The firm white meat and delicately sweet flavor of halibut, combined with its high nutritional value, make it a favorite among fish lovers. Fishing season for halibut is in the summer and fall when it is available fresh and of optimum quality. Frozen halibut is available throughout the year.
Halibut is the largest of the flatfish and one of the largest of the saltwater fish with catches that weight in at up to 660 pounds. It is a lean fish that features finely textured, snow white flesh that contains few bones; its gray-brown skin is also edible.
Halibut are truly a nutrient-dense food. A very good source of high quality protein, halibut are rich in significant amounts of a variety of important nutrients including the minerals selenium, magnesium, phosphorus and potassium; the B vitamins B12, niacin, and B6; and perhaps most important, the beneficial omega-3 essential fatty acids. Essential fatty acids are so named because they are essential for our health but cannot be made by the body; they must therefore be obtained from foods. Cold-water fish like halibut are a rich source of the omega-3 essential fats, a form of essential fatty acids in which the standard American diet is sorely deficient. (The other form of essential fatty acids, the omega-6s, are plentiful in a variety of commonly consumed oils such as corn and safflower oil. In fact, the omega-6s are so plentiful in the typical American diet that too much omega-6 is consumed in proportion to omega-3s--an imbalance that promotes inflammation, thus contributing to virtually every chronic disease in which inflammation is a key component.)
Omega-3 fatty acids provide a broad array of cardiovascular benefits. Omega-3s benefit the cardiovascular system by helping to prevent erratic heart rhythms, making blood less likely to clot inside arteries (which is the ultimate cause of most heart attacks), and improving the ratio of good (HDL) cholesterol to potentially harmful (LDL) cholesterol. And, as mentioned above, omega-3s reduce inflammation, which is a key component in the processes that turn cholesterol into artery-clogging plaques.
Halibut is also a good source of vitamin B12 and vitamin B6--two B vitamins that, along with folic acid, lower levels of homocysteine. Homocysteine, an intermediate compound produced during the methylation cycle, is directly damaging to artery walls, and elevated blood levels of homocysteine are considered an important risk factor for atherosclerosis.
Last, but far from least, halibut is a very good source of magnesium. Magnesium is Nature's own calcium channel blocker. When enough magnesium's around, veins and arteries breathe a sigh of relief and relax, which lessens resistance and improves the flow of blood, oxygen and nutrients throughout the body. Studies show that a deficiency of magnesium is not only associated with heart attack but that immediately following a heart attack, lack of sufficient magnesium promotes free radical injury to the heart.
Triglycerides are a form in which fat is carried in your bloodstream. In normal amounts, triglycerides are important for good health because they serve as a major source of energy. High levels of triglycerides, however, are associated with high total cholesterol, high LDL (bad) cholesterol and low HDL (good) cholesterol), and therefore, with an increased risk of cardiovascular disease.
In addition, high triglycerides are often found along with a group of other disease risk factors that has been labeled metabolic syndrome, a condition known to increase risk of not only heart disease, but diabetes and stroke. (Metabolic syndrome is the combined presence of high triglycerides, increased blood pressure, high blood sugar, excess weight, and low HDL (good) cholesterol.)
Triglyceride Levels | |
---|---|
Less than 150 mg/dL | Normal |
150-199 mg/dL | Borderline-high |
200-499 mg/dL | High |
500 mg/dL | Very High |
*Note: Triglycerides are most accurately measured after an 8-12 hour fast.
In this 6-month study involving 142 overweight men and women with high triglycerides, subjects were divided into 5 groups, one of which served as a control group, 2 of which ate 2 servings of fish high in omega-3s while also replacing their normal household fats with fat high in sunflower (Group 1) or canola oil made from rapeseed (Group 2), and 2 of which ate 2 weekly servings of white fish while also replacing their normal household fats with ones high in sunflower (Group 3) or canola oil made from rapeseed (Group 4).
Canola oil also provides some omega-3 fats, with an omega-6:omega-3 ratio of 2:1, while sunflower oil contains omega-6, but no omega-3 fats.
At the end of the study, triglyceride levels had dropped 6.6% in the omega-3-rich fish groups combined. Triglycerides dropped most—10.4%—in those consuming omega-3-rich fish and canola oil. In those eating omega-3-rich fish and sunflower oil, triglycerides dropped 2.8%.
Bottomline: A healthy way of eating that incorporates at least 2 weekly servings of fish and other food sources of omega-3 fats, such as flaxseed or canola oil, may significantly lower triglyceride levels. Replacing normal household fats with flaxseed oil, in which the ratio of omega-6:omega:3 fats is 1:4, might result in an even larger drop in triglyceride levels.
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 salmon, sardines, cod, halibut or tuna, 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.
Individuals whose diets provide greater amounts of omega-3 fatty polyunsaturated fatty acids—and halibut is a very good source of these essential fats—have lower blood pressure than those who consume less, shows data gathered in the International Study of Macro- and Micro-nutrients and Blood Pressure (INTERMAP) study (Ueshima H, Stamler J, et al. Hypertension).
The INTERMAP is a study of lifestyle factors, including diet, and their effect on blood pressure in 4,680 men and women aged 40 to 59 living in Japan, China, the U.S. and the U.K. Blood pressure was measured and dietary recall questionnaires were completed by participants on four occasions. Dietary data was analyzed for levels of omega-3 fatty acids from food sources including fish, nuts, seeds and vegetable oils.
Average daily intake of omega-3 fatty acids was 2 grams. Participants with a high (o.67% kcal) omega-3 fatty acid percentage of their daily calorie intake had an average systolic and diastolic blood pressure reading that was 0.55/0.57 mm Hg less, respectively, than participants with lower intake. Previous research has found that a decrease of 2 mm Hg reduces the population-wide average stroke mortality rate by 6 percent and that of coronary heart disease by 4%.
Higher omega-3 fatty acid intake among the 2,238 subjects who were not using drugs, supplements, or a special diet for hypertension, heart disease, or diabetes was associated with a 1.01/0.98 mm Hg reduction in systolic and diastolic blood pressure, respectively.
For the 2,038 subjects in this group who did not have hypertension, greater intake was associated with a 0.91/0.92 mm Hg average systolic and diastolic reduction.
Lead author Hirotsugu Ueshima, MD of Shiga University of Medical Science in Japan, noted that the beneficial effect of omega-3 fats was even greater in people who had not yet developed high blood pressure.
The researchers also found that omega-3s from nuts, seeds, and vegetable oils—such as walnuts and flaxseed—had just as much impact on blood pressure as omega-3s from fish.
"With blood pressure, every millimeter counts. The effect of each nutrient is apparently small but independent, so together they can add up to a substantial impact on blood pressure. If you can reduce blood pressure a few millimeters from eating less salt, losing a few pounds, avoiding heavy drinking, eating more vegetables, whole grains and fruits (for their fiber, minerals, vegetable protein and other nutrients) and getting more omega-3 fatty acids, then you've made a big difference," said Ueshima.
A recent study showed that eating fish lowers the risk of certain types of strokes. The study, which involved almost 80,000 nurses during a 15-year period revealed that those women who ate fish 2 to 4 times per week had a 27% reduced risk of stroke compared to women who ate fish one a month. Eating fish five or more times per week reduced the risk of certain strokes 52%.
A meta-analysis of 8 studies published in the July 2004 issue of Stroke supports earlier studies showing halibut may help prevent stroke in men as well as women. Eating fish 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). 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:
While as little as a weekly serving of fish lowers risk of ischemic stroke, enjoying a daily serving omega-3-rich fish, such as halibut, 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 Halibut to Reduce Risk of Atrial Fibrillation (Heart Arrhythmia)
Eating halibut that's 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 15 Minute Halibut with Avocado Salsashow, it's a quick, easy and most importantly, delicious prescription.
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, such as halibut, 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.
In addition to halibut's omega-3s, the selenium it contains is a necessary component in one of the body's most important antioxidants—glutathione peroxidase—which is critical for a healthy liver, the organ responsible for detoxifying and clearing potentially harmful compounds such as pesticides, drugs, and heavy metals from the body. Selenium also helps prevent cancer and heart disease.
Eating even small amounts of fish may protect against ovarian and digestive tract cancers. A total of 10,149 cancer patients with 19 different types of cancer and 7,990 controls were included in a recent study conducted in Spanish hospitals. The researchers determined that eating more fish correlates with a reduced risk of certain cancers. Fish eaters had less cancer in the ovaries, pancreas, and all parts of the digestive tract including the mouth, pharynx, esophagus, stomach, colon and rectum.
Some of the cancer protective effects of fish, such as halibut, may come from its being a great source of omega 3 fatty acids. Recent in vitro (test tube) evidence suggests that this beneficial effect is related to the fact that when omega-3s are consumed in the diet, they are incorporated into cell membranes where they promote cancer cell apoptosis via several mechanisms including: inhibiting a pro-inflammatory enzyme called cyclooxygenase 2 (COX 2), which promotes breast cancer; activating a type of receptor in cell membranes called peroxisome proliferator-activated receptor (PPAR)-Α, which can shut down proliferative activity in a variety of cells including breast cells; and, increasing the expression of BRCA1 and BRCA2, tumor suppressor genes that, when functioning normally, help repair damage to DNA, thus helping to prevent cancer development.
A diet rich in the omega-3 fats found in cold water fish, such as halibut, 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.
Fishermen have, in epidemiological studies, been identified as having a lower risk of leukemia, multiple myeloma and non-Hodgkin lymphoma, an occupational benefit that researchers thought might be due to the fact that they eat more fish.
Now, a Canadian study published in the April 2004 issue of Cancer Epidemiology Biomarkers & Prevention suggests that persons whose diet includes more weekly servings of fresh fatty fish have a much lower risk of these three types of cancer. Data drawn from a survey of the fish eating habits of 6,800 Canadians indicates that those consuming the most fatty fish decreased their risk of leukemia by 28%, their risk of multiple myeloma by 36%, and their risk of non-Hodgkin lymphoma by 29%. Overall, frequent eaters of fatty fish reduced their risk for all forms of lymphomas by 30%.(August 3, 2004)
A diet rich in the omega-3 fats found in cold water fish 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, Cetnarskyi R, 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.
Consumption of fatty fish, such as halibut, offers significant protection against renal cell carcinoma, the most common form of kidney cancer, suggests evidence presented in a 15.3-year epidemiological study involving 61,433 women who participated in the Swedish Mammography Cohort Study (Wolk A, Larsson SC, JAMA).
Renal cell carcinoma (RCC), the 10th most common form of cancer with a male:female ratio of 5:3, accounts for more than 80% per cent of all kidney cancers. Although an earlier review of prospective cohort studies (MacLean et al, JAMA) did not support the hypothesis that fish consumption is protective, the authors of the new JAMA study point out that virtually all the other studies on the subject, including MacLean's, did not take into account whether the fish consumed were fatty or lean fish.(Fatty fish contain 20 to 30 times more omega-3 (DHA and EPA) than lean fish, which provide 3-5 times more vitamin D.)
When this distinction was considered, the researchers found that those who consumed one or more serving of fatty fish each week had a 44% decreased risk of RCC compared with those who consumed no fatty fish.
Plus, those who reported long-term consumption between the beginning of the study and the 10-year follow-up had a dramatic 74% lower risk.
In contrast, no association was found between consumption of lean fish or other seafood and incidence of RCC. Wolk notes,"Our results support the hypothesis that frequent consumption of fatty fish may lower the risk of RCC, possibly due to increased intake of fish oil rich in EPA and DHA, as well as vitamin D."
A diet high in omega-3 essential fatty acids, especially from fish such as halibut, offers significant protection against both early and late age-related macular degeneration (AMD), show two studies published in the July 2006 issue of the Archives of Opthalmology.
In age-related macular degeneration, the area at the back of the retina called the macula, which controls fine vision, deteriorates, resulting in central vision loss and even blindness. AMD is the leading cause of blindness in people over 50, affecting more than 30 million people worldwide.
In the first study, Brian Chua and colleagues in Sydney, Australia, utilized data from the Blue Mountains Eye Study, which enrolled 3,654 men and women aged 49 and older between 1992 and 1994. Dietary questionnaires completed by 2,895 participants at the beginning of the study provided information on fatty acid intake.
Participants among the top one-fifth in terms of omega-3-rich fish consumption had a 42% lower risk of early AMD compared to those whose fish intake placed them in the lowest fifth. Enjoying omega-3-rich fish at least once a week provided a a 42% reduction in risk for early AMD.
Eating omega-3-rich fish at least three times a week was associated with a 75% reduction in late AMD.
In the second study, Johanna M. Seddon and colleagues at the Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, looked at modifiable and protective factors for AMD among elderly male twins enrolled in the National Academy of Sciences' National Research Council World War II Veteran Twin Registry. Of the 681 twins examined, 222 were found to have intermediate or late stage AMD, and 459 twins had no signs of AMD.
Current smokers had a 1.9-fold (almost double) increased risk of AMD. Even past smokers' risk was highly elevated—a 1.7 increase compared to men who never smoked.
Eating more fish, however, greatly reduced AMD risk. Among the men whose fish consumption put them among the top 25% of dietary omega-3 fatty acid intake, risk of AMD was 45% lower compared to those with the lowest fish / omega-3 intake.
Eating fish at least twice a week reduced AMD risk by 36% compared to those who ate less than one serving of fish per week. The authors noted that AMD is highly preventable simply by following a healthy lifestyle: "About a third of the risk of AMD in this twin study cohort could be attributable to cigarette smoking, and about a fifth of the cases were estimated as preventable with higher fish and omega-3 fatty acid dietary intake."
Dry eye syndrome (DES) afflicts more than 10 million Americans. Artificial tears offer only temporary relief. Expensive prescription drugs promise help, but at the cost of potentially serious side effects.
Could Mother Nature provide a cure? Yes, suggests research published in the October 2005 issue of the American Journal of Clinical Nutrition involving nearly 40,000 female health professionals aged 45-84 enrolled in the Women's Health Study.
Researcher Biljana Miljanovic, MD, MPH, and colleagues at Brigham and Women's Hospital looked at whether essential fatty acids—the omega-3 fats (found in high amounts in cold water fish and flaxseeds), and the omega-6 fats (found in red meat, safflower, sunflower, soy and corn oils)—play a role.
They do. Women whose diets provided the highest amounts of omega-3 fatty acids had a 17% lower risk of dry eye syndrome compared with those consuming the least of these beneficial fats.
In contrast, a diet high in omega-6 fats, but low in omega-3s, significantly increased DES risk. Women whose diets supplied a high ratio of omega-6 to omega-3 fatty acids had a 2.5-fold higher risk of DES syndrome compared to those with a more balanced intake of fatty acids.
Researchers specifically looked at eating tuna fish—a main source of omega-3 fatty acids in the American diet.
Compared with women eating less than one 4-ounce serving of tuna a week:
"These findings suggest that increasing dietary intake of omega-3 fatty acids may reduce the risk of dry eye syndrome, an important and prevalent cause of ocular complaints," Miljanovic and colleagues conclude. Like tuna fish, halibut are richly endowed with omega-3 fatty acids (as are salmon, mackerel, sardines, herring, flaxseeds and flaxseed oil). Due to concerns about mercury levels in tuna, to lower your risk of DES we recommend enjoying a variety of cold-water fish and adding flaxseeds and flaxseed oil to your Healthiest Way of Eating.
In the U.S., dementia, or at the least loss of cognitive function, is becoming virtually synonymous with old age, but recent studies suggest it doesn't have to be, that better brain function in older adults can be promoted by a diet that includes fatty fish.
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, three 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 the Hordaland Health Study, 2,031 adults (55% women) aged 70-74, underwent a battery of cognitive tests including the Kendrick Object Learning Test, Trail Making Test (part A), modified versions of the Digit Symbol Test, Block Design, Mini-Mental State Examination, and the Controlled Oral Word Association Test.
Subjects eating an average of at least 10 grams of fish a day (1 ounce = 30 grams, so eating just 2.1 ounces of fish each week would supply an average of 10 grams daily) had significantly better mean test scores and a lower prevalence of poor cognitive performance than those whose intake averaged less than 10 grams/day. The associations between total seafood intake and cognition were strongly dose-dependent with maximum benefit observed at an intake of approximately 75 grams/day (this would translate to 2.5 ounces of fish per day or approximately four 4-ounce servings of fish per week). Almost all cognitive functions were beneficially influenced by eating fish, particularly nonprocessed lean fish and fatty fish. Am J Clin Nutr. 2007 Nov;86(5):1470-8.
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:
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 halibut, at least 3 times each week.
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 halibut, is a smart move.
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 halibut, at least 3 times each week.
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.
Halibut is big. Not just in popularity and nutritional value, but also in size. It is actually one of the largest of all saltwater fishes and can weigh up to 155 pounds. Halibut can be found both in the Atlantic and Pacific Oceans, the Atlantic species being of larger size.
Halibut is delicious. With a slightly sweet yet mild flavor, it is a lean fish that features finely textured, snow white flesh.
People have been enjoying halibut as a food ever since this beautiful fish appeared in the Earth's waters, basically since time immemorial.
Halibut was considered a sacred fish throughout history and was oftentimes served on holidays, especially during medieval days in Europe. In fact, the English derivation for its name reflects the sacredness of this large flatfish since i signifies holy, and but signifies flat.
Halibut, which is found in northern seawaters, is especially concentrated in the Pacific Ocean as well as the Atlantic coasts of Newfoundland and Greenland.
Just as with any seafood, it is best to purchase halibut from a store that has a good reputation for having a fresh supply of fish. Get to know a fishmonger (person who sells the fish) at the store, so you can have a trusted resource from whom you can purchase your fish.
Fresh whole halibut should be displayed buried in ice, while fillets should be placed on top of the ice. The flesh of the halibut fillets should glistening white with no signs of browning or gaping.
Smell is a good indicator of freshness: fresh halibut smells like seawater. Since a slightly "off" smell cannot be detected through plastic, if you have the option, purchase displayed fish as opposed to pieces that are prepackaged. Once the fishmonger wraps and hands you the fish that you have selected, smell it through the paper wrapping and return it if it has too strong a fishy, ammonia-like smell.
When storing all types of seafood, including halibut, it is important to keep it cold since fish is very sensitive to temperature. Therefore, after purchasing halibut or other fish, refrigerate it as soon as possible. If the fish is going to accompany you during a day full of errands, keep a cooler in the car where you can place the halibut to make sure it stays cold and does not spoil.
The temperature of most refrigerators is slightly warmer than ideal for storing fish. Therefore, to ensure maximum freshness and quality, it is important to use special storage methods to create the optimal temperature for holding the fish. One of the easiest ways to do this is to place halibut, which has been well wrapped, in a baking dish filled with ice. The baking dish and fish should then be placed on the bottom shelf of the refrigerator, which is its coolest area. Replenish the ice one or two times per day.
The length of time that halibut can stay fresh stored this way depends upon how fresh it is, i.e. when it was caught. Fish that was caught the day before you purchased it can be stored for about four days while fish that was caught the week before can only be stored for about one or two days.
You can extend the shelf life of halibut by freezing it. To do so, wrap it well in plastic and place it in the coldest part of the freezer where it will keep for about two to three weeks.
After you unwrap your fish, rinse it under cool running water, then pat dry before cooking.
For some of our favorite recipes, click Recipes.
Government inspection is not mandated for seafood, so choose your fish purveyor carefully. Since halibut is a very large fish, it is usually marketed in steaks or fillets and more commonly sold frozen rather than fresh. The U.S. Food and Drug Administration advises that pregnant women and women of childbearing age who might become pregnant not eat certain fish, including shark, swordfish, king mackerel and tilefish. It is also recommended that nursing mothers and young children steer clear of these fish. Two groups, the Environmental Working Group and the U.S. Public Interest Group have asked the FDA to add Gulf coast oysters and eight more types of fish to the list, including tuna, sea bass, halibut, marlin, pike and white croaker. Their recommendations are based on a report on mercury contamination in fish. In addition, their report says canned tuna, mahi-mahi, cod and pollack should not be eaten more than once a month. These two research groups said fish considered safe for pregnant women include farm-raised trout and catfish, shrimp, fish sticks, flounder (summer), wild pacific salmon, croaker, mid-Atlantic blue crab and haddock. For information on the topic of seafood and mercury contamination, please see our article "Should I be concerned about mercury in fish and what fish are safe to eat?"
Halibut contain naturally-occurring substances called purines. Purines are commonly found in plants, animals, and humans. In some individuals who are susceptible to purine-related problems, excessive intake of these substances can cause health problems. Since purines can be broken down to form uric acid, excess accumulation of purines in the body can lead to excess accumulation of uric acid. The health condition called "gout" and the formation of kidney stones from uric acid are two examples of uric acid-related problems that can be related to excessive intake of purine-containing foods. For this reason, individuals with kidney problems or gout may want to limit or avoid intake of purine-containing foods such as halibut.
Although allergic reactions can occur to virtually any food, research studies on food allergy consistently report more problems with some foods than with others. It's important to realize that the frequency of problems varies from country to country and can change significantly along with changes in the food supply or with other manufacturing practices. For example, in several part of the world, including Canada, Japan, and Israel, sesame seed allergy has risen to a level of major concern over the past 10 years.
In the United States, beginning in 2004 with the passage of the Food Allergen Labeling and Consumer Protection Act (FALCPA), food labels have been required to identify the presence of any major food allergens. Since 90% of food allergies in the U.S. have been associated with 8 food types as reported by the U.S. Centers for Disease Control, it is these 8 food types that are considered to be major food allergens in the U.S. and require identification on food labels. The 8 food types classified as major allergens are as follows: (1) wheat, (2) cow's milk, (3) hen's eggs, (4) fish, (5) crustacean shellfish (including shrimp, prawns, lobster and crab); (6) tree nuts (including cashews, almonds, walnuts, pecans, pistachios, Brazil nuts, hazelnuts and chestnuts); (7) peanuts; and (8) soy foods.
These foods do not need to be eaten in their pure, isolated form in order to trigger an adverse reaction. For example, yogurt made from cow's milk is also a common allergenic food, even though the cow's milk has been processed and fermented in order to make the yogurt. Ice cream made from cow's milk would be an equally good example.
Food allergy symptoms may sometimes be immediate and specific, and can include skin rash, hives, itching, and eczema; swelling of the lips, tongue, or throat; tingling in the mouth; wheezing or nasal congestion; trouble breathing; and dizziness or lightheadedness. But food allergy symptoms may also be much more general and delayed, and can include fatigue, depression, chronic headache, chronic bowel problems (such as diarrhea or constipation), and insomnia. Because most food allergy symptoms can be caused by a variety of other health problems, it is good practice to seek the help of a healthcare provider when evaluating the role of food allergies in your health.
Halibut is an excellent source of selenium, a very good source of protein, niacin, phosphorus and magnesium, and a good source of omega-3 fatty acids, vitamin B6, vitamin B12 and potassium.
For an in-depth nutritional profile click here: Halibut.
Halibut 4.00 oz-wt 113.40 grams 158.76 calories |
||||
Nutrient | Amount | DV (%) |
Nutrient Density |
World's Healthiest Foods Rating |
---|---|---|---|---|
tryptophan | 0.34 g | 106.2 | 12.0 | excellent |
selenium | 53.07 mcg | 75.8 | 8.6 | excellent |
protein | 30.27 g | 60.5 | 6.9 | very good |
vitamin B3 | 8.08 mg | 40.4 | 4.6 | very good |
phosphorus | 323.18 mg | 32.3 | 3.7 | very good |
magnesium | 121.34 mg | 30.3 | 3.4 | very good |
omega-3 fats | 0.62 g | 25.8 | 2.9 | good |
vitamin B12 | 1.55 mcg | 25.8 | 2.9 | good |
vitamin B6 | 0.45 mg | 22.5 | 2.6 | good |
potassium | 653.17 mg | 18.7 | 2.1 | good |
World's Healthiest Foods Rating |
Rule |
---|---|
excellent | DV>=75% OR Density>=7.6 AND DV>=10% |
very good | DV>=50% OR Density>=3.4 AND DV>=5% |
good | DV>=25% OR Density>=1.5 AND DV>=2.5% |
In-Depth Nutritional Profile for Halibut