by Yeong Sek Yee & Khadijah Shaari
IRON – WHAT IT IS
Iron is a mineral essential for life and is found in red blood cells. Iron’s primary role is to carry oxygen from the lungs to the rest of the body. Much of the iron in the body occurs in the haemoglobin.
Haemoglobin is the component of red blood cells that enables them to carry oxygen and deliver it to the body’s tissues. Iron is thus an important component of haemoglobin and muscle cells. It is also necessary for the formation of many enzymes in the body.
The body recycles iron. When red blood cells die, the iron in them is returned to the bone marrow to be used again in new blood cells. A small amount of iron is lost each day, mainly in cells shed from the lining of the intestine. This amount is usually replaced by 1 to 2 milligrams of iron absorbed from the food each day.
(The body contains between 3.5gm and 4.5gm of iron, two thirds of which is present in haemoglobin. The remainder is stored in the liver, spleen and bone-marrow. A small amount is present as myoglobin, which acts as an oxygen store in muscle tissue).
The Recommended Dietary Allowance for iron in healthy adults is 10mg per day for men and 15mg for premenopausal women. Premenopausal women’s need for iron is higher than men because women lose iron during menstruation.
There are two forms of dietary iron: heme and nonheme. Iron in meat, fish and poultry is found in a chemical structure known as HEME. Heme iron is absorbed very efficiently by our body. Iron in plants such as lentils and beans, is arranged in a different chemical structure called NONHEME iron. Nonheme iron is less easily absorbed by the body than is heme iron. The amount of iron absorbed from various foods ranges from around 1 to 10% from plant foods and 10 to 20% from animal foods.
The absorption of iron is influenced by other constituents of a meal. Phytates, oxalates and phosphates present in plant foods can inhibit absorption, as can tannin in tea. Fibre may also inhibit absorption. However, Vitamin C greatly increases the absorption of nonheme iron. Foods rich in Vitamin C include papaya, green peppers, and fresh green vegetables. Good sources of iron for vegetarians include wholegrain cereals and flours, leafy green vegetables, blackstrap molasses, pulses such as lentils and kidney beans, and some dried foods (see table on Food Sources of iron).
Iron deficiency is a common mineral deficiency which is most commonly caused by loss of blood due to some internal bleeding, inadequate diet, etc. When iron reserves in the body are exhausted, anemia develops. Anemia causes paleness, weakness, irritability, drowsiness and fatigue, etc. In such cases, doctors would trace the root cause of such anemia or source of bleeding.
Once iron is absorbed by the digestive tract, the body stores it. Most of us accumulate much more iron than we need. Unfortunately, the body has no way to rid itself of excess iron except in the case of some form of bleeding or by donating blood. Although not as common as iron deficiency, iron overload can also be serious.
Hemochromatosis, a genetic disorder where individuals absorb more iron than normal, can lead to iron stores in the body eventually building up to such high levels that organs are damaged. Heme iron (from meat) poses the greatest risk for people with this disorder. Excess iron store does not provide any particular advantage and may even have adverse effects. For example, iron is a pro-oxidant – it promotes oxidative damage that is linked to many chronic diseases. In some studies, excess iron stores (and intakes) have been linked to increased risk of heart disease and certain forms of cancer, particularly colorectal cancer. Iron accumulation can damage any part of the body, including the brain, liver, pancreas, lungs or heart.
IRON AND VEGETARIAN DIETS: ARE VEGETARIANS MORE DEFICIENT THAN NON-VEGETARIANS?
If people are building their diet from grains, beans, vegetables and fruits, are they going to become iron deficient? Absolutely not, according to Dr Randall Lauffer in his book, Iron Balance.
According to Dr Randall, there are many studies in vegetarian populations where the iron levels are lower than they are in a meat-eating population, but they are certainly adequate, more than adequate. Most men have 1000 to 2000 extra milligrams of iron in their bodies, and that is iron that they are not using. It is just waiting to cause trouble.
The above fact (about vegetarians’ iron adequacy) is clearly echoed by Dr David Ogilvie whose research showed that a well-balanced vegetarian diet provides enough Iron. Vegetarians have no more iron deficiency or anemia than non-vegetarians. On the whole, research indicates that dietary intake of iron by vegetarians, particularly in the case of vegans, meets or exceeds the RDA (Recommended Dietary Allowance).
On another front, some experts contend that if fibre intake is too high the bodies are not able to absorb as much iron and related minerals because the fibre may bind with these nutrients and carry them through our system before we are able to digest them. The “experts” say that the maximum level of fibre should be around 30 – 35 grams per day, which is only about the average intake of the rural Chinese. On the iron / fibre issue, Dr Colin Campbell, PhD, Professor of Nutrition at Cornell University wrote in The China Study that fibre is not the enemy of iron absorption as so many experts claim it to be. In the massive study of nutritional habits of the Chinese in various counties in China Dr Campbell proved that there was no evidence showing that increasing fibre intake impaired iron absorption in the body. On the contrary, people who consumed more plant-based foods, thus more dietary fibre, also consume more iron (non-heme iron) all of which results in statistically significant higher levels of haemoglobin.
In his book, The Food Connection, Dr Sam Graci, a leading nutritionist in US, also mentioned that until recently, the unsubstantiated belief was that “good” non-heme iron, from non-meat sources is not absorbed well. It was argued that phytates, polyphenols, tannins and oxalates would bind to non-heme iron and reduce its absorption. The iron status of vegetarian Asians and vegetarian Westerners (their haemoglobin, plasma ferritin and plasma iron-binding capacity) has shown no particular iron mineral deficiences. The beneficial non-heme iron from plants, sea vegetables, legumes, seeds, nuts, whole grains, spirulina, does not accumulate in the body.
EXCESS IRON AND CANCER
Most of us, especially the meat eaters are unaware that excess iron generates “free radical” that damage cells and encourage a build-up of bad LDL Cholesterol. Too much iron, primarily in red meat, may promote cancer notably colon cancer. The claim that meat is a good source of iron, meat gives strength and energy are all propagated by the meat industry and this has led to a proliferation of illness ranging from heart diseases to various forms of cancers. Are there evidences that having excess iron is dangerous?
Let us look at some of the literature by various authorities … medical doctors, cancer Centres and research scientists :-
1) NATURAL STRATEGIES FOR CANCER PATIENTS by Dr Russell Blaylock, MD. Dr Blaylock was the Clinical Professor of Neurosurgery at the University of Mississippi. After 20 years of nutritional research, Dr Blaylock realised the critical importance of nutrition in the immune function. Following are the main points on iron and cancer:
a) Numerous studies have shown that cancer is highly iron dependant. This is because rapidly dividing cells require iron for DNA replication. The cancer cells’ need for iron is so great that they will steal iron from normal cells and from iron stores.
b) Higher dietary iron intake has also been associated with an increase in cancers stimulated by the powerful estrogen estradiol.
c) One of the best sources of absorbable iron is meat – the specific form it contains is called heme iron. Subjects who ate the most red meat had significantly higher rates of lung cancer than the subjects who avoided red meats. In fact, the lung cancer rate was 300% higher in the red meat eaters than in the abstainers.
d) Because iron is so destructive to the cells and tissues when it is allowed to float around freely, most of the iron in the body is bound to special proteins called transferrin. Free iron, (when there is an excess overload) is a very powerful generator of free radicals and lipid peroxidation.
e) It is vital that cancer patients avoid iron supplements and high iron-containing foods with significant absorbability, such as red meats.
f) Controlling the iron levels can be done purely through nutrition. One of the best ways to remove excess iron from your body is to increase the phytates in your diet. The phytates are natural substances found in grains, potatoes, and many other foods. These compounds bind tightly with iron in a process called chelation, preventing the iron from doing harm. Many flavonoids and plant components found in common fruits and vegetables can chelate iron.
g) Can eating too many vegetables lead to iron-deficiency anemia? Carefully done studies have shown that the flavonoids in foods allow just enough iron to be absorbed to prevent anemia. Even though broccoli and spinach contain as much iron as a comparable amount of beef, only a small amount of the iron is absorbed from the vegetables, whereas 60 to 70 percent of the iron is absorbed from beef.
h) Iron is a powerful stimulus for cancer growth, invasion and metastasis.
2) IRON OVERLOAD – THE MISSED DIAGNOSIS by Dr Paul Cutler, MD Dr Cutler, a graduate of the University of Toronto medical school, has published many research articles on excess iron in various peer medical journals. In the above titled article which appeared in the newsletter of the Consumer Health Organization of Canada, Dr Cutler made the following points:-
a) Physicians were more interested in anemias and low iron deficiency and did not really perform the necessary tests of iron metabolism to diagnose the opposite end of the spectrum – iron overload.
b) By 1989, doctors began publishing research which showed that iron was also a risk factor in cancer at levels that were far less than what they had thought safe in the past.
c) Excess iron is very dangerous. Iron is capable of inducing free radical or oxidative Pathology.
d) Tumour cells and bacteria need iron to grow, and your body tries to starve them of iron by diverting the iron from the blood to storage sites deep within the tissues. It is well known, biochemically, that if you add iron to tumour cells in cultures, they grow at a much faster rate and that breast cancer cells thrive on iron. In 1988, many studies began to surface showing that iron was indeed a risk in common cancers such as lung, colon, bladder, oesophagus, and at levels that were shockingly less than doctors had previously considered dangerous. A study in the New England Journal of Medicine (Oct 1988) by Dr Richard Stevens showed that as iron saturation levels increase, cancer rates go up. Until that time a 65% of saturation level was considered to be safe, but this study showed that at a 37% saturation level, the cancer rate started to skyrocket, and doctors began to question the levels they had previously considered safe. In January 1944, in the International Journal of Cancer, Dr Stevens reported that cancer rates were increasing at levels of only 31%.
e) The sources of nutritional dietary iron which raise the iron levels in the body are red meat and alcohol.
f) Plant iron (i.e. nonheme iron) is not considered to be a major offender of iron overload.
3) IRON: A DOUBLE EDGED SWORD by Rebecca Lavie, M.A. Rebecca Lavie is a special education teacher who was forced to give up her career after being stricken with an unidentified disabling illness. After 12 years of going from doctor to doctor, she was finally diagnosed with iron overload and elevated levels of aluminum, lead and copper by Dr Paul Cutler (see Iron Overload – The Missed Diagnosis). Following her treatment and recovery, she began researching the scientific literature on the subject of iron overload, a potentially lethal, but under diagnosed and under treated medical condition.
In her book, she states that iron can re-activate a latent infection or tumour. Iron feeds cancer cells and causes them to metastasize. Many studies have shown that up to 88% of metastasized breast cancer patients have elevated serum ferritin. Cancerous breasts have three times as much iron as normal breasts. Many people with excess iron develop liver dysfunction which can develop into enlarged liver, jaundice, and lead to cirrhosis and liver cancer.
4 ) NORRIS COTTON CANCER CENTER, an NCI Comprehensive Cancer Center Dr Leo Zacharski, MD, Professor of Medicine Dartsmouth Medical School and a member of the staff of the Hematology and Oncology of the Norris Cotton Cancer Center, conducted a large randomized clinical trial clinical trial in which effects of lowering iron stores by phlebotomy (removal of blood).
The following are some salient points pointed out by this centre under its Iron Surveillance Program:
a) The amount of iron carried in the body comes almost entirely from excessive dietary intake. Because almost everyone consumes more iron than needed over long periods of time, iron accumulation occurs in most people and may predispose to common diseases of aging.
b) Cancer cells are known to grow rapidly in response to iron in their environment.
c) Elevated iron levels induce oxidative stress that damages critical molecules to cause disease.
d) Iron intake by an unsuspecting public is generally in excess of requirements because of government mandated iron supplementation of processed foods (such as cereal grains).
e) Iron that is present naturally (usually in small quantities in vegetables is generally poorly absorbed and relatively safe. Spinach is famous for its relatively high iron content but this iron is mostly not absorbable.
f) The body does not automatically eliminate excessive quantities of iron that may be harmful.
5) AMERICAN INSTITUTE FOR CANCER RESEARCH (AICR) Karen Collins, a dietitian and nutritionist with AICR wrote in its Jan 1st 2007 newsletter What’s Your Vegetables-to-Meat Ratio?, in which she stated that studies indicate that heme iron may damage the lining of the colon. Heme iron may interact with estrogen in promoting hormone related cancers, such as breast and prostate cancers.
6) IRON BALANCE by Dr Randall Byron Lauffer, MD. Dr Randall was a professor at Harvard Medical School, and later was the director of a research laboratory at the Massachusetts General Hospital. He is a leading expert on mineral biochemistry and the use of minerals in medical diagnosis and therapy. Dr Randall made clear comments about iron’s role in cancer:
a) Iron is a key component of the free radical theory of disease.
b) The biggest contributor to both iron and high cholesterol levels is meat. So every bite of meat is contributing to problems in the body – heart and chronic diseases.
c) We have had evidence for a long time that high iron levels do increase the risk of Cancer. This is because:
a) iron’s role in free radical damage is important in cancer.
b) iron is known to be a key and best catalyst for this process, you can imagine.
d) Iron has another role in cancer: it is a key ingredient for cell division. If the cell does not have iron around, it simply does not divide. So if you can restrict the amount of iron to a cancer cell, it actually slows down cancer growth. People with higher amount of iron have plenty of iron to supply growing cancer cells.
e) For men especially, it was clear that higher iron levels were associated with increased risk for certain forms of cancer. For example, a person with inherited iron-overload has 200 times the risk of liver cancer compared to a normal person.
f) During the past 4 decades, numerous research groups have reported that the administration of excessive amounts of injected or oral iron increases markedly the risk of adenocarcinomas, colorectal tumours, hepatomas, mammary tumours, mesotheliomas, renal cell carcinomas, and sarcomas.
g) As consumption of red meat (heme iron) is the main source of oral iron, it is important to decrease or eliminate the consumption of red meats, avoidance of processed foods that have been adulterated with inorganic iron and also eliminate iron supplements unless an iron deficiency has been correctly diagnosed.
8 ) EXOGENOUS FACTORS IN COLONIC CARCINOGENESIS by W. Scheppach, M. Scheurlen. This book is the proceedings of Falk Symposium 128, held in Warzburg, Germany in 2002 and dedicated to the important issue of colonic carcinogensis and its underlying genetic and environmental factors.
A chapter: Red Meat: A dietary risk factor for Colorectal Cancer, research scientists H. Boeing, E. Riboli and T. Norat stated the following points:-
a) Meat is an excellent source of iron. In fresh meat, iron is bound mostly to Myoglobin: globin and haemoglobin are part of the heme iron fraction, and this is preferentially absorbed in the human body.
b) A high dietary iron intake will lead to a high availability of iron in the gut lumen. (High levels of iron stores are indicated by high transferrin saturation and increased.
c) We cannot refute the idea that iron is directly linked to risk of colorectal cancer.
9) NUTRITION, TOXICITY AND CANCER by Dr Ian R. Rowland, PhD. Dr Rowland, is the Professor in Human Nutrition at the School of Biomedical Sciences, University of Ulster, UK. Touching on iron excess, Professor Rowland said: Dietary iron levels are positively associated with colon cancer. Diets that are high in red meat and fat content are iron rich and also provide copious lipid substrate for peroxidation. The mechanism by which iron increases colorectal cancer risk relates to the effect of iron on oxygen radical metabolism.
10) IRON CHELATION THERAPY by Dr Chaim Hershko. This book by research scientist Dr Chaim Hershko deals with the pathophysiology of iron toxicity and the mechanism of iron chelating drugs. The section on Iron Overload Diseases (pg 28) said: There are several inherited and acquired disorders that can result in chronic iron overload in humans, and whose major outcome include hepatic fibrosis, cirrhosis, hepatocellular cancer (liver cancer), cardiac disease, and diabetes. (The liver is the main organ for iron storage and also the main site of iron toxicity during iron overload).
SCIENTIFIC / RESEARCH STUDIES
In this section, we looked at some research studies conducted by various cancer research groups, various institutions and hospitals. These are just some of the hundreds of studies conducted. To read more just go to Google.com and type in Dietary Iron and Cancer.
1) BODY IRON STORES AND THE RISK OF CANCER by RG Stevens, DY Jones, Ms Micozzi, and PR Taylor. The New England Journal of Medicine 319:1047-105,”because of evidence that increased body iron stores are associated with an increased risk of cancer, we examined iron status and cancer risk. These results are consistent with the hypothesis that high body iron stores increase the risk of cancer in men.
2) IRON OVERLOAD AND ITS ASSOCIATION WITH CANCER RISK IN HUMANS; EVIDENCE FOR IRON AS A
CARCINOGENIC METAL by Dr Xi Huang, Dept. of Environmental Medicine, NYU Cancer Institute, NYU School of Medicine, New York. Journal Mutation Research 533 (2003). In this review, evidence for iron as a carcinogenic metal was summarised from epidemiological, animal and cell culture studies. The role of iron in various cancers, such as colorectal cancer and liver cancer was presented. It also pointed out that most iron in humans exists as heme, present in heme proteins or in ferritin, an iron storage protein. Heme is an excellent source of iron for humans. Red meats contain large amounts of heme, which can be absorbed more easily than inorganic iron due to the insolubility of iron salts. Iron-induced malignant tumours were first reported in 1959. Beginning in the 1980′s, epidemiological reports have associated increased iron exposure with elevated cancer risk. The majority of existing epidemiological data support the role of iron in human cancer.
3) TRANSFERRIN SATURATION, DIETARY IRON INTAKE, AND RISK OF CANCER by Prof. Arch. Mainous, PhD, Dr James M. Gill, MD, MPH and Charles Everett, PhD The Annals of Family Medicine 2005: 3 (2): 131 – 137. Prof. Mainous is the professor in the Family Medicine Dept at the Medical University of South Carolina. The main message in this paper is: If you already have higher than normal body iron stores – indicated by high percentages of transferring saturation and then eat plenty of iron-rich food, you set yourself up for increased cancer risk. Persons with increased transferring saturation who consume high levels of dietary iron or red meat have an increased mortality risk.
4) EXCESSIVE DIETARY IRON LINKED TO INCREASED RISK OF UPPER GASTROINTESTINAL CANCER by Dr David Jacobs NJ, International J of Cancer. Dec 2005. A study, led by Dr David Jacobs and conducted by researchers at the University of Minnesota revealed that the consumption of high levels of dietary iron is linked to an increased risk of throat and stomach cancer. The researchers identified a positive correlation between iron intake and the risk of these upper digestive tract cancers. This study was conducted over 16 years.
5) DIETARY IRON, ZINC AND CALCIUM AND THE RISK OF LUNG CANCER by Zhou, Wei, Park, Sohee and others. Epidemiology 16 (6):772 – 779, Nov 2005. The above study concluded that dietary iron, zinc, and calcium may play an important role in the development of lung cancer, especially among current smokers. Dietary intakes of these micronutrients have been also associated with altered risks of colorectal, breast, and prostate cancers.
6) HIGH INTAKE OF IRON MAY INCREASE PROSTATE CANCER RISK. High intake of iron, combined with low intake of dietary antioxidants, may increase prostate cancer risk, according to results of a study presented by Ji -Yeob Choi, PhD, Dept of Cancer Prevention and Population Control, Roswell Park Cancer Institute at the 2007 centennial meeting of the American Association for Cancer Research, April 14 – 18, in Los Angeles, California. Those men who consumed higher amounts of dietary iron were found to be at increased risk of clinically aggressive prostate cancer; this risk was strongest among men who consumed fewer fruits and vegetables.
7) IRON AND HEPATOCELLULAR CARCINOMA (LIVER CANCER ) by Yves Deugnier, Bruno Turlin and Others. Journal of Gastroenterology and Hepatology, Vol 16, May 2001. This group of French researchers at Hospital Pontchaillou, France, concluded that the the high prevalence of hepatocellular carcinoma (HCC) was associated with increased body stores of iron. Evidence of a co-carcinogenic role of iron strongly support that iron is involved in the development of HCC (liver cancer).
From the above notes, it is imperative for cancer patients to:
1. AVOID all meats (pork, beef, chicken).
2. AVOID intake of iron supplements.
3. Besides the danger of excess iron intake, eating meat also mean consuming hormones, drugs such as antibiotics, growth stimulators and other chemicals that are being fed to the animals.
Meat is thus a storehouse of concentrated toxins. So when you doctors advise you to eat anything you like or eat more animal protein to beef up your blood – they only have in mind the need for you to complete your next chemo session, not so much about your health. Please think carefully and be informed.