Q: Which trace element acts as a cofactor for enzymes involved in the metabolism of sulfur-containing amino acids and nitrogen-containing compounds, and what is its adult RDA?

Molybdenum; $$45 \text{ micrograms/day}$$

Question 1

Which of the following dietary factors would most likely decrease the bioavailability of both iron and zinc in a vegan diet?

Accepted Answer

High intake of phytates and fibre

Question 2

A patient presents with microcytic, hypochromic anemia. Which trace element deficiency is most likely responsible, and what is the primary protein responsible for its transport in blood?

Accepted Answer

Iron; transferrin

Question 3

Which trace element is most abundant intracellularly and is required for the activity of over 300 enzymes, including those involved in DNA and RNA synthesis?

Accepted Answer

Zinc

Question 4

A diet high in raw cabbage, cassava, and millet may lead to which trace element deficiency, and what is the likely clinical consequence?

Accepted Answer

Iodine deficiency; goiter

Question 5

Calculate the maximum daily intake of fluoride for a 7-year-old child weighing 25 kg, according to the UL. Use the formula $$UL = 0.1 	ext{ mg/kg/day}.$$

Accepted Answer

$$2.5 	ext{ mg/day}$$

Question 6

Which trace element deficiency is associated with increased risk of cancer and a heart condition known as Keshan disease, and what is a major dietary source?

Accepted Answer

Selenium; seafood

Question 7

A patient with inherited hemochromatosis is at risk for which of the following complications due to iron overload?

Accepted Answer

Liver failure and skin pigmentation changes

Question 8

Which trace element is required for the synthesis of thyroid hormones and is most commonly obtained from iodized salt?

Accepted Answer

Iodine

Question 9

A vegan male is recommended to consume up to 17 mg/day of which trace element due to lower bioavailability from plant sources?

Accepted Answer

Zinc

Question 10

Which trace element acts as a cofactor for enzymes involved in the metabolism of sulfur-containing amino acids and nitrogen-containing compounds, and what is its adult RDA?

Accepted Answer

Molybdenum; $$45 	ext{ micrograms/day}$$

Question 11

Which trace element is incorporated into bone and teeth crystals, and in saliva helps decrease bacterial acid production and increase enamel re-mineralization?

Accepted Answer

Fluoride

Question 12

A patient presents with decreased growth, impaired immunity, and skin rashes. Which trace element deficiency is most likely, and what is a common dietary source?

Accepted Answer

Zinc deficiency; red meat

Question 13

Which trace element is required to maintain normal blood glucose levels and can be increased in food by cooking in stainless steel?

Accepted Answer

Chromium

Question 14

A diet high in nuts may upset the balance of which two antagonistic trace elements?

Accepted Answer

Zinc and copper

Question 15

Which trace element deficiency can lead to iron-deficiency anemia, decreased collagen synthesis, and changes in hair color and structure?

Accepted Answer

Copper

Question 16

A 20-year-old female has an RDA for iron of 18 mg/day. If she consumes only 9 mg/day, what percentage of her RDA is she meeting? Use the formula $$	ext{Percentage} = \frac{	ext{Intake}}{	ext{RDA}} 	imes 100.$$

Accepted Answer

$$50\%$$

Question 17

Which trace element is a constituent of superoxide dismutase and is important for bone formation and prevention of oxidative damage?

Accepted Answer

Manganese

Question 18

Excessive intake of which trace element from supplements or contaminated water can cause anxiety, abdominal pain, vomiting, and diarrhea?

Accepted Answer

Copper

Question 19

Which trace element is involved in the mobilization of vitamin A from the liver and stabilization of cell membranes?

Accepted Answer

Zinc

Question 20

A child presents with black and brown stains and pitting of the teeth. Which trace element toxicity is most likely, and what is the condition called?

Accepted Answer

Fluoride toxicity; fluorosis

Trace Elements in Human Nutrition: Functions, Sources, and Health Implications

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