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Healthnotes Newswire (July 17, 2008)—Everyone knows that fish is good for you, but it turns out that some is better than others for certain health needs and goals.

A new study, published in the Journal of the American Dietetic Association, analyzed 30 species of wild and farmed fish and found that while wild fish is generally more healthful than farm-grown, fish such as salmon and trout still maintain a beneficial fatty acid profile. Other farmed fish, such as talapia, do not, so while these may be incorporated into a regular diet as an occasional inexpensive, low-fat protein source, people wanting to maximize disease-fighting health benefits from fish will opt in favor of those with a better balance of fatty acids.

The ratio is the real measure of risk

A wealth of research shows that eating fish rich in omega-3 fatty acids may help prevent and treat diseases such as heart disease, diabetes, inflammatory and autoimmune diseases, and some cancers. However evidence increasingly points to the ratio of omega-3 to the less discussed omega-6 fatty acids in the diet as the indicator of disease risk.

• Fish with an omega-3 to omega-6 ratio of greater than one are considered beneficial because of their effect on the fatty acid profile of the entire diet.

• Fish with a ratio of 0.5 or lower are considered not protective against disease.

As a polyunsaturated fat, omega-6 also plays a role in supporting health, as long as it is consumed in moderation.

The best fish for fending off disease

The authors of the study collected samples of commonly eaten fish—including tuna, snapper, mahi-mahi, cod, sole, halibut, haddock, talapia, swordfish, catfish, salmon, and trout—from distributors in the US and Chile, from fish farms in the US, Chile, Canada, Ecuador, Honduras, Norway, and New Zealand, and from supermarkets in the US. Some highlights of their findings include:

• Sockeye salmon, Coho salmon, Copper River salmon, and farmed rainbow trout had a beneficial fatty acid pattern—in other words, a high ratio of omega-3 to omega-6 fatty acids.

• Farm-raised Atlantic salmon had high levels of omega-3 fatty acids but their levels of omega-6 fatty acids were higher than those of the wild salmon, making their ratio slightly less favorable, though still healthy.

• Tuna, one of the most commonly eaten fish in the US, had a low level of omega-3 fatty acids, but it also had a low omega-6 level, so its ratio remained favorable.

• On the other end of the spectrum, farmed talapia and catfish had low levels of omega-3 and poor ratios of omega-3 to omega-6 fatty acids.

Balancing factors besides fatty acids also important

Of all the fish reviewed in this study, tilapia has received the most attention for its unfavorable fatty acid content. “All other nutritional content aside, the inflammatory potential of hamburger and pork bacon is lower than the average serving of farmed tilapia,” the article cautions. However, keep in mind that a fish not being highly protective against heart disease does not mean it needs to be avoided entirely. Other health factors, such as heavy metal contamination—which are high in otherwise healthful fatty fish like tuna, but low in less heart-healthy fish like tilapia—should also be taken into account.

To give the pros and cons of fish consumption some real world perpective, consider that eating moderate amounts of farmed tilapia is roughly equivalent to other staples of the average diet, and may be a reasonable option for some people. For those at risk for inflammatory diseases such as heart disease, fish with a good omega-3 to -6 ratio such as salmon or trout are the best choice.

(J Am Diet Assoc 2008;108:1178–85)

Healthnotes Newswire (May 29, 2008)—The President’s Council on Physical Fitness and Sport recently released a fitness test for people over age 18. The test helps estimate aerobic fitness level, muscle strength and endurance, flexibility, and body composition.

Better overall physical fitness helps lower the risk of cardiovascular disease, diabetes, high blood pressure, stroke, and certain cancers. It can also improve mood and help avoid accidents and muscle strain due to underused and inflexible muscle groups.

The new President’s Challenge and Adult Fitness Test was created to help people understand their own fitness level and make positive gains in physical fitness. The test is available as a downloadable booklet at www.adultfitnesstest.org/resources/testbooklet.pdf; individual results can be entered and evaluated online.

Each test section is followed by a “FITT” box which stands for Frequency—how often the exercise is performed; I—the intensity at which the exercise is carried out; T—time, or how long the session lasts; and T—type of exercise being performed. These boxes help users customize their fitness goals.

Aerobic Fitness

To test aerobic, or cardiovascular, fitness, choose a 1-mile walk or a 1.5-mile run. For the walk, after a brief warm up, have a partner time you walking at a brisk pace for one mile, and take your pulse immediately after finishing. For the running option, warm up with a light jog. Then, having a partner time you, run as fast as possible for 1.5 miles. Only attempt the run if you currently run for at least 20 minutes three or more times per week.

FITT tips

Frequency: Depending on the level of intensity, exercise three to five days per week.

Intensity: Moderate-intensity exercise is a brisk walk; vigorous activity is running.

Time: For moderate activity, do at least 30 minutes per session; vigorous activity should last for 20 to 30 minutes.

Type: Examples are walking, running, dancing, cycling, and swimming.

Muscular Strength and Endurance

These tests assess basic muscle strength required to carry out household or work-related tasks. Do half sit-ups by lying face-up on a rug or mat with knees bent at a right angle and feet flat on the floor. With palms flat on the floor, sit up and slide hands forward 3.5 inches (mark distance with masking tape on the working surface before starting). Having a partner time you, do as many sit-ups as you can in one minute. Then do push-ups with legs extended (men) or with knees touching the floor (women). Do as many push-ups as you can and record the number.

FITT tips

Frequency: Do muscular strength and endurance exercises on at least three days per week.

Intensity: Vary the intensity during the workout.

Time: Gradually increase the number of half sit-ups and push-ups until you can do three sets of 25 half sit-ups and three sets of 10 to20 push-ups.

Type: Master the test movements and then add other equipment (balance balls, weights, or elastic tubing).

Flexibility

These tests assess the range of motion of muscles needed to walk, lift, and step normally. Sitting on the floor, place a yardstick between the legs with feet about a foot apart. Place a piece of tape across the yardstick at the 15-inch mark. With fingers on the yardstick, slowly reach forward as far as possible. Record to the nearest inch that your fingertips can reach.

FITT tips

Frequency: Do flexibility exercises at least three days per week.

Intensity: Stretch to the point of tension, never to pain.

Time: Hold each stretch for 20 to 30 seconds, repeating three times.

Type: Begin with static stretches, gradually adding dynamic (moving) stretches. Try learning a practice that includes flexibility exercises, such as yoga and Pilates.

Body Composition

Body mass index (BMI) and waist circumference can be measured to estimate disease risk. To calculate BMI, weigh yourself and have a partner measure your height with shoes off. Wrap a flexible tape measure around your abdomen just above the hip bones; measure and record. Determine your BMI using the booklet’s chart.

A normal BMI is between 18.5 and 24.9; overweight is between 25 and 29.9; obese is greater than 30.

If you are overweight or obese, you can improve your BMI and waist circumference by making sure that you burn more calories than you eat. In order to lose weight, emphasize whole grains, fiber, fruits and vegetables; limit processed and high-carb, high-fat foods, and work in 60 to 90 minutes of daily moderate intensity exercise.

(www.adultfitnesstest.org/adultFitnesstestLanding.aspx; accessed 26 May 2008.)