( continuation of the previous article )

Scientists believe that we may be able to adapt to high-fiber diets. But this is not known for sure. It is speculation based on a handful of studies.

The effect of fiber on minerals varies among the different types. Here is what scientists think based on current knowledge:

• Iron nutrition probably won’t be affected by eating more fiber.
• Fiber probably will decrease absorption of zinc and copper.
• If zinc and copper intake is good, the decrease in absorption probably will not create any problems.

Whole grains contain more zinc and copper than refined grains, so this may offset any loss of these minerals resulting from the fiber. But until we know this for a fact, I feel it’s best to take a moderate rather than extreme approach to the fiber content of your diet.

Another Mineral-Robber

Fiber is not the only substances in whole grain foods that can bind to minerals. Whole grains also contain phytic acid, which can also tie up minerals. Nutritionists also refer to phytic acid as phytate.

Fortunately, we now know that yeast can destroy phytate. This means that it should not be a problem in whole grain breads made with yeast. Nutritionists believe that phytate is rarely a problem, except among people eating enormous amounts of unleavened bread. Few, if any, of us eat such a diet.

Fighting Fat with Fiber

If you’re weight watcher, you probably remember the ‘starch blockers’ that came out in 1982. The too-good-to-be true claims were just that. The pills landed more than two dozen people in the hospital. The FDA had its hands full getting the stuff off the market.

Well, fiber may be the only starch blocker that doesn’t make us sick.

Nutritionists have long known that fiber blocks the absorption of some of the calories in food. It not only blocks the calories from carbohydrates; it takes on protein, fat, and carbohydrate  pretty much equally. Studies show that people absorb 1% to 3% fewer calories when eating a high-fiber diet.

Sound like a fantasy? It is not. Most of us gain weight slowly, at the rate of an extra pound or two per year. For a woman needing 100 calories a day, a 1% fall in calories absorbed would mean a loss of two pounds per year. A 3% reduction in calories absorbed translates into 6 fewer pounds per year.

There’s only one catch. These findings come from short-term studies. No one knows whether the body will adapt to a high-fiber diet so that eventually just as many calories are absorbed.

Fiber researchers have reported getting complaints from their subject about the “large” quantity of food they were asked to eat. Little did the subjects realize that the high-fiber diets contained no more calories than low-fiber diet.

This is a clue that fiber creates a feeling of fullness. Nutritionists have long suspected that it does. In the stomach, fiber swells with water. This may help curb hunger.

Some scientists also believe that high-fiber foods help with weight control because they take longer to chew.

One thing is for sure: a high-fiber diet based on whole grains, fruits, and vegetables is likely to be nutritionally sound. That is more than can be said for so many of the “miracle” weight-loss diets that come along every year.

More Benefits of Fiber

Fiber is now known to benefit the following conditions:

1. Diverticulosis and diverticulitis
2. High blood cholesterol
3. Diabetes
4. It may also help prevent tooth decay!

Let’s take a closer look at these findings.

Diverticulosis is a common condition among older people. It refers to outpouchings of the intestines. Food can get caught in these pockets. Often the result is inflammation and pain.

Doctors used to treat this problem with a low-fiber diet. But much to their surprise, they have learned that a high-fiber diet usually gives much better results. In general, patients are asked to add wheat bran to their diets.

Dental researchers believe that whole grain foods may play a role in preventing tooth decay. Studies show that something in whole grains may protect the teeth from decay-producing acids in the mouth. The bacteria in the mouth produce these acids.

( The Next Fiber’s Benefit and How to Estimate Fiber Content )

If you are concerned about your iron intake, consider some of these sources:

* Lean meats and shellfish

* Whole grain or enriched cereals

* Dried apricots, prunes, or raisins

* Nuts and wheat germ

* Dried beans and peas

* Leafy green vegetables

Liver, especially pork liver, contains large amounts of iron. But it is also rich in cholesterol. Too many of us eat too much of cholesterol-containing foods. Egg yolk has a moderate iron content; it is high in cholesterol, too.

The iron in flesh foods, called heme iron, is best absorbed by the body. Yet studies have found no more iron-deficiency anemia among vegetarians than among meat eaters.

One possible explanation is vitamin C. It enhances absorption of the iron in foods. Vegetarians often consume more vitamin C than meat-eaters. The vitamin C may compensate for the absence of meat in their diets.

A Look at Lead

Lead has long been in the headlines. Lead poisoning has occurred too frequently among children – often from eating chips of old paint that contained lead.

Whatever lead also plays any role in the cancer process is an open question. Only a few studies have been done – mostly in animals. These studies suggest that large amounts of lead might increase the risk of kidney cancer. But this form of cancer is not very common. (I never forget my friend, a medical doctor, who died 4 years ago, at the age of 40, due to kidney cancer).

The committee on Diet, Nutrition, and Cancer declined to make any recommendations regarding lead.

Some Advice about Canned Foods

Lead remains a concern to health experts for other reasons. The chances of getting lead poisoning are not great, but the problems has yet to be eliminated in U.S. and other countries. Infants, children, and pregnant women are at greatest risk.

Scientists estimate that food accounts for 55 – 85 percent of our exposure to lead. The lead in canned foods can seep into the food itself. Public pressure and encouragement from the Food and Drug Administration (FDA) have led canners to reduce the lead content of food by almost 40 percent during the last 30 years.

Acidic foods packed in cans made with lead are the most likely to absorb this mineral. Fruits and fruit juices, including tomato products, fall into this category. If these foods are stored in the can after opening, the lead content can increase fivefold in less than a week.

Lead experts urge us not to store acidic foods in cans after opening. Transfer the food to a glass or plastic container. This precaution will go a long way to preventing unnecessary lead in the diet. Foods taste better, too, when this advice is followed.

Unfortunately, there is no easy way to tell whether a csn has been soldered with lead. Evaporated milk is usually packed in lead-soldered cans. Infant formulas are not. Processed meats are also usually packed in non-leaded cans.

There’s Much More to the Story

Though research has yet to find that lead or other minerals play a major role in cancer prevention, the story of nutrition and cancer is not yet over. We have looked at vitamins, minerals, fiber, and cancer inhibitors. but there’s more to come.

The Next story tells about the dietary change that may offer the biggest dividends of all.

Encouraged by reports linking the mineral to cancer protection, people are buying – and taking – selenium supplements. In some Asia countries, they call selenium as the king of anti-cancer substances.  But, a few words of caution are in order.

At high doses, selenium can cause health problems. Fatigue and irritability, as well as brittleness or loss of hair, have been seen in patients suffering from toxic amounts of selenium. A research scientist exposed to too much selenium developed bronchitis and skin problems.

How Much is Too Much?

According to the Food and Nutrition Board of the National Research Council, a long term intake of 2400 to 3000 micrograms of selenium per day would be expected to cause a toxic reaction.

It is very unlikely that the diet could provide such a high level of selenium. In fact, there is only recorded instance of selenium toxicity caused by food. It dates back about seventy five years and occurred among people living in an area of the country where the soil was unusually rich in this mineral.

To overdose on selenium, you would probably have to work with it or take supplements. In 1977, the Food and Nutrition Board (U.S.) advised:

There is no justification at this time for the use of selenium supplements by the general population. Should selenium supplements eventually be condidered desirable for those persons living in low-selenium areas, or for those consuming vegetarian diets, a daily supplement of 50 to 100 micrograms could probably be taken safely. (Emphasis added.)

Five years later, in 1982, the Committee on diet, Nutrition, and Cancer (U..S.) seemed to agree with the Food and Nutrition Board’s opinion. “Increasing the selenium intake to more than 200 micograms a day…….. by the use of supplements has not been shown to confer health benefits exceeding those derived from consumption of  a balanced diet,” said tyhe panel.

Selenium in Our Diet

It is not easy to list the selenium content of common foods. The amount of selenium in meat, for instance, can vary. It depends partly on the amount of the mineral in the animals’ diets.

The selenium content of the soil also varies throughout the regions of each country. The soil content, inturn, greatly affects the amount of selenium in grains. But most of us  now eat foods grown from many parts of our country; no longer do we eat only foods grown nearby. Furthermore, recently so many foods were imported from Asia and other countries.

As a result, nutritionosts rarely see signs of selenium deficiency among Americans. The average selenium intake in the United States, for instance, is 150 micrograms per day, which is considered more than enough  for most people.

Good sources of selenium are:

• Meat and seafood
• Grains, unless, grown in soil low in selenium
• Asparagus and mushrooms
• Garlic
• Meats and seafood are the richest source of this mineral.

Fruits and most vegetables contain little selenium. The selenium content of dairy products and eggs varies.

Can Iron Help, Too?

Adequate iron in the diet prevents a condition called Plummer-Vinson syndrome. This condition has been linked to increased risk of developing stomach cancer and cancer of the esophagus.

Probing these findings, scientists have found that iron deficiency allows bacteria to grow in the stomach. It is possible that these bacteria turn nitrites into the cancer causing substances called nitrosamines.

But, as is the case with selenium, there is still not much evidence to go on. It certainly makes sense, though, to eat iron-rich foods (unless your doctor has advised against it. Some people, though not many, have a disorder that causes them to retain too much iron).

Iron deficiency is not truly widespread in some countries. But many people, such in case of Americans, don’t get the RDA for iron. This hardly means that all of these people have iron deficiency. The RDA is set higher than about 96 % of us need. It is not a requirement, but rather a “better-safe-than-sorry” approach.

The Best Sources of Iron

If you are concerned about your iron intake, consider some of these sources:

• Lean meats and shellfish
• Whole grain or enriched cereals
• Dried apricots, prunes, or raisins
• Nuts and wheat germ
• Dried beans and peas
• Leafy green vegetables

(  Next Story, the Part III )

It is an alluring idea. Some have even proposed that the quick fix already does exist – in the form of a mineral called selenium.

But the wishful thinking is a little premature. There is some evidence that the minerals in our food play a role in preventing cancer. More research is needed, though, before we can draw any conclusions.

The Minerals in Food

Food contains a wide range of minerals. We need some of them in large amounts. Other minerals are required in very small amounts.

Nutritionists refer to the minerals needed in large amounts as major minerals. Those that we need in small amounts are known as trace minerals or trace elements.

The most important major minerals are:

• calcium
• magnesium
• sodium
• chloride
• phosphorous
• potassium

There are many trace minerals. Scientists know a great deal about some of them, and very little about others. Some of the trace minerals include:

• copper
• chromium
• fluorine
• iodine
• iron
• manganese
• molybdenum
• selenium
• zinc

When it comes to minerals and cancer, research has focused only on trace minerals. None of the major minerals have been the focus of cancer research.

Too Soon to Tell

Most cancer institutions and foundations, including Committee on Diet, Nutrition, and Cancer (U.S.), made no recommendation about minerals. In general, the scientists found too little evidence for making judgment.
Some of them cited selenium and iron as the best-studied minerals. But though they found evidence that selenium may protect both humans and animals against some forms of cancer, the evidence was ruled preliminary.
Similarly, they found evidence that an adequate iron intake protects both humans and animals against cancer in the upper part of the digestive tract. But this findings, too, were considered inconclusive.

In this case, the Committee on Diet, Nutrition, and Cancer said that no conclusions could be drawn at all about the role of the following minerals in cancer prevention:

• copper
• zinc
• molybdenum
• iodine
• arsenic
• cadmium
• lead

It may surprise you to read the committee’s conclusions about these last three minerals – arsenic, cadmium, and lead. You may be aware that these minerals have long been linked to excessive cancer rates among workers who are heavily exposed to them. But occupational exposure to these minerals is many times higher than the levels that occur in food. For this reason, too, the committee declined to make any judgments.

The Selenium Story

Chances are that you have heard reports about the ability of selenium to prevent cancer. A few enthused promoters have inspired some people to take selenium supplements as a preventive measure.

The evidence that selenium helps to prevent cancer is promising but far from final. Research has shown, for instance, that:

1. Areas of the world where selenium intake is high have lower cancer rates than countries where the diet is low in selenium.
2. Blood selenium levels are higher in healthy people than in cancer victims.
3. Selenium added to the diet or drinking water of laboratory animals helps to protect against cancer-causing chemicals.

One problem with these findings is clear. Scientists can rarely know whether a cancer patient always had a low blood level of selenium. It is possible that the disease, once developed, cause a normal selenium level to drop suddenly.
Some research has yielded opposite results, showing no relationship between the selenium in the blood and the risk of cancer. But on the whole, the research on this mineral must be considered promising.

Oddly enough, there were once concerns that selenium might promote cancer. These fear have not been supported by the most recent research.
But research has shown that selenium can be toxic in other ways. Scientists hardly want to advocate a measure that will help prevent one disease but cause others instead.

By the way, I would be very grateful if you have some latest valuable information regarding this subject, never hesitate to write down on the comment board below.

( Next Story, the Part II )

I would drink my orange juice and eat my green peppers even if  it weren’t  for research linking vitamin C to prevention of cancer.

Some of my reasons are the same ones that bolster the advice to eat more fruits and vegetables that supply carotene.  Like these plant foods rich in vitamin A, foods rich in vitamin C are also low in saturated fat and sodium.

What’s more, fruits and vegetables that contain vitamin C are cholesterol-free. And they provide small to moderate amounts of dietary fiber. Eaten in large amounts,  the fiber in these fruits and vegetables helps to lower blood cholesterol levels.

There is more. Vitamin C is rarely recognized for its role in iron absorption. Yet we have known for many years that vitamin C helps the body to absorb iron.

The extent of iron deficiency in the United State and most industry countries have been greatly exaggerated, I believe, but there are probably more people taking in too little iron than is the case for other nutrients.

Because the body absorbs only about 10 percent of the iron taken in, factors that increase iron absorption are just as important as iron-rich food. In fact, some scientists believe that increasing absorption of iron, rather than boosting iron intake, is the key to improving iron nutrition. They may be right on target.

At moderate levels – such as 50 to 100 mg – vitamin C has been found to improve iron absorption by as much as 50 percent. Higher doses may result in even higher absorption. But very few of us truly need such as assist.

Vitamin C helps the body absorb iron in foods that are eaten at the same meal. The vitamin C in breakfast foods, for example, has little or no effect on the iron in foods eaten at lunch or dinner.

For some people, however, this is not good news. A small number of people have a condition that causes them to retain too much iron, which accumulates in various organs, causing health problems. People who have this condition should consult their physicians for advice about diet.

I would love to tell you that vitamin C will also help protect you from heart disease. But I cannot, because I am not at all convinced by these claims.

I have looked carefully at evidence that vitamin C lowers blood cholesterol levels. But I found other studies in which vitamin C supplements appeared to have raised the cholesterol level. Some studies show no difference. I really do not hold out much hope for an effect here.

But what more can you want from vitamin C? It does not have to play a role in prevention of every disease in order to be taken seriously.

In my opinion, vitamin C is as important today as it was two centuries ago, when the mysterious disease  called scurvy threatened the lives of sailors who spent months without fresh fruits and vegetables. It is hard to disagree with the advice to make more room for this familiar vitamin in our diets.