Name the affliction—heart disease, Alzheimer's, arthritis, depression, asthma—and omega-3 fatty acids can help prevent it.
Or not.
Taking omega-3 fatty acids doesn't reduce deaths from heart attacks, strokes or other cardiovascular events, a new study states. But there's much more to be said about omega-3's.
That is the confusion being stirred up by new research on omega-3s, fats found in cold-water fish and plant oils that have intrigued nutrition scientists ever since the 1970s discovery that Greenland Eskimos rarely die from heart disease, despite a diet of fatty fish.
Some 21% of U.S. adults report using omega-3 fish-oil supplements, according to the Council for Responsible Nutrition, an industry trade group, making it the most popular supplement after multivitamins and vitamin D.
But last month, the Journal of the American Medical Association published a meta-analysis of 20 clinical trials involving nearly 70,000 people that found that omega-3 fatty acids didn't prevent heart attacks, strokes or deaths from heart disease. Other recent studies in the New England Journal of Medicine and the Archives of Internal Medicine found that omega-3 supplements didn't prevent heart problems in people with Type 2 diabetes or a history of heart disease.
Experts say such studies should be viewed with caution—just like studies with positive findings.
Critics noted that the JAMA study combined clinical trials that used different doses and sources of omega-3s. Many of the subjects were also on heart medication, which may have blunted the impact. Plus, diet studies are also notoriously imprecise. "It's impossible for five researchers to control the diet of almost 70,000 patients over several years," says Duffy MacKay, the CRN's vice president for scientific and regulatory affairs.
What's more, the JAMA authors imposed an unusually strict standard for statistical significance. Using the typical standard, the analysis would have concluded that omega-3 supplements are associated with a 9% reduction in cardiac deaths.
"My colleagues are writing letters to the editor about this," said University of Pennsylvania nutritionist Penny Kris-Etherton, a spokeswoman for the American Heart Association. She says, for now, the association will continue recommending that everyone eat omega-3 rich fish at least twice a week; people with heart disease or high triglycerides could also consider taking fish-oil supplements under a doctor's care. The American Psychiatric Association and the World Health Organization have similar advice.
Omega-3 fatty acids are essential for building cell membranes and maintaining the connections between brain cells. They also may reduce inflammation,increasingly recognized as a cause of chronic diseases.
Humans can't produce omega-3 fatty acids, so we must get them from outside sources. The two most important kinds—EPA and DHA—are primarily found in fish such as salmon, sardines, tuna and herring; a third kind, ALA, is found in walnuts, flaxseed, soybean oil and some green vegetables, including Brussels sprouts, spinach and kale.
The typical American diet is far higher in omega-6 fatty acids, which come from corn and safflower oil and are plentiful in processed foods and cornfed beef and poultry. Some experts believe that reducing the ratio of omega 6s to 3s is even more important than increasing omega-3s, but the evidence is mixed.
Blood tests (typically $100 to $200) can measure the amount of omega-3s in red blood cells or plasma and a growing number of doctors are ordering them. No official deficiency standard has been set, but according to one lab, OmegaQuant Analytics, having 4% or less omega-3s out of total fatty acids is "undesirable" and indicates an elevated heart risk; 8% or more is "desirable." Most Americans score between 3% and 5% omega-3s, says William Harris, a veteran heart researcher who founded OmegaQuant.
Thousands of studies since the 1970s have shown that people with high levels of omega-3s have lower triglycerides, lower blood pressure, lower LDL cholesterol, less inflammation and a lower risk of heart disease. Those with low levels of omega-3s are more likely to be depressed, to commit suicide and have memory loss and brain shrinkage as they age.
Many of those are observational studies that can't prove cause-and-effect; it may be that people who eat more fish have more healthy behaviors in general. The evidence from randomized-controlled trials is more mixed—but experts say that's not surprising in dietary studies, where researchers often have to rely on patients to accurately report what they ate over long periods.
Recent research offers a tantalizing mix of healing possibilities:
Alzheimer's disease and dementia: Several studies show that older people who eat plenty of fish have lower levels of beta-amyloid protein, associated with Alzheimer's, than those who eat less. But giving elderly people omega-3 fish-oil supplements didn't help ward off cognitive decline, according to a meta-analysis published in June. (The authors conceded that the trials may not have been long enough to show much effect.)
Macular degeneration: A 2011 Harvard study found that women who ate fish at least once a week were 38% less likely to develop age-related macular degeneration than women who ate it less than once a month.
Attention-Deficit Hyperactivity Disorder: Children with ADHD tend to have lower omega-3 levels than their peers, and a study in the journal PLOS One last month found that DHA can improve reading and behavior in underperforming children. Still, there is no evidence to date that omega 3s are as effective as medication.
Depression: Rates of depression, bipolar disorder and postpartum depression are all lower in fish-eating populations, writes psychiatrist Drew Ramsey in his 2011 book, "The Happiness Diet." He also lists wild salmon and shrimp as the top foods for good mood, and encourages his patients to increase their fish intake. Supplements with a high ratio of EPA to DHA appear to be most effective.
Cancer: Animal studies suggest that omega-3s may suppress the growth of some cancers. But a 2006 review of 40 years of research concluded that omega-3 supplements are unlikely to prevent cancer in humans.
Rheumatoid arthritis: Fish oil doesn't appear to slow the progression of rheumatoid arthritis, but small studies show that it helps reduce symptoms like joint pain and morning stiffness, and may allow people to lower their dose of anti-inflammatory drugs.
Fetal development: Omega-3s are needed for brain and vision development in unborn babies, but concerns about mercury levels have scared some pregnant women away from eating fish. Health authorities say that many good omega-3 sources, including shrimp, salmon and tuna, are relatively low in mercury. Nursing women and young children should avoid shark, swordfish and tilefish.
Many physicians are more comfortable urging patients to eat more fish than take fish-oil supplements, since fish also contain protein, vitamin B-12, zinc and iodine.
Side effects from fish-oil supplements are minor—mostly gastrointestinal upset and burping with a fishy aftertaste. In doses of 3 grams and above, EPA and DHA can increase the risk of bleeding, so people on blood thinners should consult their physician before taking them.
What's the bottom line? Does it make sense to consume more omega-3s? "There is no single answer here," says Paul Coates, director of the Office of Dietary Supplements, part of the National Institutes of Health. "Given that there is a potential for benefit, and the harm has not yet been fully explored, at reasonable levels of intake, it's not a bad idea."
Or not.
Taking omega-3 fatty acids doesn't reduce deaths from heart attacks, strokes or other cardiovascular events, a new study states. But there's much more to be said about omega-3's.
That is the confusion being stirred up by new research on omega-3s, fats found in cold-water fish and plant oils that have intrigued nutrition scientists ever since the 1970s discovery that Greenland Eskimos rarely die from heart disease, despite a diet of fatty fish.
Some 21% of U.S. adults report using omega-3 fish-oil supplements, according to the Council for Responsible Nutrition, an industry trade group, making it the most popular supplement after multivitamins and vitamin D.
But last month, the Journal of the American Medical Association published a meta-analysis of 20 clinical trials involving nearly 70,000 people that found that omega-3 fatty acids didn't prevent heart attacks, strokes or deaths from heart disease. Other recent studies in the New England Journal of Medicine and the Archives of Internal Medicine found that omega-3 supplements didn't prevent heart problems in people with Type 2 diabetes or a history of heart disease.
Experts say such studies should be viewed with caution—just like studies with positive findings.
Critics noted that the JAMA study combined clinical trials that used different doses and sources of omega-3s. Many of the subjects were also on heart medication, which may have blunted the impact. Plus, diet studies are also notoriously imprecise. "It's impossible for five researchers to control the diet of almost 70,000 patients over several years," says Duffy MacKay, the CRN's vice president for scientific and regulatory affairs.
What's more, the JAMA authors imposed an unusually strict standard for statistical significance. Using the typical standard, the analysis would have concluded that omega-3 supplements are associated with a 9% reduction in cardiac deaths.
"My colleagues are writing letters to the editor about this," said University of Pennsylvania nutritionist Penny Kris-Etherton, a spokeswoman for the American Heart Association. She says, for now, the association will continue recommending that everyone eat omega-3 rich fish at least twice a week; people with heart disease or high triglycerides could also consider taking fish-oil supplements under a doctor's care. The American Psychiatric Association and the World Health Organization have similar advice.
Omega-3 fatty acids are essential for building cell membranes and maintaining the connections between brain cells. They also may reduce inflammation,increasingly recognized as a cause of chronic diseases.
Humans can't produce omega-3 fatty acids, so we must get them from outside sources. The two most important kinds—EPA and DHA—are primarily found in fish such as salmon, sardines, tuna and herring; a third kind, ALA, is found in walnuts, flaxseed, soybean oil and some green vegetables, including Brussels sprouts, spinach and kale.
The typical American diet is far higher in omega-6 fatty acids, which come from corn and safflower oil and are plentiful in processed foods and cornfed beef and poultry. Some experts believe that reducing the ratio of omega 6s to 3s is even more important than increasing omega-3s, but the evidence is mixed.
Blood tests (typically $100 to $200) can measure the amount of omega-3s in red blood cells or plasma and a growing number of doctors are ordering them. No official deficiency standard has been set, but according to one lab, OmegaQuant Analytics, having 4% or less omega-3s out of total fatty acids is "undesirable" and indicates an elevated heart risk; 8% or more is "desirable." Most Americans score between 3% and 5% omega-3s, says William Harris, a veteran heart researcher who founded OmegaQuant.
Thousands of studies since the 1970s have shown that people with high levels of omega-3s have lower triglycerides, lower blood pressure, lower LDL cholesterol, less inflammation and a lower risk of heart disease. Those with low levels of omega-3s are more likely to be depressed, to commit suicide and have memory loss and brain shrinkage as they age.
Many of those are observational studies that can't prove cause-and-effect; it may be that people who eat more fish have more healthy behaviors in general. The evidence from randomized-controlled trials is more mixed—but experts say that's not surprising in dietary studies, where researchers often have to rely on patients to accurately report what they ate over long periods.
Recent research offers a tantalizing mix of healing possibilities:
Alzheimer's disease and dementia: Several studies show that older people who eat plenty of fish have lower levels of beta-amyloid protein, associated with Alzheimer's, than those who eat less. But giving elderly people omega-3 fish-oil supplements didn't help ward off cognitive decline, according to a meta-analysis published in June. (The authors conceded that the trials may not have been long enough to show much effect.)
Macular degeneration: A 2011 Harvard study found that women who ate fish at least once a week were 38% less likely to develop age-related macular degeneration than women who ate it less than once a month.
Attention-Deficit Hyperactivity Disorder: Children with ADHD tend to have lower omega-3 levels than their peers, and a study in the journal PLOS One last month found that DHA can improve reading and behavior in underperforming children. Still, there is no evidence to date that omega 3s are as effective as medication.
Depression: Rates of depression, bipolar disorder and postpartum depression are all lower in fish-eating populations, writes psychiatrist Drew Ramsey in his 2011 book, "The Happiness Diet." He also lists wild salmon and shrimp as the top foods for good mood, and encourages his patients to increase their fish intake. Supplements with a high ratio of EPA to DHA appear to be most effective.
Cancer: Animal studies suggest that omega-3s may suppress the growth of some cancers. But a 2006 review of 40 years of research concluded that omega-3 supplements are unlikely to prevent cancer in humans.
Rheumatoid arthritis: Fish oil doesn't appear to slow the progression of rheumatoid arthritis, but small studies show that it helps reduce symptoms like joint pain and morning stiffness, and may allow people to lower their dose of anti-inflammatory drugs.
Fetal development: Omega-3s are needed for brain and vision development in unborn babies, but concerns about mercury levels have scared some pregnant women away from eating fish. Health authorities say that many good omega-3 sources, including shrimp, salmon and tuna, are relatively low in mercury. Nursing women and young children should avoid shark, swordfish and tilefish.
Many physicians are more comfortable urging patients to eat more fish than take fish-oil supplements, since fish also contain protein, vitamin B-12, zinc and iodine.
Side effects from fish-oil supplements are minor—mostly gastrointestinal upset and burping with a fishy aftertaste. In doses of 3 grams and above, EPA and DHA can increase the risk of bleeding, so people on blood thinners should consult their physician before taking them.
What's the bottom line? Does it make sense to consume more omega-3s? "There is no single answer here," says Paul Coates, director of the Office of Dietary Supplements, part of the National Institutes of Health. "Given that there is a potential for benefit, and the harm has not yet been fully explored, at reasonable levels of intake, it's not a bad idea."
Fish-Oil Doses Can Be Hard To Swallow
By David Stipp : WSJ Article : January 8, 2008
It's no wonder that more Americans are gulping fish oil. Hardly a month goes by without a study suggesting that the omega-3 fatty acids in fish oil can fend off disease -- including heart attacks, strokes, Alzheimer's disease, depression, rheumatoid arthritis, asthma, psoriasis and even attention-deficit hyperactivity disorder.
The problem is, to get the health benefits seen in clinical trials, you probably need to take fistfuls of capsules.
"The kind of benefits seen in most of the clinical trials with omega-3 generally have involved much higher doses than you see recommended on supplement labels," says Charles Serhan, a Harvard Medical School expert on omega-3's activity. "But although a large number of studies have used industrial-level doses," he adds, "we don't have rigorous scientific evidence about what the doses should be."
Regardless of the recommended dose, the need to stockpile bottles of supplements may diminish as more foods are fortified with omega-3 and as research shows ways of enhancing the benefits with other therapies.
While most of the scientific data on the health effects of fish oil aren't definitive, the federal National Institutes of Health concluded after a massive review three years ago that consuming omega-3 fatty acids cuts the risk of death from heart attacks and other cardiovascular causes, can reduce the joint pain of rheumatoid arthritis and "appears" important for proper brain development and function.
Because of news like that, the market for fish-oil supplements is booming. U.S. omega-3 supplement sales reached an estimated $600 million last year, up 20% from a year earlier, says the Global Organization for EPA and DHA Omega-3s, a Salt Lake City trade group. (The two key omega-3 fatty acids are called EPA and DHA.) Omega-3 fatty acids now rank as the fifth-best-selling dietary supplement, behind multivitamins, calcium and vitamins C and E.
In trials aimed at lowering high blood levels of triglycerides, a contributor to heart disease, patients took four particularly potent capsules that contained a total of more than three grams of EPA and DHA a day. You would have to pop a daily dozen of the typical omega-3 capsules on the market to get that much -- four to six times the suggested daily "serving" usually specified on their labels. That many capsules could cost you more than $2 a day, and it is a lot more than you are likely to get from consuming fish: You would need more than six servings a day of tuna, or about three of salmon, to get that much EPA and DHA.
FISHTAILING
Clinical trials suggest that fish oil can fend off a variety of ailments, but the omega-3 doses used in the studies have varied widely.
• Heart disease: one gram or more
• Rheumatoid arthritis: two grams or more
• Brain health: one-half gram or more
Fish may good for you, but you can get risky doses of mercury and other toxins by consuming lots of it. That is one reason the American Heart Association recommends that people who need to lower triglycerides to ward off heart attacks take omega-3 capsules. The suggested dose is two to four grams of EPA and DHA a day, which supplements can provide toxin-free. For healthy adults seeking merely to cut cardiac risks, the heart association says eating fatty fish, such as salmon, at least twice a week is probably enough.
But how much omega-3 should you take if you are trying to ease the joint inflammation of rheumatoid arthritis? Or ward off Alzheimer's disease? Or alleviate depression?
Unfortunately, there aren't enough clinical data to give firm answers. But the omega-3 literature affords hints. Results in various rheumatoid-arthritis trials indicate that you need to take more than two grams, perhaps 10 typical capsules, of omega-3 fatty acids a day to significantly curtail joint inflammation and pain.
For maintaining brain health, the overall data on omega-3's potential are inconclusive, according to the NIH. But a recent Dutch study showed that about 400 milligrams of EPA and DHA a day -- which you can get from two typical omega-3 capsules -- helped elderly men maintain mental acuity. The study found that the more omega-3 ingested, the greater the benefit.
In the depression data, two things stand out: EPA appears more effective than DHA. And about one gram of EPA seems optimal -- more isn't better.
All this suggests that you may have to take a half dozen or more typical omega-3 pills a day to get the kind of benefits observed in clinical trials with fish oil. But soon it may get easier to get such hefty doses without taking so many pills. A growing number of foods are fortified with omega-3, everything from yogurt to orange juice, including more than 1,200 such products launched in 2006 alone, according to the London-based market researcher Datamonitor. Such foods typically don't contain much omega-3 -- a fortified egg might contain half as much as a typical capsule. But as more fortified foods come to market, it will be easier to get omega-3 in your diet.
There is another reason popping fish-oil capsules by the fistful may be overkill. Many scientists believe omega-3's benefits flow primarily from its ability to damp low-level inflammation, which is thought to be a key culprit in just about every major scourge of aging, from clogged arteries to Alzheimer's. Studies over the past few years suggest that taking small doses of aspirin daily, which many people do to prevent heart attacks, magnifies the anti-inflammatory effect of taking fish oil.
Indeed, some of the most dramatic evidence of fish oil's heart benefits came from a 1999 Italian study in which patients who had recently had heart attacks showed a 45% reduction in subsequent "sudden cardiac death" when given modest fish-oil doses (the amount in about three typical omega-3 capsules). The supplements' striking effectiveness may well have been magnified by the fact that many of the patients were also taking aspirin daily.
Aspirin's effect on omega-3 isn't clear yet, though. So for now, big doses of the supplement probably are necessary to get the health benefits.
Omega-3 appears to be safe, even at the high doses used in clinical trials. But large doses can have side effects. Perhaps the best source on that issue is the prescribing information for Lovaza. Sold by GlaxoSmithKline PLC unit Reliant Pharmaceuticals Inc., Lovaza is prescribed for "very high" triglycerides.
In Lovaza's clinical trials, patients took four capsules a day with a total of 3.4 grams of EPA and DHA. The most common "adverse event," reported by about 5% of patients, was belching. Some 4% reported infections, compared with 2% on a placebo, but it's not clear whether fish oil caused the difference. While some research suggests that taking fish oil prolongs bleeding time, no bleeding problems were reported in the Lovaza trials.
There's no evidence Lovaza works better or is purer than high-end omega-3 dietary supplements -- such as those made by Nordic Naturals Inc., of Watsonville, Calif. -- which cost less than half as much as Lovaza does per gram of EPA and DHA.
A 2004 analysis of 44 kinds of omega-3 supplements by ConsumerLab.com, based in Scarsdale, N.Y., found that none had unsafe levels of mercury or PCBs. And Lovaza wasn't used in most of the promising clinical trials with omega-3.
By David Stipp : WSJ Article : January 8, 2008
It's no wonder that more Americans are gulping fish oil. Hardly a month goes by without a study suggesting that the omega-3 fatty acids in fish oil can fend off disease -- including heart attacks, strokes, Alzheimer's disease, depression, rheumatoid arthritis, asthma, psoriasis and even attention-deficit hyperactivity disorder.
The problem is, to get the health benefits seen in clinical trials, you probably need to take fistfuls of capsules.
"The kind of benefits seen in most of the clinical trials with omega-3 generally have involved much higher doses than you see recommended on supplement labels," says Charles Serhan, a Harvard Medical School expert on omega-3's activity. "But although a large number of studies have used industrial-level doses," he adds, "we don't have rigorous scientific evidence about what the doses should be."
Regardless of the recommended dose, the need to stockpile bottles of supplements may diminish as more foods are fortified with omega-3 and as research shows ways of enhancing the benefits with other therapies.
While most of the scientific data on the health effects of fish oil aren't definitive, the federal National Institutes of Health concluded after a massive review three years ago that consuming omega-3 fatty acids cuts the risk of death from heart attacks and other cardiovascular causes, can reduce the joint pain of rheumatoid arthritis and "appears" important for proper brain development and function.
Because of news like that, the market for fish-oil supplements is booming. U.S. omega-3 supplement sales reached an estimated $600 million last year, up 20% from a year earlier, says the Global Organization for EPA and DHA Omega-3s, a Salt Lake City trade group. (The two key omega-3 fatty acids are called EPA and DHA.) Omega-3 fatty acids now rank as the fifth-best-selling dietary supplement, behind multivitamins, calcium and vitamins C and E.
In trials aimed at lowering high blood levels of triglycerides, a contributor to heart disease, patients took four particularly potent capsules that contained a total of more than three grams of EPA and DHA a day. You would have to pop a daily dozen of the typical omega-3 capsules on the market to get that much -- four to six times the suggested daily "serving" usually specified on their labels. That many capsules could cost you more than $2 a day, and it is a lot more than you are likely to get from consuming fish: You would need more than six servings a day of tuna, or about three of salmon, to get that much EPA and DHA.
FISHTAILING
Clinical trials suggest that fish oil can fend off a variety of ailments, but the omega-3 doses used in the studies have varied widely.
• Heart disease: one gram or more
• Rheumatoid arthritis: two grams or more
• Brain health: one-half gram or more
Fish may good for you, but you can get risky doses of mercury and other toxins by consuming lots of it. That is one reason the American Heart Association recommends that people who need to lower triglycerides to ward off heart attacks take omega-3 capsules. The suggested dose is two to four grams of EPA and DHA a day, which supplements can provide toxin-free. For healthy adults seeking merely to cut cardiac risks, the heart association says eating fatty fish, such as salmon, at least twice a week is probably enough.
But how much omega-3 should you take if you are trying to ease the joint inflammation of rheumatoid arthritis? Or ward off Alzheimer's disease? Or alleviate depression?
Unfortunately, there aren't enough clinical data to give firm answers. But the omega-3 literature affords hints. Results in various rheumatoid-arthritis trials indicate that you need to take more than two grams, perhaps 10 typical capsules, of omega-3 fatty acids a day to significantly curtail joint inflammation and pain.
For maintaining brain health, the overall data on omega-3's potential are inconclusive, according to the NIH. But a recent Dutch study showed that about 400 milligrams of EPA and DHA a day -- which you can get from two typical omega-3 capsules -- helped elderly men maintain mental acuity. The study found that the more omega-3 ingested, the greater the benefit.
In the depression data, two things stand out: EPA appears more effective than DHA. And about one gram of EPA seems optimal -- more isn't better.
All this suggests that you may have to take a half dozen or more typical omega-3 pills a day to get the kind of benefits observed in clinical trials with fish oil. But soon it may get easier to get such hefty doses without taking so many pills. A growing number of foods are fortified with omega-3, everything from yogurt to orange juice, including more than 1,200 such products launched in 2006 alone, according to the London-based market researcher Datamonitor. Such foods typically don't contain much omega-3 -- a fortified egg might contain half as much as a typical capsule. But as more fortified foods come to market, it will be easier to get omega-3 in your diet.
There is another reason popping fish-oil capsules by the fistful may be overkill. Many scientists believe omega-3's benefits flow primarily from its ability to damp low-level inflammation, which is thought to be a key culprit in just about every major scourge of aging, from clogged arteries to Alzheimer's. Studies over the past few years suggest that taking small doses of aspirin daily, which many people do to prevent heart attacks, magnifies the anti-inflammatory effect of taking fish oil.
Indeed, some of the most dramatic evidence of fish oil's heart benefits came from a 1999 Italian study in which patients who had recently had heart attacks showed a 45% reduction in subsequent "sudden cardiac death" when given modest fish-oil doses (the amount in about three typical omega-3 capsules). The supplements' striking effectiveness may well have been magnified by the fact that many of the patients were also taking aspirin daily.
Aspirin's effect on omega-3 isn't clear yet, though. So for now, big doses of the supplement probably are necessary to get the health benefits.
Omega-3 appears to be safe, even at the high doses used in clinical trials. But large doses can have side effects. Perhaps the best source on that issue is the prescribing information for Lovaza. Sold by GlaxoSmithKline PLC unit Reliant Pharmaceuticals Inc., Lovaza is prescribed for "very high" triglycerides.
In Lovaza's clinical trials, patients took four capsules a day with a total of 3.4 grams of EPA and DHA. The most common "adverse event," reported by about 5% of patients, was belching. Some 4% reported infections, compared with 2% on a placebo, but it's not clear whether fish oil caused the difference. While some research suggests that taking fish oil prolongs bleeding time, no bleeding problems were reported in the Lovaza trials.
There's no evidence Lovaza works better or is purer than high-end omega-3 dietary supplements -- such as those made by Nordic Naturals Inc., of Watsonville, Calif. -- which cost less than half as much as Lovaza does per gram of EPA and DHA.
A 2004 analysis of 44 kinds of omega-3 supplements by ConsumerLab.com, based in Scarsdale, N.Y., found that none had unsafe levels of mercury or PCBs. And Lovaza wasn't used in most of the promising clinical trials with omega-3.
