Food Science Revision 2 (PDF)

# What's in Food? The foods we eat contain nutrients. There are six classes of nutrients required for the body to function and maintain overall health. They are carbohydrates, lipids, proteins, water, vitamins, and minerals. Foods also contain nonnutrients that may be harmful such as cholesterol, d...

# What's in Food? The foods we eat contain nutrients. There are six classes of nutrients required for the body to function and maintain overall health. They are carbohydrates, lipids, proteins, water, vitamins, and minerals. Foods also contain nonnutrients that may be harmful such as cholesterol, dyes, flavors, or preservatives or beneficial such as antioxidants. # A Guide to Daily Food Choices - The U.S. Department of Agriculture (USDA) created MyPlate in 2011. - The My Plate symbol is divided according to how much of each food group should be included with each meal. ## Key Principles: - Fill half of your plate with vegetables such as carrots, broccoli, salad, and fruit. - Fill one-quarter of your plate with lean meat, chicken, or fish (about 3 ounces). - Fill one-quarter of your plate with a whole grain such as ½ cup rice - Choose one serving of dairy - https://www.myplate.gov/ # What does a sticker on fruit mean? 1. **Organic:** A five-digit code beginning with 9. Organic fruits are grown without synthetic pesticides or fertilizers. 2. **Conventional:** A four-digit code denotes conventional cultivation. Fruits grow using traditional farming practices, often involving pesticides and chemical fertilizers potentially affecting soil health. 3. **Genetically modified product GMO:** A five-digit code starting with the number 8. These fruits are engineered to resist pests and may involve pesticide usage during cultivation. It is harmful to health and carcinogenic. # Factors That Affect The BMR | Factor | Effect on BMR | |---|---| | Age | The BMR is higher in youth; as lean body mass declines with age, the BMR slows. Continued physical activity may prevent some of this decline. | | Height | Tall people have a larger surface area, so their BMRs are higher. | | Growth | Children and pregnant women have higher BMRs. | | Body composition | The more lean tissue, the higher the BMR. A typical man has greater lean body mass than a typical woman, making his BMR higher.| | Fever | Fever raises the BMR. | | Stress | Stress hormones raise the BMR. | | Environmental temperature | Adjusting to either heat or cold raises the BMR. | | Fasting/starvation | Fasting/starvation hormones lower the BMR. | | Malnutrition | Malnutrition lowers the BMR. | | Thyroxine | The thyroid hormone thyroxine is a key BMR regulator; the more thyroxine produced, the higher the BMR. | # Disaccharides Disaccharides are pairs of monosaccharides, one of which is always glucose. * **Maltose** = glucose + glucose It is produced during the germination of seeds and fermentation. Sometimes known as malt sugar. * **Sucrose** = glucose + fructose (Called table sugar) Found in many fruits and vegetables, and at high concentrations in sugar beets and sugar cane. * **Lactose** = glucose + galactose (Called milk sugar) Found in milk and milk products. # Problems With Low Carbohydrate Intake - Severely restricting carbohydrates to less than 0.7 ounces (20 grams) a day can result in a process called **ketosis**. - Ketone bodies are an alternative energy source that cells can use when glucose supply is insufficient, such as during fasting. * Brain uses ketones for energy instead of glucose. * Lower Blood Glucose and Insulin. * Liver breaks down fat to ketones. * Consumed and stored Fat Burning increases. # Side Effects of Ketosis: **KETO SIDE-EFFECTS** * **Very common:** Sugar cravings, frequent urination, bad breath "keto breath", flu-like symptoms * **Common:** Sleep issues, constipation, diarrhea. * **Uncommon:** Increase in cholesterol, vitamin deficiency, disruption of menstrual cycles - Ketone bodies are acidic and high levels in the blood can cause it to become too acidic, which may develop deficiencies of vitamins and minerals, loss of bone minerals, elevated blood cholesterol, and impaired mood. - Other side effects from ketosis can include nausea, headache, mental and physical fatigue, and bad breath. # What is Protein? - **Proteins:** Large complex molecules composed of amino acids. - **Amino acids:** are commonly called protein's building blocks. - Amino acids are composed of carbon, hydrogen, oxygen, and nitrogen and some amino acids also contain sulfur. # Types of Proteins in Food - **1- Incomplete protein:** does not contain all essential amino acids. - Not sufficient for growth and health. - Considered a "low quality" protein. - Typically from plants (soy beans, nuts). - **2- Complete protein:** contains sufficient amounts of all 9 essential amino acids. - Considered a "high quality" protein. - Typically from animal products # Protein Digestion and Absorption 1. **Protein digestion** begins in the stomach by hydrochloric acid and the enzyme pepsin. 2. **Protein-digesting enzymes** are secreted from the pancreas into the small intestine. 3. **The small intestine** is the major site of protein digestion; final digestion occurs here. 4. **Absorbed amino acids** enter the blood and travel to the liver. 5. **The liver regulates distribution** of amino acids to the rest of the body. 6. **A small amount of dietary protein** is lost in the feces. # Types of Vegetarians 1. **Lacto-ovo vegetarian:** This is the most common form. This type of vegetarian eats eggs and dairy. 2. **Lacto-vegetarian:** This type of vegetarian eats dairy products but not eggs. 3. **Ovo-vegetarian:** This type of vegetarian eats eggs but not dairy products. 4. **Vegan:** This type of vegetarian does not eat dairy, eggs, or any type of animal product or by-product. # Marasmus - Disease resulting from severely inadequate intakes of protein, energy, and other nutrients. - Marasmus symptoms include: - Severe wasting of muscle tissue - Stunted physical growth and many cannot stand without support. - Stunted brain development. - Anemia - Prone to dehydration, infections, and unnecessary blood clotting. - Body temperature and blood pressure are low. # Kwashiorkor - Disease resulting from an extremely diet high in grains and low protein intake due to diet or infection. - Kwashiorkor symptoms include: - Some weight loss and muscle wasting. - Swelling (edema) of the feet and abdomen. - Poor skin health. - Liver malfunction. - Diarrhea, fatigue. - Retarded growth and development. - Hair is brittle and easy to pull out. - Prone to infection, rapid heart rate, excess fluid in lungs, pneumonia, septicemia, and water and electrolyte imbalances. # Benefits of Omega-3 Fatty Acids - Forms a vital part of cell membranes. - Improves heart health. - Supports health weight management. - Reduce inflammation. - Supports infant brain development. - Promotes brain health. - Decrease liver fat. - Promote bone health. # Food Source of Omega 3 - Found in fish, seafood, chia seeds, walnuts, beans. - Also found in nuts, seeds, whole grains, legumes, and vegetable oil such as soybean, canola, and flaxseed. # Omega-3 Rich Food Sources: - Plant Based Included - Salmon - Hemp Seeds - Walnuts - Edamame - Flax Seeds - Seaweed - Other - Eggs - Chia Seeds # Omega-3 Deficiency ## 6 Ways Your Health Could Be Suffering: 1. **Obesity:** Omega-3 fatty acids work to increase cell activity. So they are highly Important for cell metabolism. 2. **Heart Disease:** Adding Omega-3 fatty acids can help reduce these levels, lowering the chance of sudden cardiac failure. 3. **Eczema:** According to one study, it can be Improved by up to 23% simply by supplementing Omega-3 fatty acid DHA. 4. **Arthritis:** Omega-3's are powerful inflammation fighters. They can decrease the swelling between joints experienced by those suffering from arthritis. 5. **Learning Disabilities:** In some studies a link has been found between increasing Omega-3s in the diet and decreased learning disability symptoms, such as ADD. 6. **Depression:** Serotonin is mostly responsible for a person's sense of happiness. A large component of this neurotransmitter is Omega-3 fatty acids. ## Deficiency of Omega-3 Fatty Acid - Symptoms of omega-3 fatty acid deficiency include fatigue, poor memory, dry skin, heart problems, mood swings or depression, and poor circulation. - Omega-3 fatty acids are highly concentrated in the brain and appear to be important for cognitive (brain memory and performance). - Infants who do not get enough omega-3 fatty acids from their mothers during pregnancy are at risk of developing vision and nerve problems. # Trans Fat = Partially Hydrogenated Fat - Most trans fatty acids are not found naturally in foods, but are a result of a process called hydrogenation. - **Hydrogenation** is the process of adding hydrogen(H) to liquid vegetable oils to make them more solid. - Trans fats are used in many processed foods such as cookies, cakes, chips, doughnuts, and snack foods to give them their crispy texture and increased shelf life. # Cholesterol - Cholesterol is a waxy type of fat or lipid. - Nearly all the cholesterol in the body is produced by the liver and is also used by the liver to make bile, which helps digest foods. - Cholesterol is only found in foods that come from animals such as seafood, liver, kidney, and eggs. - Cholesterol is present in all body cells as it is an important substance in cell membrane structure. - Cholesterol serves important body functions such as vitamin D and synthesis of the sex hormones, progesterone, testosterone, and estrogens. - Also, it is important in the cell membrane and brain structure for this, approximately 25 percent of the cholesterol in the body is localized in brain tissue. - Cholesterol is carried around the body in the bloodstream combined with proteins, these are called lipoproteins. # Types of Cholesterol - There are two main types of lipoprotein that are used to measure cholesterol levels in the blood, **LDL** – low-density lipoprotein and **HDL** – high-density lipoprotein. - **Low-density lipoprotein (LDL)** is often called ‘bad' cholesterol. - LDLs carry cholesterol and other lipids from the liver to tissue throughout the body. - High levels of LDL cholesterol will deposit into the walls of blood vessels, which can lead to harmful disease. - **High-density lipoprotein (HDL)** is considered ‘good' cholesterol that carries bad cholesterol from other parts of the body back to the liver, then the liver removes the cholesterol from the body. # What Causes High Cholesterol? - An unhealthy diet - Smoking - Having Diabetes or Hypertension - Having a family history - Poor thyroid function - hypothyroidism - Liver problems or fatty liver - Kidney Disease - Stress # What are Normal Levels of Cholesterol? - Cholesterol levels vary by age, weight, and sex. - The body produces more cholesterol over time, so doctors recommend that everyone 20 years and older check their cholesterol levels regularly, ideally about every 5 years. - **Total cholesterol:** Less than 200 mg/dL* - **LDL ("bad" cholesterol):** Less than 100 mg/dL - **HDL ("good" cholesterol):** 40 mg/dL or higher - **Triglycerides:** Less than 150 mg/dL *Cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood.