Monahan K, Wilson T, et al. Omega-3 Fatty Acid Supplementation Augments Sympathetic Nerve Activity Responses to Physiological Stressors in Humans. Hypertension 2004;44:732

An inverse relation exists between omega-3 fatty acid intake and risk of cardiovascular disease development/mortality and sudden cardiac death in humans. Mechanisms underlying this cardioprotective effect are unknown, but could involve the autonomic nervous system.

We tested the hypothesis that omega-3 fatty acid supplementation ("fish oil") would reduce muscle sympathetic nerve activity (MSNA) at rest and attenuate increases during physiological stressors. MSNA (peroneal microneurography) was measured during rest, ischemic handgrip to fatigue (IHG), and a cold pressor test (CPT).

Measurements were obtained before (PRE) and after (POST) 1 month of daily ingestion of either fish oil (experimental group, n=9) or olive oil capsules (control group, n=9). MSNA at rest was comparable PRE and POST in control (3±1 versus 3±1 bursts/30 seconds) and experimental (4±1 versus 5±1 bursts/30 seconds) subjects. IHG and CPT increased MSNA in both groups PRE and POST. MSNA, arterial blood pressure, and heart rate responses to the stressors were similar PRE and POST in the control group.

In contrast, MSNA responses to IHG (4±2 and 9±2 bursts/30 seconds; P<0.05 for PRE and POST, respectively) and CPT (4±1 versus 10±2 bursts/30 seconds; P<0.05) were augmented after omega-3 fatty acid supplementation whereas arterial blood pressure and heart rate responses were unchanged.

These data indicate that 1 month of omega-3 fatty acid supplementation does not change MSNA at rest but augments sympathetic outflow to physiological stressors. The mechanism underlying augmented MSNA responses to physiological stressors after omega-3 fatty acid supplementation is unknown, but may involve impaired peripheral vasoconstriction.

Hibbeln J, Nieminen L, Lands W. Omega-6 fat intake massively correlated to violence. Lipids 2004;39(12):1207-1213.

Clinical intervention trials and animal studies indicate that increasing dietary intakes of long chain n-3 FA or reducing linoleic acid intake may reduce aggressive and violent behaviors.

Here we examine if economic measures of greater n-6 consumption across time and countries correlate with greater risk of homicide.

Linoleic acid available for human consumption was calculated from World Health Organization disappearance data for 12 major seed oils in the food supply for the years 1961 to 2000 in Argentina, Australia, Canada, the United Kingdom, and the United States (US).

Homicide mortality rates, adjusted for age, were obtained from the central judicial authority of each country. Apparent linoleic acid intake from seed oil sources ranged from 0.29 en% (percentage of daily food energy) (Australia 1962) to 8.3 en% (US 1990s).

Greater apparent consumption of linoleic acid correlated with higher rates of homicide mortality over a 20-fold range (0.51-10.2/100,000) across countries and time in an exponential growth regression model (r = 0.94, F = 567, P < 0.00001).

Within each country, correlations between greater linoleic acid disappearance and homicide mortality over time were significant in linear regression models.

Randomized controlled trials are needed to determine if reducing high intakes of linoleic acid by seed oils with alternative compositions can reduce the risk of violent behaviors.

These dietary interventions merit exploration as relatively cost-effective measures for reducing the pandemic of violence in Western societies, just as dietary interventions are reducing cardiovascular mortality.

Low linoleate diets may prevent behavioral maladies that correctional institutions, social service programs, and mental health providers intend to treat.

Fish Oil Eases Depression Adding Supplement to Drug Therapy Reduces Symptoms
By Jennifer Warner
Reviewed By Michael Smith, MD
WebMD Medical News

It may sound fishy, but researchers say taking a daily fish-oil supplement may boost the effectiveness -- or even replace -- antidepressants for treating depression in some people.

In a new study, people who added a daily dose of omega-3 fatty acids to their regular antidepressant treatment had significant improvement in symptoms, including anxiety, sleeping problems, sadness, decreased sexual desire, and suicidal tendencies.

Although there are many effective treatments for depression, most only work in a limited number of patients or have significant side effects that prompt users to stop taking them. That's inspired researchers to look for new ways to treat the mental illness or increase the effectiveness of existing treatments.

Previous studies have suggested that depressed people have lower-than-normal levels of a fatty acid known as EPA (eicosapentaenoic acid), which plays an important role in maintaining normal brain function.

In this study, the researchers examined the effectiveness of adding various dosages of EPA supplement to normal drug therapy in 70 people with persistent depression that was not responding to standard antidepressants. The results appear in the October issue of the Archives of General Psychiatry.

Researcher Malcolm Peet, MD, of Swallownest Court Hospital in Sheffield, England, and colleagues found that patients who took the lowest, 1-gram daily, fish-oil dose showed significant improvements on all major measures of depression compared with those who took a placebo. In particular, 69% of the patients who took the 1-gram dose had a 50% reduction in their symptoms, compared with only 25% of those who took a placebo.

A 2-gram dose showed little effect, but those taking the highest, 4-gram, dose showed a trend toward improvement in symptoms. The researchers say larger studies are needed to confirm these effects.

The omega-3 fatty acid may work to ease depression by improving the effectiveness and absorption of existing medications, the researchers say. But they note that a limited number of their patients who are not on antidepressant therapy have seen improvements similar to those seen in this study through treatment with fish-oil supplements alone.

In addition, they say treatment with omega-3 fatty acid may be especially beneficial for depressed patients who are at risk for heart disease, in light of recent research about fish oil's heart-healthy effects.

Hamazaki K, Itomura M, et al. Effect of omega-3 fatty acid-containing phospholipids on blood catecholamine concentrations in healthy volunteers: a randomized, placebo-controlled, double-blind trial.
Nutrition 2005;21(6):705-710

OBJECTIVE: We previously reported that administration of fish oil rich in docosahexaenoic acid (DHA) increased the plasma ratio of epinephrine to norepinephrine (NE) at rest in young adults who were under chronic stress and that this effect was achieved mainly through depression of NE. However, not many reports have documented the effects of eicosapentaenoic acid (EPA) and DHA on blood catecholamine levels in healthy humans.

Therefore, we performed another intervention study to test their effect on catecholamines with healthy subjects under no chronic stress.

METHODS: Twenty-one healthy young adults (15 men and 6 women) were randomly assigned to an omega-3 group (n = 9) or a control group (n = 12) in a double-blind manner. Twenty capsules of shellfish-derived lipids containing 762 mg of EPA plus DHA per day were administered to the omega-3 group for 2 mo. The controls took the same amount of placebo capsules.

Fasting blood samples after a 30-min rest with a catheter in a forearm vein were obtained at the start and the end of the study for catecholamine measurements.

RESULTS: EPA but not DHA concentrations in red blood cells significantly increased in the omega-3 group compared with the control group (P < 0.001). Plasma NE concentrations were significantly decreased in the omega-3 group (from 1.49 +/- 0.39 nmol/L to 1.05 +/- 0.14 nmol/L) compared with the control group (from 1.12 +/- 0.24 nmol/L to 1.39 +/- 0.32 nmol/L) with analysis of covariance (P < 0.001).

The differences remained significant (P = 0.01) even after deletion of three subjects in the omega-3 group who had the highest baseline NE values and one in the control group who had the lowest baseline NE value to nullify a significant baseline differences in NE between groups.

CONCLUSION: This study demonstrated that EPA plus DHA supplementation lowered plasma NE concentrations in normal volunteers even at the small dose of 762 mg of EPA plus DHA per day.

This effect of EPA plus DHA to lower plasma NE concentrations may be important to understand some of the effects of fish oils on diseases.

By Stephen Mihm

Most prisons are notorious for the quality of their cuisine (pretty poor) and the behavior of their residents (pretty violent). They are therefore ideal locations to test a novel hypothesis: that violent aggression is largely a product of poor nutrition. Toward that end, researchers are studying whether inmates become less violent when put on a diet rich in vitamins and in the fatty acids found in seafood.

Could a salmon steak and a side of spinach really help curb violence, not just in prison but everywhere? In 2001, Dr. Joseph Hibbeln, a senior clinical investigator at the National Institutes of Health, published a study, provocatively titled "Seafood Consumption and Homicide Mortality," that found a correlation between a higher intake of omega-3 fatty acids (most often obtained from fish) and lower murder rates.

Of course, seeing a correlation between fatty acids and nonviolence doesn't necessarily prove that fatty acids inhibit violence. Bernard Gesch, a senior research scientist at Oxford University, set out to show that better nutrition does, in fact, decrease violence. He enrolled 231 volunteers at a British prison in his study; one-half received a placebo, while the other half received fatty acids and other supplements.

Over time, the antisocial behavior (as measured by assaults and other violations) of the inmates who had been given the supplements dropped by more than a third relative to their previous records. The control group showed little change. Gesch published his results in 2002 and plans to start a larger study later this year. Similar trials are already under way in Holland and Norway.

What would it mean if we found a clear link between diet and violent behavior? To start with, it might challenge the notion that violence is a product of free will. "But how do you exercise that free will without using your brain?" Gesch asks. "And how, exactly, is the brain going to work properly without an adequate nutrient supply?" The belief that people choose to be violent may be irrelevant if the brain isn't firing on all cylinders. This may especially be the case for impulsive acts of violence, which are less a choice than a failure to rein in one's worst instincts.

Consider, for example, a study conducted by researchers in Finland. They tested prisoners convicted of violent crimes and found that they had lower levels of omega-3 fatty acids than ordinary, healthy subjects. Why? Omega-3's foster the growth of neurons in the brain's frontal cortex, the bit of gray matter that controls impulsive behavior.

Having enough of these fatty acids may keep violent impulses in check. Violent criminals may not be the only ones who would benefit from more fatty acids in their diet. In a recent double-blind trial, when omega-3's were given to people with a history of substance abuse, the symptoms of "anger" fell by 50 percent.

Of course, omega-3's are widely hailed these days as a miracle substance, credited with boosting health in dozens of ways. But Gesch warns against what he calls "silver bullets." The state of the evidence, he says, "doesn't allow us to pinpoint which dietary fat is responsible for changes in behavior." In his new study, he will look into whether several interdependent nutrients may play a role.

Gesch further adds that we shouldn't expect nutrition alone to banish violent behavior. "The brain needs to be nourished in two ways. It needs to be educated, and it needs nutrients. Both social and physical factors are important." Simply throwing fish and vegetables at violent criminals is unlikely to have a lasting effect on its own.

Caveats aside, there's something that many people may find unnerving about the idea of curing violent behavior by changing what people eat. It threatens to let criminals evade responsibility for their actions. Think, for example, of the infamous "Twinkie defense," in which an accused murderer's lawyer suggested that junk food was partly to blame for his client's compromised mental state. More controversial, perhaps, is the brave-new-world idea of using diet to enforce docility and conformity to the rules, a sort of state-sponsored version of that timeless parental demand to children everywhere: "Eat your vegetables."

Then again, we already live in a society in which parents have resorted to drugs like Ritalin to quell unwanted outbursts and impulsive behavior. And when you approach it from that perspective, changing what people eat may not be so radical after all.

Stephen Mihm teaches history at the University of Georgia.
Source: http://www.nytimes.com/2006/04/16/magazine/16wwln_idealab.html?_r=1&oref=slogin

Fedorova I, Salem Jr. N, Omega-3 fatty acids and rodent behavior. Prostag Leukot Essent Fatty Acids,2006;75(4-5):271-289.

This paper reviews the role of the n-3 fatty acids in the regulation of cognitive functions, locomotor and exploratory activity and emotional status in rodents.

There are disparate data on the performance of n-3 fatty acid deficient animals in the open field test and elevated plus maze. Results obtained in our laboratory indicated slower habituation to the open field in deficient mice, which affects total locomotor and exploratory parameters.
We also observed no change in plus maze performance of deficient mice under low-stress but elevated anxiety under high-stress conditions. There is some evidence of elevated aggression and increased immobility time in the forced swimming test caused by n-3 fatty acid deficiency in rodents.

Effects of n-3 fatty acid deficiency and supplementation on learning in several tests such as the Morris water maze, two odor olfactory discriminations, radial arm maze performance and avoidance tasks are reviewed in detail.

There is some evidence of an enhanced vulnerability to stress of n-3 fatty acid deficient animals and this factor can influence performance in a variety of tests.

Thus, behavioral tasks that involve a higher level of stress may better differentiate behavioral effects related to brain docosahexaenoic acid (DHA) status. It is suggested that a fruitful area for future investigations of functional alterations related to brain DHA status will be the delineation of the factors underlying changes in performance in behavioral tasks.

The possible role of non-cognitive factors like emotionality and attention in the impaired performance of n-3 fatty acid deficient animals also requires further investigation.