June 2007 HEART HEALTH

Transcription

1 HEART HEALTH Taking a Statin? Adding Fish Oil May Boost Its Power Many people consume statin drugs to lower their blood LDL-cholesterol levels and reduce the likelihood of having a heart attack. However, statins have only a small effect on blood triglyceride (fat) levels. When triglycerides are elevated above normal, they increase the chance of heart disease. That s where fish oils rich in omega-3 fatty acids enter the picture. Fish oils lower blood triglyceride levels, especially in people with very high levels. Combining statins with fish oils might improve the blood lipids of patients with high cholesterol and triglycerides. The JELIS Study from Japan compared the effects of statin drugs alone or combined with EPA, an omega-3 fatty acid in fish oil, to see which treatment was more effective in improving patients blood lipids. This combined therapy has been evaluated in patients with high cholesterol and triglycerides and, as expected, improvements in the patients blood lipids were greater with both treatments than with either one alone. In addition, these treatments increased HDL-cholesterol levels, the so-called good cholesterol. A new report from Japan, known as the JELIS Study, compared the effect of statins alone or combined with purified eicosapentaenoic acid (EPA), one of the major long-chain omega-3 fatty acids in fish oil. Participating in the study were more than 18,000 men and women, on average 61 years old. Two-thirds were postmenopausal women, all had high cholesterol and triglyceride levels and most had coronary artery disease. Study participants consumed statins alone or statins plus 1.8 g/day of EPA. That is more EPA than in 2 servings of cooked salmon. At the end of 4½ years, patients consuming both statins and EPA had 19% fewer major coronary events, 19% fewer non-fatal coronary episodes (e.g., angioplasty, non-fatal heart attack) and 24% less unstable angina than patients taking only statins. Deaths did not differ in the 2 groups. When the investigators analyzed their results based on whether the patients had coronary artery disease, the effect of statins plus EPA was significant only in patients with coronary disease. As in many other studies, fish oil or omega-3 fatty acids reduced the chance of death or myocardial infarction mainly in patients with heart disease, not in those free of the condition. For this reason, omega-3 fatty acids are important for the secondary prevention of heart disease. After nearly 5 years, patients taking statins with EPA had fewer coronary events and less unstable angina than patients taking only statins. As other studies in Japanese patients have reported, this study did not find an effect of EPA on death from heart disease. However, other large studies have reported significant reductions in heart disease mortality with the consumption of fish oil or the omega-3 fatty acids found in fish oil. One reason for this discrepancy may be that people in Japan may have already obtained most of the heart health benefits associated with fish oils, because they consume fish frequently. Indirectly, the JELIS study confirms this view, as there were very few deaths in either group over the 5-year study period. Fish Oil EPA Slows Progress of Atherosclerosis in Diabetic Patients People with type 2 diabetes are more likely to develop heart disease, circulatory problems and damaged organs than people without the condition. Impaired blood circulation, particularly in the small blood vessels, contributes to damaged eyes, kidneys and feet. Thus, in caring for diabetic patients, doctors pay close attention to blood circulation. To date, there are not 1

2 many ways of improving the damaged blood vessels that develop in atherosclerosis and type 2 diabetes. Patients with type 2 diabetes who consumed nearly 2 g/day of EPA for 2 years experienced a reduction in the thickness of their carotid artery wall. In control patients, the artery wall became thicker. The fatty acids in fish oils, known as long-chain omega- 3s, are known to improve blood vessel function in patients with heart disease. They relax the muscles in the blood vessel walls, reduce inflammation and lower blood clotting. These properties make them good candidates for improving blood vessel function in type 2 diabetics. Accordingly, a team of Japanese investigators examined the effect of consuming nearly 2 g/day of EPA on the thickness of the carotid artery wall in diabetic patients. EPA is one of the major long-chain omega-3 fatty acids in fish oil. This dose is about the equivalent of 2 servings of salmon/day. Study participants consumed the omega-3 supplements for 2 years. Patients who were given standard medical treatment, but no supplements, were used for comparison. At the end of the study, patients consuming EPA had a significant decrease of 4.7% in the thickness of their carotid wall compared with an increase of 2.4% in patients receiving standard care. Measurements of blood flow also improved in the EPA patients. There was a small increase in glycosylated hemoglobin, a sensitive measure of elevated blood glucose, in the EPA group and a decrease in the control patients. While this outcome was undesirable, such values in individual patients would call for aggressive patient management. This finding indicates that diabetic patients who consume large amounts of fish oil should be regularly monitored by their doctors for blood glucose control. With regular check-ups, diabetic patients can obtain the heart and circulatory system benefits of fish oil without compromising their diabetes status. Overall, this study adds to the growing evidence that long-chain omega-3 fatty acids may slow the progression of atherosclerosis in patients with type 2 diabetes or coronary artery disease. Got Rhythm? High Fish Consumption Linked to Improved Electrocardiograms The traditional Mediterranean diet, high in fruits, vegetables, bread and cereals, beans, nuts, seeds, some fish and olive oil, is associated with lower incidence of several chronic diseases, including heart disease. It is often recommended as the basis for a healthy diet in western countries. Although Mediterranean food habits have many healthful components, it is not clear how substantial the contribution of fish is to the good health of Mediterranean people. Low consumption of red meats, dairy fats and processed foods may also contribute to their health. Regular fish consumption favorably affects the electrical properties of the heart in most people. Regular fish consumption favorably affects the electrical properties of the heart in most people. The oils in fish contribute to stable heart rhythms, thereby offsetting one of the underlying abnormalities in sudden cardiac death. This is believed to be one of the most important cardiovascular benefits of eating fish. Investigators at the University of Athens wished to find out whether fish consumption was related to the heart s electrical properties in middle-aged people living in Greece. They enrolled just over 3,000 inhabitants of the province of Attica, most of whom lived in Athens, who had no history of heart disease and were between the ages of 25 and 67. On average, participants were 50 years old. Participants had their diets evaluated and electrocardiograms taken. Ninety percent of the participants consumed fish at least once/week, mainly small fish, such as sardines. The investigators then evaluated the volunteers electrocardiograms according to the amount of fish the participants ate. The researchers homed in on the corrected QT interval an estimate of the ventricular (lower chamber of the heart) action potential because people with a prolonged QT interval are at higher risk of sudden death. The investigators observed a trend for decreasing QT interval with increasing fish intake in both men and 2

3 Figure. Segments of a normal electrocardiogram. women. When the analysis took into account several potential confounding factors (e.g., age, sex, smoking, physical activity, etc.), the QT interval remained inversely related to fish intake. In men and women consuming more than 300 g (nearly 11 ounces) of fish per week, the highest category of intake, the QT interval was 14% lower compared with participants who ate no fish. These observations confirm other studies where higher fish consumption has been associated with a lower chance of a prolonged QT wave and other desirable electrical properties of the heart, such as lower heart rate. However, not all studies agree. It is hoped that a study currently underway among survivors of a heart attack will solve some of the puzzles in the conflicting reports. Taking Fish Oil Omega-3s to Heart As several reports in this and previous issues of Fats of Life have described, the long-chain omega-3 fatty acids in fish and fish oils have favorable protective effects on the heart. One of the most striking is their ability to alter the heart s electrical properties. They make abnormal heart rhythms more stable, lower heart rate, improve heart rate variability a reflection of the heart s ability to handle a changing environment and most important, they lower the chance of sudden cardiac death. Unstable heart rhythms are the underlying cause of sudden cardiac death, the Taking a high dose of fish oil within 3 weeks of a heart attack can rapidly increase the content of DHA in the heart and reduce the chance of having a second one. most common cause of heart-related deaths. From this snapshot, it seems desirable to have these substances stashed in our hearts. In this study, researchers at the Royal Adelaide Hospital in Australia had the opportunity to measure the effects on heart tissue of consuming fish oil containing long-chain omega-3s or flax oil providing ALA* compared with the effects of olive oil. They wanted to know if you could raise the heart s content of omega-3s and whether there were differences in uptake among the various omega-3 fatty acids. Fish oils contain EPA* and DHA,* which are long-chain omega-3s, while flax oil contains ALA, a mediumchain omega-3. The patients in this study were undergoing coronary artery bypass surgery or valve repair. Prior to surgery, patients were invited to consume one of the oils for varying times (7 to 63 days) before their operation. Each of the omega- 3 oils contained a large dose of fatty acids, about 6 times more than a serving of salmon. You could call it omega-3 loading! A small sample of heart tissue was extracted during the surgery and analyzed for its fatty acid content. Prior to taking the fish or flax oil, the patients heart tissues contained about 10 times as much DHA (4.8%) as EPA (0.5%) and very little ALA (0.1%). Within 10 days of consuming fish oil, the DHA content increased by 41% to 6.8%, while the EPA content increased to 0.9%. Thus, the heart had a strong preference for DHA over EPA and accumulated this fatty acid more quickly. After about 3 weeks, the accumulation of DHA leveled off. Consuming fish oil for a month doubled the amount of EPA and DHA in heart tissue. * ALA, alpha-linolenic acid; EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid 3

4 In the patients taking flax oil, the ALA content of the heart nearly tripled, but was still low (0.3%). The EPA content increased with the consumption of flax oil, but was just a quarter of the EPA content achieved by Photo reproduced courtesy of the Alaska Seafood Marketing Institute. taking fish oil. DHA did not increase, confirming other reports that consuming flax oil does not raise DHA levels. Overall, consuming flax oil did not have any significant effect on the heart s content of long-chain omega-3s. Are these observations important? They could be lifesaving because the greatest likelihood of sudden cardiac death in heart attack survivors is the one-month period immediately after a heart attack. In those weeks, the chance of sudden cardiac death is 3 times greater than during the period from 1 to 6 months after a heart attack. By taking a high dose of fish oil right after a heart attack, a person can rapidly increase the content of DHA and EPA in the heart and reduce the chance of developing unstable cardiac arrhythmias. For those not facing heart surgery, a more gradual accumulation of EPA and DHA in the heart is possible through the regular consumption of fish or fish oil supplements. Boosting one s intake of long-chain omega-3s is worth taking to heart. MOTHERS & INFANTS Eating for Two: Extra DHA in Pregnancy Benefits Infants Visual Acuity One healthy outcome in infants, which is attributable to the mother s consumption of enough long-chain omega-3s during pregnancy, is improved visual acuity. Long-chain omega-3s are the polyunsaturated fatty acids found mainly in fish. One reason for this finding is that the retina of the eye avidly accumulates DHA, one of the main long-chain omega-3s. In the retina, DHA has a key part in transferring light energy to visual signals. Throughout life, retinal DHA content is important for good visual function. During fetal development, DHA is transferred selectively to the developing baby for use in the rapidly growing brain and eye among other functions. What happens if mothers do not eat fish or have low stores of DHA? Will their infants visual acuity be affected? A practical study conducted at the University of Connecticut, USA, suggests an answer. Infants whose mothers consumed DHA-enriched snack bars had significantly higher visual acuity scores at 4 months of age compared with infants whose mothers ate unenriched bars. The researchers recruited pregnant women who were not beyond 20 weeks gestation and randomly assigned them to 2 groups. Each received a cereal-based snack bar. The bars in the test group were enriched with 300 mg of DHA, the amount recommended by a working group of fatty acid experts. Control group mothers received unenriched bars that looked identical. When the infants were 4 and 6 months of age, the investigators assessed their visual acuity. The investigators found that at 4 months of age, the infants whose mothers consumed the DHA-enriched bars had significantly higher visual acuity scores compared with the infants whose mothers ate the unenriched bars. By the time the infants reached 6 months of age, their scores no longer differed. That result is not necessarily surprising, because visual acuity changes more slowly around that time. Further, the differences in visual acuity were apparent regardless of how the infants were fed after birth. This observation suggests that pregnancy is a critical period for the consumption of DHA, which can make a measurable difference to the infant s visual development. How much DHA did the study group mothers actually consume? On average, each mother obtained about 200 mg/day of DHA from the cereal bars. The rest of their diet provided only 80 mg, confirming what is well known: most pregnant women in western countries consume very little long-chain omega-3s. The amount 4

5 in the DHA-cereal bars was about equivalent to 2 servings of baked or broiled fish (e.g., salmon) a week. Increasing Long-Chain Omega-3 Intake in Pregnancy Benefits Mothers and Infants In countries where eating fish is common, women have plenty of omega-3s in their diets and tissues. But in most western countries, many women eat little or no fish, so their diets provide very little long-chain omega-3 fatty acids, the kind found almost exclusively in fish and shellfish. Pregnant women who eat little or no fish have few other food sources of omega-3s except for eggs and fish oil supplements. However, food manufacturers are adding omega-3 fatty acids to an array of foods and this should make these nutrients more widely available. In the last trimester of pregnancy and after birth, the mother s tissue levels of long-chain omega-3 fatty acids diminish. It is not clear how much omega-3s it would take to prevent this loss. What are the implications of low omega- 3 intakes for women and their children? During pregnancy, the developing fetus draws on its mother s supply of long-chain omega-3 polyunsaturated fatty acids (omega-3s) for its developing nervous system. The transfer of omega-3s from mother to fetus, especially of DHA, is greatest in the last trimester. DHA (docosahexaenoic acid), one of the key long-chain omega-3s, is especially concentrated in the brain and eye where it is critical for optimum function. As described in the preceding article, [Link] low maternal omega-3 consumption can affect the visual function of the infant, at least in the short term. The effects on the mother are less clear. In the last trimester of pregnancy and after birth, the mother s tissue levels of long-chain omega-3 fatty acids diminish. However, this loss of omega-3s can be prevented if the woman consumes fish often or takes a fish oil supplement. There is not much information, however, about how much a woman should consume. That could depend, in part, on her body stores. Consuming just a small amount of omega-3s was not enough to prevent the decline in omega-3s at the end of pregnancy. When large amounts of omega-3s were provided- the equivalent of eating fatty fish 3 to 4 times/day the loss of DHA was prevented and the amount transferred to the fetus was increased. Is there a happy medium? Mothers who consumed the equivalent of 3 servings of salmon/week maintained their blood levels of omega-3s at delivery and increased the amount found in cord blood. Findings from a study conducted in 3 European countries suggests there may be. A team of German researchers and their colleagues in other countries examined the effects of giving pregnant women a moderate amount of long-chain omega-3s from the first half of pregnancy until delivery. They examined the mother s blood DHA level and the amount of DHA in cord blood, a reflection of the infant s circulation. The amount provided, 650 mg of long-chain omega-3s, mostly as DHA, is equivalent to 3 servings of salmon a week. As you would expect, the mother s blood level of DHA increased significantly in the supplemented mothers, whereas in women consuming a placebo supplement, it fell. Thus, it took less than 1 g/day of long-chain omega-3s to prevent the decline in the mother s omega-3 status. Moreover, this level of supplementation increased the DHA in cord blood, providing more to the infant. Did having a higher blood DHA level at delivery help the mother? This study can t answer that question, because mothers were not followed after delivery. But it suggests that the supplemented mothers maintained their own reserves of omega-3s. There is some evidence that maternal diets low in long-chain omega-3s increase the chance of post-partum depression. This work suggests that boosting long-chain omega-3 intake throughout pregnancy is likely to help both mother and child. IMMUNE FUNCTION Beyond Skin Deep: Eating Fish in Late Pregnancy Lowers Chance of Infant Eczema An important question in efforts to reduce the likelihood of infant allergies is, Does the mother s exposure to potential allergens during pregnancy affect the 5

6 infant s allergic responses? This question is especially important to mothers whose infants are at high risk of developing allergies because of family history. Infants of mothers who ate fish frequently during the last month of pregnancy were the least likely to develop eczema, an itchy skin condition. In a recent study from Germany, researchers examined the relationship between the development of eczema and other allergies in children during their first 2 years of life and their mother s diet during the last month of pregnancy. Allergic sensitivity was assessed through blood tests of common food and inhaled allergens and the children s immunoglobulin E levels, an indication of immune response. The study included information on 2,500 healthy children. The prevalence of eczema (also called atopic dermatitis) and sensitization to allergens was nearly 18%. Food allergens were the most common type of allergy, affecting 9% of the children. Sensitivity to airborne substances was half as common, observed in 4.5% of the children. The mother s intake of citrus fruits was most frequently linked with the chance of food allergies in the children, whereas her consumption of raw sweet peppers was linked to sensitivity of inhaled allergens. Even more striking, infants of mothers who ate fish frequently in the last month of pregnancy were the least likely to develop eczema, an itchy skin condition. No other foods in the mother s diet during pregnancy were associated with lower risk of allergies. Readers should be aware that studies disagree about whether a mother s food habits increase the risk of allergies in her infant. Several studies have failed to find any links between the foods a mother eats during pregnancy and a greater risk of infant allergies. But evidence is growing that fish consumption protects against the development of allergies in young children. Why this might be so is unclear. Some have suggested that the oils in fish increase the maturation of the infant s immune system, making it better able to handle the adjustment to air and solid foods. Maternal Fish Intake in Pregnancy May Reduce the Child s Chance of Eczema How important is a mother s food habits during pregnancy in affecting her child s chance of developing allergies? A group of investigators in the Netherlands wondered if there were particular foods consumed during pregnancy that might be linked to the risk of allergies in children. To find out, they obtained information from about 1,200 mothers about their diets during pregnancy, their history and current allergy sensitivities and the presence of allergies in their children at the age of 5. The most common childhood allergy was eczema, confirmed in 30% of the children. Hay fever and asthma occurred less frequently, affecting about 17% to 25% of the children, respectively. A mother s consumption of apples during pregnancy increased the chance of eczema in her child at age 5, whereas eating fish once or more times/week reduced the likelihood by 70%. In the mothers food patterns, two foods stood out: apples and fish. Eating apples was associated with greater frequency of eczema, whereas fish consumption one or more times/ week was linked to a 70% lower chance of eczema when the children were 5 years old. Consumption of oily fish once or more times/week was not related to eczema, but was linked to a reduced chance of having hay fever. The investigators also noted that the child s intake of these foods had no bearing on the chance of developing these allergies. These associations remained strong even after the researchers adjusted for a variety of other conditions, such as maternal history of allergies, smoking, breastfeeding and many others. Neither of these food links between childhood eczema and maternal consumption of apples or fish indicates that these foods cause allergies. To determine whether these foods actually have a causal link to allergies, studies comparing groups of pregnant women who do or do not eat these foods during pregnancy would have to be undertaken. The usefulness of this study, however, is to identify foods that deserve closer attention as potential foods to avoid or indulge. This study supports several other reports linking fish and fish oils to the development of childhood allergies. To complicate the matter, other contradictory reports about fish consumption and allergies suggest that there is much more to unravel 6

7 before we understand the complexities of diet and immune function. Does Fish Oil Hasten Immune System Maturation in Infants? Exposure to fish or the long-chain omega-3 fatty acids they contain alters immune responses in infants, young children and adults. For infants and children at greater risk of developing food and environmental allergies, finding ways to lower the chance of these conditions would improve their health and quality of life. It is only recently that scientists have reported links between what mothers eat during pregnancy and the development of allergies in their offspring. Fish consumption is emerging as a possible protective factor. The foundation of the immune system is set during fetal life. Immune function continues to mature through the first few years of childhood. During this process, the balance of the T helper (Th) cells, a type of immune cell from the thymus gland, shifts from predominantly Th-2 to Th- 1 (Figure). Some Figure. Simplified illustration of mature Th-1 helper cells. Image Russell Kightley Media. believe this maturation may be key to developing effective defenses against allergens from the air and food. They note that children with allergies have a different ratio of Th-2 and Th-1 cells from non-allergic children. Another difference in allergic children is altered polyunsaturated fatty acids, particularly higher levels of the omega-6 polyunsaturated fatty acids, the kind found in many vegetable seeds and oils. However, studies with varying polyunsaturated fatty acid intakes in children have yielded conflicting results. In this Danish study, researchers gave 9-month old infants a fish oil supplement for 3 months and compared several of their immune responses with those In 9-month old infants consuming fish oil for 3 months, levels of substances made by Th-1 cells, typical of a more mature immune system, were greater than in infants not receiving fish oil. in infants not given any supplement. Infants consumed either standard infant formula or whole cow s milk. The investigators found that the infants who consumed fish oil had twice the production of interferon-gamma, a product of Th-1 cells, as infants not receiving fish oil. This observation would be consistent with a greater shift to Th-1 cells and more mature immune function. Although other evidence from the study was consistent with this observation, large variations in the responses prevented conclusions about them. The study used high levels of fish oil, but the infants showed no signs of impaired immune responses or adverse effects. These suggestive findings will likely encourage further examination of the processes in immune maturation. MENTAL HEALTH Improved Attention, Activity and Impulsiveness in ADHD Children Given Fish and Primrose Oils Children with ADHD have shown improved behaviors following the consumption of fish oil supplements. However, in studies using a combination of treatments the results cannot be attributed to a single treatment. Hope that help is on the way for youngsters with attention deficit hyperactivity disorder (ADHD) comes from promising studies of fish oil supplementation. In one large study, British children with attention and learning problems had improved reading and spelling scores after they consumed fish oil supplements. Some studies have provided children a combination of treatments, but this approach means the results cannot be attributed to a single treatment. For example, providing ADHD children with vitamin and mineral supplements plus fish oil clouds the results. Recognizing these difficulties, researchers in Adelaide Australia designed a study among 7

8 ADHD children aged 7 to 12 years where the effect of fish oil with a small amount of evening primrose oil was evaluated separately from the effect of vitamins and minerals. The study had 3 groups: one with fish and evening primrose oils, a second with the oils plus vitamin and minerals and a third given only a placebo supplement. The study tested whether vitamins and minerals would alter the findings observed with only the fish oil supplement. The children were not taking any medications. The children consumed the supplements for 15 weeks. After this time, the placebo group was switched to consume the fish oil supplement and the study continued for another 15 weeks. This strategy allowed the investigators to see whether the placebo children s behaviors would be affected after they took the fish oil and whether there would be any further change with an additional 15 weeks of supplementation. Children s behaviors were assessed by parents and teachers independently. After the first 15 weeks, children consuming the fish oil and the fish oil plus vitamins and minerals showed significant improvement in their attention, hyperactivity and impulsive behaviors compared with the placebo group. These 3 behaviors are the hallmark characteristics of ADHD, so they represent important responses to the supplement. Other assessments, such as oppositional behavior, cognitive problems and the ADHD index also improved. There were no differences between those taking just the fish oil and those consuming the fish and primrose oils plus vitamins and minerals. At the end of 30 weeks, the placebo group children, who had been switched to take the oil supplement, showed significant improvements in attention, hyperactivity and impulsive behaviors similar to the other children in the first 15 weeks. The children who continued to Children with ADHD who consumed fish oil and small amounts of evening primrose oil for 15 weeks had significant improvements in inattention, hyperactivity and impulsive behavior. Continued intake for another 15 weeks led to further improvements. take the fish oil supplements for another 15 weeks showed further improvements in these behaviors as well. This suggests that longterm supplementation is necessary to achieve maximum benefits. One unexplained observation in the study is that the improved behaviors were noted only in the parents ratings, not in those of the teachers. Why this is so is unclear, as teachers ratings are sometimes preferred. On the other hand, up to half the children showed positive changes in behavior by the time the study ended and the extent of the improvements was as much as 50% or more in some assessments. This study is among the most promising to date and supports the case for including fish oils in the treatment of ADHD. Feeling Down? Maybe It s Time for a Fat Checkup People who eat fish often are less likely to develop depression, according to studies comparing the rates of depression with fish intake across many countries. In addition, people diagnosed with depression often have low levels of long-chain omega-3 fatty acids, the kind found in fish. We do not know, however, whether low levels of these omega-3s are a prelude to the condition or might affect its occurrence. To shed some light on these possibilities, a team of researchers at the University of Pittsburgh examined a group of adult volunteers with high cholesterol levels who were participating in another study. None of the participants had a history of psychiatric illness or other serious ailments. Study participants with high levels of DHA, one of the main omega-3s found in fish, had higher scores for agreeableness and were the least likely to have high depression scores. The investigators conducted several psychological assessments in the volunteers and checked their blood levels of polyunsaturated fatty acids. They observed that participants with 8

9 higher depression scores (less favorable) were more likely to have low levels of long-chain omega-3s than those whose depression scores were low. In contrast, participants with high levels of DHA, one of the main omega- 3s found in fish, had higher scores for agreeableness and were the least likely to have high depression scores. Of course, higher depression scores among healthy adults do not necessarily mean these individuals are clinically depressed. But these observations suggest there is a spectrum of psychological scores ranging from normal to clinical that moves in the opposite direction from people s long-chain omega-3 status. The higher a person s omega-3 status, the lower the chance of poorer psychological assessments. If these observations were confirmed in other studies, it would suggest that boosting one s omega-3 status could help protect both the heart and mind. Brain Volume in Key Areas Linked to Omega-3 Intake: Is Bigger Better? A swelled head has its disadvantages, but selectively increased brain volume might be a plus. That is the implication from a report relating brain measurements in middle-aged people to their intake of long-chain omega-3 fatty acids, the kind found predominantly in fish. The impetus for this study came from the wish to monitor changes in living brain tissue under various conditions. There are, at present, very few ways of doing this. The only way to verify the diagnosis of some neurodegenerative conditions, particularly Alzheimer s disease, is from tissue pathology after death. It would be helpful to be able to establish an early diagnosis and monitor the effectiveness of treatment. Magnetic resonance imaging machine. Image courtesy of Siemens AG. With that idea in mind, researchers at the University of Pittsburgh, USA, applied magnetic resonance imaging (MRI) to a sample of healthy middle-aged volunteers from whom they also collected dietary information. The MRI technique creates a 3-dimensional image of the brain using radio waves. These soft tissue measurements can be compared against norms and tracked over time to see whether treatments have affected particular areas of the brain. In this study, the University of Pittsburgh researchers related researchers observed that estimates of the volume of specific brain the volume of 3 regions in the brain was related to regions to the volunteers intake of longchain omega-3s. They the consumption of longchain omega-3s. Volume observed a significant was greater in people who association between consumed more omega-3s. the participants consumption of omega-3s and the volume of 3 regions in the cortex, including the right hippocampus. This is the main region affected by Alzheimer s disease. It is also known that the levels of DHA, one of the main long-chain omega-3s, are substantially reduced in the hippocampi of Alzheimer s patients. Further, low intakes of fish and DHA are associated with a greater chance of developing the disease. Now the researchers need to find out whether changes in brain volume occur during the progression of Alzheimer s and other degenerative brain diseases. This study could be important for improving the diagnosis of various brain diseases if these observations are confirmed by others and by direct measurements. It would be especially helpful to learn whether changes in brain volume are directly related to dietary changes, such as increased consumption of omega-3s or DHA. This study may not have given the brain a work-out, but it may be able to tell whether you are keeping your brain in shape. CLINICAL CONDITIONS Alzheimer s Disease New Ways Omega-3 DHA Fights Alzheimer s Disease Some factors within a person s control can influence the development of Alzheimer s disease. One of these is fish consumption. Fish are the richest food source of long-chain omega-3s and DHA, a type of omega-3 9

10 Evidence continues to accumulate indicating that DHA is especially important in maintaining brain cell function and protecting against Alzheimer s disease. polyunsaturated fatty acid found almost exclusively in fish. People who eat fish regularly are less likely to develop the disease. Scientists have also learned that the amount of DHA in the brain region most damaged by Alzheimer s is substantially lower in people with the disease. Moreover, DHA is used to make a substance that helps protect brain cells from the damage and destruction that occurs once the disease sets in. Evidence continues to accumulate indicating that DHA is especially important in maintaining brain cell function and protecting against Alzheimer s disease. Studying Alzheimer s disease in humans is difficult because few techniques can be used in people. For that reason, scientists use animal models to examine the effects of different interventions, especially diet. In a study conducted at the University of California in the U.S., researchers examined the effects of different long-chain polyunsaturated fatty acids over the course of the progression of Alzheimer s disease. They used a mouse model of the condition to evaluate diets enriched in DHA or DHA plus either of 2 omega-6 fatty acids. They focused their attention on the development of the abnormal proteins that accumulate in the brains of Alzheimer s victims. In the early stages of the disease, the animals eating fats typical of western diets began accumulating betaamyloid, one of the abnormal proteins characteristic of the disease. By comparison, all the animals consuming diets with DHA had significantly lower levels of abnormal beta-amyloid. At the mid-stage of the disease, the control animals continued to increase their brain content of the abnormal protein as did the animals consuming DHA plus AA, the predominant long-chain omega-6 fatty acid found in the brain. This suggests that AA overrides the effect of DHA in reducing the beta amyloid protein. In contrast, animals fed the DHA-enriched diet or DHA plus a different omega-6 fatty acid (DPA) had significantly lower levels of abnormal protein. They appeared to be protected from the build-up of beta-amyloid. Finally, at the last stage of the disease, only animals fed the DHAenriched diet had lower abnormal beta-amyloid levels. Thus, the protective effects of omega-6s observed in the early stages of the disease had completely disappeared in the end stages. On the other hand, DHA retained its protective effects throughout the course of the disease, although its effects weakened with time. This study also At all stages of the disease, DHA explored several other pro- greatly reduced the build-up of two abnormal proteins found cesses involving the abnor- in Alzheimer s patients. When the omega-6 fatty acid AA mal proteins in was added, the effect of DHA Alzheimer s disease. In these, was abolished. The brain usually contains both DHA and too, DHA exhibited protective AA, but the content of DHA is effects. With reduced in Alzheimer s patients. animal studies, one always wonders whether the findings mean something for people. Even though these results were obtained in animals, the disease processes examined in this study mimic those in the human condition. Thus, the findings could lead to the development of medications aimed at halting the progress of this insidious disease. The study also increases our understanding of how DHA affects Alzheimer s disease and supports the growing evidence that increased DHA consumption just might be the best insurance against this scourge of aging. Age-Related Macular Degeneration Omega-3 DHA May Keep You Seeing Through the Looking Glass Clearly As we age, many body functions reveal the toll of time. Eyesight dims, hearing fades and footsteps shorten. While glasses, hearing aids and fitness programs combat these insults, there are some ways to prevent or slow down the effects of aging. To maintain good eyesight, food choices can make a big difference. That conclusion has become clear from studies of agerelated macular degeneration (AMD), the most common cause of vision loss after age 65. Some 1.8 million people in the U.S. have AMD and another 7 million are at risk for it. 10

11 A long-running study on AMD and nutrients found that vitamins C and E, beta-carotene and the mineral zinc as well as certain carotenoids found in plants, lutein and zeaxanthin, help reduce the likelihood of developing AMD. Adequate intake of vitamin D or exposure to sunlight, which generates vitamin D in the skin, may also be useful. Non-smokers have an advantage, too, as smokers have 4 times the chance of developing AMD as non-smokers. The latest dietary link to a substantially lower chance of AMD is long-chain omega-3 polyunsaturated fatty acids. These are the omega-3s found almost exclusively in fish. Investigators at the National Eye Institute in Bethesda, Md., USA, report on the relationship between the consumption of DHA, a long-chain omega-3, and the chance of developing severe AMD. The 4,500 volunteers participating in this study had some degree of AMD, ranging from very early to advanced disease. Their consumption of DHA was Many nutrients are linked to lower chance of advanced agerelated macular degeneration (AMD). These include vitamins C and E, beta-carotene and the mineral zinc. Other carotenoids in plants, lutein and zeaxanthin help lower the chance of AMD. Figure. Loss of central field vision typical of AMD. Image courtesy of the Center for the Partially Sighted. determined from food intake questionnaires. When the investigators analyzed the relationship between DHA consumption and AMD, they observed that participants with the highest DHA intakes were the least likely to develop advanced AMD. Among participants eating 2 servings of fish/week, the chance of advanced disease was 40% lower. However, DHA consumption was not related to the chance of early stage AMD. The researchers also identified high intakes of arachidonic acid, a long-chain omega-6 fatty acid found mainly in meats, poultry, eggs and fish, as increasing the chance of developing advanced AMD by 1½ times. This observation suggests that these two long-chain fatty acids are out of balance in the typical diets of these volunteers. Western diets usually contain large amounts of linoleic acid, an omega-6 fatty acid that the body converts to arachidonic acid. The typical western diet is also low in omega-3s and this pattern of dietary fats is considered askew by many experts. The easiest way to improve the intake of these fats is to include more fish, especially fatty fish, to boost long-chain omega-3s and eat less vegetable and salad oils made from corn, soy and safflower oils to lower one s omega-6 intake. Bone Health Eating More Fish Might Build Stronger Bones As people live longer, the prevalence of osteoporosis increases and with it the occurrence of bone fractures. The suffering and setbacks caused by fractures, especially among the elderly, exact an enormous toll on health, quality of life and the cost of care. As osteoporosis is the leading cause of fracture, it has become urgent to halt the deterioration of bone health that leads to this condition. According to the National Osteoporosis Foundation, 1 in 2 women over the age of 50 will fracture a bone in her lifetime. So will 1 in 4 men. Osteoporosis is a bone disease resulting from the loss of bone mineral density and deterioration in bone architecture (Figure). It affects 4 times more women than men. This is because after menopause, the lack of estrogen facilitates the loss of bone mineral. Men lose bone mineral too, but because they have more dense bones to begin with, osteoporosis develops in them later in life. Since the consequences of osteoporosis are so great and millions of older adults are at risk, it is important to slow 11

12 and blood fatty acid measurements. Then, they analyzed the data for relationships between blood fatty acids and changes in bone mineral density. Figure. Normal (left) and osteoporotic bone (right). Photos courtesy of and the Norman Endocrine Surgery Clinic. the loss of bone mineral in older adults. Diet, physical activity, not smoking and medication to increase bone calcium are the most common tactics. Eating well for bone health means having plenty of calcium and vitamin D (from sunshine or dietary supplements), abundant fruits and vegetables, and moderate amounts of protein. This list may grow to include longchain omega-3 polyunsaturated fatty acids, if the findings from research in animals and people continue to expand. In the report described here, young men with higher intakes of long-chain omega-3s had higher spine bone densities than young men with low intakes. Researchers at Umea University in Sweden decided to investigate the effect of long-chain omega-3 consumption in young men whose bone density was still increasing. They recruited 17-year-old volunteers from schools and sports clubs and monitored them for 8 years. At enrollment, the investigators measured the men s bone mineral density in several locations and collected blood samples. Eight years later, they repeated the bone density After 8 years, the increase in bone density in spine was significantly related to higher blood levels of total omega-3s and DHA, one of the main long-chain omega-3s found primarily in fish. Bone density was greater in men with higher blood levels of arachidonic acid, a long-chain omega-6 fatty acid. Upon further analysis, taking into consideration the volunteers weight, height and physical activity, total bone mineral density was related only to total omega-3s, DHA and EPA, another long-chain omega-3. These observations are important for several reasons. The study is one of only a few in humans and it relied on the gold standard measurement of bone health- -bone mineral density. The study also related bone density to blood fatty acid measurements, a more reliable indicator of omega-3 status than dietary assessments. Third, the study observed that dietary factors could positively affect bone mineral density in young men. This indicates that adolescence is an ideal time to boost mineral deposition in bone. Greater bone density means stronger bones and more mineral reserves to see one through the changes that come later in life. It is tempting to speculate that long-chain omega-3s might increase bone mineral density in older people, too. This possibility remains to be fully evaluated, but there is some evidence they might. In older adults, the dynamics of bone metabolism changes so that bone removal exceeds bone building. It would strengthen the march against osteoporosis if omega-3s were to tilt the balance toward greater bone density. Editor: Joyce A. Nettleton, DSc, joyce@fatsoflife.com Communications Manager: Angela Dansby, angela@fatsoflife.com Sponsor: DSM Nutritional Products, Inc., Kaiseraugst, Switzerland, Subscribe to the Fats of Life Newsletter at