Eating a diet rich in omega-3 fatty acids appears to protect seniors against the onset of a serious eye disease known as age-related macular degeneration (AMD). Researchers did a fresh analysis of a one-year dietary survey conducted in the early 1990s. The poll involved nearly 2,400 seniors between the ages of 65 and 84 living in Maryland’s Eastern Shore region, where fish and shellfish are eaten routinely.
While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD had consumed less fish and seafood containing omega-3 fatty acids. After their food intake was assessed, participants underwent eye examinations. About 450 had AMD, including 68 who had an advanced stage of the disease, which can lead to severe vision impairment or blindness. Prior evidence suggested that dietary zinc is similarly protective against AMD, so the researchers looked to see if zinc consumption from a diet of oysters and crabs reduced risk of AMD, but no such association was seen.
The researchers believe that the low dietary zinc levels relative to zinc supplements could account for the absence of such a link. However, they cautioned against people to start taking omega-3 supplements to protect against AMD based on this study because they are not sure that the above results have sufficient power to draw any conclusions. The correlation is important but larger studies with longer term follow-up are needed before being able to properly assess the impact.
The steep rate of death from stroke in a swath of Southern states often referred to as America's “stroke belt” may be linked to a higher consumption of fried fish in that region, new research suggests. A study published in the journal Neurology shows people living in the stroke belt — which comprises North Carolina, South Carolina, Georgia, Alabama, Mississippi, Tennessee, Arkansas and Louisiana — eat more fried fish and less non-fried fish than people living in the rest of the country, and African-Americans eat more fried fish than Caucasians. “Differences in dietary fish consumption, specifically in cooking methods, may be contributing to higher rates of stroke in the stroke belt and also among African Americans,” says study author Fadi Nahab, medical director for the Stroke Program at Emory University Hospital in Atlanta.
The research, part of a large government-funded study, Reasons for Geographic and Racial Differences in Stroke (REGARDS), involved 21,675 participants from across the country; the average age was 65. Of the participants, 21% were from the “stroke buckle,” the coastal plain region of North Carolina, South Carolina and Georgia where stroke mortality rates are even higher than they are in the rest of the stroke belt. Another 34% were from the rest of the stroke belt and 44% were from the other states.
Participants were interviewed by phone and then given an in-home physical exam. The questionnaire asked how often they ate oysters, shellfish, tuna, fried fish and non-fried fish. The American Heart Association recommends people eat fish high in omega-3 fatty acids—essential fatty acids humans get through their diet—at least twice a week, baked or grilled but not fried. Fewer than one in four overall ate two or more servings of non-fried fish a week. Stroke belt residents were 32% more likely to eat two or more servings of fried fish each week than those in the rest of the country.
African-Americans were more than 3.5 times more likely to eat two or more servings of fried fish each week than Caucasians, with an overall average of about one serving per week of fried fish compared with about half a serving for Caucasians. When it came to eating non-fried fish meals, stroke belt residents ate an average of 1.45 servings per week, compared with 1.63 servings eaten by people elsewhere.
“This is good stuff. It's a well-done study, but I think one thing to bear in mind is that it's not specifically a study of stroke risk. You're looking at a community and seeing how it's behaving on the whole,” says Daniel Labovitz, a stroke neurologist at Montefiore Medical Center in the Bronx. “This study can't tell you causation. It can't tell you there's a direct link between one thing and another, it just tells you they're associated,” says stroke neurologist Victor Urrutia, an assistant professor at Johns Hopkins University School of Medicine.
How might eating fried fish impact stroke?
It could be that frying the fish leaches out the omega-3s, says Jeremy Lanford, stroke director at Scott & White Healthcare in Roundrock, Texas. Or the increased fat calorie content from the frying oil may contribute to stroke, says author Nahab. He also notes that fish used for frying, such as cod and haddock, tend to be the types lower in healthy fats. More research is needed to tease out whether cooking methods affect stroke risk, Labovitz says. “In other words, is fried fish a problem, or is it another red herring?” he says.
The study was supported by the National Institute of Neurological Disorders and Stroke, the National Institutes of Health, and the Department of Health and Human Services. Funding was provided by General Mills for coding of the food frequency questionnaire.
According to a 2007 University of Toronto study published in the journal Diabetes Care, a quarter-cup of chia seeds supplies as much omega-3 fatty acid as a salmon fillet, 25 percent more dietary fiber than flaxseed, 30 percent more antioxidants than blueberries and as much calcium as three cups of milk.
The study, so far the only peer- reviewed one concerning the health claims of chia seeds, showed that diabetes patients reduced cardiovascular risks by ingesting chia seeds along with standard diabetes therapy.
Dr. Sheri Zidenberg-Cherr of the UC Davis nutrition department says chia seeds have a “nice nutritional profile” but hastens to add they are not the dietary cure-all some are trumpeting. “The redeeming qualities of it is omega-3s, specifically the lenlinic (acid) that's in there,” Zidenberg-Cherr says. “Because of that tie-in with heart disease and diabetes, I see potential for it as something that could be added to someone's diet if they're already following a healthy eating plan with the proper recommendations.”
At the very least, she adds, chia seeds can't hurt.
Researchers at Wilmer Eye Institute, Johns Hopkins School of Medicine, wanted to know how the risk of age-related macular degeneration (AMD) would be affected in a population of older people who regularly ate fish and seafood, since some varieties are good sources of omega-3 fatty acids. A diet rich in omega-3s probably protects against advanced AMD, the leading cause of blindness in whites in the United States, according to the Age-Related Eye Disease Study (AREDS) and other recent studies. High concentrations of omega-3s have been found in the eye's retina, and evidence is mounting that the nutrient may be essential to eye health. The new research, led by Sheila K. West, PhD, was part of the Salisbury Eye Evaluation (SEE) study.
Food intake information with details on fish and shellfish consumed was collected over one year using a validated questionnaire for 2,391 participants aged 65 to 84 years who lived along Maryland's Eastern Shore. After dietary assessment was complete, participants were evaluated for AMD. Those with no AMD were classified as controls (1,942 persons), 227 had early AMD, 153 had intermediate-stage disease, and 68 had advanced AMD. In the advanced AMD group, the macular area of the retina exhibited either neovascularization (abnormal blood vessel growth and bleeding) or a condition called geographic atrophy. Both conditions can result in blindness or severe vision loss.
“Our study corroborates earlier findings that eating omega-3-rich fish and shellfish may protect against advanced AMD.” Dr. West said. “While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD were significantly less likely to consume high omega-3 fish and seafood,” she said.
The study also looked at whether dietary zinc from crab and oyster consumption impacted advanced AMD risk, but no significant relationship was found. Zinc is also considered protective against AMD and is included in an AMD-vitamin/nutrient supplement developed from the AREDS study. Dr. West speculated that her study found no effect because the levels of zinc obtained from seafood/fish were low compared to supplement levels.
The research is published in the December issue of Ophthalmology, the journal of the American Academy of Ophthalmology.
Eating a diet rich in omega-3 fatty acids appears to protect seniors against the onset of a serious eye disease known as age-related macular degeneration (AMD), a new analysis indicates.”Our study corroborates earlier findings that eating omega-3-rich fish and shellfish may protect against advanced AMD,” study lead author Sheila K. West, of the Wilmer Eye Institute at Johns Hopkins School of Medicine in Baltimore, said in a news release from the American Academy of Ophthalmology.
“While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD were significantly less likely to consume high omega-3 fish and seafood,” she added.
The observations are published in the December issue of Ophthalmology.
West and her colleagues based their findings on a fresh analysis of a one-year dietary survey conducted in the early 1990s. The poll involved nearly 2,400 seniors between the ages of 65 and 84 living in Maryland's Eastern Shore region, where fish and shellfish are eaten routinely. After their food intake was assessed, participants underwent eye exams. About 450 had AMD, including 68 who had an advanced stage of the disease, which can lead to severe vision impairment or blindness. In the United States, AMD is the major cause of blindness in whites, according to background information in the news release.
Prior evidence suggested that dietary zinc is similarly protective against AMD, so the researchers looked to see if zinc consumption from a diet of oysters and crabs reduced risk of AMD, but no such association was seen. However, the study authors theorized that the low dietary zinc levels relative to zinc supplements could account for the absence of such a link.
Anand Swaroop, chief of the neurobiology, neuro-degeneration, and repair laboratory at the U.S. National Eye Institute, interpreted the findings with caution. “It does make huge sense theoretically,” he said. “Photoreceptors have a very high concentration of a specific type of fatty acids and lipids, relative to many other cell types. So it would make sense that omega-3 consumption would be beneficial. The theory is sound.”
“However, I wouldn't want people to start taking grams of omega-3 to protect against AMD based on this finding because I'm not really sure that this study has sufficient power to draw any conclusions,” Swaroop added. “This is just a one-year analysis and AMD is a long-term disease. The correlation is important, and it should be explored further. But we need larger studies with longer term follow-up before being able to properly assess the impact.”
SOURCE: Anand Swaroop, Ph.D senior investigator and chief of neurobiology, neurodegneration, and repair laboratory, U.S. National Eye Institute, Bethesda, Md.; American Academy of Ophthalmology, news release, Dec. 1, 2010
The new study looked into the effects of four different diet combinations on blood lipid metabolism, in 117 patients with metabolic syndrome.
In accordance with previous suggestions, the researchers found that a low-fat, high-complex carbohydrate diet had “several detrimental effects”, including significantly increasing total triglyceride levels, and triglyceride rich lipoprotein cholesterol levels.
In contrast, intake of the same diet supplemented with omega-3 was found to have no effects on blood lipid levels, with researchers observing that a diet rich in monounsaturated fats, or a low-fat diet rich in complex carbohydrates and omega-3 fatty acids, resulted in lower circulating blood lipid levels than a diet rich in high saturated fats or a diet low in fats and high in complex carbohydrates.
The data from the study suggest a place for higher omega-3 intake in people with metabolic syndrome, and supports previous research that suggests monounsaturated fatty acids can have a positive effect on blood lipid levels.
“The long-term effect of the low-fat, high-complex carbohydrate diet, pre vs. post intervention phases, showed several beneficial effects of long chain omega-3 PUFA supplementation,” stated the researchers.
“Our data suggest that long-term intake of an isocaloric, low-fat, high-carbohydrate diet supplemented with long chain omega-3 … have beneficial effects on postprandial lipoprotein response in patients with metabolic syndrome,”
Source: The Journal of Nutrition
“A Low-Fat, High-Complex Carbohydrate Diet Supplemented with Long-Chain (n-3) Fatty Acids Alters the Postprandial Lipoprotein Profile in Patients with Metabolic Syndrome”
Authors: Y. Jimenez-Gomez, C. Marin, P. Perez-Martinez, et al
“It may be that the amount of omega-3 fatty acids in fish oil supplements are higher than most people would typically get from their diet,” White said.
However, White cautioned against gleaning any recommendations from the results of one study.
“Without confirming studies specifically addressing this,” she said, “we should not draw any conclusions about a causal relationship.”
Edward Giovannucci, M.D., Sc.D., professor of nutrition and epidemiology at the Harvard School of Public Health and an editorial board member of Cancer Epidemiology, Biomarkers & Prevention, agreed.
“It is very rare that a single study should be used to make a broad recommendation,” said Giovannucci. “Over a period of time, as the studies confirm each other, we can start to make recommendations.”
Still, fish oil continues to excite many, as evidence emerges about its protective effect on cardiovascular disease and now cancer.
Harvard researchers are currently enrolling patients for the randomized Vitamin D and Omega-3 Trial (also called VITAL), which will assess the impact of fish oil supplements and vitamin D on cancer, heart disease and stroke.
The researchers plan to enroll 20,000 U.S. men aged 60 years and older and women aged 65 years and older who do not have a history of these diseases and have never taken supplements.
Increased intakes of omega-3 fatty acids may decrease the risk of heart disease and heart attack in people with low fish intakes, says a new study from The Netherlands. Daily intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) of about 240 milligrams was associated with a 50 per cent reduction in the risk of coronary heart disease (CHD), compared with intakes of about 40 milligrams, according to findings published in the Journal of Nutrition. Furthermore, the highest average intake of DHA and EPA was associated with a 38 per cent reduction in the heart attack, said researchers from Wageningen University following a study with over 21,000 people with low fish intakes.
The heart health benefits of consuming oily fish, and the omega-3 fatty acids they contain, are well-documented, being first reported in the early 1970s by Jorn Dyerberg and his co-workers in The Lancet and The American Journal of Clinical Nutrition. To date, the polyunsaturated fatty acids (PUFAs) have been linked to improvements in blood lipid levels, a reduced tendency of thrombosis, blood pressure and heart rate improvements, and improved vascular function.
Omega-3 fatty acids, most notably DHA and EPA, have been linked to a wide-range of health benefits, including reduced risk of cardiovascular disease (CVD) and certain cancers, good development of a baby during pregnancy, joint health, and improved behaviour and mood.
Intakes of EPA plus DHA, and fish were assessed in 21,342 people aged between 20 and 65. Fish intakes ranged from 1.1 to 17.3 grams per day. Over the course of an average of 11.3 years, the researchers documented 647 deaths, of which 82 were linked to coronary heart disease, with 64 of these being heart attack.
According to the results, the highest average intake of EPA plus DHA (234 milligrams per day) was associated with a 51 per cent reduction in the risk of fatal CHD, compared to the lowest average intake (40 mg per day).
“In conclusion, in populations with a low fish consumption, EPA+DHA and fish may lower fatal CHD and [heart attack] risk in a dose-responsive manner,” wrote the researchers.
Source: Journal of Nutrition
“Marine (n-3) Fatty Acids, Fish Consumption, and the 10-Year Risk of Fatal and Nonfatal Coronary Heart Disease in a Large Population of Dutch Adults with a Low Fish Intake”
Authors: J. de Goede, J.M. Geleijnse, J.M. A. Boer, D. Kromhout, W. M.M. Verschuren
Eating a diet of plenty of oily fish daily can protect women against infertility, says a new study. Researchers have carried out the study of 70,000 nurses and found those who ate the most tuna, salmon, mackerel and other fish high in omega-3 fatty acids were nearly 22 per cent less likely to develop endometriosis which is known to causes infertility.
However, the study found that those whose diets were heavily laden with harmful transfats – chemically altered vegetable oils – found in thousands of products from cakes and biscuits to pies and chips were 48 per cent more at risk of developing endometriosis. The condition arises when cells normally found in the womb lining attach themselves to other parts of the pelvic area, causing inflammation and often leading to infertility.
The study, the largest to have investigated the link between diet and endometriosis, followed the nurses for 12 years from 1989. It found while the total amount of fat consumed did not matter, the type did.
Gynaecologist Dr Stacey Missmer, of Harvard Medical School, Boston, said her findings, not only suggest that diet may be important in the development of endometriosis but also provide more evidence for eliminating trans fats, which are used to bulk up foods and increase their shelf life.
“Millions of women worldwide suffer from endometriosis. Many have been searching for something they can do for themselves, or their daughters, to reduce the risk of developing the disease. These findings suggest dietary changes may be something they can do. The results need to be confirmed by further research, but this study gives us a strong indication that we are on the right track in identifying food rich in omega-3 oils as protective for endometriosis and trans fats as detrimental,” she said.
The study is published in the 'Human Reproduction' journal.