MINERALS IN NUTRITION
SUBMITTED TO:
MA’AM FATIMA IFTIKHAR
SUBMITTED BY:
KINZA BASHIR M-16833
DNS-VI
Question 1:
What is selenium? Write down its sources.
Selenium is an essential Ultra Trace mineral. The mineral selenium shares some of the chemical
characteristics of the mineral sulfur. This similarity allows selenium to substitute for sulfur in the amino
acids methionine, cysteine, and cystine.
Sources:
Significant Sources are seafood, meat, whole grains, fruits, and vegetables (depending on soil content).
Selenium is found in the soil, and therefore in the crops grown for consumption. Selenium is found in
association with protein in foods. Eating as few as two Brazil nuts a day effectively improves selenium
status.
People living in regions with selenium-poor soil may still get enough selenium, partly because they eat
vegetables and grains transported from other regions and partly because they eat meats, milk, and eggs,
which are reliable sources of selenium.
Recommended dietary allowance:
The RDA is based on the amount needed to maximize glutathione peroxidase activity.
RDA Adults: 55 μg/day
UL Adults: 400 μg/day
Question 2:
What are the functions of selenium?
Antioxidant nutrient
Selenium is one of the body’s antioxidant nutrients, working primarily as a part of proteins—most
notably, the glutathione peroxidase enzymes.
Glutathione peroxidase
Glutathione peroxidase and vitamin E work in tandem. Glutathione peroxidase prevents free-radical
formation, thus blocking the chain reaction before it begins; if free radicals do form and a chain reaction
starts, vitamin E stops it.
Thyroid hormones and selenoprotein
Other selenium-containing enzymes selectively activate or inactivate the thyroid hormones. Type I
iodothyronine 5'-deiodinase, an enzyme capable of converting T4 to T3, is a selenoprotein. Moderate
selenium intakes (40 mcg/day) seem adequate to maintain activities of these deiodinases. However,
high intakes (350 mcg/day) are associated with depressed T3 levels, suggesting less activity of
iodothyronine deiodinase.
Endocrine systems
GSH-Px enzymes have also been shown to be critical in several endocrine systems.
Distributation in body
Selenium, as selenomethionine or selenocysteine, exists in several proteins that are widely distributed in
the body. Cellular GSH-Px (cGSH-Px) has been found in almost all cells and extracellularly in serum and
milk. This family of enzymes may help provide a reserve of selenium in proteins that can be drawn on
when needed.
Lipid metabolis
Phospholipid hydroperoxide GSH-Px (phGSH-Px), which has a distribution in lipid-soluble fractions of the
cell, may have other roles in lipid metabolism.
Question 3:
What is cobalt? Write down its sources.
Cobalt is a chemical element, symbol Co and atomic number 27. Cobalt is found in the Earth's crust only
in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free
element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
Quantity in human body:
In human body, present in amounts from 1 to 2 mg: in the heart, liver, kidney, and spleen, and smaller
quantities in the pancreas, brain, and serum.
Sources:
The organic form of cobalt is present in green parts of plants, fish, cereals, and water.
Organ and muscle meat are good sources.
Recommended dietary allowance:
The dietary requirement for cobalt is expressed in terms of vitamin B12. Approximately 2 to 3 mcg of
vitamin B12 is needed daily.
Question 4:
What are the functions of chromium in body?
Chromium is an essential mineral that participates in carbohydrate, protein and lipid metabolism. Like
iron, chromium assumes different charges. In chromium, the Cr+++ ion is the most stable and most
commonly found in foods.
Maintain glucose homeostasis
Chromium helps maintain glucose homeostasis by enhancing the activity of the hormone insulin.
Glucose tolerance factors contain chromium
Small organic compounds that enhance insulin’s actions are called glucose tolerance factors (GTF). Some
glucose tolerance factors contain chromium.
Improves insulin responses
When chromium is lacking, a diabetes-like condition may develop, with elevated blood glucose and
impaired glucose tolerance, insulin response, and glucagon response. Some research suggests that
chromium supplements lower blood glucose or improve insulin responses in type 2 diabetes, but
findings have not been consistent.
Question 5:
What are the results of deficiency of cobalt in human body?
Deficiency of cobalt is very rare. A cobalt deficiency develops only in relation to a vitamin B12 deficiency.
Insufficient vitamin B12 causes a macrocytic anemia. A genetic defect limiting vitamin B12 absorption
results in pernicious anemia, which is treated appropriately with massive doses of the vitamin.
Results:
The common symptoms due to acute cobalt deficiency are:
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paleness
weakness
fatigue
loss of appetite
weight loss
subsequent poor growth
shortness of breath
dizziness
scaly ears
watery discharge from the eyes