NUTR240-Module3-Glucose+Regulation flashcards

Chapter Overview

• Focus on the science of nutrition, particularly blood glucose regulation and diabetes.

• Key components include metabolism, hormone function, and the management of glucose levels in the body.

Blood Glucose Regulation

• Blood glucose levels are maintained within a narrow range.

• Key hormones involved:

  • Insulin

  • Glucagon

  • Epinephrine

  • Norepinephrine

  • Cortisol

  • Growth hormone

Insulin Regulation

• Originates from beta cells in the pancreas.

• Functions of insulin:

  • Stimulates glucose transporters, enabling glucose uptake by cells.

  • Encourages liver and muscle cells to store glucose as glycogen (glycogenesis).

  • Promotes fat storage through lipogenesis.

  • Fructose differs from glucose; it does not trigger insulin release, nor does it signal satiety.

High Blood Glucose Response

1. Insulin secretion: Triggered post-meal when blood glucose rises.

2. Cellular uptake: Insulin enhances glucose transporter activity, facilitating glucose entry into cells.

3. Glucose storage:

• Stored as glycogen in liver and muscles.

• Converted into triglycerides in adipose tissue.

Glucagon Function

• Produced by alpha cells of the pancreas during low blood glucose levels.

• Functions of glucagon:

  • Stimulates the conversion of glycogen to glucose (glycogenolysis).

  • Promotes gluconeogenesis, creating glucose from amino acids.

Low Blood Glucose Response

1. Glucagon secretion: Activated when blood glucose is low.

2. Glycogenolysis: Converts stored glycogen into glucose.

3. Gluconeogenesis: Converts body proteins into glucose, increasing blood glucose levels.

Epinephrine and Norepinephrine

• Secreted by adrenal glands and nerve endings during low blood glucose.

• Functions include:

  • Stimulating glycogen breakdown in the liver.

  • Enhancing gluconeogenesis.

  • Triggering the body’s fight-or-flight response.

Cortisol and Growth Hormone

• Secreted by adrenal glands, affecting liver, muscle, and adipose tissue.

• Cortisol:

  • Increases gluconeogenesis.

  • Reduces glucose uptake by muscles and organs.

  • Associated with stress and weight gain risk.

• Growth Hormone:

  • Decreases muscle glucose uptake.

  • Increases fatty acid mobilization and gluconeogenesis.

Glycemic Index

• Represents the potential of a food to raise blood glucose (reference: pure glucose = 100).

• High glycemic foods cause rapid increases in blood glucose and insulin, potentially followed by drops in glucose.

• Low glycemic foods result in moderate and stable blood glucose fluctuations.

Glycemic Load

• More useful than glycemic index for assessing food's impact on blood glucose.

• Calculation: grams of carbohydrates in food multiplied by its glycemic index.

• Recommended strategies for people with diabetes include:

  • Increasing fiber intake.

  • Using the plate method for portion sizes.

  • Carbohydrate counting for type 1 diabetes.

Diabetes Overview

• Diabetes mellitus refers to impaired blood glucose regulation, leading to various symptoms.

• Types:

  • Type 1 Diabetes:

    • Accounts for 5-10% of cases.

    • Autoimmune destruction of insulin-producing beta cells.

    • Requires insulin therapy.

  • Type 2 Diabetes:

    • Often linked to obesity and insulin resistance.

    • Requires lifestyle interventions, medication, and possibly insulin treatment.

Diabetes Complications

• Uncontrolled diabetes can lead to:

  • Neuropathy (nerve damage)

  • Nephropathy (kidney damage)

  • Retinopathy (eye damage)

  • Cardiovascular disease

• Symptoms include polyuria, polydipsia, and polyphagia.

• Hyperglycemia indicates elevated blood glucose levels.

Diabetes Diagnosis

• Methods for diagnosis include:

  • Fasting plasma glucose (FPG)

  • Oral glucose tolerance test (OGTT)

  • Glycosylated hemoglobin test (A1c)

Type 2 Diabetes Prevention

• Lifestyle changes can lower diabetes risk:

  • Reduce added sugar intake.

  • Choose fiber-rich whole grains.

  • Limit red and processed meat consumption.

  • Engage in regular exercise.

  • Avoid smoking.

Gestational Diabetes

• Occurs during pregnancy, affecting about 7% of pregnancies.

• Increases risk of developing type 2 diabetes.

• Potential complications for mother (e.g., preeclampsia) and child (e.g., macrosomia).

Hypoglycemia

• Symptoms include shakiness, sweating, anxiety.

• Types include:

  • Reactive hypoglycemia: excess insulin post high-carb meal.

  • Fasting hypoglycemia: insulin secretion without food intake.