NUTR 202 FLASHCARDS: Exam #3

Water is composed of…

2 hydrogen atoms and 1 oxygen atom bonded together

The bonding of the hydrogen and oxygen atoms in water molecules causes…

A shift in charge among the individual atoms, with the hydrogen side being slightly positive and the oxygen side being slightly negative

Water’s structure enables it to…

Attract other water molecules and dissolve other charged substances

Within the body, water is found in two major compartments. What are these two compartments?

Intracellular and extracellular

Intracellular Water

Makes up 60% of body water

Extracellular Water

Makes up 40% of body water; includes interstitial fluid and intravascular fluid

Water intake comes from…

Beverages, foods, and metabolic water (produced through the breakdown of carbohydrates, fats, and proteins; approximately 1 to 1.5 cups of water per day)

Water loss comes from…

Urine, feces, and insensible losses (sweating and air expiration)

True or False: Water fluctuations in the body are common

True

The body has no…

Water storage mechanism

Water losses must be replaced by…

Water consumption (water is essential and consumption is required every day)

What is the critical function of water in the body?

Body temperature regulation (water absorbs body heat, heat is released at the skin via sweat)

What structure in the brain controls the body’s perceived need for water (thirst)?

Hypothalamus

The hypothalamus is triggered when…

Water levels in the blood decrease and solute concentration increases

When the body first needs water…

Perception of thirst lags behind time

Two hormones help maintain hydration. What are these two hormones?

Antidiuretic hormone and aldosterone

Antidiuretic Hormone

Released by the pituitary gland in order to signal the kidneys to retain water

Aldosterone

Produced by the adrenal glands above the kidneys; induces the kidneys to retain sodium and water

What is the recommended amount of water intake per day for adults?

1-1.5 ml/kcal of energy expenditure (foods and beverages combined; requirements vary based on disease state and activity level)

Excess water consumption can result in…

Water intoxication (dilution of blood electrolytes, particularly sodium; also known as hyponatremia)

Dehydration can occur from…

Excessive water loss via sweat, vomiting, and diarrhea

The body’s function is altered at…

All levels of dehydration

Mild Dehydration

Characterized by thirst, some lack of mental clarity, and mild fatigue

Moderate Dehydration

Characterized by reduced athletic ability

Severe Dehydration

Characterized by cramping and heat exhaustion; if water loss continues beyond this point, hallucinations and heatstroke occur

Urine is the primary path for…

Water loss, excretion of metabolic waste, and regulation of extracellular fluid composition

The kidneys control…

Urine and blood composition

Nephron

Microscopic structures that filter blood; 1 million in each kidney

Urine is composed of…

Water, electrolytes, urea, and creatinine

Electrolytes

Minerals that, when placed in water, become charged particles

Cations

Minerals with a positive charge

Anions

Minerals with a negative charge

What are the electrolytes important for water balance?

Sodium (Na +), potassium (K +), and chloride (Cl -)

Sodium (Na +)

Primary cation in extracellular fluid

Potassium (K +)

Primary intracellular cation

Chloride (Cl -)

An anion that is more concentrated in extracellular fluid

True or False: The primary source of salt in our diets is the salt that we add to food

False

The main dietary source of sodium is…

Processed foods (77%); very little comes from naturally occurring sodium

The salt added to foods for taste and/or as a preservative is approximately…

5-12% of the salt in our diets

What is the adequate intake (AI) for sodium?

1500 milligrams (mg) per day for adults up to age 50/1200 mg per day for those over age 70

What is the tolerable upper intake level (UL) for sodium?

2300 mg for adults

The natural chloride content of most foods is…

Low

Sodium chloride, or table salt, is approximately what percent chloride?

60%

What is the adequate intake (AI) for potassium?

4700 mg per day (most Americans eat less than this)

Some rich sources of potassium include…

Fresh fruits and vegetables, legumes, milk, meats, whole grains, and salt substitutes (KCl)

What are the different functions of electrolytes?

Water and electrolyte balance, acid-base balance (pH), nerve transmission, and gastric pH

Water and electrolytes are moved across cell walls through two processes. What are these two processes?

Diffusion and osmosis

Diffusion

Movement from an area of greater concentration to an area of lesser concentration

Osmosis

The movement of water across a membrane from an area with fewer particles to an area with greater particles

Acid-Base Balance (pH)

Maintenance of normal blood pH

When dissolved in water, sodium and potassium become…

Charged

Sodium and potassium assist the in function of…

Excitable cells in nerves (sodium moves into the cell and potassium moves out)

Hydrochloric acid (which contains chloride) is responsible for…

Protein digestion and absorption of some minerals

True or False: Sodium deficiencies are fairly common

False

What causes sodium deficiencies?

Sodium loss accompanied by loss of body water

What are the effects of sodium deficiencies?

Shock-like symptoms, blood volume decreases, and veins collapse

Water Intoxication

Can result in condition associated with low sodium in blood; also commonly referred to as hyponatremia

What are the two components of blood pressure readings?

Systolic blood pressure and diastolic blood pressure

Systolic Blood Pressure

Peak pressure generated when the heat contracts and forces blood to move

Diastolic Blood Pressure

Lowest blood pressure reading during cardiac relaxation

What percentage of Americans had high blood pressure based on the textbook definition of hypertension?

25%

What percentage of adults have high blood pressure based on the 2017/2018 definitions of hypertension?

54%

High blood pressure can result in…

Increased risk for coronary heart disease and stroke (may also lead to kidney damage)

Essential Hypertension

High blood pressure due to an unknown cause

What percentage of hypertension cases are due to unknown causes?

85%

Most hypertension is treatable with…

Diet and exercise modifications and/or medication

Consuming high amounts of sodium may increase…

Risk of hypertension in some people (required on food labels)

Potassium appears to…

Relax blood vessels, which decreases blood pressure (recommendation to increase intake)

What are two minerals important in blood pressure control?

Calcium and magnesium

Increased fruits and vegetables…

Increases potassium intake

Increased whole grains…

Increases magnesium intake

Low fat dairy…

Increases calcium intake

Other dietary approaches which can be used in order to prevent/control hypertension include…

Lowering intake of saturated fats, decreasing sodium intake, and avoiding or limiting consumption of processed foods and fast foods

Some lifestyle changes which can be used in order to prevent/control hypertension include…

Obtaining or maintaining a healthy body weight and a healthy level of physical activity

Micronutrients

Not energy yielding - assist in providing energy; involved in metabolic processes

What are the two different categories of micronutrients?

Vitamins and minerals

Vitamins are…

Organic

Minerals are…

Inorganic

Enrichment

Vitamins may be lost during processing and added back to meet needs

Fortification

Vitamins may be added to foods but are not naturally present in food

Fat Soluble Vitamins

Provide storage in the body for longer periods of time in larger amounts in liver and fat cells; require bile and dietary fat for absorption; increased likelihood of adverse effects or toxicity

Water Soluble Vitamins

Provide storage in the body for shorter periods of time in smaller amounts; decreased likelihood of toxicity; pose greater risk of deficiency

Vitamin A occurs in three different chemical forms. These are…

Retinol (most active form; stored in the liver), retinal, and retinoic acid

What are the different functions of vitamin A?

Helps to enhance integrity of epithelial cells, bone growth, cell membrane stability, gene regulation, vision, and immune function

What is the recommended daily intake of vitamin A for men?

900 μg RAE per day (may also be listed in international units (IU))

What is the recommended daily intake of vitamin A for women?

700 μg RAE per day (may also be listed in international units (IU))

Women who are pregnant and breastfeeding…

Have increased needs for vitamin A

Preformed Vitamin A

Ready to use; found in animal-based or fortified foods (some examples of sources include fortified milk, cheese, cream, butter, eggs, liver, etc.)

Provitamin A

Converted to active form as needed; found in plant-based foods, including green leafy vegetables and orange and red produce (apricots, cantaloupe, carrots, sweet potatoes, and pumpkins)

An example of provitamin A is…

Beta-carotene

Vitamin A deficiency can result in…

Night blindness (reversible in early stages, however, if prolonged, can damage the cornea, resulting in blindness), poor cell health (insufficient mucus production in intestines), impaired immunity (production of white blood cells), and poor bone health (stimulate bone cells that break down the inner part of the bone; often results in poor bone growth in children)

Vitamin A toxicity occurs when…

Vitamin A is stored in fat tissue and the liver for prolonged periods of time

Symptoms of vitamin A toxicity include…

Liver damage and birth defects

Vitamin A deficiency may coexist with…

Iron deficiency

Another name for vitamin D is…

Cholecalciferol

Cholecalciferol is classified as…

A vitamin, a hormone, and a steroid

What is a function of vitamin D?

Regulation of calcium metabolism

What is one way in which vitamin D regulates calcium metabolism in the body?

It stimulates the cells of the small intestine to produce calbindin

What is calbindin and what does it do?

A calcium-binding protein; it increases calcium absorption

What are two other ways in which vitamin D regulates calcium metabolism in the body?

By stimulating the kidneys to conserve calcium (decreases urinary calcium excretion) and by stimulating calcium release from bone in order to help maintain blood calcium levels