North Main ‘road diet’ work to begin tonight

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Work is scheduled to start tonight on a controversial “road diet” that will reduce North Main Street’s four car lanes to two lanes with a center turn lane.

The road diet will create room for bike lanes on a stretch of North Main Street on Ashland’s north side that runs from Helman Street out to Jackson Road, which is near a railroad overpass.

A crew from the Portland-area-based contracting company SPM will work nights from 8 p.m. to 6 a.m. on the project, said Ashland Public Works Director Mike Faught.

The job to blast off old road stripes and apply new ones will last an estimated five nights, although SPM has until Monday, Oct. 22, to finish the work, Faught said.

SPM will remove stripes and add new ones in sections, he said.

The new lane configuration will be tested for one year to see if it provides more room for bicyclists and pedestrians without causing major traffic woes.

Some residents have welcomed the chance to add bike lanes to North Main Street as it comes into Ashland, but others have said it will lead to traffic congestion.

Some neighbors also are concerned about plans to restrict left turns at three intersections along North Main Street, which they have said will cause more traffic in neighborhoods as drivers seek out intersections that allow left hand turns.

Faught said that car, bicycle and pedestrian data was analyzed before the road diet goes into effect. Various measurements will continue to be taken — including bicycle and pedestrian counts and the time it takes to drive through the reconfigured part of North Main Street.

“We feel confident that this will work, but at the same time, we’ll monitor it,” he said.

The total cost for engineering and on-the-ground work to remove old stripes and add new ones for the road diet is an estimated $174,000.

The city of Ashland is paying $15,000 for the road diet, with Oregon Department of Transportation grants covering the remaining $159,000, Faught said.

The Ashland City Council voted to approve the road diet in 2011, but first wanted a dangerous intersection fixed where Hersey Street and Wimer Street join North Main Street.

Work on that $1 million intersection fix wrapped up at the end of September. Federal funding paid for $682,696 of the cost, with the city delaying repaving projects in other parts of town to cover the rest.

Crews realigned Hersey Street and Wimer Street so that they would face each other directly as they join North Main Street.

The side streets had not lined up, which caused vehicle collisions when people tried to negotiate that intersection.

Faught said the intersection was the most problematic in town, and he thanked affected property owners, drivers and residents for their cooperation during the intersection realignment.

To make room for the intersection realignment, neighboring business Colwell Chiropractic had to have a new parking area built farther away from Hersey Street.

The project also included putting overhead power lines underground and building new bike lanes on Hersey Street, retaining walls and new alley access from Lori Lane to North Main Street, according to city officials.

Staff reporter Vickie Aldous can be reached at 541-479-8199 or vlaldous@yahoo.com.

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3 Diets Worth Checking Out

Each year, dozens of new diet programs hit the market. Most of them are completely useless, as they focus on short-term weight loss at the expense of the dieter’s health.

However, dieting isn’t always a bad idea. Here are three scientifically valid diets that can help you cut weight if you follow them to the letter.

The Virgin Diet – This three-cycle diet removes inflammatory foods and replaces them with good fats such as olive oil.

Oddly enough, the “virgin” in the diet’s name has nothing to do with olive oil. The Virgin Diet was developed by J.J. Virgin, PhD, who believes that seven highly reactive foods cause the majority of weight instability issues. Those foods include eggs, gluten, soy, dairy, corn, peanuts and sugar.

The first phase involves completely removing these foods from your diet. Any amount of the food could trigger problematic inflammation. In the second phase, you find the foods that are causing digestive and weight-gain issues. The third phase involves weeding these foods out of your diet and re-introducing the non-problematic foods.

We like the Virgin Diet because it shows long-term results. It’s not a crash diet, and because every dieter customizes the program based on their own bodies’ reactions to problematic foods, it’s highly effective for all participants.

P90X Nutrition Plan – You’ve probably seen the infomercials for this workout system. It’s extreme, and it works–just as any everyday workout plan would help you lose weight–but the P90X nutrition plan is probably the most important aspect of the entire program. If you’re not ready for a hefty workout, you can still add some cardio to your everyday routine while following the nutrition plan for results.

This is a low-carb, high-protein diet that focuses on strict calorie counts that give you exactly what you need for high energy. It also cuts out a lot of harmful substances that could aggravate your body and make exercise more difficult, so if you’re already working out, this diet plan is worth a try.

Calorie Counting – There are several websites such as CalorieCount and MyFitnessPal that allow you to track your own calories. Cutting your calories safely takes a lot of work and some careful tracking, but online tools make it easier to keep track of what you’re putting into your body.

Many dietitians recommend keeping a diet journal, so even if you’re not ready to use an online tool, try tracking your foods and portions on a notepad. You’ll quickly identify your problem foods, and by substituting unsaturated fats for saturated fats and cutting your calories, you can quickly see results.

This article is an original contribution by Dane Thompson.

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Joe Biden Debate Prep Diet: Candy, Energy Drinks And Animal Crackers?

Paul Ryan may be a fitness and health nut, but it seems Joe Biden could have a somewhat opposing strategy: the Obama campaign released some light-hearted information about Vice President Joe Biden’s preparation this week in Wilmington, Del. It apparently included a steady diet of junk food. Reported Politicker’s Hunter Walker:

Apparently, Mr. Biden relied on a strict regimen of candy, sandwiches, energy drinks and caffeine to get him in shape for his matchup with Republican vice presidential nominee Paul Ryan.

According to the White House pool report, the VP may have gotten his strength thanks to a steady stream of MMs, animal crackers, Gatorade, coffee, tea and subs from a popular sandwich shop called Capriotti’s.

So what’s with the carb-loading? Long, exhausting mock debates could have left everyone feeling tired and studies show that people crave junk food even more when they are sleepy. That’s Healthy Living’s pet theory anyway. While we’ll never know if there was a method behind all the added sugar or oversized sandwiches, it seemed to have little impact on the well-performing incumbent. While there obviously isn’t a study on junk food and presidential debate performance, studies in school children suggest that long-term junk diets affect academic performance, though there’s little evidence to suggest an occasional binge would do the same.

Want more about Joe Biden? Here’s photos of his reactions from last night:

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Mediterranean diets have great health benefits

Mediterranean and low-carbohydrate diets have long-lasting positive effects even with partial weight regain, according to a follow-up study by researchers from Ben-Gurion University of the Negev (BGU) and Israel’s Nuclear Research Center.

The results were published as an update to the landmark study, the workplace-based Dietary Intervention Randomized Controlled Trial (DIRECT), a tightly controlled 24-month dietary intervention.

“Our follow-up subsequent data shows lasting, positive effects of Mediterranean and low-carbohydrate diets six years later,” said Dr. Dan Schwarzfuchs from the Nuclear Research Center Negev in Dimona, Israel,

The results suggest that the lipid profile (lower cholesterol, triglycerides and arteriosclerosis) improved for the long term, regardless of partial regain.

“Data from trials comparing the effectiveness of weight-loss diets are frequently limited to the intervention period,” explained BGU Prof. Iris Shai.

Overall six-year weight loss was significantly lower from baseline for Mediterranean and low-carbohydrate diets, but not for the low-fat group.

In the four-year post-intervention, participants regained nearly six pounds. Total weight change for the entire six-year period was approximately -7 lbs. for the Mediterranean diet and -3.7 lbs. for the low-carbohydrate diet.

After four years post-intervention, more than two-thirds (67 percent) of the DIRECT participants had continued with their original assigned diet, 11 percent switched to another diet and 22 percent were not dieting at all.

The researchers also found that after six years, the HDL/LDL ratio remained significantly lower only in the low-carbohydrate diet. Triglyceride levels remained significantly lower in the Mediterranean and low-carbohydrate diets. Overall, total cholesterol levels remained persistently and significantly lower in all diet groups as compared to baseline.

In the original study, 322 moderately obese subjects were randomly assigned to one of three diets: low-fat; restricted-calorie; Mediterranean; or low-carbohydrate, non-restricted-calorie, and were provided colour-labelled food per diet daily in the workplace cafeteria.

The two-year adherence rate was 85 percent. The results suggested beneficial metabolic effects to low-carb and Mediterranean diets. Moreover, the researchers found a significant diet-induced regression in the carotid vessel wall volume across all diet groups. This change was mainly dependent on diet-induced reduction of blood pressure.

“This breakthrough, even years later, continues to yield valuable information that can help every one of us make healthier diet choices,” said Doron Krakow, executive vice president of American Associates, Ben-Gurion University of the Negev.

“It is another example of BGU and Israeli researchers, thanks to generous funding by the Atkins foundation, improving the quality of our lives,” Krakow added.

The results were published in a peer-reviewed letter in the current New England Journal of Medicine (NEJM).

Diet drink consumption increasing

The percentage of men and women consuming diet drinks increased over the past 10 years.

Diet Rich in Tomatoes May Reduce Stroke Risk

A long-term study has found that people who routinely eat a lot of tomatoes are less likely to suffer strokes.  Tomatoes are rich in lycopene, an antioxidant that scientists believe reduces the risk of heart disease.  

Researchers followed the dietary habits of more than 1,000 men living near the University of Eastern Finland.  The subjects were divided into four groups based on how much lycopene was measured in their blood at the start of the study.  After more than a dozen years, there were 25 strokes in a group of 258 men with the lowest levels of lycopene, compared to just 11 strokes in the high-lycopene group of 259 males, a reduction in stroke risk of 55 percent.

Larry Goldstein, director of the Duke University Stroke Center in Durham, North Carolina, believes lycopene may reduce the risk of stroke by protecting cells against the damaging effects of free radicals.  These are harmful molecules produced by the breakdown of food and toxic environmental substances such as tobacco smoke and radiation.  Experts say antioxidants can reduce the inflammation and blood clotting that can lead to stroke.

Goldstein says lycopene is a powerful antioxidant.

“Having said that, other ..compounds in that class really haven’t been associated with reduced risk of stroke.  So, again, this is an area for further research,” said Goldstein.

Lycopene is the substance in fruits and vegetables that gives them their bright red or orange color, including not only tomatoes but red peppers, papayas and watermelon.
 
Goldstein cautions that studies such as the one carried out in Finland have to be repeated to confirm the results.  He says participants questioned at the beginning of the study a dozen years ago may not remember what they ate over the course of the investigation, and the findings would need to be repeated in different populations – and in groups of women, as well – to draw any firm conclusions.

What has been established, according to Goldstein, is that taking lycopene supplements does not appear to reduce the risk of stroke.

“So it may be something else that we are not measuring that really is leading to the better outcomes,” he said.

The American Heart Association recommends a daily diet of five servings of fruits and vegetables, including tomatoes.

An article on lycopene and the reduced risk of stroke is published in the journal Neurology.

Knox St. “road diet” effectively calms traffic, improves safety

Patrick Kennedy of Walkable Dallas-Fort Worth


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Balancing the infrastructure correlated with increased pedestrian activity.


Knox Street before the road diet that reduced it from a four lane road to two travel lanes with a shared center turn lane.

Photo by Patrick Kennedy

Knox Street before the “road diet” that reduced it from a four lane road to two travel lanes with a shared center turn lane.

— As you may know, Knox Street was identified on the Dallas Complete Streets plan as a road suitable for being, ahem, “completed.” The gist of a complete street is that it isn’t just for cars, but the infrastructure is essentially balanced for all forms of transportation.

Though Knox is not well-served by mass transit, to complete it without significant changes to the public transportation system, means a road diet. In this case, the road diet took a four lane road and reduced it to two travel lanes in each direction and a shared center turn lane. The leftover space from the removal of the fourth lane became a two-way cycle track, effectively extending the Katy Trail onto Knox as “an urban detour.”


During the road diet, traffic predictably slowed all along Knox where it was installed.

Photo by Patrick Kennedy

During the “road diet,” traffic predictably slowed all along Knox where it was installed.

Throughout the country, similar road diets such as this one have proved to effectively calm traffic, improve safety, and actually move MORE vehicles with no evidence of any negative economic impact (usually there is economic improvement, but these numbers are harder to come by. This is why I often point out that traffic isn’t necessarily a bad thing. Places need energy. But to create a center of gravity that energy must be “condensed into a slow vibration,” to paraphrase from physics). Though this seems counter-intuitive, there are two primary reasons: 1) the place is more desirable when it is safer, so more people are attracted to it, and yes, drive there, and 2) the slowed traffic reduces headways between vehicles thereby increasing its overall capacity as more cars can fit on the road. As people drive slower, drivers feel more comfortable being within 2-3 car lengths of other vehicles. There is adequate stopping time and even if something were to happen, at such low speeds, damage would be minimal.

Because I knew this was happening, I decided to take speed readings before the installation and after. Here was my methodology:

    Data readings before and during the road diet demonstration were taken at similar times from 12-2pm on a weekday.

    Data readings taken shortly after installation was complete, but before any of the programmed festivities so as to avoid distortions to the data.

    Measurements were taken using a handheld radar gun from behind vehicles so as to avoid detection and subsequent unnatural slowing thinking I might be 5.0

    Vehicular speed measurements were ONLY recorded when there were no break lights present and a green light ahead so as to record only “full speed.”

RESULTS

The ranges shown in black at each segment of road show the full range of speeds on those particular street segments.

No vehicle moved along these segments at speeds greater or lower than these ranges with two exceptions. There were only two exceptions. One was a Porsche heading towards Highland Park at 27 mph and the other was an SUV heading towards 75 at 24 mph.

These are shown in brackets next to the segment where it was recorded.

In red parentheses is the reduction in speed on average per segment.

Predictably, traffic slowed all along Knox where the road diet was installed.

Interestingly, the vehicle speeds as cars entered Knox was the same as before, but then slowed noticeably as they approached McKinney Ave., where the start of the road diet was visible.


This section of Lemmon Avenue ranks 0 for integration because there is no pedestrian crossing.

Photo by Patrick Kennedy

This section of Lemmon Avenue ranks “0” for integration because there is no pedestrian crossing.

NOTES

    The vast majority of vehicles actually moved slower than above, as most approached red lights or used their brakes. As noted, these were not recorded.

    During the time of recording, traffic generally moved at a steady flow, generally 1-3 car lengths apart. Stacking at red lights rarely over a few cars at a time.

    Choke points/backups/conflicts occurred not at intersections but at mid-block alleys, curbcuts, and crossing traffic into on-street parking.

    There were more pedestrians present at this time than before, though not in overwhelming numbers. Also, it was 92 degrees during, and 98 degrees when the Before measurements were taken.

    The right turn only lane from Knox to McKinney was critical in reducing conflicts.


This section of Greenville Avenue ranks a 1 because pedestrians can cross, but only at control points, such as crosswalks and intersections.

Photo by Patrick Kennedy

This section of Greenville Avenue ranks a “1” because pedestrians can cross, but only at control points, such as crosswalks and intersections.

How “Tethered” is the street?

A street can be considered knitted together based on the degree to which pedestrians are willing to cross a road for various reasons including cross-shopping, an intricate component to synergy of place. How knitted a street is, is a measure of inherent pedestrian comfort and confidence in their safety.

    A road where pedestrians do not cross at all can be considered to have 0 knitted value.

    Where they cross only at control points, such as crosswalks and intersections is a 1.

    Where pedestrians cross at desire lines, a road can be considered to have a ‘knitted’ value of 2.


This section of Main Street can be considered to have a knitted value of 2 because pedestrians cross at desire lines.

Photo by Patrick Kennedy

This section of Main Street can be considered to have a “knitted” value of 2 because pedestrians cross at desire lines.

Based on observation, it is believed that Knox as it is currently designed and operating generally functions as a 1 or slightly below. When pedestrians cross, they will use the crosswalks at signalized intersections. However, there seems to be little evidence of cross-shopping, partially due to tenant mix/location, and partially due to road design.

During the demonstration project however, pedestrian crossing at intersections was rare as most crossed where they pleased, at desire lines between origin and destination. Though pedestrian activity at the time was relatively low (compared to Main Street as shown above, though higher than normal), it operated closer to a 2. As traffic speeds were suitably reduced by the demonstration road diet to below 20 mph, pedestrians felt more comfortable to cross the street without using crosswalks or waiting for the crossing signal.

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Great White Shark Diet is More Than Seals

A shark-bitten elephant seal rests on an Año Nuevo State Park Beach. Photo by the author.

Late last year, while on a tour of California’s Año Neuvo State Park, I saw a shark attack victim lying on the beach. She was a Northern elephant seal, and looked quite placid despite the gaping, crescent-shaped hole in her neck. She bore the traumatic hallmark of the great white shark.

Years of watching Discovery’s Shark Week taught me that seals and sea lions are the preferred prey of Carcharodon carcharias. Nothing like blubber to fuel the body of a constantly-swimming predator with a physiology that runs hotter than that of the average shark. I remember one researcher likened baby elephant seals, in particular, to hot dogs – the bread of the snack corresponds to the fat content of the young pinnipeds, making the weener seals easy-to-catch and energy-rich mouthfuls for the sharks.

When the sensational documentaries weren’t showing awful re-enactments of great white shark attacks on humans, they brought their cameras in close to seal kills. The programs took a philosophy similar to the fictional marine biologist Matt Hooper in JAWS – all great white sharks do is swim and eat. (Yes, yes, “and make little baby sharks”, but I have yet to see that on basic cable.) If they aren’t chomping people, then they strip the fat from seals. We think of them in the typological way that we approach many species. Great white sharks eat seals and sea lions. That’s all that there is to it.

But great white sharks don’t live on a strict diet of marine mammals. Study sites situated near pinniped colonies, as well as nature films, have restricted our view of what great white sharks feed on. In actuality, great white sharks consume different prey based upon age, size, and location. When they are just pups, for example, the leviathans-to-be seek out a wide variety of smaller fare before graduating to more difficult menu options. And, as a new paper indicates, many sharks retain their cosmopolitan tastes as they age.

A great white shark. Photo by Terry Goss, image from Wikipedia.

In a PLoS One study published this week, University of Wyoming researcher Sora Kim and colleagues used chemical clues in great white shark vertebrae to track feeding preferences among fifteen individuals collected between 1957 and 2000. The logic behind their technique is simple, and has been used on a variety of other creatures – living and extinct – to outline diet. As an animal feeds, chemical tracers in the form of carbon and nitrogen isotopes become incorporated into their teeth and bones. There is a correspondence between certain carbon isotope ratios and particular food sources. Match the chemical signature in the consumer in with the isotopic profile of what’s being consumed, and you can reconstruct an animal’s diet.

Even better, shark vertebrae contain long-running records of these isotopes. As great white sharks grow, their vertebrae accrete new rings on a yearly schedule. Each ring, therefore, holds a chemical snapshot from a year in the shark’s life. By comparing the isotope ratios in different vertebral bands, Kim and collaborators were able to follow how the diets of individual sharks shifted during their lives.

Contrary to assertions that pinnipeds are a great white shark staple, the fish sampled in the study were highly variable. Both age and individual variation were at play in their diets. For example, five sharks in the sample showed the expected shift from a diet of fish and small prey to marine mammals and other more substantial fare at about age four. But this wasn’t true of all sharks. Five other sharks in the same sample showed no difference between juvenile and adult diet. These sharks may have scavenged pinniped carcasses or fed on large squid while young, giving them an “adult” feeding profile at a young age. There are some possible confounding factors with this hypothesis – such as young sharks inheriting an adult isotope signal from their mothers – but the researchers appear to favor the idea that some sharks were more precocious in their prey choices than others of their kind. Not all great white sharks follow the same life history.

While Kim and colleagues point out that some sharks followed the expected dietary switch, the change was not the dominant signal in their results. Many of the Pacific great white sharks they sampled were generalists who took different prey in varying locations. Some sharks were nearshore marine mammal specialists, but others had more flexible foraging approaches. And even though the isotopic data are not refined enough to tell us exactly what species the sharks were eating, the cataloged chemical traces are enough to detect distinct dietary patterns.

The study raises new questions about great white shark biology. For one thing, why did the sharks have such individualistic diets? Competition may be the key, Kim and co-authors hypothesize. Imagine if all adult great white sharks were seal specialists who congregated at the same beaches. There may not be enough food for all, and swimming in the same waters as bigger, more experienced sharks would be risky for smaller novices who could wind up as meals themselves. By being flexible – able to tackle elephant seals as well as squid, tuna, and other food sources – great white sharks may lessen competition with their own kind.

As the researchers behind the new study state, further isotopic studies and satellite tracking programs may help marine biologists better understand the ecology of their prodigious fish. For now, though, one thing is clear. The sharks weren’t all cruising near shore, looking up for seal silhouettes. Great white sharks have much more varied tastes than blood-spattered basic cable shows would have you believe.

Reference:

Kim SL, Tinker MT, Estes JA, Koch PL (2012). Ontogenetic and Among-Individual Variation in Foraging Strategies of Northeast Pacific White Sharks Based on Stable Isotope Analysis PLoS One DOI: 10.1371/journal.pone.0045068

Illegally labeled diet, immune-boosting pills ‘potentially dangerous,’ report …

Dozens of weight loss and immune system supplements on the market are illegally labeled and lack the recommended scientific evidence to back up their purported health claims, government investigators warn in a new review of the $20 billion supplement industry.

The report, being released Wednesday by the Department of Health and Human Services’ inspector general, found that 20 percent of the 127 weight loss and immune-boosting supplements investigators purchased online and in retail stores across the country carried labels that made illegal claims to cure or treat disease.

Some products went so far as to state that the supplements could cure or prevent diabetes or cancer, or that they could help people with HIV or AIDS, which is strictly prohibited under federal law.

Consumers may not just be wasting their money on pills or tablets, but they could be endangering their health if they take a supplement in place of a drug thinking it will have the same effect, the report concluded.

“Consumers rely on a supplement’s claims to determine whether the product will provide a desired effect, such as weight loss or immune support,” the report said. “Supplements that make disease claims could mislead consumers into using them as replacements for prescription drugs or other treatments for medical conditions, with potentially dangerous results.”

The market for dietary supplements — which can include anything from Vitamin C tablets to capsules of Echinacea — is a huge one with hundreds of products. The inspector general’s investigation focused on one segment that officials said is booming.

Federal regulations do not require the Food Drug Administration to review supplement companies’ scientific evidence for most of their products’ purported health benefits before they hit the market.

The Office of Inspector General found that in numerous cases, when companies did submit evidence to back up their health claims, it fell far short of government recommendations.

One company submitted a 30-year-old handwritten college term paper to substantiate its claim, while others included news releases, advertisements and links to Wikipedia or an online dictionary, according to the report.

Overall, the review raises questions about whether the system is allowing companies to mislead consumers, investigators said, and recommended that FDA ramp up its oversight. The report did not name individual brands or products, and also did not estimate the total number of dietary supplements on the market.

In response, the food safety agency said it would consider asking Congress for more oversight powers to review supplement companies’ evidence proving their products’ purported health benefits. FDA agreed that the agency should expand surveillance of the market to detect spurious claims that supplements can cure or treat specific diseases.

Investigators also found that 7 percent of the weight loss and immune support supplements they surveyed lacked the required disclaimer stating that FDA had not reviewed whether the statement on the label was truthful.

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Questioning the Superpowers of Omega-3 in Diets

Name the affliction—heart disease, Alzheimer’s, arthritis, depression, asthma—and omega-3 fatty acids can help prevent it.

Or not.

That is the confusion being stirred up by new research on omega-3s, fats found in cold-water fish and plant oils that have intrigued nutrition scientists ever since the 1970s discovery that Greenland Eskimos rarely die from heart disease, despite a diet of fatty fish.

Some 21% of U.S. adults report using omega-3 fish-oil supplements, according to the Council for Responsible Nutrition, an industry trade group, making it the most popular supplement after multivitamins and vitamin D.

But last month, the Journal of the American Medical Association published a meta-analysis of 20 clinical trials involving nearly 70,000 people that found that omega-3 fatty acids didn’t prevent heart attacks, strokes or deaths from heart disease. Other recent studies in the New England Journal of Medicine and the Archives of Internal Medicine found that omega-3 supplements didn’t prevent heart problems in people with Type 2 diabetes or a history of heart disease.

Experts say such studies should be viewed with caution—just like studies with positive findings.

Critics noted that the JAMA study combined clinical trials that used different doses and sources of omega-3s. Many of the subjects were also on heart medication, which may have blunted the impact. Plus, diet studies are also notoriously imprecise. “It’s impossible for five researchers to control the diet of almost 70,000 patients over several years,” says Duffy MacKay, the CRN’s vice president for scientific and regulatory affairs.

What’s more, the JAMA authors imposed an unusually strict standard for statistical significance. Using the typical standard, the analysis would have concluded that omega-3 supplements are associated with a 9% reduction in cardiac deaths.

“My colleagues are writing letters to the editor about this,” said University of Pennsylvania nutritionist Penny Kris-Etherton, a spokeswoman for the American Heart Association. She says, for now, the association will continue recommending that everyone eat omega-3 rich fish at least twice a week; people with heart disease or high triglycerides could also consider taking fish-oil supplements under a doctor’s care. The American Psychiatric Association and the World Health Organization have similar advice.

Omega-3 fatty acids are essential for building cell membranes and maintaining the connections between brain cells. They also may reduce inflammation,increasingly recognized as a cause of chronic diseases.

Humans can’t produce omega-3 fatty acids, so we must get them from outside sources. The two most important kinds—EPA and DHA—are primarily found in fish such as salmon, sardines, tuna and herring; a third kind, ALA, is found in walnuts, flaxseed, soybean oil and some green vegetables, including Brussels sprouts, spinach and kale.

The typical American diet is far higher in omega-6 fatty acids, which come from corn and safflower oil and are plentiful in processed foods and cornfed beef and poultry. Some experts believe that reducing the ratio of omega 6s to 3s is even more important than increasing omega-3s, but the evidence is mixed.

Blood tests (typically $100 to $200) can measure the amount of omega-3s in red blood cells or plasma and a growing number of doctors are ordering them. No official deficiency standard has been set, but according to one lab, OmegaQuant Analytics, having 4% or less omega-3s out of total fatty acids is “undesirable” and indicates an elevated heart risk; 8% or more is “desirable.” Most Americans score between 3% and 5% omega-3s, says William Harris, a veteran heart researcher who founded OmegaQuant. “In Japan, it’s about 10%, and they have much less cardiovascular disease and live, on average, four years longer than we do,” he says.

Thousands of studies since the 1970s have shown that people with high levels of omega-3s have lower triglycerides, lower blood pressure, lower LDL cholesterol, less inflammation and a lower risk of heart disease. Those with low levels of omega-3s are more likely to be depressed, to commit suicide and have memory loss and brain shrinkage as they age.

Many of those are observational studies that can’t prove cause-and-effect; it may be that people who eat more fish have more healthy behaviors in general. The evidence from randomized-controlled trials is more mixed—but experts say that’s not surprising in dietary studies, where researchers often have to rely on patients to accurately report what they ate over long periods.

Recent research offers a tantalizing mix of healing possibilities:

Alzheimer’s disease and dementia: Several studies show that older people who eat plenty of fish have lower levels of beta-amyloid protein, associated with Alzheimer’s, than those who eat less. But giving elderly people omega-3 fish-oil supplements didn’t help ward off cognitive decline, according to a meta-analysis published in June. (The authors conceded that the trials may not have been long enough to show much effect.) Giving omega-3s to people with Alzheimer’s did not slow the disease’s progression.

Macular degeneration: A 2011 Harvard study found that women who ate fish at least once a week were 38% less likely to develop age-related macular degeneration than women who ate it less than once a month.

Attention-Deficit Hyperactivity Disorder: Children with ADHD tend to have lower omega-3 levels than their peers, and a study in the journal PLOS One last month found that DHA can improve reading and behavior in underperforming children. Still, there is no evidence to date that omega 3s are as effective as medication.

Depression: Rates of depression, bipolar disorder and postpartum depression are all lower in fish-eating populations, writes psychiatrist Drew Ramsey in his 2011 book, “The Happiness Diet.” He also lists wild salmon and shrimp as the top foods for good mood, and encourages his patients to increase their fish intake. Supplements with a high ratio of EPA to DHA appear to be most effective.

Cancer: Animal studies suggest that omega-3s may suppress the growth of some cancers. But a 2006 review of 40 years of research concluded that omega-3 supplements are unlikely to prevent cancer in humans.

Rheumatoid arthritis: Fish oil doesn’t appear to slow the progression of rheumatoid arthritis, but small studies show that it helps reduce symptoms like joint pain and morning stiffness, and may allow people to lower their dose of anti-inflammatory drugs.

Fetal development: Omega-3s are needed for brain and vision development in unborn babies, but concerns about mercury levels have scared some pregnant women away from eating fish. Health authorities say that many good omega-3 sources, including shrimp, salmon and tuna, are relatively low in mercury. Nursing women and young children should avoid shark, swordfish and tilefish.

Many physicians are more comfortable urging patients to eat more fish than take fish-oil supplements, since fish also contain protein, vitamin B-12, zinc and iodine.

Side effects from fish-oil supplements are minor—mostly gastrointestinal upset and burping with a fishy aftertaste. (Freezing the capsules or taking them with food may help.) In doses of 3 grams and above, EPA and DHA can increase the risk of bleeding, so people on blood thinners should consult their physician before taking them. Some hospitals advise patients to discontinue taking omega-3s before surgery.

What’s the bottom line? Does it make sense to consume more omega-3s? “There is no single answer here,” says Paul Coates, director of the Office of Dietary Supplements, part of the National Institutes of Health. “Given that there is a potential for benefit, and the harm has not yet been fully explored, at reasonable levels of intake, it’s not a bad idea.”


Write to
Melinda Beck at HealthJournal@wsj.com