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Fish oil may help the heart beat mental stress: Testing the products

Fish oil may help the heart beat mental stress, says a recent study, "Fish Oil and Neurovascular Reactivity to Mental Stress in Humans." It appears online in the May 2013 edition of the American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology, published by the American Physiological Society.

Fish oil may help the heart beat mental stress: Testing the products.
Photo by Dondi Tawatao/Getty Images

The omega 3 fatty acids in fish oil have long been thought to protect against cardiovascular disease—so much so that the American Heart Association currently recommends eating at least two servings of fish a week, particularly fatty varieties rich in omega 3s. However, the mechanism behind this protective effect still remains a mystery.

In the recent study, scientists led by Jason R. Carter of Michigan Technological University shed light on this phenomenon by providing evidence that fish oil might specifically counteract the detrimental effects of mental stress on the heart. Their findings show that volunteers who took fish oil supplements for several weeks had a blunted response to mental stress in several measurements of cardiovascular health, including heart rate and muscle sympathetic nerve activity (MSNA), part of the "fight or flight" response, compared to volunteers who took olive oil instead. The results may explain why taking fish oil could be beneficial to the heart and might eventually help doctors prevent heart disease in select populations.

The participants took either 9 grams of fish oil daily or the same amount of olive oil

Carter and his colleagues worked with 67 adult volunteers. At the beginning of the study, each volunteer underwent a battery of tests to assess cardiovascular function, including heart rate, blood pressure, MSNA, and blood flow through the forearm and calf. These tests were performed first when the volunteers were at rest, and then again while they were performing a mental arithmetic test while the investigator encouraged them to hurry, a situation designed to induce acute mental stress.

The study subjects were then nearly equally assigned to take either 9 grams of fish oil per day or 9 grams of olive oil, a placebo that hasn't been shown to have the same beneficial cardiovascular effects as fish oil. None of the volunteers were aware of which supplement they were taking. After 8 weeks of this intervention, the study subjects underwent the same tests again.

Results focused on the health benefits of fish oil under mental stress

The researchers found that test results didn't change between the two groups of study subjects when they were at rest. However, results for the volunteers who took fish oil and those who received the placebo differed significantly for some of the tests during the mental stress.

Those in the fish oil group showed blunted heart rate reactivity while they were stressed compared to those who took olive oil. Similarly, the total MSNA reactivity to mental stress was also blunted in the fish oil group.

Importance of the Findings

These results show that fish oil could have a protective effect on cardiovascular function during mental stress, a finding that adds a piece to the puzzle on why taking fish oil helps the heart stay healthy, the authors suggest. Future studies might focus on the effects of taking fish oil for longer time periods and examining this effect on older populations or people with cardiovascular disease.

"Overall," the study authors say, according to the May 22, 2013 news release, Fish oil may help the heart beat mental stress, "the data support and extend the growing evidence that fish oil may have positive health benefits regarding neural cardiovascular control in humans and suggest important physiological interactions between fish oil and psychological stress that may contribute to disease etiology."

In addition to Jason R. Carter, the study team also includes Christopher E. Schwartz of Michigan Technological University and New York Medical College, Huan Yang of Michigan Technical College, and Michael J. Joyner of Mayo Clinic. Physiology is the study of how molecules, cells, tissues, and organs function in health and disease.

Testing some of the various fish oil brands for quality

Fish oil pills versus claims by industry is an excellent article on Consumer Reports on page 11 of the January 2012 issue. The only issue is that by the February 2012 issue, the magazine corrected it's claim that a certain brand of fish oil came out as spoiled in the lab test. No, the oil wasn't spoiled after all. It turned out that lemon-flavored fish oil can't be tested because the measurements and results won't be correct. The oil was just fine as is and lemon flavored.

The situation it caused a lot of customers of that oil was to throw out their oil thinking it was spoiled when it was not spoiled. The oil was in good shape. And magazine article was not correct about that brand of oil mentioned. Again, fish oil flavored with lemon can't be tested in that way for spoilage because the results will not be correct.

So if customers had a chance to see the February 2012 issue of the magazine, they'd learn their oil was perfectly okay to use. See the Functional Ingredients article, "Nordic Naturals defends omega-3 supplements against claims of spoilage." That article explains in the paragraph, "Nordic Naturals fights back," that Nordic Naturals confronted Consumer Reports on the mistake, calling it a false positive, and the publication has issued a correction withdrawing the lemon-flavored fish oils from the test results.

The problem with some of these tests is that a company is judged guilty until proven innocent

It turns out that if the oil has lemon flavoring in it, that particular test can't be used to see whether the oil already in the bottle and already lemon flavored is spoiled, which it wasn't. Notice that the magazine didn't test the oil before the lemon flavoring went into it. The important point to remember is that the oil was not spoiled and was perfectly okay to consume, and a lot of customers who didn't catch the February 2012 issue of the correction threw out their oil for no reason.

If you check out that January 2012 issue, you can view the ratings of fish oil is there for you to see. But how reliable are ratings? And do you need to check each month's issue to see whether there's a correction of the ratings or other changes? Consumer Reports found elevated levels of compounds that indicate spoilage in the fish oil pills of one brand. And two samples another fish oil brand failed the USP's disintegration test for pills with enteric coatings. In the article you'll find the ratings and cost per day and per year.

There is a section on fish oils that met quality standards

Those fish oils included in this list of fish oils meeting quality standards (of those oils tested) include the following: Spring Valley (Walmart) which is the least costly. And in order going from least costly to more costly, all the other fish oils tested included Finest natural (Walgeens), Barlean's Organic Oils, Nature Made, The Vitamin Shoppe, Carlons Super Omega-3 gems, Norwegian Gold (Ultimate Critical Omega, and Nature's Way (Fisol).

The list of those fish oils that didn't meet enteric-coating claim was Kirkland Signature (Enteric 1200 (Costco). Whenever a test of a product is done, industry will probably refute everything and give reasons why Consumer Reports can't speak for all batches, just the batch they tested, and other reasons. You can check out the brand listed in the January 2012 Consumer Reports issue on page 11.

Then you may wish to checkout the February 2012 article where the magazine admits the test did not prove spoilage because the lemon flavoring prevents the test from getting accurate results on the oil. And of course, not all brands of fish oil you see in most stores or online were tested. Only those brands listed in the article were tested.

There's no mention of krill or calamari oils or alternative sources of omega 3 fatty acids, or microalgae and various vegetarian sources of omega 3 fatty acids on that article. So, just focusing on fish oil, customers expected industry to defend itself against any issue that Consumer Reports had made at that time about a certain container of fish oil tested. Note also that one or two samples of various fish oil brands tested (and named in the article) were above the California total PCB limit.

Some brands tested at that time had no PCBs but have other issues that are noted in the 2012 Consumer Reports article. For example, on the one or two samples of fish oil named in that 2012 issue of Consumer Reports that were above California total PCB limit on fish oils included brands such as CVS Natural, Sundown Naturals, Nature's Bounty Odorless, and GNC Triple Organic.

What Consumer Reports at that time tested were fish oils by brand that mainly had 1,000 mg of fish oil per capsule unless otherwise noted. And the testing was done based on 1,000 mg of omega-3 fatty acids (which usually are two or three capsules).

People take fish oil for a variety of reasons including prevention or treatment of heart disease where doctors sometimes recommend a gram per day of omega 3 fatty acids. But remember, the fatty acids need to have a balance of omega 6, omega 9, and omega 3 in a ratio or proportion that's healthy for you.

Sometimes fish oils can interact with other medicines. So you need to ask your doctor whether taking fish oil supplements is recommended for your particular condition and medicines you're taking.

If you're choosing a fish oil because of the Consumer Reports article, at least pick one listed under the title, "met quality standards." Those on this list also are listed not only by brand name but also by cost per day and cost per year per capsule or pill.

The prices range per day from the cheapest listed, Spring Valley, (Walmart) costing 17 cents daily per capsule or $60 per year to the most expensive Nature's Way (Fisol), costing 64 cents per capsule daily or $235 per year. Basically, our family takes Carlson's lemon-flavored cod liver oil and Neptune krill oil. You choose what you need according to your individual health requirements.

Other Types of Testing of Fish Oils

What's the future of fish oil in Sacramento in the form of supplements? Are people turning to calamari or krill oil instead when told to get at least 600 mg of DHA and a little less EPA for brain and artery health? How much toxins such as carcinogenic PCBs are in your fish oil? Sacamento consumers buy a lot of fish oil supplements in local health food stores, online, and in discount stores such as Sacramento's Walmart and Target stores.

Several years have passed since the March 2010 PCB levels in fish oil (contamination) lawsuit, and yet news is hard to find online about which changes were made in various brands of fish oil. Is what's on the label the same as what's in the bottle, capsule or soft-gel?

Testing found that levels of PCBs in supplements in popular fish oil products varied from about 12 nanograms per recommended dose in one brand of fish oil to more than 850 nanograms in the worst performer - a factor of 70. Before you give your child a spoonful of fish oil, you should know that last year a lawsuit brought by environmentalists in California claimed that 10 popular brands of fish oil dietary supplements contained unsafe and illegal levels of the carcinogenic chemicals known as polychlorinated biphenyls, or PCBs. Download a copy of the lawsuit here.

Consumers buy the fish oil at stores such as Walmart, Target, GNC, and similar stores or online, for example at The two Twinlab. See, A.F.'s Twinlab among 8 companies sued over fish oil supplements, Solgar, Now Foods, Twinlab, Nature Made named in Lawsuit, and for the industry's side of the story, see Industry Responds to California Fish Oil Lawsuit | NBJ Blog. You can be sure the fish oil industries are fighting back.

Why didn't supplement manufacturers and distributors warn consumers that 10 of their fish oil supplements contain toxic chemicals that can cause cancer and birth defects? Naturally, industry responded. Who's doing the suing? The plaintiffs are two citizen environmentalists and the Mateel Environmental Justice Foundation. Also see the sites, Environmental Justice Foundation EJF: Protecting People and Planet, and Lawsuit: Disclose PCB Levels in Fish Oil - CBS News.

A few years ago back in 2010, Twinlab Corp, was accused in a lawsuit filed by Mateel Environmental Justice Foundation and two environmentalists of misleading consumers about the levels of polychlorinated biphenyls, or PCBs, in two of their fish oil supplements, Twinlab's Norwegian Cod Liver Oil and Emulsified Norwegian Cod Liver Oil. The use of the word 'Norwegian' somehow puts an idea in the brains of consumers that because the fish come from icy waters, it has to be free of PCBs and other toxins. But what's the reality and how do the various supplement manufacturers fight back or answer the law suit?

It's not the first lawsuit aimed at Twinlab. See, Shareholders Sue Twinlab Corporation for Stock Fraud, Says Berman. Only this time, the law suit focuses on fish oil. See, Industry Responds to California Fish Oil Lawsuit | NBJ Blog. There's two sides to every story. For consumers, shoppers of fish oil want the industry to agree that the customer is supposed to be right.

Even though these two Twinlab supplements claim they are "PCB and heavy metal free," the lawsuit reports that the fish oil supplements "allegedly contain PCBs above the 'safe harbor' limits set for human consumption under California's Proposition 65, which requires consumers to be warned about exposure to toxic chemicals," according to the San Francisco Superior Court suit.

In addition to Twinlab, the suit names several retailers and manufacturers of fish oil, shark oil, fish liver oil and shark liver oil supplements. They include: CVS Pharmacy Inc.; General Nutrition Corp.; Now Health Group Inc.; Omega Protein Inc.; Pharmavite LLC (which sells fish oils under the Nature Made brand); Rite Aid Corp.; and Solgar Inc.

According to an article in Time magazine, research has shown that since 2006, the U.S. market for omega-3 supplements has doubled, to an estimated $1 billion, and that doesn't count the billions of dollars more that consumers paid for infant formula, orange juice, breakfast cereals and a host of other products that have added these wonder nutrients. But how safe from PCBs and other contaminants is the fish oil you take as a supplement or in put into your packaged foods? For example, DHA from fish oil is added to some jars of baby foods.

There's a shortage of fish

In fact so many fish are being taken out of circulation to make fish oil so people can drink their DHA and omega 3 fatty acids, that there's a shortage of fish, and some people are turning to calamari oil or krill oil to save sea life from over-fishing just to get a dose of omega 3 that's widely touted on TV and in consumer magazines as being good for the brain, arteries, and cholesterol as well as anti-aging. So what's the future of fish oil?

There are over 100 fish oil supplement products on the market, according to the site, and you, the consumer, have no way of knowing whether some have more or less PCB contamination than the ones we have tested. will be doing more testing and more analysis. The organization also plans to ask the manufacturers to commit to doing meaningful testing themselves (and making the results public so consumers can make informed choices). In the meantime, these results give consumers a way to make comparisons among these 10 products, with more information to come.

You can check out the lawsuit which was filed in California Superior Court in San Francisco. The suit targeted eight supplement manufacturers or distributors - CVS Pharmacy, Rite Aid, General Nutrition Corp., Solgar, Twinlab, Now Health, Omega Protein and Pharmavite - for alleged violations of California's Proposition 65, which requires that consumers be warned about chemical exposures. Eventually, a total of 10 companies were added to the list. But the suit claims that all of the manufacturers are in violation of Proposition 65 for not disclosing any non-zero PCB levels in their products.

The plaintiffs and their attorneys claim that that labels saying "Screened for PCBs" or "Treated to Remove PCBs" are especially problematic, because those labels imply - falsely - that PCBs have been removed entirely. They also believe that the manufacturers already have extensive data on the amount of PCBs present in their product. Will the companies release their tests and data?

PCBs were officially listed as known carcinogens and known reproductive toxins in California back in 1990, making them subject to the California's warning requirement. On the other hand, if you look at the manufacturers, Only three years ago reports found no unsafe levels of dioxin, mercury or PCBs in many edible products - one from Consumer Reports and another from the well-regarded supplement testing publication ConsumerLab. So who do you believe? Check out the sites, PCBs in Fish Oil Supplements? - Dr. Weil

The California lawsuit was filed by environmentalists who claim that certain fish oil supplements sold in the state contain unsafe and illegal levels of PCBs (polychlorinated biphenyls). The manufacturing of these chemicals was banned in the United States in 1979, but they were widely used as plasticizers in paints, plastics, and rubber products and many other industrial applications.

If you're ingesting PCBs in fish oil or any other supplement, the PCBs are not going to break down. What you have stored in your body from the past and what's in the environment are still being released into the food chain and air, including Sacramento's polluted air. PCBs are known to have adverse health effects in humans and animals and are regarded as potential carcinogens. Check out the following sites regarding the law suit filed last spring.

Download a copy of the lawsuit here. Check out these sites: Lawsuit: Disclose PCB Levels in Fish Oil - CBS News and

According to the site, The brand name supplements named in the lawsuit include the following information:

1. Nature Made Cod Liver Oil

2. Nature Made Odorless Fish Oil

3. TwinLab Norwegian Cod Liver Oil

4. TwinLab Emulsified Norwegian Cod Liver Oil

5. Now Foods Shark Liver Oil

6. Now Foods Double Strength Cod Liver Oil

7. Now Foods Salmon Oil

8. Solgar 100% Pure Norwegian Shark Liver Oil Complex

9. Solgar Norwegian Cod Liver Oil

10. GNC Liquid Norwegian Cod Liver Oil


Resources to Check Out

A.F.'s Twinlab among 8 companies sued over fish oil supplements

A.F.'s Twinlab among 8 companies sued over fish oil supplements

PCBs in Fish Oil Supplements? - Dr. Weil

Fish Oil Supplements -- Want PCBs With That? | Food | AlterNet

How safe is the fish oil you're giving your kids? : The Mommy Files

Industry Responds to California Fish Oil Lawsuit | NBJ Blog

Fish oil supplements and PCBs - should you worry? Part 2

Lawsuit Claims PCBs Found in 10 Fish Oil Supplements; Product

PCBs found in fish oil capsules, suit says -

Fish Oil, Other Fatty Acids, and Pregnancy

A possible link between what a mother eats during pregnancy and the risk of her child developing allergies has been identified in new research published in this month's The Journal of Physiology. Also see other studies, such as the following articles or abstracts of studies: Maternal nutritional history predicts obesity in adult offspring independent of postnatal diet, Effects of a dietary and environmental prevention program on the incidence of allergic symptoms in high atopic risk infants: three years follow-up, Effects of a dietary and environmental prevention program on the incidence of allergic symptoms in high atopic risk infants: three years follow-up, Multiple food allergy: a possible diagnosis in breastfed infants, Long chain fatty acids and dietary fats in fetal nutrition,and Cows's milk allergy: newborns.

According to the latest study noted in the news release, "Mother's diet influences baby's allergies -- new research," The research found that if a mother's diet contains a certain group of polyunsaturated fatty acids (PUFAs) – such as those found in fish, walnut oil or flaxseed – the baby's gut develops differently. The PUFAs are thought to improve how gut immune cells respond to bacteria and foreign substances, making the baby less likely to suffer from allergies.

Until now, several clinical trials have shown that fish and walnut oil supplementation in pregnant women reduces the risk of allergy in their children, but the mechanism was unknown

"There is intense research interest in maternal diet during pregnancy. In the western diet, the group of polyunsaturated fatty acids that we have shown to help gut function are actually disappearing – our dietary intake of fish and nut oils is being replaced by corn oils which contain a different kind of fatty acid". Said Dr Gaëlle Boudry, of the INRA research institute in Rennes, France, according to the news release, "Mother's diet influences baby's allergies -- new research."

"Our study identifies that a certain group of polyunsaturated fatty acids – known as n-3PUFAs – causes a change in how a baby's gut develops, which in turn might change how the gut immune system develops. These changes are likely to reduce the risk of developing allergies in later life."

The team found that supplementing a mother's diet with n-3PUFA caused the new-born's gut to become more permeable

A more permeable gut enables bacteria and new substances to pass through the lining of the gut into the bloodstream more easily. These new substances then trigger the baby's immune response and the production of antibodies.

"The end result is that the baby's immune system may develop and mature faster – leading to better immune function and less likelihood of suffering allergies," added Dr Boudry in the news release.

This research adds to previous studies which have shown that an intake of n-3 PUFAs during pregnancy increases gestational length and maturation of the central nervous system of a baby and that their performance on mental tasks also seemed to be improved in childhood.

"Other studies have found that a diet containing fish or walnut oil during pregnancy may make your baby smarter – our research adds to this, suggesting such supplements also accelerate the development of a healthy immune system to ward off food allergies."

In terms of next steps, the team's findings were based on piglets so research will continue to see if they translate to humans. The porcine intestine is an excellent model of the human gut however, so they are hopeful that the findings can be extrapolated. The team also plans to investigate whether the apparent gut function-boosting effects of n-3PUFA that they have identified in new-borns extends into later life.

Are too many pregnant women avoiding long-chain fatty acids?

You have numerous pregnant women substituting only medium chain fatty acids (coconut oil/coconut milk) or using only monounsaturated fats (such as olive oil) during pregnancy to control their own cholesterol, but long chain polyunsaturated fatty acids are essential nutrients for a healthy diet. The different kinds consumed by the mother during gestation and lactation may influence pregnancy, fetal and also neonatal outcome, according to the abstract of the study, "Long chain fatty acids and dietary fats in fetal nutrition." There's a difference between long-chain saturated fats and long-chain polyunsaturated fats. Also see the article, "Long-chain Polyunsaturated Fatty Acids in Chronic Childhood Disorders."

One example of long-chain polyunstaturated fats is the DHA from purified fish oils that don't contain PCBs. According to the article, "Long-chain Polyunsaturated Fatty Acids in Chronic Childhood Disorders," Recent research indicates that providing supplements of specific fatty acids, namely docosahexaenoic acid (DHA) and arachidonic acid (AA), to infants, pregnant women and individuals with certain metabolic disorders may offer preventive and therapeutic benefits, especially in relation to brain development.

In addition, supplementing both fatty acids together in prescribed amounts may augment their effects on neurotransmission and membrane maturation. Recently, a small group of experts has concluded that “infant formulas for term infants should contain at least 0.2% of total fatty acids as DHA and 0.35% as AA, while formulas for preterm infants should include at least 0.35% DHA and 0.4% AA.”

All recent reviews and recommendations have underlined the lack of adverse effects from these supplementations. In addition, providing supplements of DHA to pregnant women was recently shown to be associated with improved early developmental outcome of the offspring.

How Many Fatty Acids are Transferred from Mother to Unborn Baby?

The amount of fatty acids transferred from mother to fetus depends not only on maternal metabolism but also on placental function, i.e. by the uptake, metabolism and then transfer of fatty acids to the fetus. The third trimester of gestation is characterized by an increase of long chain polyunsaturated fatty acids in the fetal circulation, in particular docosahexaenoic acid, especially to support brain growth and visual development.

These mechanisms may be altered in pathological conditions, such as intrauterine growth restriction and diabetes, when maternal and fetal plasma levels of long chain polyunsaturated fatty acids undergo significant changes. The aim of this review is to describe the maternal and placental factors involved in determining fetal fatty acid availability and metabolism, focusing on the specific role of long chain polyunsaturated fatty acids in normal and pathological pregnancies.

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