NIH Evidence Report Confirms Benefits of Fish Oil
Fish oil can help reduce deaths from heart disease, according to new evidence reports by the Agency for Healthcare Research and Quality in a study financed by the National Institutes of Health. The systematic reviews of the available literature found evidence that long chain omega-3 fatty acids, the beneficial component ingested by eating fish or taking a fish oil supplement, reduce heart attack and other problems related to heart and blood vessel disease in persons who already have these conditions, as well as their overall risk of death. Although omega-3 fatty acids do not alter total cholesterol, HDL cholesterol, or LDL cholesterol, evidence suggests that they can reduce levels of triglycerides-a fat in the blood that may contribute to heart disease.
The review also found other evidence indicating that fish oil can help lower high blood pressure slightly, may reduce risk of coronary artery reblockage after angioplasty, may increase exercise capability among patients with clogged arteries, and may possibly reduce the risk of irregular heartbeats-particularly in individuals with a recent heart attack.
The evidence reports of the health effects of omega-3 fatty acids are part of a series conducted by AHRQ-supported Evidence-based Practice Centers at the request of the National Institutes of Health's Office of Dietary Supplements, which plans to use the findings to develop research agendas on the issues. Five reports are currently being issued, and an additional 6 reports will be issued next year.
Findings from the 3 other AHRQ evidence reviews indicate that:
* Omega-3 fatty acids do not affect fasting blood sugar or glycosylated hemoglobin in people with type 2 diabetes, nor do they appear to affect plasma insulin levels or insulin resistance.
* Alpha-linolenic acid (ALA), a type of omega-3 fatty acid from plants such as flaxseed, soybeans, and walnuts, may help reduce deaths from heart disease, but to a much lesser extent than fish oil.
* Based on the evidence to date, it is not possible to conclude whether omega-3 fatty acids help improve respiratory outcomes in children and adults who have asthma.
* Omega-3 fatty acids have mixed effects on people with inflammatory bowel disease, kidney disease, and osteoporosis and no discernible effect on rheumatoid arthritis.
Summaries of evidence reviews are available on AHRQ's Web site at http://www.ahrq.gov/clinic/epcindex. htm#dietsup and on the National Guideline Clearing-house Web site at http://www.guideline.gov (select "EPC reports"). Free printed copies are available from the AHRQ Publications Clearinghouse by calling 800-358-9295 or sending an e-mail to [email protected].
High-Calorie Diet May Lead to Prostate Enlargement
Although prostate cancer is the most common cancer in American men, prostate enlargement affects half of all men over age 50. Benign prostatic hyperplasia (BPH), or prostate enlargement, does not indicate prostate cancer risk by itself, but it occurs when normal prostate cells grow abnormally, and therefore it is considered a possible risk factor.
The risk factors for BPH are age and family history. Recent studies link high caloric intake, as well as diets high in protein and some polyunsaturated fats, with prostate enlargement. Researchers suggest that excess calorie consumption could somehow directly stimulate prostate enlargement through excess body fat and its effects on hormone levels. This is an active field for research at present, so stay tuned.