Headlines (Scroll down for complete stories):
1. Tilapia Contains Possibly Dangerous Omega-6 Fatty Acids
2. Antidepressants Tied to Gastrointestinal Bleeding
3. Treating Blood Pressure May Help Prevent Dementia
4. More Sex Means Less Chance of ED
5. Food Diary Can Double Weight Loss
1. Tilapia Contains Possibly Dangerous Omega-6 Fatty Acids
Farm-raised tilapia, one of the most highly consumed fish in America, has very low levels of beneficial omega-3 fatty acids and, perhaps worse, very high levels of omega-6 fatty acids, according to new research from Wake Forest University School of Medicine.
The researchers say the combination could be a potentially dangerous food source for some patients with heart disease, arthritis, asthma and other allergic and auto-immune diseases that are particularly vulnerable to an “exaggerated inflammatory response.” Inflammation is known to cause damage to blood vessels, the heart, lung and joint tissues, skin, and the digestive tract.
“In the United States, tilapia has shown the biggest gains in popularity among seafood, and this trend is expected to continue as consumption is projected to increase from 1.5 million tons in 2003 to 2.5 million tons by 2010,” write the Wake Forest researchers in an article published this month in the Journal of the American Dietetic Association.
They say their research revealed that farm-raised tilapia, as well as farmed catfish, “have several fatty acid characteristics that would generally be considered by the scientific community as detrimental.” Tilapia has higher levels of potentially detrimental long-chain omega-6 fatty acids than 80-percent-lean hamburger, doughnuts and even pork bacon, the article says.
“For individuals who are eating fish as a method to control inflammatory diseases such as heart disease, it is clear from these numbers that tilapia is not a good choice,” the article says. “All other nutritional content aside, the inflammatory potential of hamburger and pork bacon is lower than the average serving of farmed tilapia.”
The article notes that the health benefits of omega-3 fatty acids, known scientifically as “long-chain n-3 polyunsaturated fatty acids” (PUFAs), have been well documented. The American Heart Association now recommends that everyone eat at least two servings of fish per week, and that heart patients consume at least 1 gram a day of the two most critical omega-3 fatty acids, known as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).
But, the article says, the recommendation by the medical community for people to eat more fish has resulted in consumption of increasing quantities of fish such as tilapia that may do more harm than good, because they contain high levels of omega-6 fatty acids, also called n-6 PUFAs, such as arachidonic acid.
“The ratio of arachidonic acid (AA) to very long-chain n-3 PUFAs (EPA and DHA) in diets of human beings appears to be an important factor that dictates the anti-inflammatory effects of fish oils,” the researchers write. They cite numerous studies, including a recent one that predicts “that changes in arachidonic acid to EPA or DHA ratios shift the balance from pro-inflammatory [agents] to protective chemical mediators … which are proposed to play a pivotal role in resolving inflammatory response” in the body.
The researchers found that farmed tilapia contained only modest amounts of omega-3 fatty acids – less than half a gram per 100 grams of fish, similar to flounder and swordfish. Farmed salmon and trout, by contrast, had nearly 3 and 4 grams, respectively.
At the same time, the tilapia had much higher amounts of omega-6 acids generally and AA specifically than both salmon and trout. Ratios of long-chain omega-6 to long-chain omega-3, AA to EPA respectively, in tilapia averaged about 11:1, compared to much less than 1:1 (indicating more EPA than AA) in both salmon and trout.
Floyd H. “Ski” Chilton, Ph.D., professor of physiology and pharmacology and director of the Wake Forest Center for Botanical Lipids, is the senior author of the Journal article. “We have known for three decades that arachidonic acid is the substrate for all pro-inflammatory lipid mediators,” Chilton said in an interview. “The animal studies say unequivocally that if you feed arachidonic acid, the animals show signs of inflammation and get sick.
Chilton said tilapia is easily farmed using inexpensive corn-based feeds, which contain short chain omega-6s that the fish very efficiently convert to AA and place in their tissues. This ability to feed the fish inexpensive foods, together with their capacity to grow under almost any condition, keeps the market price for the fish so low that it is rapidly becoming a staple in low-income diets.
“Cardiologists are telling their patients to go home and eat fish, and if the patients are poor, they’re eating tilapia. And that could translate into a dangerous situation.”
Editor's Note:
2. Antidepressants Tied to Gastrointestinal Bleeding
A class of drugs used by many people to treat depression may increase chances of gastrointestinal bleeding, although the risk remains low, Spanish researchers said on Monday.
The research looked at antidepressants known as selective serotonin reuptake inhibitors, or SSRIs, and found that bleeding in the upper gastrointestinal tract is more common in people taking them than in those not doing so. The study indicated that taking acid-suppressing drugs cut the risk.
The study also found a heightened risk for such bleeding in people taking Wyeth's Effexor, also called venlafaxine, another type of antidepressant called a serotonin and norepinephrine reuptake inhibitor, or SNRI.
The researchers stressed that such bleeding remains uncommon in people taking SSRIs or Effexor, and people taking them generally should continue to do it.
"The risk in the general population taking SSRIs is very low -- 1 case in 2,000 patients treated -- and no specific action is required if the antidepressant is correctly indicated by a physician," Dr. Francisco de Abajo of the Spanish Agency for Medicines and Healthcare Products, who helped lead the study in the Archives of General Psychiatry, said by e-mail.
"People with other relevant risk factors for GI bleeding should be considered for protecting their stomach with acid-suppressing agents. By no means, patients treated correctly with SSRIs should discontinue their treatment because of the fear (of having) a GI bleeding risk," de Abajo added.
Such risk factors for gastrointestinal bleeding include a peptic ulcer or being elderly, he said.
Some SSRIs include: Forest Laboratories Inc's Celexa (citalopram); GlaxoSmithKline's Paxil (paroxetine); Pfizer Inc's Zoloft (sertraline); and Prozac, introduced by Eli Lilly and Co in 1987 but now off patent and widely available generically as fluoxetine.
De Abajo said he was involved in research published in 1999 suggesting an increased risk of GI bleeding in people taking SSRIs, but that other studies had questioned that finding.
This study involved 1,321 people treated for upper gastrointestinal tract bleeding and about 10,000 people of the same age and sex who did not have such bleeding.
It found that 5.3 percent of the people with such bleeding were taking SSRIs, while 3.0 percent of the people who did not have such bleeding were taking SSRIs. In addition, 1.1 percent of the people who were had bleeding were taking Effexor, compared to 0.3 percent of those who did not have bleeding.
The risk was even higher in people taking SSRIs and other drugs harmful to the GI tract such as pain relievers known as non-steroidal anti-inflammatory drugs, or NSAIDs.
Copyright Reuters
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3. Treating Blood Pressure May Help Prevent Dementia
Treating high blood pressure in the very elderly may help reduce their risk of developing dementia, researchers said on Monday.
Blood pressure treatment in the over-80 set has already been shown to reduce risk of heart problems and fatal strokes.
"There may be an additional benefit in terms of prevention of dementia," said Dr. Ruth Peters of Imperial College London, whose study appears in the journal Lancet Neurology.
The findings were based on a new analysis of a study of nearly 4,000 people that was among the first to show the benefit of offering treatment for high blood pressure to people over 80, a group often overlooked in medical studies.
That study found patients whose high blood pressure was treated with a diuretic, with or without a second blood pressure drug called an ACE inhibitor, had a reduced risk of death from stroke and death from any cause.
Several studies have found a link between high blood pressure and dementia, which is marked by a loss of memory and other cognitive abilities, including the ability to speak, identify objects or think abstractly.
The latest analysis looks at whether treatment of high blood pressure helped to stave off dementia.
Participants had no clinical diagnosis of dementia at the start of the trial. Their cognitive function was assessed at the start and then each subsequent year with a standard test called the mini-mental state examination.
The trial was halted early because death and stroke rates had fallen so much it would have been unethical not to offer blood pressure medication to everyone in the study.
"Anything that can help reduce dementia incidence is important," Peters said. "The population of the elderly are growing. The very elderly are the fastest-growing section of the elderly and at high risk from dementia," she said.
Because treatment for high blood pressure has already been shown to help reduce the risk of strokes and heart problems, any reduction in dementia would be an added benefit, she said.
More than 5 million Americans have Alzheimer's disease, the most common form of dementia, accounting for 60 to 80 percent of cases. The second most common form is vascular dementia, which is often caused by strokes.
Copyright Reuters
Editor's Note:
4. More Sex Means Less Chance of ED
There's new advice for older men who want to preserve their sexual function: have sex, and have it often, researchers say.
In a study that followed nearly 1,000 older Finnish men for five years, researchers found that those who were regularly having sex at the start of the study were at lower risk of developing erectile dysfunction (ED) by the study's end.
In fact, the more often the men had sex, the lower their ED risk.
The implication, say the researchers, is that men should be encouraged to stay sexually active into their golden years.
Dr. Juha Koskimaki and colleagues at the University of Tampere in Finland report the findings in the American Journal of Medicine. The study included 989 men who were between the ages of 55 and 75 at the outset.
Overall, those who said they had sex less than once per week were twice as likely to develop ED over the next five years as men who had sex at least once a week. Furthermore, compared with men who had sex three or more times per week, their ED risk was increased nearly four-fold.
A number of factors contribute to ED development, many of which could also affect a man's sexually activity -- such as age, diabetes and heart disease. However, after taking account of those factors, sexual activity itself remained linked to ED risk, Koskimaki's team found.
It may be a matter of "use it or lose it," according to the researchers. Just as exercise boosts physical fitness, they note, regular sexual activity may help a man preserve his erectile function.
ED occurs when there are problems with blood flow to the penis. Regular sexual activity, Koskimaki's team writes, may help maintain healthy blood vessel function in the erectile tissue.
SOURCE: American Journal of Medicine, July 2008.
Copyright Reuters
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5. Food Diary Can Double Weight Loss
Keeping a food diary can double a person’s weight loss according to a study from Kaiser Permanente’s Center for Health Research. The findings, from one of the largest and longest running weight loss maintenance trials ever conducted, will be published in the August issue of the American Journal of Preventive Medicine.
Funded by the National Heart, Lung and Blood Institute at the National Institutes of Health, the study is one of the few studies to recruit a large percentage of African Americans as study participants (44 percent). African Americans have a higher risk of conditions that are aggravated by being overweight, including diabetes and heart disease. In this study, the majority of African American participants lost at least nine pounds of weight, which is higher than in previous studies.
“The more food records people kept, the more weight they lost,” said lead author Jack Hollis Ph.D., a researcher at Kaiser Permanente’s Center for Health Research in Portland, Ore. “Those who kept daily food records lost twice as much weight as those who kept no records. It seems that the simple act of writing down what you eat encourages people to consume fewer calories.”
In addition to keeping food diaries and turning them in at weekly support group meetings, participants were asked to follow a heart-healthy DASH (a Dietary Approaches to Stop Hypertension) diet rich in fruits and vegetables and low-fat or non-fat dairy, attend weekly group sessions and exercise at moderate intensity levels for at least 30 minutes a day. After six months, the average weight loss among the nearly 1,700 participants was approximately 13 pounds. More than two-thirds of the participants (69 percent) lost at least nine pounds, enough to reduce their health risks and qualify for the second phase of the study, which lasted 30 months and tested strategies for maintaining the weight loss.
“More than two-thirds of Americans are overweight or obese. If we all lost just nine pounds, like the majority of people in this study did, our nation would see vast decreases in hypertension, high cholesterol, diabetes, heart disease and stroke,” said study co-author Victor Stevens, Ph.D., a Kaiser Permanente researcher. For example, in an earlier study Stevens found that losing as little as five pounds can reduce the risk of developing high blood pressure by 20 percent.
“Keeping a food diary doesn’t have to be a formal thing. Just the act of scribbling down what you eat on a Post-It note, sending yourself e-mails tallying each meal, or sending yourself a text message will suffice. It’s the process of reflecting on what you eat that helps us become aware of our habits, and hopefully change our behavior,” says Keith Bachman, MD, a Weight Management Initiative member.
“Every day I hear patients say they can’t lose weight. This study shows that most people can lose weight if they have the right tools and support. And food journaling in conjunction with a weight management program or class is the ideal combination of tools and support.”
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