youth: At least 1 hour daily.

   • Adults: 2 hours and 30 minutes per week of moderate activity.

Understanding Nutrition Facts Labels

1. Speaker

   • Jessica Shipley, Registered Dietitian.

2. The "New Label" Updates

   • Features bold fonts for calories and serving sizes.

   • Includes new requirements for added sugars and nutrients.

3. Serving Size Calculation

   • Information per serving; adjust consumption accordingly.

4. Added Sugar Identification

   • Look for names such as glucose, high fructose corn syrup.

Strategies for Eating Out

1. Beverages

   • Choose healthier options like water or unsweetened tea.

2. Portion Control

   • Opt for smaller portions or share dishes.

3. Food Choices

   • Select whole grain and vegetable-rich meals.

   • Avoid fried foods and heavy sauces.

1. Introduction

   • Definition of essential nutrients

   • Importance of nutrients in human body

   • Differentiation between synthesized and consumed nutrients

2. Types of Essential Nutrients

   1. Essential Fatty Acids

      • Examples:

      • Omega-3 alpha-linolenic acid

      • Omega-6 linoleic acid

      • Role in cell membranes (phospholipid membranes)

   2. Vitamins

      • Definition: Essential organic molecules

      • Function: Serve as coenzymes for enzyme activity

   3. Minerals

      • Definition: Essential cofactors

      • Role in structural integrity and regulation of bodily functions

   4. Amino Acids

      • Definition: Building blocks of proteins

      • Importance for overall bodily function

3. Food as a Source of Essential Nutrients

   • Explanation of how food provides essential nutrients necessary for life

Introduction to High-Detail Nutrition Facts Labels

• Speaker Profile

  • Jessica Shipley is a Registered Dietitian (RD) and a Certified Diabetes Care and Education Specialist (CDCES) at Stanford Health Care.

  • Over ten years of experience teaching weight management and diabetes classes.

• Primary Objectives

  • Provide a definitive guide on reading and interpreting Nutrition Facts labels.

  • Applications for portion control and carbohydrate monitoring.

• The "New" Label

  • Updated by the Food and Drug Administration (FDA) reflecting new scientific information.

  • Key updates: provides both physical amount and percent daily value ($\%DV$) focusing on carbohydrates.

Anatomy of the Label: Serving Information

• Starting Point

  • Begins with Serving Size or Servings per Container.

• Scaling Information

  • Numerical data below serving size applies to one serving.

  • Example: If serving size is $2/3$ cup and there are $8$ servings, eating two servings (i.e., $1\frac{1}{3}$ cups) requires doubling the values.

• Practical Recommendation

  • For those new to label reading, manually measuring the serving size is advised to visualize portion sizes accurately.

Calorific Intake and Individualized Needs

• General vs. Individual Needs

  • Labels reference a $2,000$-calorie daily diet as a general guide.

  • Individual calorie needs vary based on age, height, weight, gender, activity level, and nutrition goals.

• Example Analysis

  • Sample label lists $230\,\text{calories}$ per one serving of $2/3\,\text{cup}$.

Percent Daily Value ($\%DV$)

• Definition

  • $\%DV$ shows a nutrient's contribution to daily diet.

• The 5/20 Rule

  • $5\,\%$ or Less: Low nutrient per serving.

  • $20\,\%$ or Greater: High nutrient per serving.

• Nutritional Choices

  • Encouraged (Look for High %DV): Fiber, Vitamin D, Calcium, Iron, Potassium.

  • Restricted (Look for Low %DV): Saturated Fat, Sodium, Added Sugars.

Understanding Total Carbohydrates

• Definition

  • Total carbohydrates include starches, fibers, added sugars, and naturally occurring sugars.

• Example Data

  • Total Carbohydrate of $37\,g$ per $2/3\,\text{cup}$ serving.

• Blood Sugar Impact

  • Monitoring grams is vital as they affect blood sugar levels.

Dietary Fiber and the Net Carb Debate

• Fiber Specifics

  • Fiber does not raise blood sugar; daily goals are $25\,g$ to $38\,g$.

  • Example: The sample shows $4\,g$ of fiber ($14\,\%$ of daily value).

• The "Subtracting Fiber" Rule

  • If a product has $5\,g$ or more of fiber, subtract half for carb counting.

  • Since the sample has $4\,g$, total carbs would count as $37\,g$.

• Net Carbohydrates Terminology

  • No legal definition; not recognized by the FDA or ADA.

  • Manufacturers may calculate by subtracting fiber and sugar alcohols from total carbohydrates.

Total Sugars vs. Added Sugars

• Enhanced Transparency

  • New labels include a row for "Added Sugars."

• Added Sugar Sources

  • Includes sugars from processing: table sugar, syrups, honey, agave syrup.

• Example and Conversion

  • $1\,\text{teaspoon of sugar} = 4\,g$.

  • Sample shows $10\,g$ of added sugar, equating to approximately $2.5\,\text{teaspoons}$.

• High Added Sugar Warning

  • $10\,g$ represents $20\,\%DV$, which is considered high; limit added sugars to avoid blood sugar spikes.

Practical Application for Meal Planning

• Carbohydrate Targets

  • General targets: Per Meal (Breakfast, Lunch, Dinner) $30\,g$ to $60\,g$; Per Snack $0\,g$ to $30\,g$.

• Choosing Quality Carbohydrates

  • Focus on Less Processed: Whole grains, fresh fruits/vegetables, beans, lentils, and dairy.

  • Limit Refined/Low Nutrient: Refined carbs, sweets, and syrups.

• Step-by-Step Label Review Strategy

  1. Look at the Serving Size to determine actual consumption.

  2. Review Total Carbohydrates for glucose impact.

  3. Analyze Fiber and Added Sugar for quality and subtraction.

  4. Compare and Adjust based on your portion and carbohydrate count.