Saturday, November 28, 2009

Omega 3 Food against Alzheimer's Disease

Omega-3s are a type of polyunsaturated fatty acid (PUFA). Research has linked certain types of omega-3s to a reduced risk of heart disease and stroke. The U.S. Food and Drug Administration (FDA) permits supplements and foods to display labels with “a qualified health claim” for two omega-3s called docosahexaneoic acid (DHA) and eicosapentaenoic acid (EPA). The labels may state, “Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease,” and then list the amount of DHA or EPA in the product. The FDA recommends taking no more than a combined total of 3 grams of DHA or EPA a day, with no more than 2 grams from supplements.

Research has also linked high intake of omega-3s to a possible reduction in risk of dementia or cognitive decline. The chief omega-3 in the brain is DHA, which is found in the fatty membranes that surround nerve cells, especially at the microscopic junctions where cells connect to one another.

A Jan. 25, 2006, literature review by the Cochrane Collaboration found that published research does not currently include any clinical trials large enough to recommend omega-3 supplements to prevent cognitive decline or dementia. But the reviewers found enough laboratory and epidemiological studies to conclude this should be a priority area for further research. The Cochrane Collaboration is an independent, nonprofit organization that makes objective assessments of available evidence on a variety of issues in treatment and health care.

Theories about why omega-3s might influence dementia risk include their benefit for the heart and blood vessels; anti-inflammatory effects; and support and protection of nerve cell membranes. There is also preliminary evidence that omega-3s may also be of some benefit in depression and bipolar disorder (manic depression).

A report in the April 2006 Nature described the first direct evidence for how omega-3s might have a helpful effect on nerve cells (neurons). Working with laboratory cell cultures, the researchers found that omega-3s stimulate growth of the branches that connect one cell to another. Rich branching creates a dense “neuron forest,” which provides the basis of the brain’s capacity to process, store and retrieve information.

In the study, researchers examined the effects of DHA in mice bred to develop the plaques and brain tangles associated with Alzheimer’s disease. The results appear in the Journal of Neuroscience.

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One group of mice was given food that resembled the typical American diet, with 10 times more omega-6 fatty acids, such as those found in corn, peanut and sunflower oils, than omega-3 fatty acids.

Omega-6 fatty acids are essential fatty acids like omega-3 fatty acids that people obtain from their diet. A high ratio of omega-6 to omega-3 has been linked to increased risk for many diseases.

Three other groups were fed diets with a healthier 1:1 ratio of omega-6 to omega-3 fatty acids: One received supplemental DHA only, and the other two groups received DHA plus additional omega-6 fatty acids. The amounts of carbohydrate, protein, and calories were the same for all the diets.

After three months, all of the mice on the DHA diets had lower levels of beta-amyloid and tau proteins than those in the control group. But at nine months, only those on the DHA-only diet had lower levels of both proteins.

Researchers say those results suggest that DHA works better on its own than with omega-6 fatty acids. They say additional studies on DHA in humans are now needed to assess how well the omega-3 fatty acid might work against Alzheimer’s disease.

So what are good DHA sources and EPA sources?

Basically this comes down to fish. Fish eat various forms of microscopic algae, amongst other things, and micro algae has the 2 most important Omega 3 fatty acids, DHA and EPA, and so these are present in the oil of the fish that has eaten it. It is really only fish that are able to produce substantial sources of these 2 essential fatty acids in any quantity.
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That is why the initial studies done some decades ago that started to establish the health giving properties of Omega 3 fats were done on Eskimos. Eskimos eat a large amount of fish and it was found that they were particularly healthy. They had very low rates of many of the lifestyle diseases that afflict so many people in the US such as heart disease and others and this was linked to their intake of Omega 3 fatty acids from their diet high in fish.

So the best Omega 3 sources for anyone seeking to increase their intake of healthy polyunsaturated fats is to eat fish. Unfortunately there is a problem with this. The American Heart Association recognizes the importance of increasing our intake of fish and recommends that we do so however the FDA also warns that fish is contaminated with toxins such as Mercury and therefore we ought not eat too much fish.
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So we have a conundrum. We are told to eat more fish because fish are good Omega3 sources and we are also told to eat less fish because fish are contaminated. What do we do?

The only way to safely and effectively a good food sources of Omega 3 fats to our diet is to increase our intake of fish oil using high quality fish oil supplements. The very best fish oil supplements are not contaminated with Mercury or any of the other contaminants found in fish. Note that not all fish oil supplements are good.

Now let’s examine the issue as it relates to vegetarians. Some vegetarians choose to eat fish and some choose not to eat fish. Obviously those who choose to eat fish would also be happy to take daily fish oil supplements and therefore they overcome the problem of finding good clean Omega3 sources in the same way as the rest of us.

However for those vegetarians who cannot eat fish there is a particular problem. Obviously they cannot take regular fish oil supplements as the rest of us can. What can they do?

It is possible to get Omega 3 supplements using the same Omega3 sources as fish use. Fish eat micro algae and convert this into DHA and EPA. It is now possible to get Omega 3 supplements that are made from micro algae that a good EPA and DHA sources.

And of course none of us are restricted to merely taking fish oil supplements. There is more that we can do to increase our intake of Omega3 fats. There are good plant based dietary sources of Omega3 fats even though they are ALA. It is better to eat vegetables and other food sources of Omega 3 fats than not to do so even know increasing our intake of ALA is not as effective as taking fish oil.

Here are some good plant sources of Omega 3 fats:

• Canola oil.
• Flax seed oil.
• Soy beans and soy bean oil.
• Olive oil.
• Walnuts and pumpkin seeds.
• Flax seed oil supplements.

Traditionally meat and eggs have also been good sources of Omega 3 fats however modern intensive farming practices such as grain feeding have reduced the incidence of good polyunsaturated healthy fats in meat and eggs.
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Practical Recommendations:

Omega-3s are essential to good health, but their benefits may be missed because the American diet is chock full of omega-6 fatty acids instead. Many foods contain both fatty acids. To ensure you get your fill of -3, you'll need to be conscientious at the grocery store. Here are 11 ways to get this done:

• Salmon. This fatty fish is exploding with omega-3 and is relatively low in omega-6. It just may be the best omega-3 bang for your buck in the seafood aisle.
• Bluefin tuna. This fatty fish is packed with omega-3s and low in omega-6. Not so keen on tuna? You've got choices: mackerel, herring, and rainbow trout.
• Anchovies and sardines. Though not everyone's favorite, these slimy, oily options are other good omega-3 sources. They also tend to be high in sodium, though.
• Crustaceans. Fish isn't the only kind of seafood that packs an omega-3 wallop. Shrimp, mollusks, and Alaskan king crab are also excellent sources that also won't load you up with omega-6.
• Oils. Throw a dash of flaxseed oil onto salad and start cooking with canola oil for a nice hit of omega-3. By subbing out other vegetable oils (like soybean, corn, and cottonseed oils), you'll also lessen your omega-6 load.
• Beans. Some legumes are better than others for tipping the omega balance your way. Kidney, pinto, and mungo beans will do you right. Chickpeas are less helpful.
• Nuts and seeds. Add a nutty flavor to salad, yogurt, or morning mueslix with walnuts or flaxseed. A small handful of either will up your omega-3 intake.
• Spinach. Popeye was on to something. Serve up this leafy green in a salad, or sauté it and add it to pasta.
• Winter squash. Keep an eye out for this seasonal vegetable—it makes an interesting side dish that boosts your omega-3 intake.
• Broccoli and cauliflower. These cruciferous veggies are on your side when it comes to omega-3s.
• Papaya. A tropical delight, papaya may be the only fruit in your supermarket with more omega-3 than omega-6.

Sources and Additional Information:
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