Food myths die hard -- here's the real story on healthy eating

Even if you're up on nutrition news, it can be hard to keep score on the latest super-food or the newest no-no. That's because science is still in the process of learning what our bodies need - and the best way to get it. While research advances, what's considered a nutritional certainty today may crumble under mounting evidence next year. For now, though, test your knowledge of the healthiest way to eat.

Myth: Zero trans fat means zero.

The U.S. Food and Drug Administration has enforced the labeling of trans fats since January 2006. Despite the unmistakable "0 trans fat" label on many foods, zero may not actually mean zero. Food manufacturers are allowed to label foods with less than 0.5 gram of trans fat as zero on the Nutrition Facts panel.

Most everyone is aware that trans fats increase total blood cholesterol and LDL (the bad cholesterol), while lowering HDL (the good cholesterol). They also cause a rise in apolipoprotein A, another risk factor for heart disease, decrease insulin sensitivity affecting blood sugar balance, and enhance the production of pro-inflammatory hormones (prostaglandin E2) - bad news for arthritics or anyone with pain or allergies.

Read labels carefully. Avoid hydrogenated margarines as well as any foods that list "hydrogenated" or "partially hydrogenated" on the label. Look also at portion sizes. Some manufacturers limit portions to amounts providing just under 0.5 grams of trans to avoid labeling them.

Myth: Margarine is healthier than butter.

Butter won that debate a long time ago, but a great deal of misinformation still exists.

Both have the same amount of calories (about 100 calories per teaspoon); both taste great on toast. As far as health goes, butter is better.

Butter has its issues: it is a saturated fat and a source of cholesterol, but the long-term studies on butter vs. margarine have not shown what health experts of yesterday expected. In fact, while margarine (nicknamed "plastic fat") may be cholesterol-free, trans fats found in margarine and shortening are a much bigger problem.

Nonhydrogenated spreads, like Earth Balance, are available at your local grocery and health food store. Organic coconut oil is another option. It's a saturated fat (solid at room temperature) but is cholesterol-free. The healthiest fat is fish oil, but you can't spread that on toast.

Myth: Nuts contain cholesterol.

Plant foods do not contain cholesterol (despite what your doctor may think!). Cholesterol is found only in animal foods. A number of studies have shown that regular intake of nuts, walnuts in particular, can result in a sevenfold improvement of arterial function thanks to omega-3 oils.

A handful of nuts supply about 150 calories and one tablespoon of nut butter provides about 100 calories, so to avoid weight gain, they should be substituted for another source of calories. Ensure that the nuts you purchase are unsalted and raw to protect those precious omega-oils.

Myth: Whole wheat is the healthiest grain.

"Whole grain" means that all three parts of a grain - the bran, germ, and endosperm are included. While whole wheat is a whole grain, it is only one of many available whole grains and is not necessarily the best. Wheat is the main source of dietary gluten, a stretchy protein found also in rye, and barley.

Gluten causes inflammation in the absorptive tissues of the small intestine in people with gluten intolerance. Those who experience symptoms may recognize that bloating, cramping, and diarrhea are associated with the intake of wheat and other grains.

Food labeled "multigrain" includes a mix of grains and is often a better option than whole wheat. Read the label to determine if all grains included are whole grains. Look also for foods made from alternate grains such as brown rice pasta, spelt bread, and products labeled "gluten-free."

Myth: All yogurt is healthy.

Probiotic yogurts have become a favorite marketing tool, and with good reason.

More than 1,000 different species of bacteria make their homes on and in the human body. While many of these bacteria are "friendly" and protective, combating digestive problems, yeast infections, and boosting immunity, some can have negative influences on human health. The balance of microbial strains should favor the beneficial bacteria over the potentially harmful ones.

Yogurt contains bacteria similar to those naturally found in the human intestine, but flavored yogurts often contain unnecessary and unhealthy ingredients including sugar, cream, cornstarch, gelatin, aspartame, and sucralose (in the sugar-free varieties).

The healthiest yogurt is a plain, naturally made yogurt. Feel free to add whatever you like to it, but start off with plain. Choose yogurts containing natural bacterial strains including Lactobacillus acidophilus and Bifidobacterium bifidus.

Myth: All salad greens are equal.

Iceberg lettuce has been teased for its low nutritional value and nicknamed the "polyester of lettuce." Compared to other leafy greens, its nutrient makeup is extremely low, containing 95 percent water, a trace of fiber, and only one-twentieth the vitamins and minerals provided by other leafy greens.

If you cannot part with iceberg, mix other greens into your salad - spinach, kale or romaine; the darker the lettuce, the more nutrients it provides.

Myth: Sodium is only found in salt.

A teaspoon of salt provides over 2,300 mg of sodium - a far cry from the recommended 1,200 mg - but salt is not the only offender.

Tomato sauce, processed meat, condiments, prepared soup, cheese, and fast food will tip the sodium scales faster than a pinch of salt. Read labels carefully and watch for signs of excess sodium like swelling of fingers, ankles and feet, tingling in your legs, and excessive thirst.

Myth: Brown sugar is healthier than white.

Brown sugar is refined white sugar (sucrose) with some molasses mixed in. While the molasses contain a small amount of minerals, differences in the nutritional makeup of brown and white sugar are negligible.

Sugar cane, the plant from which sugar is derived, contains the nutrients riboflavin (vitamin B2), niacin (vitamin B3), potassium, calcium, iron, and magnesium. Remember that all forms of sugar will raise blood sugar levels and should be used in moderation.

Myth: Low-fat diets are ideal.

Not necessarily. Fat should not exceed 25 percent of your total calories and most (if not all) of those fats should derive from omega-3 (fish, fish oil supplements, and nuts).

Recent studies show that a low-fat diet is one of the least effective methods of losing weight and body fat. They also show that since 70 percent of your brain is fat, low-fat diets can impair cognitive functions. Don't count calories and fat. Count nutrients instead.