posted by - @ 8:33 PM
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Thursday, May 6, 2010
Dietary fibre = health
You've probably heard that dietary fibre is good for your heart. But if you've been eating lots of whole wheat bread and high-fibre cereal in the hope that you're doing your cardiovascular system a favour, then you may have been barking up the wrong tree.
Two recent studies reinforce previous research that revealed a clear relationship between dietary fibre and heart health. And the studies show that choosing your fibre sources carefully can make all the difference. Because there are two types of fibre, and while both are good for you, one has a more positive effect on your heart than the other.
Fibre choresThere's no need to stop the presses for the 'news' that dietary fibre is good for you. Low fibre intake has been associated with an increased risk of a variety of cancers (including breast and colon cancers), and I think it would be a very rare HSI member who was not aware that dietary fibre helps maintain a healthy digestive system.
All dietary fibres are classified as either water-soluble or insoluble. And because water-soluble fibres have been shown to support cardiovascular health, a team of researchers at Tulane University studied the dietary and medical records of nearly 10,000 subjects enrolled in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study (NHEFS) looking for correlations between water-soluble fibre intake and coronary heart disease (CHD).
All subjects were disease-free when the study began. During an average follow-up period of 19 years, 1843 cases of CHD were recorded. Examination of the dietary records showed that subjects with the highest intake of insoluble fibre (approximately 21 grams per day) had about 12 percent lower risk of developing CHD as those with the lowest intake (approximately 6 grams per day).
When the same records were compared for water-soluble fibre intake, subjects with the highest intake of this fibre (approximately 6 grams per day) had a 15 percent lower risk of developing CHD, compared to those with the lowest intake (less than one gram per day).
Cereal killer Another recent study among almost 1,000 heart patients in Milan, Italy, produced conclusions similar to the Tulane study.
Dietary factors were assessed in interviews that showed that higher fibre intake reduced the risk of heart attack by well over 25 percent. But among those who had the highest intake of fruit and water-soluble fibre, heart attack risk was reduced by an impressive 36 percent.
One surprising fact emerged from the collected data: Those with the highest intake of cereal fibre actually increased their heart attack risk by more than 10 percent. This was attributed to the fact that the sources of this type of fibre appeared to be refined grains. It's no secret to most of us that many food products claim to be 'whole grain' or 'whole wheat,' but actually contain very little of either.
Go to the sourceMost people don't eat enough unrefined, water-soluble fibre to produce the positive results shown in the Milan and Tulane studies. But good quality water-soluble fibre is easy to come by when a little care is taken to find unrefined sources of these foods:
Fruits, including oranges, peaches, apples, and grapes
Vegetables, including carrots, squash, and corn
Nuts and seeds (in particular, psyllium seeds)
Legumes, including peanuts, lentils, peas, and kidney and pinto beans
Oats and barley
Some people add fibre supplements to their diets, but Dr William Campbell Douglass, has warned against using these supplements and eating fibre-enriched food, stating that the total effect they may have on the human body is still unknown and potentially dangerous. Dr. Douglass compares fibre-enriched foods to trying to make a silk purse out of a sow's ear, noting that, 'adding fibre to foods with refined carbohydrates and artery clogging vegetable fats isn't going to make these already unhealthy foods any less bad for you.'
You've probably heard that dietary fibre is good for your heart. But if you've been eating lots of whole wheat bread and high-fibre cereal in the hope that you're doing your cardiovascular system a favour, then you may have been barking up the wrong tree.
Two recent studies reinforce previous research that revealed a clear relationship between dietary fibre and heart health. And the studies show that choosing your fibre sources carefully can make all the difference. Because there are two types of fibre, and while both are good for you, one has a more positive effect on your heart than the other.
Fibre choresThere's no need to stop the presses for the 'news' that dietary fibre is good for you. Low fibre intake has been associated with an increased risk of a variety of cancers (including breast and colon cancers), and I think it would be a very rare HSI member who was not aware that dietary fibre helps maintain a healthy digestive system.
All dietary fibres are classified as either water-soluble or insoluble. And because water-soluble fibres have been shown to support cardiovascular health, a team of researchers at Tulane University studied the dietary and medical records of nearly 10,000 subjects enrolled in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study (NHEFS) looking for correlations between water-soluble fibre intake and coronary heart disease (CHD).
All subjects were disease-free when the study began. During an average follow-up period of 19 years, 1843 cases of CHD were recorded. Examination of the dietary records showed that subjects with the highest intake of insoluble fibre (approximately 21 grams per day) had about 12 percent lower risk of developing CHD as those with the lowest intake (approximately 6 grams per day).
When the same records were compared for water-soluble fibre intake, subjects with the highest intake of this fibre (approximately 6 grams per day) had a 15 percent lower risk of developing CHD, compared to those with the lowest intake (less than one gram per day).
Cereal killer Another recent study among almost 1,000 heart patients in Milan, Italy, produced conclusions similar to the Tulane study.
Dietary factors were assessed in interviews that showed that higher fibre intake reduced the risk of heart attack by well over 25 percent. But among those who had the highest intake of fruit and water-soluble fibre, heart attack risk was reduced by an impressive 36 percent.
One surprising fact emerged from the collected data: Those with the highest intake of cereal fibre actually increased their heart attack risk by more than 10 percent. This was attributed to the fact that the sources of this type of fibre appeared to be refined grains. It's no secret to most of us that many food products claim to be 'whole grain' or 'whole wheat,' but actually contain very little of either.
Go to the sourceMost people don't eat enough unrefined, water-soluble fibre to produce the positive results shown in the Milan and Tulane studies. But good quality water-soluble fibre is easy to come by when a little care is taken to find unrefined sources of these foods:
Fruits, including oranges, peaches, apples, and grapes
Vegetables, including carrots, squash, and corn
Nuts and seeds (in particular, psyllium seeds)
Legumes, including peanuts, lentils, peas, and kidney and pinto beans
Oats and barley
Some people add fibre supplements to their diets, but Dr William Campbell Douglass, has warned against using these supplements and eating fibre-enriched food, stating that the total effect they may have on the human body is still unknown and potentially dangerous. Dr. Douglass compares fibre-enriched foods to trying to make a silk purse out of a sow's ear, noting that, 'adding fibre to foods with refined carbohydrates and artery clogging vegetable fats isn't going to make these already unhealthy foods any less bad for you.'
posted by - @ 8:10 PM
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More about dietary fibre
Dietary fibre is a term that refers to a group of food components that pass through the stomach and small intestine undigested and reach the large intestine virtually unchanged. Most other nutrients are digested and are being used in other parts of the body by this stage. During its passage through the large intestine some components of dietary fibre are broken down to varying degrees and absorbed by the body; the remaining components are excreted in the faeces.
To the extent that products of dietary fibre breakdown in the large intestine are absorbed, a small amount of energy is contributed, probably of the order of 13 kilojoules (3 kilocalories) per gram of dietary fibre ingested. Diets that are high in dietary fibre produce a slower rate of stomach emptying, and bulky faeces which pass more quickly through the large intestine.
The current attention being given to the role of dietary fibre in prevention of certain diseases is largely due to the observation that patterns of disease observed in Africa and Asia were different from those in Western countries. It was suggested that the dietary fibre content was associated with this difference. Although it is not yet proven, there is evidence to suggest that a diet high in dietary fibre can be of value for treating or preventing such disorders as constipation, irritable bowel syndrome, diverticular disease, hiatus hernia and haemorrhoids. Some components of dietary fibre may also be of value in reducing the level of cholesterol in blood and thereby decreasing a risk factor for coronary heart disease and the development of gallstones. Dietary fibre is beneficial in the treatment of some diabetics.
The actual role of dietary fibre in many of these disorders is not known. It may be that dietary fibre as such is not the major factor. When high dietary fibre foods are eaten, other foods, which may be responsible for the disease, are either reduced in quantity or completely excluded. For example, diets that are high in fibre tend to be low in energy and these diets can be useful in weight control. People who are grossly overweight (more than 130 per cent of desirable weight or with a body mass index of about 30 kilograms per square metre, are more prone to heart disease and diabetes.
The analysis of dietary fibre in food is very complex and only a limited number of foods have been examined in detail. Dietary fibre from different foods, and even different samples of the same food, contain varying quantities of the components that collectively make up dietary fibre. Each of these components has different biological properties and it is frequently not clear which of these is most beneficial.
Dietary fibre is a term that refers to a group of food components that pass through the stomach and small intestine undigested and reach the large intestine virtually unchanged. Most other nutrients are digested and are being used in other parts of the body by this stage. During its passage through the large intestine some components of dietary fibre are broken down to varying degrees and absorbed by the body; the remaining components are excreted in the faeces.
To the extent that products of dietary fibre breakdown in the large intestine are absorbed, a small amount of energy is contributed, probably of the order of 13 kilojoules (3 kilocalories) per gram of dietary fibre ingested. Diets that are high in dietary fibre produce a slower rate of stomach emptying, and bulky faeces which pass more quickly through the large intestine.
The current attention being given to the role of dietary fibre in prevention of certain diseases is largely due to the observation that patterns of disease observed in Africa and Asia were different from those in Western countries. It was suggested that the dietary fibre content was associated with this difference. Although it is not yet proven, there is evidence to suggest that a diet high in dietary fibre can be of value for treating or preventing such disorders as constipation, irritable bowel syndrome, diverticular disease, hiatus hernia and haemorrhoids. Some components of dietary fibre may also be of value in reducing the level of cholesterol in blood and thereby decreasing a risk factor for coronary heart disease and the development of gallstones. Dietary fibre is beneficial in the treatment of some diabetics.
The actual role of dietary fibre in many of these disorders is not known. It may be that dietary fibre as such is not the major factor. When high dietary fibre foods are eaten, other foods, which may be responsible for the disease, are either reduced in quantity or completely excluded. For example, diets that are high in fibre tend to be low in energy and these diets can be useful in weight control. People who are grossly overweight (more than 130 per cent of desirable weight or with a body mass index of about 30 kilograms per square metre, are more prone to heart disease and diabetes.
The analysis of dietary fibre in food is very complex and only a limited number of foods have been examined in detail. Dietary fibre from different foods, and even different samples of the same food, contain varying quantities of the components that collectively make up dietary fibre. Each of these components has different biological properties and it is frequently not clear which of these is most beneficial.
posted by - @ 8:05 PM
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Dietary fibre functions and benefits
Functions and benefits
Adds bulk to your diet, making you feel full faster
May reduce appetite
Attracts water and turns to gel during digestion, trapping carbohydrates and slowing absorption of glucose
Lowers variance in blood sugar levels
Lowers total and LDL cholesterol
Reduces risk of heart disease
Regulates blood sugar
May reduce onset risk or symptoms of metabolic syndrome and diabetes
Speeds the passage of foods through the digestive system
Facilitates regularity
Adds bulk to the stool
Alleviates constipation
Balances intestinal pH and stimulates intestinal fermentation production of short-chain fatty acids
May reduce risk of colorectal cancer
Fibre does not bind to minerals and vitamins and therefore does not restrict their absorption, but rather evidence exists that fermentable fibre sources improve absorption of minerals, especially calcium.
Some plant foods can reduce the absorption of minerals and vitamins like calcium, zinc, vitamin C, and magnesium, but this is caused by the presence of phytate (which is also thought to have important health benefits), not by fibre.
Functions and benefits
Adds bulk to your diet, making you feel full faster
May reduce appetite
Attracts water and turns to gel during digestion, trapping carbohydrates and slowing absorption of glucose
Lowers variance in blood sugar levels
Lowers total and LDL cholesterol
Reduces risk of heart disease
Regulates blood sugar
May reduce onset risk or symptoms of metabolic syndrome and diabetes
Speeds the passage of foods through the digestive system
Facilitates regularity
Adds bulk to the stool
Alleviates constipation
Balances intestinal pH and stimulates intestinal fermentation production of short-chain fatty acids
May reduce risk of colorectal cancer
Fibre does not bind to minerals and vitamins and therefore does not restrict their absorption, but rather evidence exists that fermentable fibre sources improve absorption of minerals, especially calcium.
Some plant foods can reduce the absorption of minerals and vitamins like calcium, zinc, vitamin C, and magnesium, but this is caused by the presence of phytate (which is also thought to have important health benefits), not by fibre.
posted by - @ 8:03 PM
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Plant sources of fiber
Legumes such as soybeans contain dietary fibers.Some plants contain significant amounts of soluble and insoluble fiber. For example plums (or prunes) have a thick skin covering a juicy pulp. The plum's skin is an example of an insoluble fiber source, whereas soluble fiber sources are inside the pulp.
Soluble fiber is found in varying quantities in all plant foods, including:
legumes (peas, soybeans, and other beans)
oats, rye, chia, and barley
some fruits and fruit juices (including prune juice, plums, berries, bananas, and the insides of apples and pears)
certain vegetables such as broccoli, carrots, and Jerusalem artichokes
root tubers and root vegetables such as sweet potatoes and onions (skins of these are sources of insoluble fiber)
psyllium seed husk (a mucilage soluble fiber).
Sources of insoluble fiber include:
whole grain foods
wheat and corn bran
nuts and seeds
potato skins
flax seed
lignans
vegetables such as green beans, cauliflower, zucchini (courgette), celery, and nopal
some fruits including avocado, and bananas
the skins of some fruits, including tomatoes
The five most fiber-rich plant foods, according to the Micronutrient Center of the Linus Pauling Institute, are legumes (15–19 grams of fiber per US cup serving, including several types of beans, lentils, and peas), bran (17 grams per cup), prunes (12 grams), Asian pear (10 grams each, 3.6% by weight), and quinoa (9 grams).
Rubus fruits such as raspberry (8 grams of fiber per serving) and blackberry (7.4 grams of fiber per serving) are exceptional sources of fiber.
Legumes such as soybeans contain dietary fibers.Some plants contain significant amounts of soluble and insoluble fiber. For example plums (or prunes) have a thick skin covering a juicy pulp. The plum's skin is an example of an insoluble fiber source, whereas soluble fiber sources are inside the pulp.
Soluble fiber is found in varying quantities in all plant foods, including:
legumes (peas, soybeans, and other beans)
oats, rye, chia, and barley
some fruits and fruit juices (including prune juice, plums, berries, bananas, and the insides of apples and pears)
certain vegetables such as broccoli, carrots, and Jerusalem artichokes
root tubers and root vegetables such as sweet potatoes and onions (skins of these are sources of insoluble fiber)
psyllium seed husk (a mucilage soluble fiber).
Sources of insoluble fiber include:
whole grain foods
wheat and corn bran
nuts and seeds
potato skins
flax seed
lignans
vegetables such as green beans, cauliflower, zucchini (courgette), celery, and nopal
some fruits including avocado, and bananas
the skins of some fruits, including tomatoes
The five most fiber-rich plant foods, according to the Micronutrient Center of the Linus Pauling Institute, are legumes (15–19 grams of fiber per US cup serving, including several types of beans, lentils, and peas), bran (17 grams per cup), prunes (12 grams), Asian pear (10 grams each, 3.6% by weight), and quinoa (9 grams).
Rubus fruits such as raspberry (8 grams of fiber per serving) and blackberry (7.4 grams of fiber per serving) are exceptional sources of fiber.
posted by - @ 8:00 PM
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Dietary Fiber (sometimes called roughage) is the indigestible portion of plant foods having two main components:
1.soluble (prebiotic, viscous) fibre that is readily fermented in the colon into gases and physiologically active byproducts
2.insoluble fibre that is metabolically inert, absorbing water throughout the digestive system and easing defecation.
It acts by changing the nature of the contents of the gastrointestinal tract, and by changing how other nutrients and chemicals are absorbed. Soluble fibre absorbs water to become a gelatinous, viscous substance and is fermented by bacteria in the digestive tract. Insoluble fibre has bulking action and is not fermented,although a major dietary insoluble fibre source, lignin, may alter the fate and metabolism of soluble fibres.
1.soluble (prebiotic, viscous) fibre that is readily fermented in the colon into gases and physiologically active byproducts
2.insoluble fibre that is metabolically inert, absorbing water throughout the digestive system and easing defecation.
It acts by changing the nature of the contents of the gastrointestinal tract, and by changing how other nutrients and chemicals are absorbed. Soluble fibre absorbs water to become a gelatinous, viscous substance and is fermented by bacteria in the digestive tract. Insoluble fibre has bulking action and is not fermented,although a major dietary insoluble fibre source, lignin, may alter the fate and metabolism of soluble fibres.
posted by - @ 7:57 PM
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