Health for life

Taking enough omega-3 fatty acid supplements to change the balance of oils in the diet could slow a key biological process linked to aging, new research suggests.

The study showed that most overweight but healthy middle-aged and older adults who took omega-3 supplements for four months altered a ratio of their fatty acid consumption in a way that helped preserve tiny segments of DNA in their white blood cells.

These segments, called telomeres, are known to shorten over time in many types of cells as a consequence of aging. In the study, lengthening of telomeres in immune system cells was more prevalent in people who substantially improved the ratio of omega-3s to other fatty acids in their diet.

Omega-3 supplementation also reduced oxidative stress, caused by excessive free radicals in the blood, by about 15 percent compared to effects seen in the placebo group.

“The telomere finding is provocative in that it suggests the possibility that a nutritional supplement might actually make a difference in aging,” said Jan Kiecolt-Glaser, professor of psychiatry and psychology at Ohio State and lead author of the study.

In another recent publication from this study, Kiecolt-Glaser and colleagues reported that omega-3 fatty acid supplements lowered inflammation in this same group of adults.

“Inflammation in particular is at the heart of so many health problems. Anything that reduces inflammation has a lot of potentially good spinoffs among older adults,” she said.

Study participants took either 2.5 grams or 1.25 grams of active omega-3 polyunsaturated fatty acids, which are considered “good fats” that, when consumed in proper quantities, are associated with a variety of health benefits. Participants on the placebo took pills containing a mix of oils representing a typical American’s daily intake.

The researchers say this combination of effects suggests that omega-3 supplements could represent a rare single nutritional intervention that has potential to lower the risk for a host of diseases associated with aging, such as coronary heart disease, Type 2 diabetes, arthritis and Alzheimer’s disease.

The study is published online and scheduled for later print publication in the journal Brain, Behavior, and Immunity.

Participants received either the placebo or one of the two different doses of omega-3 fatty acids. The supplements were calibrated to contain a ratio of the two cold-water fish oil fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), of seven to one. Previous research has suggested that EPA has more anti-inflammatory properties than DHA.

In the case of fatty acids, omega-3 supplementation alone doesn’t tell the whole story of how this dietary change can affect health, explained Martha Belury, professor of human nutrition at Ohio State and a co-author of the study. Also important is the ratio of omega-6 fatty acids to omega-3 fatty acids that are present in a person’s blood.

Omega-6 fatty acids come from vegetable oils, and since the 1960s, research has suggested that these oils, too, can help protect the cardiovascular system. However, the typical American diet tends to be heavy on omega-6 fatty acids and comparatively low in omega-3s that are naturally found in cold-water fish such as salmon and tuna. While the ratio of omega-6 to omega-3 fatty acids averages about 15-to-1, researchers tend to agree that for maximum benefit, this ratio should be lowered to 4-to-1, or even 2-to-1.

The long chains – or bigger molecules – that make up EPA and DHA fatty acids are believed to be the secret to their effectiveness, Belury said.

Both groups of participants who took omega-3 supplements showed, on average, lengthening of telomeres compared to overall telomere effects in the placebo group, but the relationship could have been attributed to chance. However, when the researchers analyzed the participants’ omega-6 to omega-3 ratio in relationship to telomere lengthening, a lower ratio was clearly associated with lengthened telomeres.

“The idea we were looking at with the ratio of omega-6 to omega-3 fatty acids was an increase in the denominator to make the ratio smaller. In the United States, we need to focus on the omega-3 part because we don’t get enough of those,” Belury said.

The researchers also measured levels of compounds called F2-isoprostanes to determine levels of oxidative stress, which is linked to a number of conditions that include heart disease and neurodegenerative disorders. Both omega-3 groups together showed an average overall 15 percent reduction in oxidative stress compared to effects seen in the placebo group.

When the scientists revisited their earlier inflammation findings, they also found that decreases in an inflammatory marker in the blood called interleukin-6 (IL-6) were associated with telomere lengthening. In their earlier paper on omega-3s and inflammation, they reported that omega-3 supplements lowered IL-6 by 10 to 12 percent, depending on the dose. By comparison, those taking a placebo saw an overall 36 percent increase in IL-6 by the end of the study.

“This finding strongly suggests that inflammation is what’s driving the changes in the telomeres,” Kiecolt-Glaser said.

Telomeres are a hot topic in science, and their tendency to shorten is associated with such age-related problems as heart disease and early mortality. These short fragments of DNA act as caps at the end of chromosomes, and can be likened to the protective plastic at the end of a shoelace.

“Anything that reduces inflammation has a lot of potentially good spinoffs among older adults.”

“If that plastic comes off, the shoelace unravels and it doesn’t work anymore,” said study co-author Ron Glaser, professor of molecular virology, immunology and medical genetics and director of the Institute for Behavioral Medicine Research (IBMR) at Ohio State. “In the same way, every time a cell divides, it loses a little bit of its DNA at the ends, and over time, that can cause significant problems.”

Kiecolt-Glaser noted that this population was disease-free and reported very little stress. The study included 106 adults, average age 51 years, who were either overweight or obese and lived sedentary lives. The researchers excluded people taking medications to control mood, cholesterol and blood pressure as well as vegetarians, patients with diabetes, smokers, those routinely taking fish oil, people who got more than two hours of vigorous exercise each week and those whose body mass index was either below 22.5 or above 40.

“People who are less healthy than this group, and especially those who experience chronic stress, may gain even more benefits from omega-3 supplementation,” she said.

Many brain-training companies tout the scientific backing of their products – the laboratory studies that reveal how their programs improve your brainpower. But according to a new report, most intervention studies like these have a critical flaw: They do not adequately account for the placebo effect.

The new analysis appears in the journal Perspectives on Psychological Science.

The results of psychological interventions, like medical ones, must be compared to improvements in a control condition, said University of Illinois psychology professor Daniel Simons, who co-wrote the article with Walter Boot, Cary Stothart and Cassie Stutts, of Florida State University. In a clinical trial for a new drug, some participants receive a pill with the critical ingredients, and others receive an identical-looking pill that is inert – a placebo. Because participants cannot tell which they received, people in each condition should be equally likely to expect improvements.

In contrast, for most psychology interventions, participants know whats in their "pill," Simons said.

"Its not possible to use a brain-training program for 10 hours without knowing the type of training you received," he said. "People can form expectations for what will improve based on their experiences with the training tasks, and the existence of differences in expectations between people in treatment and control groups potentially undermines any claim that improvements were due to the treatment itself. Not one of the studies cited by the brain-training companies looks at differing expectations between the groups."

Merely having an "active control group," one that does something for the same amount of time as the treatment group, does not protect against the placebo effect, Simons said. A treatment group that completes an intensive memory-training regimen might expect improved performance on other cognitive tasks assessing memory. A control group that does crossword puzzles or watches DVDs for the same amount of time likely wont expect the same amount of improvement on the same tasks, he said.

"These problems are not limited to brain-training studies," Simons said. "They hold true for almost all intervention studies."

To illustrate the pervasiveness of this problem, the researchers examined expectations for improvement in studies of the effect of playing action video games on measures of perception and attention.

"Such studies find greater improvements in performance on attention and perception tasks after training with action video games than after training with non-action games for the same amount of time," Boot said. "However, even with this sort of active control condition, these interventions still are at risk for differential placebo effects."

The researchers measured expectations in two survey studies involving 200 participants each. Participants watched either a short video of an action game ("Unreal Tournament") or one of the games commonly used as controls in these studies ("Tetris" or "The Sims"). They then read descriptions of the cognitive tests used in the studies, watched short videos of the tests, and answered questions about whether they thought their performance on the tests would improve as a result of training on the video game they had viewed.

The results showed that expectations for improvement were greater for the action-game group than for the control games on exactly the same tests that showed bigger improvements for action-game training in the intervention studies. In fact, the pattern of expected improvements exactly matched actual improvements seen in video game intervention studies, the researchers found.

"If expectations for improvement align perfectly with the actual improvements, then any claim that the treatment was effective is premature," Simons said. "Researchers must first eliminate differences in expectations across conditions."

"Even though participants in psychology interventions typically know the nature of their intervention – you cant play a video game without knowing the game youre playing – there are steps researchers can take to ensure that the advantages of the treatment group are not due to expectations," Boot said.

For example, researchers can mislead participants as to the expected benefits of a particular intervention, giving those in the control group higher expectations for improvement than those in the treatment group. Researchers also can assess expectations generated by treatments in a separate sample of participants to ensure that expectations do not differ between intervention and control treatments.

"Although placebo effects can be helpful as well, we need to know what causes improvements in an intervention," Simons said. "We dont want to recommend new therapies, change school curricula, or encourage the elderly to buy brain-training games if the benefits are just due to expectations for improvement. Only by using better active controls that equate for expectations can we draw definitive conclusions about the effectiveness of any intervention."

Since 1977, there has been a 70% increase in caffeine consumption among children and adolescents. Whether it is coffee, tea, soda, or energy drinks, our children are consuming more of it. One well documented effect of caffeine is improved cognitive performance on certain tasks. However, scientists also hypothesize that habitual caffeine use may lead to greater neural rewards if the caffeine drinker were to consume illicit drugs.

To add more to the research base regarding caffeines effect on cognition in children and teens, Jennifer Temple, PhD, University at Buffalo, recently investigated with graduate student Adam Graczyk whether male and female children perform differently on 5 separate tasks in response to caffeine. Using a sample size of 96 children and adolescents, they measured developmental and gender differences in subjects who were given caffeine or placebo and then put through memory tests, reaction time tests, and color-word tasks. The results showed that caffeine increased the number correct in the memory tests, and that females had more correct responses than males in simple reaction time and color-word tasks. There were also differences across the menstrual cycle in the females.

According to Temple, "This is the first study in children and adolescents to report sex differences in responses to caffeine on cognitive tasks as well as different responses according to the girls menstrual cycles. It suggests that if we look at caffeine as a model for illicit drugs, men and women respond differently because of circulating steroid hormones. Moving forward, this could be helpful in developing treatments for drug addictions based on gender." This poster will be presented at the American Society for Nutritions scientific sessions at Experimental Biology.

This study was funded by NIDA grant RO1 DA030386 and by the Gender Institute at the University at Buffalo.

Caffeine Pairing: A Potential New Way to Eat Your Veggies?

In a separate study addressing caffeine, Temple along with her PhD student Leah Panek wanted to find out whether pairing a flavored food (in this case yogurt) with caffeine consumption would increase ones perceived likeability of that food.

They tested whether a caffeinated beverage paired with a novel flavored yogurt would increase perence for that yogurt compared with placebo. A total of 68 men and women ages 18-50 were randomized to receive a beverage containing placebo or caffeine and then consumed a low energy density yogurt or high energy density yogurt. The flavors were not typical of yogurt in order to avoid any taste perences in place prior to the study; they included almond, maple, peppermint, pumpkin pie, raspberry-lemon, strawberry coconut, and savory (cumin).

Results showed that after rating and ranking the seven yogurts over 4 days, yogurt liking increased over time, with the yogurt paired with caffeine liked more than yogurt paired with placebo.

"Next wed like to do the same experiment with fruits and vegetables, in order to capitalize on the fact that people already consume caffeine," Temple said.

Imagine if you could learn to love the one vegetable you hate by administering caffeine!