Chapter 12 The Trace Elements. Copyright 2010, John Wiley & Sons, Inc. Review on Sodium and nerve conduction

Chapter 12The Trace Elements

Copyright 2010, John Wiley & Sons, Inc.

Review on Sodium and nerve conduction


Trace Elements Talk The trace elements include

Iron Zinc Copper Manganese Selenium Iodine Fluoride Chromium Molybdenum.

Trace Minerals

They are required in amounts less than 100 mg per day.

Trace elements have been difficult to study, as they are difficult to remove from the diet.

Rate of bioavailability is a concern for trace elements.



Lack of which trace element is the most common nutritional deficiency worldwide?

copper

iodine

iron

zinc


Iron Talk

Iron from the diet is absorbed into the intestinal mucosal cells.

Iron from animal products is heme iron. Heme iron is more efficiently absorbed than

nonheme iron. Iron from plant products is nonheme iron.

Iron cookware can be a source of nonheme iron in the diet.


Heme Group


Iron in the Diet


Which of the following is a good source of heme iron?

a) beef

b) chicken

c) salmon

d) spinach


Heme Iron Absorption Fe2+= ferrous form. Acids help to keep iron in ferrous form, which is more easily absorbed. Ie) Vit C can enhance absorption 6x.

Fe3+ ferric iron

Excess iron stored in the liver as ferritin

Most iron loss is due to blood loss. Iron is conserved in normal cell death

Meat can enhance absorption of non-heme iron.


Iron in the Body

Ferritin is the major iron storage protein. Transferritin is an iron transport protein in the blood. Iron is essential for the delivery of oxygen to cells. Two

oxygen-containing proteins, hemoglobin and myoglobin, contain iron.

Most of the iron in the body is part of hemoglobin, which is the iron containing protein in blood.


Which is the best indicator of iron stores in the body?

ferritin

hematocrit

hemoglobin

transferrin


DRIs for Iron


Iron Deficiency When iron is deficient, hemoglobin cannot be

produced. When there is insufficient hemoglobin, red blood

cells are microcytic and hypochromic and unable to deliver sufficient oxygen to the tissues. This is known as iron deficiency anemia.

It is estimated that as much as 80% of the world’s population may be iron deficient and 30% suffer from iron deficiency anemia.

People low in iron and other minerals can exhibit pica

Iron Deficiency


1. Low iron stores2. Low iron in

plasma3. Low iron in

RBC


Iron Toxicity and Overload Iron is essential for cellular metabolism, but too much can be

toxic. A UL has been set at 45 mg/day from all sources. Iron poisoning can be life-threatening. It can damage the

intestinal lining and cause abnormalities in body pH, shock and liver failure.

Iron overload can happen over time and accumulates in tissues such as the heart and the liver.

Hemosiderin is an insoluble iron storage compound produced by the body when iron exceeds the storage capacity of ferritin.

The most common form of iron overload is hemochromatosis.


Which of the following is not a true statement?

Cooking in iron skillets can provide dietary iron

Vitamin C enhances the absorption of iron

Phytates in cereal enhance the absorption of iron

Calcium supplements decrease iron absorption


___________ is an inherited condition that causes individuals to absorb and accumulate too much iron.

hemochromatosis

hematocrit absorption syndrome

hyperferritosis

reverse anemia


Zinc Talk Zinc is essential in the diet for growth and

development. Zinc from animal sources is better absorbed than zinc

from plant sources (where it is bound to phytates). Zinc can be bound by phytates, affecting bioavailability.

Sprouting and fermenting deactivates. Refined grains are a poor source because zinc is lost

during milling and not added back.

Zinc talk Absorption

In order to pass from mucosal cells into the blood, zinc must bind to metallothionein. This also binds copper.

Functions Zinc is the most abundant intracellular trace element. Zinc is involved in the functioning of over 300 different

enzymes, including superoxide dismutase, important for protecting cells from free radical damage.

Gene expression: proteins containing zinc fold around it to form a loop or finger which can bind to regulatory regions on DNA. (binds to: Vit A, Vit D, sex hormones, etc)


Zinc Talk Zinc for colds

Can prevent cold virus from binding to cells of the mucous membranes of nose and throat

Many studies show that it can decreased duration if consumed within 24 of symptom onset

Would not work in supplement form. Deficiency

Poor growth/development, skin rash, neurological change, impaired reproduction, skeletal abnormalities, reduced immune function

Can mimic deficiency states of A or D.



Zinc in the Diet


The symptoms of zinc deficiency include all of the following

hair loss

impaired reproduction

reduced immune function


Copper Talk Copper may be important in helping to prevent certain

types of anemia. The richest dietary source of copper is organ meats.

Seafood, chocolate, nuts, seeds and whole-grain foods are also good sources.

30-40% of consumed copper is absorbed. Affected by other minerals, antacids, Vit C.

Copper must travel bound to proteins (albumin, ceruloplasmin) because copper ions can trigger oxidation leading to cell damage.

The RDA for copper for adults is 900 micrograms per day.

Copper talk

Functions Iron and lipid

metabolism Connective tissue

synthesis Maintenance of heart

muscle Function of immune

and nervous system. A part of superoxide

dismutase (SOD) Copyright 2010, John Wiley &

Sons, Inc.

Most common deficiency is anemia. It can also cause skeletal abnormalities similar to scurvy.


The following are functions of copper

connective tissue synthesis

maintenance of heart muscle

functioning of the central nervous system


Manganese Talk Manganese is a constituent of some enzymes and an

activator of other enzymes. Manganese-requiring enzymes are involved in amino

acid, carbohydrate and cholesterol metabolism, cartilage formation, urea synthesis and antioxidant protection.

Manganese, like copper and zinc, is needed for the activity of a form of superoxide dismutase.

The best sources of manganese are whole grains and nuts.

A naturally occurring Mn def has never been reported, but has occurred under lab conditions.


Selenium Talk The selenium content of plant foods, such

as grains and seeds, depends on the selenium content of the soil in which they are grown (true for all minerals)

Selenium functions via its interaction with ‘selenoproteins’ of which glutathione peroxidase is one. Similar to Superoxide dismutase it protects cells against oxidative damage.

Selenium Talk

Selenium deficiency can lead to Keshan disease, affecting the heart muscle. (maybe a combo of viral infection and Se deficiency).

Symptoms of selenium deficiency include muscular discomfort and weakness.

There may be a connection, still being researched, between diets low in selenium and higher incidences of cancer.



Selenium in the Diet


Iodine Talk

The iodine content of food depends on the soil where plants are grown or where animals graze.

Soil near the ocean or sea is higher in iodine than soil inland.

Most of the iodine in the diet comes from iodized salt. Iodized salt is salt fortified with iodine. “Natural” sea salt may be very low in iodine.

More than half the iodine in the body is found in the thyroid gland.

Iodine is an essential component of thyroid hormones, including thyroxine.


What is the primary function of iodine in the body?

an antioxidant, to reduce the number of free radicals

a component of hemoglobin

a component of thyroid hormones, which regulate metabolic rate

it functions in carbohydrate metabolism


Thyroid Hormones


A deficiency of iodine often causes an enlarged thyroid gland that forms

a) a blockage of arteries leading to the heart

b) a cyst

c) a goiter

d) a shmoiter


Iodine and Thyroid Hormones


Iodine Talk

When the supply of iodine is adequate, the body can produce the needed thyroid hormones.

The RDA for iodine for adult men and women is 150 micrograms per day. The RDA for iodine is higher during pregnancy and lactation.

Consuming diets high in goitrogens, such as cabbage, cassava and millet, limits the bioavailability of iodine.

Iodine deficiency may result in hereditary cretinism. The UL for adults is 1100 micrograms of iodine per day.

Iodine toxicity is possible.


Substances that interfere with the utilization of iodine or with the function of the thyroid gland are called

deleterious iodine compounds

goitrogens

thyroid function abusers (TFA)

thyroid interference aggregates


Chromium Talk Dietary sources of chromium include brewer’s yeast,

liver, nuts and whole grains. Cooking in stainless steel can increase food’s

chromium content. Chromium is involved in carbohydrate and lipid

metabolism.


Marginal chromium deficiency has been linked to

breast cancer

polio

strokes

type 2 diabetes


Fluoride Talk Fluoride is important for dental health. Fluoride is present in small amounts in almost all soil,

water, plants and animals. The most common sources of fluoride are fluoridated

water, tea, marine fish eaten with their bones, such as canned salmon or sardines, and topical toothpaste.

Tea contributes to Fl intake in countries that drink large amounts (1-6mg fl per liter)

Water and toothpaste contributes to FL in the U.S. (0.7-1.2 mg/ liter)

Calcium-rich foods reduce the bioavailability of fluoride.


Fluoride Toxicity


Summary of Trace Elements


Summary of Trace Elements


Benefits and Risks of Trace Element Supplements


Which mineral functions to protect the body from oxidative damage and also helps synthesize thyroid hormone?

copper

manganese

selenium

zinc


Chapter 12

Copyright 2010 John Wiley & Sons, Inc.

All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein.

.

Documents

Chapter 12 The Trace Elements. Copyright 2010, John Wiley & Sons, Inc. Review on Sodium and nerve conduction