Nutrition, Metabolism, and Body Temperature Regulation
Nutrition
Nutrient -- a substance that promotes normal growth, maintenance, and repair
Major nutrients -- carbohydrates, lipids, and proteins
. Other nutrients -- vitamins and minerals (and technically speaking, water)
Grains, fruits, vegetables, meats and fish, and milk products
Carbohydrates
Complex carbohydrates (starches) are found in bread, cereal, flour, pasta. nuts, and potatoes
: Simple carbohydrates (sugars) are found in soft drinks, candy, fruit, and ice
cream
Glucose is the molecule ultimately used by body cells to make ATP
: Neurons and RBCs rely almost entirely upon glucose to supply their energy needs
.: Excess glucose is converted to glycogen or fat and stored
: The minimum amount of carbohydrates needed to maintain adequate blood glucose levels is 100 grams per day
: Starchy foods and milk have nutrients such as vitamins and minerals in
addition to complex carbohydrates
: Refined carbohydrate foods (candy and soft drinks) provide energy sources only and are referred to as "empty calories'
Lipids
The most abundant dietary lipids, triglycerides. are found in both animal
and plant foods
Essential fatty acids -- linoleic and linolenic acid, found in most vegetables. must be ingested
: Dietary fats:
: Help the body to absorb vitamins
: Are a major energy fuel of hepatocytes and skeletal muscle
: Are a component of myelin sheaths and all cell membranes
Fatty deposits in adipose tissue provide:
. A protective cushion around body organs
. An insulating layer beneath the skin
: An easy-to-store concentrated source of energy
: Prostaglandins function in:
: Smooth muscle contraction
. Control of blood pressure
. Inflammation
Cholesterol stabilizes membranes and is a precursor of bile salts and steroid hormones
Lipids: Dietary Requirements
: Higher for infants and children than for adults
The American Heart Association suggests that:
. Fats should represent less than 30% of one's total caloric intake
: Saturated fats should be limited to 10% or less of one's total fat intake
: Daily cholesterol intake should not exceed 200 mg
Proteins
Complete proteins that meet all the body's amino acid needs are found in eggs, milk, milk products, meat, and fish
Incomplete proteins are found in legumes, nuts, seeds, grains, and vegetables
: Proteins supply:
: Essential amino acids, the building blocks for nonessential amino acids
.: Nitrogen for nonprotein nitrogen-containing substances
. Daily intake should be approximately 0.8g/kg of body weight
Proteins: Synthesis and Hydrolys