E' un breve articolo in inglese. Vale la pena di leggerlo perchè di multivitaminici si parla e straparla.
Secondo voi come è la cosa?
ippo
Are vitamins from pills really a waste of money?
According to one of the biggest ever studies of food supplements, vitamins from pills are a "waste of money" and do not protect against heart disease, cancer or a range of other illnesses.
Vitamins are popular dietary supplements used widely by Americans and Europeans. One of the main reasons for their popularity is the association between high levels of antioxidant vitamins in the blood and a reduced risk of chronic diseases, such as heart disease, and some forms of cancer.
However, this recent trial — published in the Lancet — has led many people to question their regular use of vitamins.
Vitamins
In the study, scientists from Britain's Oxford University followed 20,536 people from a number of British hospitals. The vitamins given to the group included 600 milligrams of vitamin E, 250 milligrams of vitamin C, and 20 milligrams of beta-carotene [5].
Blood tests showed that the vitamin regimen approximately doubled the plasma concentration of alpha-tocopherol (a form of vitamin E), increased that of vitamin C by a third and quadrupled that of beta-carotene.
Despite this, the researchers found that the daily doses of vitamins made no difference to the rate of heart disease, cancer, cataracts, bone fractures, asthma, or mental decline. In fact, according to, Rory Collins, Professor of Medicine and Epidemiology at Oxford and co-author of the study,
"Over five years we saw absolutely no effect. Vitamin pills are a waste of time. There was no evidence of any protective effect against heart disease, cancer or any other outcome. They are safe but they are useless."
The mechanism by which antioxidant vitamins, such as vitamin E or vitamin C, are supposed to protect against disease is a reduction in a process known as oxidative stress.
Free radicals
Your body is made up of millions of tiny cells. Think of each cell like a miniature city. Inside each city, you'll find the power stations of the cell — known as the mitochondria (pronounced my-toe-kon-dree-a). It's inside the mitochondria where food is turned into energy.
Unfortunately, mitochondria also appear to have a major design flaw — they leak electron electricity. This, in turn, leads to an increase in the production of free radicals.
Free radicals are molecules with an unpaired electron. A molecule that's missing an electron is a very "unhappy" molecule. So, rather than just accept the fact they're destined to spend the rest of their life single, they search for an extra electron. However, when it snatches an electron from a nearby molecule, that molecule in turn is left with an unpaired electron.
This process continues until two free radicals meet and react, satisfying their lone electrons. While this provides a happy ending for the two lone electrons, their search has left a trail of destruction. Cell machinery has been wrecked beyond repair. Some molecules have been ripped apart.
Antioxidants
One of the functions of an antioxidant is to "quench" these free radicals before they create too much damage. You can see antioxidants at work in your own kitchen. Slice an apple in half, and watch it turn brown. That's an example of oxidation. If, however, you dip the apple in lemon juice, the rate at which the apple turns brown is slowed. That's because the vitamin C in the lemon juice slows the rate of oxidative damage.
Science has long held that damage by free radicals is behind many of the disease states associated with aging, including heart disease and cancer.
Several long-term studies show that a high intake of fruit and vegetables appears to protect against some of these diseases. However, attempts to duplicate these findings with vitamin supplements haven't met with as much success.
That's because fruit and vegetables contain nutrients other than antioxidant vitamins. And while a rise in the level of blood antioxidants is associated with a degree of protection against disease, it doesn't mean they're causing this protection.
Many people make the common mistake of believing that association implies causation. In England, for example, the rapid rise in obesity since the 1970's is associated with an increase in the number of hours people spend in front of the TV [9]. It's not that watching TV is causing them to gain weight. Rather, it's the fact that watching TV has replaced physical activity. And it's this drop in physical activity, rather than TV itself that's partly to blame for the rapid rise in obesity.
So, if the vitamins in fruit and vegetables aren't primarily responsible for their health...
Secondo voi come è la cosa?
ippo
Are vitamins from pills really a waste of money?
According to one of the biggest ever studies of food supplements, vitamins from pills are a "waste of money" and do not protect against heart disease, cancer or a range of other illnesses.
Vitamins are popular dietary supplements used widely by Americans and Europeans. One of the main reasons for their popularity is the association between high levels of antioxidant vitamins in the blood and a reduced risk of chronic diseases, such as heart disease, and some forms of cancer.
However, this recent trial — published in the Lancet — has led many people to question their regular use of vitamins.
Vitamins
In the study, scientists from Britain's Oxford University followed 20,536 people from a number of British hospitals. The vitamins given to the group included 600 milligrams of vitamin E, 250 milligrams of vitamin C, and 20 milligrams of beta-carotene [5].
Blood tests showed that the vitamin regimen approximately doubled the plasma concentration of alpha-tocopherol (a form of vitamin E), increased that of vitamin C by a third and quadrupled that of beta-carotene.
Despite this, the researchers found that the daily doses of vitamins made no difference to the rate of heart disease, cancer, cataracts, bone fractures, asthma, or mental decline. In fact, according to, Rory Collins, Professor of Medicine and Epidemiology at Oxford and co-author of the study,
"Over five years we saw absolutely no effect. Vitamin pills are a waste of time. There was no evidence of any protective effect against heart disease, cancer or any other outcome. They are safe but they are useless."
The mechanism by which antioxidant vitamins, such as vitamin E or vitamin C, are supposed to protect against disease is a reduction in a process known as oxidative stress.
Free radicals
Your body is made up of millions of tiny cells. Think of each cell like a miniature city. Inside each city, you'll find the power stations of the cell — known as the mitochondria (pronounced my-toe-kon-dree-a). It's inside the mitochondria where food is turned into energy.
Unfortunately, mitochondria also appear to have a major design flaw — they leak electron electricity. This, in turn, leads to an increase in the production of free radicals.
Free radicals are molecules with an unpaired electron. A molecule that's missing an electron is a very "unhappy" molecule. So, rather than just accept the fact they're destined to spend the rest of their life single, they search for an extra electron. However, when it snatches an electron from a nearby molecule, that molecule in turn is left with an unpaired electron.
This process continues until two free radicals meet and react, satisfying their lone electrons. While this provides a happy ending for the two lone electrons, their search has left a trail of destruction. Cell machinery has been wrecked beyond repair. Some molecules have been ripped apart.
Antioxidants
One of the functions of an antioxidant is to "quench" these free radicals before they create too much damage. You can see antioxidants at work in your own kitchen. Slice an apple in half, and watch it turn brown. That's an example of oxidation. If, however, you dip the apple in lemon juice, the rate at which the apple turns brown is slowed. That's because the vitamin C in the lemon juice slows the rate of oxidative damage.
Science has long held that damage by free radicals is behind many of the disease states associated with aging, including heart disease and cancer.
Several long-term studies show that a high intake of fruit and vegetables appears to protect against some of these diseases. However, attempts to duplicate these findings with vitamin supplements haven't met with as much success.
That's because fruit and vegetables contain nutrients other than antioxidant vitamins. And while a rise in the level of blood antioxidants is associated with a degree of protection against disease, it doesn't mean they're causing this protection.
Many people make the common mistake of believing that association implies causation. In England, for example, the rapid rise in obesity since the 1970's is associated with an increase in the number of hours people spend in front of the TV [9]. It's not that watching TV is causing them to gain weight. Rather, it's the fact that watching TV has replaced physical activity. And it's this drop in physical activity, rather than TV itself that's partly to blame for the rapid rise in obesity.
So, if the vitamins in fruit and vegetables aren't primarily responsible for their health...
...... al massimo 1gr in + del rda.
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