Download CHAPTER 16 NUTRIENTS THAT REGULATE BODY FUNCTIONS

CHAPTER 15: NUTRIENTS THAT REGULATE
BODY FUNCTIONS
Answers to Review Questions
ANSWERS TO CASE STUDY
1. Evan’s diet should be closely monitored for vitamin C (ascorbic acid).
2. Symptoms would appear rapidly because vitamin C is water-soluble and cannot be stored.
3. Foods other than citrus fruits that provide vitamin C include strawberries, melons, green and
colored peppers, spinach, broccoli, and tomatoes.
4. Symptoms of a vitamin C deficiency include slow wound healing, bleeding gums, sore joints,
and/or pinpoint hemorrhages.
5. a. No, vitamin supplements are not necessary if healthy food choices are made. Many foods
other than citrus fruits contain vitamin C. Since this vitamin is not stored in the body, any
excess (from a supplement) will simply be excreted in urine and feces.
b. Excessive vitamin C intake may result in diarrhea, formation of kidney stones, and
“rebound scurvy” in which the requirement is increased in response to large dose intake.
ANSWERS TO CHAPTER REVIEW
A. By Yourself
1. The two major minerals necessary for energy metabolism are (a) phosphorus, a structural part
of ATP, and (b) magnesium, necessary for reactions that result in the formation and
breakdown of ATP.
2. Phosphorus and magnesium are also essential for cellular division and growth. Phosphorus is
a structural part of both DNA and RNA; magnesium is necessary for the synthesis of DNA
and RNA and for the stability of the ribosomes upon which proteins are synthesized.
3. All enzymes are composed of amino acids; as are some hormones (thyroxin, insulin).
4. Water is the major regulator of body temperature.
5. Water is a major component of all body cells. It is required for replacement, chemical
reactions, transporting nutrients throughout the body, and the formation of body
fluids/secretions such as saliva, hormones, and perspiration.
B. As a Group
1. Health benefits associated with vegetarian diets include: lowered risk of high blood pressure,
cardiovascular heart disease, type 2 diabetes, colon and breast cancer; lower BMI; and lower
“bad” (LDL) cholesterol among others. Specific claims are difficult to measure because there
is much individual variation in the type of vegetarian diet followed. The limitations of a
vegetarian diet, especially for children, again depend on the type of dietary pattern that is
practiced. Nutrients most often considered to be at risk for children are vitamin B-12 (found
primarily in animal products), calcium (if no dairy products are consumed), zinc, vitamin D
(if exposure to sunshine is limited), and iron.
2. Several factors may be contributing to recent concerns about low vitamin D levels among
child and adult populations, including: decreased sun exposure; decreased milk consumption;
and, recommended levels that may originally have been set too low. Researchers are
discovering that vitamin D may play an important role in cancer and cardiovascular disease
prevention, fighting infection, and reducing the risk of bone fractures. Vitamin D also
regulates calcium and phosphorus absorption and promotes calcium deposition in bones.
Sources of vitamin D include sunshine exposure and foods such as: fortified milk, cereals,
juices, and margarine; salmon and tuna; and, egg yolks.
3. Non-dairy sources of calcium include salmon and sardines, greens such as collard or turnip,
soybeans, and tofu. However, the amount of calcium in these sources is significantly less
than is found in dairy products; thus, a greater quantity must be consumed to achieve an
equivalent intake.
4. Vitamins A and C are considered to be at risk for young children because they are derived
primarily from fruits and vegetables—foods than many children are not exposed to or may
refuse to eat.
5. If a person consumes a well-balanced diet he/she will most likely get all of the required
nutrients from the food. Vitamin supplements containing fat-soluble vitamins can be toxic in
large amounts. On the other hand, water-soluble vitamins taken in excess of what an
individual requires will simply be excreted and, thus, become expensive “insurance.” Most
children probably do not need to take vitamins in supplement form unless they have a special
medical condition that interferes with absorption or they are extremely picky eaters. Families
should always check with the child’s physician before giving vitamin supplements to
children.