What are minerals?
Elements needed by the body in small amounts for structure and regulation of chemical reactions and body processes.
What are major minerals?
Minerals that your body needs more than 100 mg of in a day.
What are trace elements?
Minerals that your body needs less than 100 mg of in a day.
What are the major minerals?
- Na - Sodium
- Mg - Magnesium
- K - Potassium
- Ca - Calcium
- P - Phosphorus
- S - Sulphur
- Cl- Chlorine
What are the trace minerals?
Lots of them, but they're all ch. 12 material.
What are some good sources of minerals?
They are in every food group but there are a lot in meats and grains especially.
Can food processing methods change mineral content of food?
A the bran is often taken off of grains of wheat during processing and with it minerals are also removed. Minerals in food can also stick to the equipment used to process it and be absent from the product you eat.
Can minerals be destroyed by heat, light, or oxygen?
Even if you burn food down to ash, the ash will still have the minerals that were in the food. So they are not destroyed in cooking.
What is bioavailability of minerals?
How well the mineral can be absorbed and used by the body.
What are some things that can affect bioavailability of minerals?
- Absorption capacity -
- Nutritional status and life stage - Someone with a greater need for a mineral will have better absorption for that mineral.
- Competition among minerals - different minerals can sometiems get into the body ( into the blood stream ) through the same route. If there is a larger amount of one of these minerals in the diet it will be absorbed more and the mineral competing for the same route will be absorbed less.
- Other substances present in food - Acidic foods like orange juice can improve absorption of iron.
What are some substances that can interfere with absorption of minerals?
Phytate, tannins, and oxalates can all interfere with absorption of minerals.
Phytate is an organic compound found in whole grains, bran, and soy products which can bind minerals and limit their absorption.
Oxalates are organic acids found in spinach, other leafy greens, chocolate, rhubarb which can interfere with iron anc calcium absorption.
Not really sure how tannins work.
What are major sources of calcium in the diet?
In the US the main source of calcium is milk. The second biggest source is fish - from the tiny bones that are often eaten along with the meat.
Active transport absorption of calcium...
Calcium can be absorbed in the digestive tract through passive or active transport.
For active transport to work, active form of Vit D is necesarry. The vit D activates the synthesis of the calcium transport proteins which pull calcium into cells in the diegestive tract. A calcium pump then moves the mineral from the digestive tract to the bloodstream.
If a person's diet is deficient in Vit D, they cannot absorb calcium very well.
Calcium is most often abosrbed into the body in this way but it is also absorbed passive transport as well.
Does absorption of calcium increase or decrease as intake of calcium goes up?
The greater the intake of calcium, the lower the percentage of it is absorbed. So when you're eating lots of this stuff, less of it gets absorbed.
What are some things that decrease the absorption of calcium?
Tannins, phytates, oxalates.
Where is calcium stored in the body?
99% of calcium in the body is stored in bones and teeth. If the body needs more calcium it is released from the bones into the blood stream. Osteoclasts are small cells that break down the bone to release the calcium.
1% of the calcium in your body is in the blood stream. This amount must stay very close to 1%.
What are some functions of calcium in the body?
Important for bone health, gives bones strength. Necesarry for nerve function, allowing nerves to transmit signals back and forth. Necesarry for muscle contraction. Also important for release of hormones.
How does the body react to low blood-calcium levels?
Parathyroid glands ( which are glands that sit in the thyroid gland itself ) release parathyroid hormone, or, PTH.
Release of PTH causes bones to release stored calcium into the blood stream.
PTH also causes kidneys to reabsorb calcium filtered from the blood.
PTH also activates Vit D which increases calcium absorption in digestive tract.
How does the body react to high calcium-blood levels?
Parathyroid glands release less PTH. This causes the kidney to excrete more calcium in the urine rather than sending it back to blood stream. It also decreases activation of Vit D.
Thyroid gland releases calcitonin which causes bones to release less calcium.
There are no short term signs of calcium deficiency. A person could not be getting enough calcium in their diet for a few months and not see any noticable side effects.
Not enough calcium in the diet can cause bones to release more calcium which depletes bone mass.
Calcium deficiency can lower peak bone mass - the highet amount of bone in your body. So if a person is calcium deficient for a while they may not get all the bone back they once had even after recovery.
Clacium deficency can also increase the rate at which bone is lost.
Too much calcium in the diet can cause symptoms like nausea, vomiting, loss of appetite, increased thirst, increased urination. More serious toxicity can cause confusion, coma, and death.
Calcium toxicity is rare and unlikey to be caused by normal diet. But, too much Vit D supplements ( which increases absorption of calcium ), diseases affecting kidneys or thyroid gland that disrupt their calcium regulating functions can cause too much calcium to be present in blood stream.
Too much calcium in blood stream can lead to kidney stones and calcification of soft tissues.
What are AIs and ULs for calcium?
- AI for adults 19yo. to 50yo. - 1000mg / day
- AI for people 51 + yo. - 1200mg / day
- AI for children 9yo. - 18yo - 1300mg / day
UL - 2500mg / day
What are osteoclasts?
Osteoclasts are cells that break down bone.
What are osteoblasts?
Oteoblasts are cells that build bone.
What is compact / cortical bone?
Dense, smooth bone that makes up the outside layer of a bone.
What is spongy / trabecular bone?
Less dense bone with lots of little holes it it. Found inside of bones.
Bone is made of a matrix / network of protein which forms collagen fibers. Hydroxyapatite crystals made of calcium and phosphorus coat the collagen fiber network which makes it solid and strong.
What is bone remodeling?
The process of bone being broken down by osteoclasts and rebuilt by osteoblasts.
What is osteoperosis?
As a person grows older ( after about age 40 ) bone is being broken down faster than it is being rebuilt. Because of this bone mass begins to decrease.
Osteoperosis is a loss of both the collagen fiber framework and the minerals coating it which leads to a decrease in the total amount of bone.
Osteoperosis is a major health problem.
What are some risk factors for osteoperosis?
- Age - People older than 40 will suffer some bone loss.
- Gender - Weomen tend to have smaller body mass and smaller bones because of this. Since there is less bone more of it is lost sooner.
- Smoking - tobacco use weakens bones.
- Exercise - muscles need strong bones as anchors and bones need to be strong to support extra weight so exercise and weight bearing exersice can strengthen bone. Absence of it can weaken it.
- Body size - small, light bodies have weaker bones since they don't need to support much weight.
- Alcohol - alcohol abuse can interfere with calcium absorption in digestive tract
What are some steps a person can take to prevent osteoperosis?
Exercise, increase amount of calcium in diet, increase vit D in diet. Hormone replacement therapy ( replacin hormones lost during menopause ) can slow bone loss and replace some lost bone but it has side effects. Calcitonin injections or nasal inhaler can slow release of calcium from bone.
What are som functions of phosphorus?
- Helps form hydroxyapatite crystals which coat the collagen fiber network in bones and give it strength.
- Part of phospholipids which make up cell membranes.
- Component of DNA.
- Component of ATP.
- Important for bones and teeth.
What is RDA of phosphorus?
700mg / day
What are some good sources of phosphorus?
It's pretty much in everything.
Since it is part of hydroxyapatite, the crystal that coats collagen network of bones and gives them strength, not enough phosphorus can lead to bone loss. Since it is necesarry for ATP, not enough of it can lead to weakness.
Very rare but can lead to bone resorption where bone is broken down.
700mg / day
What are some functions of magnesium?
- Cofactor for over 300 enzymes. ( cofactor is something that allows an enzyme to work ).
- Positively charged ion inside cells.
- Essential for nerve function.
Magnesium RDA, UL...
- Men 400mg / day
- Women 310mg / day
UL - 350mg / day
50% of magnesium consumed in diet is absorbed by the body.
High levels of calcium in the diet can reduce the amount of magnesium absorbed.
Not common but has occured in older people with kidney problems.
Rare but can happen in people with alcoholism, gastrointestinal disorders, kidney disease, or those suffering malnutrition.
Good sources of magnesium...
Leafy greens, vegetables, seeds, bananas, whole grains, and hard water.