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Importance of balanced diet: Excess iron in the body is a risk factor in coronary heart disease

More on my favourite subject — eating and health. This time it is iron on the chopping block.

From 1981, a theory has been expounded by various doctors in the Lancet, the apex international medical journal, that excess iron in the body is a risk factor in coronary heart disease. It was regarded only as a theory, however, until 1992 — when a team of Finnish epidemiologists found, after a five-year study financed by the Finnish government, that the amount of stored iron in the body ranks second only to smoking as the strongest risk factor for heart disease and heart attacks.

The study involved 1,931 Eastern Finnish men between the ages of 42-60. Eastern Finnish men have the highest recorded incidence of coronary heart disease in the world.

The researchers measured the amount of serum ferritin as an estimate of stored iron. They found that for each 1 percent increase in the amount of ferritin in the blood, there was a more than four percent increase in heart attack risk. A serum ferritin level of above 200 micrograms per litre of blood more than dou­bled the risk (up till now medical science has said that 100-400 micrograms have generally been considered as safe). This study has been widely reported and discussed by newspapers all over the world, including Circulation, the journal of the American Heart Associa­tion.

How does iron work in the body?

 Importance of balanced diet: Excess iron in the body is a risk factor in coronary heart disease

Representational image. Getty Images

One of its most important functions is the transport of oxygen in the blood. It is also required for the burning of fuel in the form of food and stored body fat and in the creation of new cells to replace the old. It is critical for the body to store excess iron efficiently, in case there is a sudden shortage, and it does this by constantly recycling the iron in the blood without ex­creting it.

Because iron is not excreted, the daily need for it from food is quite small. If the body needs more iron, the absorption of iron from food in the intestines increases.

Three questions arise in this iron-heart study. What role does cholesterol play? How does excess iron contribute to heart dis­ease and attacks? How does the body accumulate excess iron in the first place?

The first two questions have a single answer. Cholesterol and iron apparently work together. The result of an extended cross-population study in 1991 showed that heart disease mortality rates were correlated to a combination of iron and cholesterol, rather than with either one alone. The highest mortality rate occurred in men from the United States, England, Australia and North Europe where both iron and cholesterol levels are high. Another finding was that in South and Central America, certain groups, which had a moderate level of heart disease, showed low cholesterol levels but very high iron levels. The conclusion of both the Finnish and this international report was the same: In men with both high iron and high ‘bad’ cholesterol (called LDL — low density lipoprotein), the risk of heart attack more than quadrupled.

Iron and cholesterol work together in the development of atheros­clerosis, which is a disease involving the clogging of arteries. How does atherosclerosis develop? LDL cholesterol is trapped by cells in the artery wall leading to the development of the disease. But LDL must be oxidised before the artery walls will trap it. Iron promotes the LDL oxidation, triggering the disease. Repeated tests by scientists have shown that unless iron is present, cholesterol does not oxidise efficiently. As the cho­lesterol is oxidised and trapped by the cells, the latter become enlarged and multiply. The inside of the artery becomes narrower and the blood supply to the heart is diminished, increasing the potential of a heart attack.

Once the heart attack occurs, iron again plays a role in damaging the heart. During a heart attack, the blood flow to the heart is cut off. The supply of oxygen is thus diminished and iron is released from storage sites in the heart cells. The damage is done when blood flow is resumed and oxygen re-enters the cells. A wild, uncontrolled process, known as iron catalysed oxidation, takes place and the heart cells suffer severe damage. Several investi­gations have shown that an iron-inhibiting drug reduces tissue damage considerably.

If excess iron is so toxic to our bodies why is it so pervasive in the West and increasing in the East? The answer is that meat is a staple in the West. Meat is high in iron, and the iron in meat is easily absorbable, unlike the iron in fruits, vegetables and grains. While the absorption of plant-based iron will decrease in people with high iron levels, our bodies do not seem to have a way to decrease the percentage of meat-iron absorbed when iron stores are sufficient. People who eat meat, place an excess iron burden, which increases as they age. The strongest dietary determinants of serum ferritin concentra­tion are the intake of alcohol and meat. Vegetarians have much lower iron stores and much less heart disease.

You might say that vegetarians have lower heart disease levels because they consume less cholesterol — not because they eat less iron. Not really. The vegetarians in this country have only slightly less cholesterol levels because they eat and drink huge quantities of dairy food (ghee, milk, paneer, channa, chaas, cheese, butter, sweetmeats, khoya, kheer, ice cream) in the mistaken belief that these are health foods. These foods add enormously to the cholesterol level, bringing them almost up to the cholesterol levels of meat eaters. So it is not less cholesterol, but less iron that is the mitigating factor.

Other studies have implicated iron in other diseases, among them cancer and arthritis. In the presence of oxygen, iron is a carci­nogen. Iron is required for the growth of cells, and the rapid growth of cancer cells requires iron to sustain itself. The most influential of the studies, supporting a link between high iron levels and cancer, was published in the 1988 issue of the New England Journal of Medicine. This study found that men who had high blood levels of iron were 37 percent more likely to develop cancer of the lungs, colon, oesophagus and bladder, than men who had lower levels.

A Norwegian study provided the first scientif­ic evidence to support the theory that diet could alleviate rheumatoid arthritis symptoms and iron was connected to it. In 1991, the Lancet published a study about a group put on a vege­tarian diet who showed a significant improvement compared to a meat — vegetable diet.

The theory, that iron plays a significant role in such diseases as arthritis, cancer and heart disease, is corroborated further by the symptoms shown by people who are afflicted with hemochromatosis, a disorder in which the body absorbs and stores excessive iron. Hemochromatosis patients typically suffer from cancer, heart disease, arthritis and diabetes — and the disorder is not uncommon. While it is mostly hereditary, it can appear in people who take in excessive amounts of iron — for instance, women who begin taking iron pills early, to combat anaemia and continue taking them for over ten years.

Balance is extremely important for the body chemistry to work. This is what is recommended for an iron balance:

- Not eating meat

- Eating fruit, vegetables and grains

- Eating food rich in phytic acid (it is a sponge for excess iron in the colon) such as wheat bran, whole wheat products, rye

- Avoiding, or cutting, alcohol to a minimum

- Getting a moderate amount of exercise. According to the Finnish study, as cardio-respiratory fitness increased, serum ferritin levels went down.

The bottomline, of course, remains: Don’t eat meat.

To join the animal welfare movement contact gandhim@nic.in, www.peopleforanimalsindia.org.

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Updated Date: Dec 26, 2016 19:16:30 IST

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