Info source: http://www.m.webmd.com/a-to-z-guides/omega-3-fatty-acids-fact-sheet
There are many health benefits of omega-3 fatty acids. Research shows strong evidence that the omega-3s EPA and DHA can help lower triglycerides and blood pressure. And there are studies showing that omega-3 fatty acids may help with other conditions, including rheumatoid arthritis, depression, and many more.
Just what are omega-3 fatty acids exactly? How much do you need? And what do all those abbreviations -- EPA, DHA, and ALA -- really mean? Here's a rundown on omega-3 fatty acids.
Omega-3 Fatty Acids: Basics
Omega-3 fatty acids are considered essential fatty acids. We need them for our bodies to work normally. Because essential fatty acids (ALA, DHA, EPA) are not made in the body or are inefficiently converted from ALA to EPA and DHA, we need to get them from our diet .
Omega-3s have a number of health benefits. Omega-3s are thought to play an important role in reducing inflammation throughout the body -- in the blood vessels, the joints, and elsewhere. However, omega-3 supplements (EPA/DHA) may cause the blood to thin and cause excess bleeding, particularly in people taking anticoagulant drugs.
There are several types of omega-3 fatty acids. Two crucial ones -- EPA and DHA -- are primarily found in certain fish. Plants like flax contain ALA, an omega-3 fatty acid that is partially converted into DHA and EPA in the body. Algae oil often provides only DHA.
Most experts say that DHA and EPA -- from fish and fish oil -- have better established health benefits than ALA. DHA and EPA are found together only in fatty fish and algae. DHA can also be found on its own in algae, while flaxseed and plant sources of omega-3s provide ALA -- a precursor to EPA and DHA, and a source of energy.
Blood fat [triglycerides]. According to a number of studies, fish oil supplements can lower elevated triglyceride levels. Having high levels of this blood fat is a risk factor for heart disease. DHA alone has also been shown to lower triglycerides.
Rheumatoid arthritis. A number of studies have found that fish oil supplements [EPA+DHA] significantly reduced stiffness and joint pain. Omega-3 supplements also seem to boost the effectiveness of anti-inflammatory drugs.
Depression. Some researchers have found that cultures that eat foods with high levels of omega-3s have lower levels of depression. Fish oil also seems to boost the effects of antidepressants. Fish oil may help reduce the depressive symptoms of bipolar disorder.
Prenatal health. DHA appears to be important for visual and neurological development in infants. However, studies are inconclusive as to whether supplementing omega-3 during pregnancy or breastfeeding benefits the baby.
Asthma. Evidence suggests that a diet high in omega 3s reduces inflammation, a key component in asthma. However, more studies are needed to show if fish oil supplements improve lung function or reduce the amount of medication a person needs to control their disease.
ADHD. Some studies show that fish oil can reduce the symptoms of ADHD in some children and improve their cognitive function. However, more research is needed in this area, and omega-3 supplements as a primary treatment for this disorder are not supported by research.
Alzheimer's disease and dementia. The evidence is preliminary, but some research suggests that omega-3s may help protect against Alzheimer's disease and dementia. Recent studies have also evaluated whether the omega-3 supplement DHA can slow the decline seen in those with Alzheimer's dementia or in age-associated memory impairment. One recent study showed that DHA can be a beneficial supplement and may have a positive effect on gradual memory loss associated with aging. However, more research needs to be done.
Past evidence pointed to omega-3 fatty acids reducing risk of heart attacks, strokes and death from heart disease, but recent research has refuted these findings. More specific research is needed to sort this out.
You may have heard about the importance of having a healthy balance of omega-3s with another fatty acid, omega-6s. Omega-6s are found in many oils, meats, and processed foods. Some experts believe that most people in the U.S. are eating far too many omega-6s and far too few omega-3 fatty acids. They argue that this imbalance may be causing many chronic diseases. However, other experts disagree. They don't believe the ratio of omega-6s to omega-3s is actually significant. They also argue that the health benefits of omega-6s are being ignored. For now, the full implications aren't clear. But the bottom line is simple. Whether the ratio turns out to matter or not, increasing your intake of omega-3 fatty acids is still a good idea.
Omega-3 Fatty Acids: Food Sources
When possible, try to get omega-3 fatty acids from foods such as fish rather than supplements. Fish high in DHA and EPA omega-3 fatty acids include:
anchovies
bluefish
herring
mackerel
salmon (wild has more omega-3s than farmed)
sardines
sturgeon
lake trout
tuna
Many experts recommend eating these fish two to three times a week.
Good food sources of ALA -- which is converted into omega-3 fatty acids in the body -- include:
walnuts
flax and flaxseed oil
canola oil
olive oil
soybean oil
While foods containing omega-3 fatty acids have health benefits, some -- like oils and nuts -- can be high in calories. So eat them in moderation.
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