Lecture Notes on Nutrition

Fat, Gender, and Age

• Females generally have higher fat content due to their role as nurturers and childbearers.
• Body composition changes with age.
• Basal Metabolic Rate (BMR) information can be found on page 456 of the textbook.

Calorie Intake and Weight Management

• A common weight loss strategy involves reducing daily calorie intake.
• Example: Consuming 400 calories instead of the recommended 1,600 calories.
• A deficit of 400 calories daily results in a 2,100 calorie deficit over a week (400 \times 7 = 2100).
• Some people prefer to monitor calorie intake weekly rather than daily.
• Adjustments can be made for occasional higher calorie days, like birthday parties, by reducing intake on subsequent days.

Hunger, Satiety, and Adipose Tissue

• Hunger and satiety regulate food intake.
• Satiety is the feeling of satisfaction after eating.
• Adipose tissue plays a role in signaling hunger.
• It secretes leptin, which signals the brain to eat, and signals satiety when enough food has been consumed.
• Leptin resistance can occur, similar to insulin resistance in diabetics, leading to a lack of fullness and satiety.
• It's a misconception that overweight individuals constantly eat unhealthy foods; hormonal and chemical imbalances can influence body weight.

Ghrelin and Parietal Cells

• Parietal cells secrete ghrelin, which signals fullness.
• Ghrelin's effect typically lasts for about three hours.
• Ghrelin is secreted by parietal cells in the stomach.
• Gastric bypass surgery reduces stomach size, leading to increased ghrelin concentration and reduced hunger.
• Patients who have undergone gastric bypass can only consume small amounts of food due to the increased ghrelin secretion.
• Over time, some individuals can stretch the stomach pouch, enabling them to eat larger quantities of food.

Eating Habits and Ghrelin

• Eating slowly allows food to reach the stomach, stimulating ghrelin secretion and promoting fullness.
• Eating quickly can lead to overconsumption as ghrelin secretion is delayed.

Insulin Levels

• Insulin is released when we eat, signaling the body has glucose and doesn't need more food.
• Type 1 diabetics may lose weight because they don't produce insulin, so glucose doesn't reach their cells.
• Cells think they are hungry, so people eat continuously, but nutrients aren't being absorbed.
• Various secretions regulate eating habits, fullness, and nutrient distribution.

Peptide Secretion

• Peptides are released in the ileum and signal satiety.

CCK (Cholecystokinin)

• CCK is a hormone that releases enzymes to break down food into nutrients.

Brain and Adipose Tissue

• The brain may perceive hunger.
• Adipose tissue is present in the brain.
• Adipose tissue releases leptin, signaling satiety.
• Leptin resistance in the brain can lead to obesity.

Hunger Sensation

• Hunger isn't a continuous sensation.
• The speaker doesn't experience typical hunger pangs or a growling stomach.
• Instead, she recognizes the need to eat when her blood sugar drops, causing vision changes or irritability.

Thyroid and Metabolism

• Hyperthyroidism increases metabolism, causing the body to burn calories rapidly.
• Treatment for hyperthyroidism can involve killing the thyroid with nuclear medicine, which can then lead to weight gain.
• Thyroid levels need to be monitored and regulated with medication to maintain a healthy weight.
• Thyroid controls metabolism, affecting how quickly our body uses calories.

Calorie Intake and Metabolism

• The speaker expresses frustration that she maintains a larger size despite healthy eating and exercise habits.
• It's important to consume enough calories to burn calories.
• Restricting calorie intake too much can trigger starvation mode, causing the body to store fat.
• A balanced diet with carbohydrates, dairy, and proteins is necessary for proper metabolism.

Macronutrients vs. Micronutrients

• Macronutrients are needed in large amounts (carbohydrates, fats, water).
• Micronutrients are needed in small amounts (vitamins, minerals).
• Micronutrients are obtained from macronutrients.
• Essential nutrients must be obtained through diet because the body can't produce them.

Simple Sugars

• Monosaccharides: Simple sugars found in fruits, veggies, and milk like: glucose, fructose, and galactose.
• Disaccharides: Table sugar, milk, maltose

Complex Carbohydrates (Polysaccharides)

• Complex carbohydrates (starches) should form the foundation of our diet
• Found in leafy green vegetables, grains, potatoes, rice, and legumes (beans).
• Eat edible peels (peach, apple, potato) for insoluble fibers.
• Avoid overcooking foods to preserve nutrients.

Insoluble Fibers

• Insoluble fibers cleanse the GI system.
• They don't break down, add calories, or get absorbed in the intestines.
• Fiber promotes beneficial gut bacteria, boosts immunity, and builds strong bones.
• Fiber lowers the bowel pH, preventing pathogen growth.
• It also nourishes the epithelium, maintains intestinal mucosa integrity, calms intestinal inflammation, and helps prevent colon cancer.

Healthy Bowel Movements

• Healthy bowel movements float; consistency is good; nutritionally, no.

Fiber

• Fiber absorbs water, aiding bowel movements.
• Complex carbohydrates take longer to break down, preventing blood sugar spikes.
• Avoid consuming large amounts of simple sugars like those found in fruits, watermelon, or ice cream.

Good Fiber Sources

• Raspberries, pears (with skin), apples (with skin), blueberries.
• Blueberries are rich in polyphenols and boost the immune system.
• Incorporate salads with spinach, strawberries, blueberries, blackberries, and mixed nuts.
• Use low-calorie, sugar-free dressings like raspberry vinaigrette.

Rice, Bread, Pasta

• Choose whole wheat over white refined grains.
• Refining processes concentrate sugars and remove nutrients.

Lipids (Fats)

• Some vitamins (A, D, E, K) require fat for absorption.
• Excess fat-soluble vitamins can cause toxicity due to storage.
• Cholesterol is a cell structure and insulates/protects the body.

Healthy Fats

• Unsaturated fats (from plant sources like nuts, olive oil, coconut oil) are considered healthy.
• Saturated fats (mainly from animals) are solid at room temperature, making them less healthy.
• Trans fats (found in potato chips) are the worst as they don't break down.

Coconut Oil

• Despite being plant-based, coconut oil contains trans fats due to being solid at room temperature.

Proteins

• Complete proteins (mostly animal-based) are sustainable.
• Animal proteins provide vitamin B12 for healthy red blood cells.
• Soy is a phytoestrogen that can be used during menopause, but excessive soy intake can increase cancer risk.
• Complete proteins provide essential amino acids, while incomplete proteins (animal source) lack some essential amino acids and vitamin B12.

Amino Acids

• There are nine essential and 11 nonessential amino acids.
• The body needs amino acids as building blocks.
• Nonessential amino acids can be created by the body, while essential amino acids must be obtained from food.

Vitamins

• Vitamin B12 (from animal sources) prevents anemia and builds healthy red blood cells.
• Vitamin C (ascorbic acid) supports blood vessels and bones and aids other vitamins.
• Biotin is beneficial for neurologic symptoms and may help with hair loss.

Blood Work

• Metabolic panels and CBC tests assess vitamin and mineral levels.
• Red blood cell count indicates potential deficiencies.
• Dietary habits (vegan, meat consumption) are considered to determine supplementation needs.

Minerals and Electrolytes

• Positive cations end in "ium" (potassium, sodium, calcium).
• Potassium affects muscles, nerves, and the heart.
• Sodium deficiency can cause weakness and confusion.
• Calcium deficiency can cause muscle spasms.
• Phosphorus deficiency can lead to bone breakdown and osteoporosis.

Major vs. Trace Minerals

• Major minerals are needed in larger quantities.
• Trace minerals are needed in smaller quantities.
• Iron is a trace mineral and is usually obtained through meat consumption.

Lactose Intolerance and Alternatives

• Calcium can be obtained from cheeses, dairy products, eggs, algae, and calcium-fortified foods like orange juice and almond milk.

Metabolism

• Metabolism is the sum of all chemical processes in the body.
• Catabolism breaks down carbohydrates and lipids for energy.
• Anabolism uses energy to break down and build up proteins to amino acids to use for new cells and tissues..etc

Aerobic vs. Anaerobic Processes

• Aerobic means with oxygen; anaerobic means without oxygen.
  • Glucose \rightarrow ATP for energy
• Aerobic respiration uses oxygen to break down glucose.
• Anaerobic fermentation occurs without oxygen, leading to lactic acid buildup and muscle cramps.

Marathon Runners

• When breathing and energy are uncoordinated. Lactic acid builds up.

Aerobic Benefits

• With aerobic, there's oxygen. It converts to acetyl coenzyme, followed by a bunch of reactions that breaks down glucose and produces ATP

End Products

• Anaerobic end product: Lactic acid.
• Aerobic end product: CO2, H2O, and energy.

Glycogenesis

• Excess glucose in the bloodstream is converted to glycogen and stored in the liver.

Glycogenolysis

• When blood glucose levels drop, stored glycogen is converted back to glucose and released into the bloodstream.
• Metformin slows the process of glycogenolysis in diabetics to prevent elevated glucose levels.

Gluconeogenesis

• The body creates glucose from non-carbohydrates (fats and amino acids).
• It's important in helping diabetics so they don't have those elevated levels.

Lipids

• The body breaks down fatty acids, potentially leading to ketoacidosis.
• Keto and Atkins diets aim to induce ketosis for weight loss.

Protein Balance

• Protein breakdown yields amino acids for new proteins (plasma, muscles, skin).
• Negative nitrogen balance (excess protein catabolism) can affect the liver and kidneys.
• The kidneys excrete urea nitrogen.

Thermal Regulation

• Thermal regulation functions through negative feedback.
• Cold causes blood vessels to constrict, conserving heat.
• Shivering warms up the body.
• Heat causes blood vessels to dilate, leading to sweating to cool the body.

Key Concepts

• Ultimate destination of all nutrients: cells.
• Unit of measure for energy: ATP.
• Factors affecting metabolic rate: age, gender, and body size.
• Hunger is felt in the brain.
• Leptin released to signal "no need for more food."
• Brain is fats.