CH09: Nutrients Essential to Healthy Tissues

Occurs During Times of High Blood Calcium

1. Less calcium is reabsorbed by the kidneys. 2. Osteoclasts are inhibited, leading to decreased breakdown of bone. 3. Parathyroid glands decrease secretion of PTH.

Occurs During Times of Low Blood Calcium

1. Parathyroid glands increase secretion of PTH. 2. Increased production of PTH stimulates activation of vitamin D. 3. PTH and vitamin D stimulate increased breakdown of bone.

It is important to understand where to find calcium in food, but there are a variety of factors that can interfere with the absorption of even the best sources of calcium. Which of these statements describe ways calcium bioavailability or absorption may be reduced?

1. choosing calcium sources high in oxalates, like spinach 2. consuming large amounts of calcium at one time

Ultraviolet rays react with _____ in the skin to begin the process of forming vitamin D.

7-dehydrocholesterol

Calcium supplements are recommended for many individuals. However, effectiveness of these supplements can vary based on factors like quantity consumed, intake of other foods and supplements, and time of day the supplement is taken. This section will address these factors. Choose the correct statement about calcium supplements.

All calcium supplements should be consumed in amounts of 500 mg or less per dose.

Among other things, calcium assists in maintaining healthy __________.

Blood pressure

Bone density refers to the compactness and strength of bones.

Bone density

Dual energy x-ray absorptiometry (DEXA) provides a measure of bone __________.

Density

Once absorbed into the blood, the cholecalciferol travels to the kidney for the final step in activation.

False

Does Not Occur DuringRegulation of Blood Calcium

Increased vitamin D activation leads to decreased calcium absorption from the intestines.

Hypocalcemia occurs when blood concentration of calcium falls abnormally low. Symptoms can include muscle spasms and convulsions. Which of these is least likely to lead to hypocalcemia?

Low calcium intake

Osteoclasts break down bone when calcium levels are low.

Osteoclasts

A vitamin D-deficiency disease that occurs mainly in children is __________.

Rickets

Which of the following nutrients supports increased calcium absorption?

Vitamin D

Good sources of fluoride include dental products and __________.

Water

The bioavailability of calcium can depend on a person's age and calcium needs.

bioavailability

The active form of vitamin D, also known as a hormone, is called _____.

calcitriol

Over 99% of the body's calciumOver 99\% of the body's calcium is in the bones and teeth. is in the bones and teeth.

calcium

Too much calcium in the blood, or hypercalcemia, can lead to impaired kidneys and calcium deposits in the body.

hypercalcemia

Certain foods like spinach are high in oxalates, which can interfere with absorption of certain minerals.

oxalates

When blood calcium is low, the parathyroid glands stimulate the production of parathyroid hormone (PTH).

parathyroid hormone (PTH)

Which meal is the highest contributor to dietary vitamin K intake?

spinach salad with broccoli, red peppers, and ranch dressing at lunch