Absorption and Transport of Iron in Human Body

Absorption and Transport of Iron in Human Body
Entry of iron into the body us carefully regulated by its absorption, a very complex and poorly understood process. This regulation of absorption in the normal, healthy individual is closely tied to the level of the iron stores; absorption increases when iron stores are low and decreases as stores become greater. The rate of erythropoiesis also appears to influence iron absorption.

Food iron is presented to the body either as heme iron, found only in animal products, or as non-heme iron, which comprises all the iron occurring in plant foods and about 60% of that in animal foods.

Whether the iron is heme or non-heme has a major influence in the amount of the mineral absorbed. Since heme iron is so limited in most diets absorption of non-heme iron deserves the greater emphasis.

Overall absorption is estimated to range from 10 – 15%. Iron absorption can occur throughout the small intestine but is most efficient in the proximal portion, particularly the duodenum. Heme iron is absorbed as an intact metalloporphyrin, perhaps having first been split from global chain while in lumen of the gastrointestinal (GI) tract.

Heme is well absorbed but rates of absorption are inversely related to iron stores and may range form 15% to 35%. Within the mucosal cells the absorbed heme is broken down by a heme oxygenase, and the iron released moves through the mucosal cells in the form of small molecules.

The non-heme iron is less well absorbed with rate of absorption ranging from approximately 2% to 20%. Its specific rate of absorptions highly dependent on the amount of iron stores and the influence of concomitantly ingested dietary components.

Also affecting rate of absorption are existing conditions within the lumen of the proximal GI tract. The chemical form of the non-heme iron that enters the mucosal cells, the nature of receptor sties, and the trans-mucosal transport are unknown.
Absorption and Transport of Iron in Human Body

Deficiency of Chromium

Deficiency of Chromium
Researchers estimate that two out of every three Americans are hypoglycemic, pre-hypoglycemic or diabetic. The ability to maintain normal blood sugar levels is jeopardized by the lack of chromium in our soil and water supply and by a diet high in refined white sugar, flour and junk foods. A number of human and animal studies have found that chromium supplements can improves insulin sensitivity and blood sugar in the face of insulin resistance, elevated blood sugar levels, impaired glucose tolerance and diabetes.

A deficiency of chromium can lead to anxiety, fatigue, glucose intolerance, (particularly in people with diabetes), inadequate metabolism of amino acids and an increased risk of arthrosclerosis. Excessive intake (the level depends upon individual tolerance) can lead to chromium toxicity, which has been associated with dermatitis, gastrointestinal ulcers, and kidney and liver impairment.

Supplemental chromium is best absorbed by the body when it is taken in a form called chromium picolinate (chromium chelated with picolinate, a naturally occurring amino acid metabolite). Picolinate enables chromium to readily enter into the body’s cells, where the mineral can then help insulin do its job much more effectively.
Deficiency of Chromium

Chromium

Chromium
Because it is involved in the metabolism of glucose, Chromium (sometimes also called glucose tolerance factor of GTF) is needed for energy. It is vital in the synthesis of cholesterol, fats, and proteins. This essential mineral maintains stable blood sugar levels through proper insulin utilization, and can be helpful both for people with diabetes and those with hypoglycemia. Studies have shown that low plasma chromium levels can be an indication of coronary artery disease.

Additional chromium is needed during pregnancy because the developing fetus increases demand for this mineral. Chromium supplements can help an expectant mother maintain healthy blood sugar levels during pregnancy.

The average American diet is chromium deficient. Only one in the Americans has an adequate amount of chromium in his or her diet. There are five main reasons for this:

• The form of chromium in many foods is not easily absorbed (only 0.4 to 2.5 percent of dietary chromium is absorbed)

• Not enough foods containing chromium are consumed

• Much of the chromium is lost during processing

• Many people do not like the foods that are the best sources of chromium

• High quantities of sugar in the diet cause of loss of chromium from the body

Chromium

Calcium Diets

Calcium Diets
Calcium is found in dairy foods, salmon (with bones), sardines, seafood and dark green leafy vegetables.

Food sources include almonds, asparagus, blackstrap molasses, brewer’s yeast, broccoli, buttermilk, cabbage, carobs, cheese, collards, dandelion green, dulse, figs, filberts, goat’s milk, kale, kelp, milk, mustard greens, oats, prunes, sesame seeds, soybeans tofu, turnip greens, watercress, whey and yogurt.

Herbs that contains calcium include alfalfa, burdock root, cayenne, chamomile, chickweed, chicory, dandelion, eyebright, fennel seed, fenugreek, flaxseed, hops, horsetails, kelp, lemongrass, mullein, nettle, oat straw, paprika, parsley, peppermint, plantain, raspberry leaves, red clover, rose hips, shepherd’s purse, violet leaves, yarrow, and yellow dock.

A diet that is high in protein, fat and/or sugar affects calcium uptake. The average American diets of meats, refined grains, and softdrinks leads to increase excretion of calcium.

Consuming alcoholic beverages, coffee, junk foods, excess salt, and/or white flour also leads to the loss of calcium by the body. A diet based on foods such as vegetables, fruits and wholesome grains, which contain significant amounts of calcium but lower amounts of phosphorus, is preferable.

Oxalic acid (found in almonds, beet greens, cashews, chard, cocoa, soybeans and spinach) interferes with calcium absorption by binding with it in the intestines and producing insoluble salts that cannot be absorbed.

The normal consumption of foods containing oxalic acids should not pose a problem, but overindulgence in these foods inhibits the absorption of calcium. Oxalic acid can also combine with calcium to form calcium-oxalate kidney stones. However, that taking magnesium and potassium supplements can prevent the formation of this types of stone.
Calcium Diets

Calcium: Function and Deficiency

Calcium: Function and Deficiency
Calcium is vital for the formation of strong bones and teeth and for the maintenance of healthy gums. It is also important in the maintenance of a regular heartbeat and in the transmission of nerve impulses. Calcium lowers cholesterol levels and helps prevent cardiovascular disease. It is needed for muscular growth and contraction, for the prevention of muscle cramps. It may increase the rate of bone growth and bone mineral density in children.

This important mineral is also essential in blood clotting and helps prevent cancer. It may lower blood pressure and prevent bone loss associated with osteoporosis as well. Calcium provides energy and participates in the protein structuring of RNA and DNA. It is also involved in the activation of several enzymes, including lipase, which breaks down fats for utilization by the body. In addition, calcium maintains proper cell membrane permeability, aids in neuromuscular activity, helps to keep the skin healthy, and protects against the development of preeclampsia during pregnancy, the number one cause of maternal death. If high blood pressure develops due to pregnancy, it can be reduced by calcium intake.

Calcium protects the bones and teeth from lead by inhibiting absorption of this toxic metal. If there is a calcium deficiency, lead can be absorbed by the body and deposited in the teeth and bones.

Calcium deficiency can lead to the following problems: arching joints, brittle nails, eczema, elevated blood cholesterol, heart palpitation, hypertension (high blood pressure), insomnia, muscle cramps, nervousness, numbness in the arms and/or legs, a pasty complexion, rheumatoid arthritis, rickets and tooth decay. Deficiencies of calcium are also associated with cognitive impairment convulsions, depression, delusions and hyperactivity.
Calcium: Function and Deficiency