Scallops

Increases Heart Rate Variability—A Measure of Heart Muscle Function

One of the ways in which consuming fish rich in omega-3 fats, such as scallops, promotes cardiovascular health is by increasing heart rate variability (HRV), a measure of cardiac function, in as little as three weeks, according to a study published in the April 2005 issue of Chest.

By providing greater variability between beats, the marine omega 3 fatty acids, EPA and DHA, reduce the risk of arrhythmia and/or sudden death.

Researchers from Atlanta, GA, Boston, MA, and Cuernavaca, Mexico, took the HRV of 58 elderly patients every other day for two months to establish an HRV baseline for each participant. For the next 11 weeks, half of the study participants took a daily 2 gram supplement of fish oil and the other half took a daily 2 gram supplement of soy oil.

Patients in both groups experienced a significant increase in HRV, with those who took fish oil achieving a greater increase in a shorter time period. Patients who received fish oil experienced increased HRV within the first 2.7 weeks, whereas it took 8.1 weeks for a significant increase in HRV to be seen in the group taking soy oil.

On the other hand, while none of the study participants experienced significant negative side effects, 41% of participants in the fish oil group reported belching, compared to 16% in the soy oil group.

"Our findings contradict the current belief in the medical community that increasing the intake of omega-3 fatty acids produces only long-term cardiac benefits," said the study's lead author, Fernando Holguin, MD, Emory University School of Medicine, Atlanta, GA. "In fact, our study group showed improvements in heart function in as little as two weeks."

"Studies like this demonstrate that there are additional approaches we can take to protect ourselves from heart attacks," said Paul A. Kvale, MD, FCCP, President of the American College of Chest Physicians. "It's exciting to see the potential for omega-3 fatty acids in improving heart function when it complements a healthy lifestyle of exercising, maintaining a healthy weight, and getting eight hours of sleep." We'd add eating healthful foods to this proactive list. Rather than pop a daily pill, we'd rather enjoy a daily "dose" of delicious scallops, soyfoods, or tuna. For recipes certain to not only increase your heart rate variability but also your delight in eating, click Recipes.

Protection against Fatal Heart Arrhythmia

A healthy way of eating that includes at least 10 ounces of omega-3-rich fish each week improves the electrical properties of heart cells, protecting against fatal abnormal heart rhythms, suggests a study from Greece.

"Long-term consumption of fish is associated with lower QT interval in free-eating people without any evidence of cardiovascular disease. Thus, fish intake seems to provide anti-arrhythmic protection at a population level," wrote the authors in the American Journal of Clinical Nutrition. (Chrysohoou C, et al.)

The QT interval is a measure of the heart's electrical cycle, from the beginning of ventricular depolarization, the Q wave, to the end of the T wave, at which point cardiac repolarization is complete.

A lower QT score indicates a lower resting heart rate. As a higher resting heart rate has been linked to an increased risk of sudden death, the result of approximately 50% of heart attacks, lowering the resting heart rate provides significant health benefit.

Researchers at the University of Athens enrolled 3,042 people (1,514 men, aged 18-87, and 1,528 women, aged 18-89), who used a validated food frequency questionnaire to record their food intake of 156 different foods. Along with alcohol consumption and physical activity were also recorded, and electrocardiography was used to measure several indexes of study participants' heart rate.

After the raw data scan, those who ate more than 10 ounces (300 grams) of fish per week were found to have QT scores 13.6% lower than people who did not eat fish.

After adjusting the results for potentially confounding factors such as age, sex, physical activity status, BMI, smoking habits and intake of nuts, the reduction in QT scores in those eating 10 or more ounces of fish each week rose to 29.2%, compared to those who did not eat fish.

In an earlier study, Harvard researchers reported that among those consuming the most fish, heart rate was 2.3 beats per minute lower and likelihood of prolonged QT was 46% lower. Similar results were found in study participants taking 1 gram of omega-3s daily. The mechanism behind these benefits is thought to be omega-3 fats' effects on the flow of sodium and calcium in the ion channels, which are involved with electrical signaling in cells. Practical Tip: A typical serving of fish is 4 ounces, so just 3 servings of omega-3-rich fish, such as scallops, each week would provide 2 ounces more than the 10 ounces this research indicates confers significant protection against sudden death from a heart attack. For great, quick and easy recipe ideas, take a look at our Recipe Assistant.

Protection against Stroke

Eating fish, such as scallops, as little as 1 to 3 times per month may protect against ischemic stroke (a stroke caused by lack of blood supply to the brain, for example, as a result of a blood clot), suggests a meta-analysis of 8 studies published in the July 2004 issue of Stroke.

Data on nine independent groups participating in eight different studies found that, compared to those who never consumed fish or ate fish less than once per month, risk of ischemic stroke dropped:

• 9% in those eating fish 1 to 3 times per month
• 13% in those eating fish once per week
• 18% in those eating fish 2 to 4 times per week
• 31% in those eating fish 5 or more times each week

Eating Fish Daily Provides Substantially More Protection against Heart Attack

While as little as a weekly serving of fish lowers risk of ischemic stroke, enjoying a daily serving omega-3-rich fish, such as scallops, provides significantly greater reduction in the risk of coronary heart disease than eating fish even as frequently as a couple of times a week, show the findings of a study published in the January 17, 2006 issue of Circulation, the journal of the American Heart Association.

Researchers in Japan followed 41,578 men and women aged 40 to 59, none of whom had cardiovascular disease or cancer when the study began, from 1990-1992 to 2001. Food frequency questionnaires completed at the beginning of the study and in 1995, provided information on weekly fish intake, which was analyzed for omega-3 content.

When individuals whose fish consumption was in the top one-fifth of participants at 8 times per week were compared to those whose intake was in the lowest fifth at once per week, they were found to have a 37% lower risk of developing coronary heart disease and a 56% percent lower risk of heart attack.

When the effect of omega-3 fatty acid intake on cardiovascular risk was analyzed, coronary heart disease risk was lowered by 42% among those whose intake was the highest at 2.1 grams per day or more compared to those whose intake was the lowest at 300 milligrams per day. Those whose intake of omega 3s was in the top fifth received a 65% reduction in the risk of heart attack compared to those whose omega 3 intake was lowest.

The authors theorize that daily fish consumption is highly protective largely due to the resulting daily supply of omega-3 fatty acids, which not only reduce platelet aggregation, but also decrease the production of pro-inflammatory compounds called leukotrienes. Lowering leukotrienes reduces damage to the endothelium (the lining of the blood vessels), a key factor in the development of atherosclerosis.

"Our results suggest that a high fish intake may add a further beneficial effect for the prevention of coronary heart disease among middle-aged persons," note the study's authors.

Choose Broiled or Baked, but Not Fried Scallops to Reduce Risk of Atrial Fibrillation (Heart Arrhythmia)

Eating scallops that are broiled or baked, but not fried, may reduce risk of atrial fibrillation, the most common type of heart arrhythmia, especially in the elderly, according to a Harvard study published in the July 2004 issue of Circulation. In the 12-year study of 4,815 people 65 years of age or older, eating canned tuna or other broiled or baked fish 1 to 4 times a week correlated with increased blood levels of omega-3 fatty acids and a 28% lower risk of atrial fibrillation. Eating broiled or baked fish 5 times a week lowered risk even more—a drop in atrial fibrillation risk of 31%. Eating fried fish, however, provided no similar protection. Not only is fried fish typically made from lean fish like cod and Pollack that provide fewer omega-3 fatty acids, but in addition, frying results in the production of damaged, free-radical-laden fats in the fish as well as the frying oil.

In further research to determine if the omega-3 fats found in fish oil were responsible for fish's beneficial effects on the heart's electrical circuitry, Dariush Mozaffarian and colleagues from Harvard Medical School analyzed data on fish intake and electrocardiogram results from 5096 adults, aged 65 or older, who were enrolled in the Cardiovascular Health Study from 1989-1990.

Eating tuna or other broiled or baked fish at least once a week was associated with lower heart rate (-3.2 beats/minute) and a 50% lower likelihood of prolonged ventricular repolarisation (the period of time it takes the heart to recharge after it beats, so it can beat again), compared to those consuming fish less than once a month.

Consuming 1 gram/day of omega-3 fatty acids from fish was associated with 2.3 beats/minutes lower heart rate and a 46% lower risk of prolonged ventricular repolarisation. Eating fish at least 5 times per week was associated with an even healthier heart rhythm. However, eating fried fish (typically sold in the U.S. as fish burgers or fish sticks) was not associated with increased blood levels of omega 3 fats or any beneficial electrocardiogram results. In fact, a previous study led by the same researcher (Mozaffarian, Am J Cardiol 2006 Jan) found that while eating baked or broiled fish was linked to a slower but more powerful heart beat and lower blood pressure, eating fried fish was associated with heart muscle motion abnormalities, a reduced ejection fraction, lower cardiac output, and higher blood pressure. Since irregular heart beats are a major precipitating factor in sudden death due to cardiac arrest, promoting a healthy heart rhythm by eating baked or broiled—not fried—fish several times a week makes very good sense. Happily, as our recipes, such as our serving ideas for scallops (immediately below) show, it's a quick, easy and most importantly, delicious prescription.

Fish, Fruit and Vegetables Protective against Deep Vein Thrombosis, Pulmonary Embolism

Deep vein thrombosis is a dangerous condition in which blood clots develop in the deep veins of the legs, thighs or pelvis, causing swelling and pain. An embolism is created if a part or all of the blood clot in the deep vein breaks off from the site where it was created and moves through the venous system. If the clot lodges in the lung, a very serious condition, pulmonary embolism, arises.

Fortunately, a healthy way of eating offers significant protection, as demonstrated by a prospective study over 12 years that involved almost 15,000 middle-aged adults. While those eating the most red and processed meat doubled their risk of deep vein thrombosis (DVT), those in the upper 3 quintiles of fruit and vegetable intake had a 41-53% lower risk of DVT. And those eating fish at least once each week were found to have a 30-45% lower DVT risk. (Steffen LM, Folsom AR, et al.,Circulation.)

Practical Tip: For protection against deep vein thrombosis, increase your consumption of fruit and vegetables; eat fish at least once a week; and decrease consumption of red and processed meats.

A Canadian study published in Cancer Epidemiology Biomarkers(Fritschi L, Ambrosini GL, et al.) suggests that eating fish frequently may provide serious protection against three types of cancer: leukemia, multiple myeloma, and non-Hodgkin's lymphoma. Researchers compared the diets of almost 3,000 individuals with these cancers to those of 4,200 healthy controls. People who ate the most fish and who got most of their total fat calories from fish were 28% less likely to have leukemia, 36% less likely to have multiple myeloma, and 29% less likely to have non-Hodgkin's lymphoma.

Omega-3-Rich Fish Protective against Colorectal Cancer

A diet rich in the omega-3 fats, which are found in scallops, greatly reduces risk of colorectal cancer, indicates a study comparing 1,455 subjects with colorectal cancer to 1,455 matched healthy controls.

Those whose diets provided the most omega-3s had a 37% reduction in colorectal cancer risk, compared to those whose diets provided the least. Colorectal cancer risk was 41% lower in those with the highest average intake of EPA, and 37% lower in those whose diets supplied the most DHA. (Theodoratou E, McNeill G, et al. Am J Epidemiol.)

Practical Tip: Each of the World's Healthiest Foods' fish is a good to excellent source of omega-3s. Let our Recipe Assistant provide you with delicious, quick ways to add more omega-3s to your healthy way of eating.

Fish and Whole Grains Highly Protective against Childhood Asthma

According to the American Lung Association, almost 20 million Americans suffer from asthma, which is reported to be responsible for over 14 million lost school days in children, and an annual economic cost of more than $16.1 billion.

Increasing consumption of whole grains and fish could reduce the risk of childhood asthma by about 50%, suggests the International Study on Allergy and Asthma in Childhood (Tabak C, Wijga AH, Thorax).

The researchers, from the Dutch National Institute of Public Health and the Environment, Utrecht University, University Medical Center Groningen, used food frequency questionnaires completed by the parents of 598 Dutch children aged 8-13 years. They assessed the children's consumption of a range of foods including fish, fruits, vegetables, dairy and whole grain products. Data on asthma and wheezing were also assessed using medical tests as well as questionnaires.

While no association between asthma and intake of fruits, vegetables, and dairy products was found (a result at odds with other studies that have supported a link between antioxidant intake, particularly vitamins C and E, and asthma), the children's intake of both whole grains and fish was significantly linked to incidence of wheezing and current asthma.

In children with a low intake of fish and whole grains, the prevalence of wheezing was almost 20%, but was only 4.2% in children with a high intake of both foods. Low intake of fish and whole grains also correlated with a much higher incidence of current asthma (16.7%). compared to only a 2.8% incidence of current asthma among children with a high intake of both foods.

After adjusting results for possible confounding factors, such as the educational level of the mother, and total energy intake, high intakes of whole grains and fish were found to be associated with a 54 and 66% reduction in the probability of being asthmatic, respectively.

The probability of having asthma with bronchial hyperresponsiveness (BHR), defined as having an increased sensitivity to factors that cause narrowing of the airways, was reduced by 72 and 88% when children had a high-intake of whole grains and fish, respectively. Lead researcher, CoraTabak commented, "The rise in the prevalence of asthma in western societies may be related to changed dietary habits." We agree. The Standard American Diet is sorely deficient in the numerous anti-inflammatory compounds found in fish and whole grains, notably, the omega-3 fats supplied by cold water fish and the magnesium and vitamin E provided by whole grains. One caution: wheat may need to be avoided as it is a common food allergen associated with asthma.

Protection against Alzheimer's and Age-related Cognitive Decline

Can eating fish high in the omega-3 fatty acids, DHA(docosahexaenoic acid) and EPA (eicosapentaenoic acid), help lessen the cognitive decline and Alzheimer's disease growing in our aging population? A number of studies indicate the answer to this question is a resounding "Yes."

A report from the Framingham Heart Study published in the Archives of Neurology showed that persons whose blood levels of DHA placed them in the top quartile of values had a significantly (47%) lower risk of developing all-cause dementia than did those in the bottom quartile. Plus, greater protection against cognitive decline was obtained from consuming 2.9 than 1.3 fish meals per week. (Schaefer EJ, Bongard V, et al.).

Now, two additional positive studies have been published in the American Journal of Clinical Nutrition:

In the Zutphen Elderly Study, which involved 210 men aged 70-89 years (van Gelder BM, Tijhuis M, et al.), a linear relation was found between the estimated intake of DHA and EPA and prevention of cognitive decline.

A DHA+EPA intake of approximately 380 mg per day seemed to prevent cognitive decline. This amount of DHA+EPA would be found in just 20 grams (just 2/3 of one ounce) of Chinook salmon or in 100 grams (about 3 ounces) of cod.

Eating just two to three meals of fish a week would supply approximately 380 mg EPA+DHA per day.

In the Minneapolis study (Beydoun MA, Kaufman JS et al.) of 2251 men and women, risk of cognitive decline increased as levels of omega-6 (arachidonic acid) increased in subjects' cholesterol and other blood lipids, but decreased as the concentration of omega-3 fat (linoleic acid) increased in their blood fats.

Among subjects with high blood pressure and high cholesterol, cognitive decline was clearly associated with lower blood levels of omega-3 fats (DHA+EPA).

In all of these studies, fish consumption and the resulting increase in blood levels of omega-3 fatty acids significantly lessened mental decline over time.

How? A number of mechanisms have been suggested in recent studies to explain fish's protective effects against cognitive decline and Alzheimer's:

• EPA's anti-clotting and anti-inflammatory actions promote a healthy blood supply to the brain and lower inflammation.
• Since EPA and arachidonic acid are metabolized by the same enzymes, an increase in levels of EPA helps lessen the production of the pro-inflammatory compounds derived from arachidonic acid. (Arachidonic acid is a precursor of proinflammatory cytokines eicosanoids that are thought to be associated with greater cognitive decline.)
• Increasing consumption of DHA may correct the DHA deficiency in the cerebral cortex characteristically seen in patients with Alzheimer disease.
• DHA is involved in the membrane of ion channels in the brain, making it easier for them to change shape and transmit electrical signals.
• DHA is the source of an anti-inflammatory compound made in the brain called NPD1 that lessens amyloid-beta production in cytokine-stressed human brain cells.
• DHA slows the accumulation of tau, a protein involved in the development of neurofibrillary tangles, and also decreases beta amyloid formation by reducing levels of presenilin, the enzyme that separates beta amyloid from its parent protein. (Neurofibrillary tangles and beta amyloid plaques are the two types of brain lesions seen in Alzheimer's disease.)

Frank LaFerla, co-author of research published in the Journal of Neuroscience showing that DHA helps prevent the formation of neurofibrillary tangles and decreases beta amyloid formation, commented: "We are greatly excited by these results, which show us that simple changes in diet can positively alter the way the brain works and lead to protection from Alzheimer's disease pathology." Practical Tip: To keep your cognitive edge, cut back on sources of omega-6 fats, such as beef, and corn, palm, peanut, safflower and sunflower oils, and enjoy omega-3-rich cold water fish, such as scallops, at least 3 times each week.

Omega-3 Fat, DHA, Destroys Alzheimer's Plaques

DHA boosts production of the protein LR11, which destroys the beta-amyloid plaques associated with Alzheimer's disease, shows brain cell research.

"Because reduced LR11 is known to increase beta-amyloid production and may be a significant genetic cause of late-onset Alzheimer's disease (LOAD), our results indicate that DHA increases in LR11 levels may play an important role in preventing LOAD," wrote the researchers in the Journal of Neuroscience.

"Genetic polymorphisms that reduce LR11 expression are associated with increased AD risk," explained the researchers. "However these polymorphisms account for only a fraction of cases with LR11 deficits, suggesting involvement of environmental factors."

The new research investigated if fish oil and DHA could boost LR11 levels, since having high levels of LR11 have been reported to prevent plaque formation, while low levels in patients are believed to be a factor in causing the disease.

Even low doses of DHA increased the levels of LR11 in rat brain cells. Dietary DHA increased LR11 levels in the brains of rats or older mice genetically engineered to develop Alzheimer's disease. The positive effects of DHA on LR11 levels and the protection against Alzheimer's was again seen human brain cells were used. (Ma QL, Teter B, et al. J Neurosci.)

As a result of these findings, the National Institutes of Health has begun a large-scale clinical trial with DHA in patients with well established Alzheimer's disease. Lead researcher, Greg Cole, associate director of UCLA's Alzheimer Disease Research Center, thinks it may be too late for DHA to benefit these patients, but that DHA is highly likely to benefit patients in the earliest stages of Alzheimer's. And, we would add, help prevent the development of the disease in the rest of us!

DHA is the most abundant essential fatty acid in the brain, is crucial for healthy brain development, and low levels have been linked to cognitive impairment. According to the national Alzheimer's Association, approximately 5.1 million Americans suffer from Alzheimer's disease, a number that is projected to increase to 11 to 16 million sufferers by 2050.

Practical Tip: Enjoying several weekly servings of fish high in DHA, such as scallops, is a smart move.

Omega-3-Rich Diet Improves Mood, Reduces Depression

When researchers from Ohio State University evaluated blood samples taken from 43 older adults (average age 67), they found that study participants with high ratios of omega-6 to omega-3 not only had higher levels of various compounds involved in inflammation, but were more likely to suffer from depression.

Both depression and stress promote the production of pro-inflammatory cytokines. Researchers measured a number of these pro-inflammatory compounds including tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and the IL-6 soluble receptor (sIL-6r). Symptoms of depression were assessed using the Center for Epidemiological Studies Depression Scale.

Levels of pro-inflammatory cytokines increased progressively as depressive symptoms increased. But when depressive symptoms were combined with high omega-6:omega-3 ratios, levels of proinflammatory cytokines skyrocketed by up to 40% more than normal—far beyond the 18% increase resulting from the presence depressive symptoms alone.

Chronic inflammation has already been linked to heart disease, type 2 diabetes, osteoporosis, cognitive decline and Alzheimer's. Earlier epidemiological (population) studies have also linked higher levels of pro-inflammatory cytokines with depressive symptoms. This new study suggests that a diet that is rich in omega-6 fats but includes few of the foods rich in omega-3 fats—such as the standard American diet—promotes not only inflammation, but depression.

The positive take-away is that increasing consumption of foods rich in omega-3s, while decreasing consumption of omega-6-rich foods, can provide some protection against depression, particularly as depressive symptoms increase.

Omega-3s are found in cold water fish, nuts, such as walnuts, and flaxseeds. Alpha-linolenic acid (ALA), the omega-3 in nuts and seeds, can be converted—albeit inefficiently—in the body to the omega-3s found in fish, eicosapentaenoic acid (EPA) and docosahexaenioc acid (DHA).

EPA improves blood flow and is also suggested to affect hormones and the immune system, both of which have a direct effect on brain function. DHA is active in the membrane of ion channels in the brain, making it easier for them to change shape and transmit electrical signals, and is involved in serotonin metabolism (reduced serotonin production and/or activity is a key factor in depression). Practical Tip: Be of good cheer. Cut back on sources of omega-6 fats, such as beef, and corn, palm, peanut, safflower and sunflower oils. Enjoy a handful of omega-3-rich walnuts and/or flaxseeds daily, and a serving of cold water fish, such as scallops, at least 3 times each week.