Nearly everyone has received e-mails proclaiming that a particular food possesses magical qualities. One such e-mail espouses bananas to be a superfood. The e-mail claims that a professor of physiological psychology provided the amazing information about bananas. There are a number of urban legend websites posting this message that don’t point out what is fact and fiction. Here are some of the claims and the facts about them.
Claim: "Bananas contain three natural sugars — sucrose, fructose and glucose — combined with fiber. A banana gives an instant, sustained and substantial boost of energy."
Facts: This claim is reasonable. A medium banana contains about 15 grams of sugar and six grams of starch. About 20 percent of the sugar is sucrose, and the rest is half fructose and half glucose. The glucose is likely absorbed rapidly and the other sugars a bit more slowly, providing a quick (but not exactly instant) and somewhat sustained supply of carbohydrate energy.
Claim: "Research has proved that just two bananas provide enough energy for a strenuous 90-minute workout."
Facts: This claim is false, unless you consider walking at a pace of 1 mile per hour to be a strenuous workout. Two large bananas provide about 240 calories, about what it takes for a 170-pound person to walk 1.5 miles in 90 minutes. If this person jogged for 90 minutes at a 10-minute-per-mile pace, they would expend the calories found in more than four large bananas.
Claim: Depressed people feel better after eating a banana because it provides "tryptophan, a type of protein that the body converts into serotonin, known to make you relax, improve your mood and generally make you feel happier."
Facts: Tryptophan is an amino acid component of virtually all proteins. The level of tryptophan in bananas is extremely low, and claims that the small amount of tryptophan in bananas will help prevent depression are highly unlikely. Then again, bright yellow bananas are shaped like a smile and might subliminally make a person feel happier.
Claim: Bananas are high in iron and can help cases of anemia.
Facts: False! A large banana provides less than 2 percent of the daily iron needed by a woman. This percentage does not consider that the iron in many plant foods is poorly absorbed by the body.
Claim: Bananas are extremely high in potassium.
Facts: Sort of true. One large banana provides almost 500 mg of potassium, a little more than 10 percent of the daily recommended intake for an adult.
Claim: Bananas help the body recover from the effects of nicotine withdrawal, partially because of the vitamin B-12 they contain.
Facts: False! Bananas contain no vitamin B-12 unless they are rotten, not just overripe. Also, it is highly unlikely that vitamin B-12 would help with nicotine withdrawal.
Bananas are a good food that can be a valuable component of a healthful diet. They don’t need misinformation to promote their value because they do provide a number of essential nutrients. No food provides all the nutrients we need. A balance of wholesome foods is what comprises a "superdiet."
Joannie Dobbs, Ph.D., C.N.S., and Alan Titchenal, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.