Eating While Distracted

We’ve all heard about driving while distracted is dangerous– are there any negative consequences to eating while distracted?

According to recent research, people who eat while playing computer games cannot remember what they ate as well as people who are not distracted when they eat. They also report that they feel less full after eating, and therefore they tend to eat more at the next meal.

The findings support the hypothesis that memory plays an important part in satiety. It’s tempting to speculate that a trend toward multitasking (including eating while working or playing games) may be contributing to the current obesity epidemic.

Obesity and Body Size Misperception

According to a recent report in the Archives of Internal Medicine, about 8% of obese individuals don’t recognize that they need to lose weight. Researchers call the phenomenon “body size misperception”. Obese individuals who misperceive their body size tend to be more satisfied with their overall health and are more likely to believe that they have a low lifetime risk of chronic diseases related to obesity, than are those who acknowledge that they are obese. Two-thirds of them actually believe that they are at low risk of developing obesity in their lifetimes, even though they already ARE obese according to the standard government definition.

But are there other possibilities for these people’s failure to acknowledge their obesity besides body size misperception? Perhaps these individuals do know that they are obese, but because they don’t think they can lose weight or don’t want to try, they are unwilling to acknowledge it even on a survey. It’s called denial. Or perhaps they just don’t accept the current definition of obesity (a Body Mass Index of 30 or above) and/or its health consequences.

How people perceive obesity and its consequences need to be explored further if we wish stem the rising tide of obesity in the U.S. and around the world.

Oral Immunotherapy for Food Allergies

Some people have food allergies so severe that even the slightest contact with the food can lead to a life-threatening allergic response. A rare but potentially fatal allergic response to peanuts, for example, is why most airlines no longer serve peanuts on their flights. Other sufferers are equally allergic to milk or to eggs, commonly used as ingredients in many food products and recipes. Is there anything that can be done for people with life-threatening food allergies aside from having them try to avoid the food?

Current research efforts are focused on oral immunotherapy (OIT). OIT consists of exposing the patient to miniscule quantities of the allergen in a supervised research setting (under close medical supervision), and then if an allergic reaction fails to occur or remains mild, slowly increasing the dose over days or months to “desensitize” the patient.

Researchers caution that the technique is not yet ready for widespread clinical use, however. The risk of an adverse reaction to the first dose is fairly high, and little is known about the safety of OIT when done at home under a variety of conditions. In addition, it is not known how long desensitization lasts if/when regular desensitizing dosing is ended. There is a danger that desensitized patients might develop a false sense of security once they become partially desensitized or quit their therapy altogether.

Nevertheless, OIT might become a useful therapy for severe food allergies in the future, once we better understand how to perform it safely. For sufferers of truly severe food allergies, the risks associated with desensitization would have to be balanced against the risk of accidental exposure to the allergen and perhaps even death.

Using Bacteria to Fight Bacteria

A recent article in the New York Times is a good primer on the astonishing variety of bacteria that colonize our bodies, and what they may be doing there. It turns out that our individual microbiomes (all of the microbes in a defined environment within our bodies) are quite different. And at any one time, each of us probably has only about 20% of the species of bacteria that can inhabit the human body.

An interesting new idea is that the “good” bacteria in certain people’s microbiomes might actually be used to treat certain diseases. Doctors have actually cured several stubborn cases of severe diarrhea caused by a particularly difficult bacterium to treat (Clostridium difficile) by transplanting human fecal matter from a healthy person into the patients’ colons! Granted, having a fecal transplant in order to cure disease sounds a bit strange. But apparently the “good” bacteria in the fecal transplant outcompete the C. difficile and wipe them out.

Someday maybe there’ll be ointments or pills containing especially “good” bacteria for treating certain antibiotic-resistant infections such as flesh-eating Staphylococcus aureus or diarrhea-causing C. difficile. Using bacteria to kill bacteria – like using fire to fight fire.

Reference: Zimmer, C., How Microbes Defend and Define Us. New York Times, July 13, 2010.

Caffeine Made Easy

Remember Sweet’n Low, the first really convenient sugar substitute? Well, now somebody has finally come up with a similar easy-to-use product containing caffeine. Fein energy crystals (pronounced FEEN) are being promoted as an energy-boosting product that can be added to any drink, including water. Fein has no calories, no artificial ingredients, and no taste, according to the company marketing it. Drop a single stick of FEIN into your drink of choice and you’re getting 75 mg of pure crystalline caffeine, roughly the amount of caffeine in some energy drinks. And Fein costs less than 70 cents per stick. You probably won’t find it in stores yet, but it’s available over the internet.

Henceforth, getting that caffeine buzz (if that’s important to you) will be as easy as sweetening your tea. This is not an endorsement; just a fact.

Getting That Caffeine Buzz

The latest entry into the world of marketing hype - “energy shots”, a mere two ounces of bad-tasting liquid loaded with caffeine. Manufacturers won’t say how much caffeine for proprietary reasons (and probably to add to the drinks’ mystique), but most energy shots are thought to contain on the order of 120-200 mg. That’s the equivalent of one to two ordinary cups of coffee or a 16-oz energy drink.

Energy shots may also contain B-vitamins, amino acids and various plant extracts, but these aren’t likely to give you much of an energy boost despite the products’ claims. And then there’s the cost – upwards of $3 apiece.

If it’s a caffeine buzz you need, what’s wrong with plain-old maximum strength (200 mg) No-Doz? It was your grandfather’s drug of choice nearly 50 years ago for pulling an all-nighter, and it still works. Plus it only costs about 20 cents per dose.

Caloric Restriction and Longevity

It has been known for some time that severe caloric restriction can retard the aging process and prolong the life of a variety of species, from worms to mice. But skeptics of the idea that caloric restriction might also slow the aging process in humans point out that the metabolisms of worms and mice are quite different from that of humans.

Now a new study reports that caloric restriction slows the aging process in primates, too. Macaque monkeys that have been on a calorie-restricted diet (by 30%) for the past 20 years are living longer and are healthier than their age-matched control counterparts. Excluding animals that died of non-age-related causes (accidents for example), 50% of the animals on a normal diet have died of age-related causes, compared to only 20% in the restricted-diet group. The calorie-restricted animals also have fewer age-associated diseases such as diabetes, cancer, and cardiovascular disease. The study is still ongoing.

Is Being Overweight a Health Risk?

It depends on the question - a health risk for what? People who are overweight, defined by the U.S. government and the World Health Organization as a Body Mass Index (BMI) of between 25 and 30, apparently do have a slightly increased risk for certain diseases such as diabetes, coronary artery disease and hypertension. But for other parameters, such as risk of death, the evidence is not that clear-cut (See “Is ‘Overweight’ Overstated?”, pp. 346-347, Human Biology 5th ed.). In fact, a recent study of over 11,000 Canadian adults reveals that as a group, people who are defined as overweight have a slightly lower risk of death than the normal-weight group, though not by much.

Taking this new mortality data into account and reviewing the graph on p. 346 of Human Biology, one wonders whether the range of “normal” weight shouldn’t be shifted about 3 BMI to the right. A word of caution, however; the shape of the weight-vs.-risk curve is likely to be different for every disease, age group, etc. It’s probably going to be impossible to come up with a perfect functional definition of overweight, no matter how much we’d like to.

New Nutrient Standards for Packaged Foods

Finally, someone has decided to make it easy for consumers to pick the healthiest packaged foods! A coalition of some of the biggest food companies has teamed up with scientists and the federal government to develop and promote a simple front-of-package logo called “Smart Choices” to indicate that a food meets certain nutritional standards. The standards include limited quantities of total and saturated fats, cholesterol, added sugars and salt, as well as minimum quantities of nutrients for good health, such as calcium, potassium, fiber, and certain vitamins. And like the “Heart Healthy” program originally developed by the American Heart Association, the new program is based on good scientific evidence.

Once consumers understand what the logo means and accept its underlying health assumptions, they can simply look for the logo on the front of the package. “Pattern recognizers” such as myself (who can’t find their favorite products in the grocery store if the manufacturer changes the packaging!) will appreciate the help in picking healthful foods. The logo is a green check mark in a square along with the words, “Smart Choices Program”. For a complete listing of the nutritional requirements to earn the Smart Choices label, visit the Smart Choices website. The logo should begin appearing on products in stores by the middle of next year.

Irradiation of Foods

Would your students buy lettuce and spinach that had been irradiated in order to kill micro-organisms such as E. coli and salmonella? In fact, the government has already approved of the practice. Irradiation of oysters, beef, poultry and eggs has been allowed for some time now, but irradiation of lettuce and spinach is fairly new.

Until now the market for irradiated foods has remained small because current FDA regulations require that irradiated foods be labelled as “irradiated” and display an irradiation logo. The labels have convinced some consumers that irradiated foods may be radioactive (they’re not). To encourage consumer acceptance, the FDA has proposed changes to the labelling rules so that in the future, irradiated foods would only have to be labelled as “cold pasteurized”, or simply pasteurized.

How accurate are your student’s perceptions about food irradiation? How many of them mistakenly believe that irradiated foods are radioactive? The safety of food irradiation might make a good out-of-class research project or topic for discussion.

Fatness, Fitness, and Health

Human Biology, 5th ed. (pp. 346-34) has a Current Issue feature on the topic of whether or not being “overweight” (BMI 25-30) is overstated as a risk factor for poor health or mortality. A report out just last week in The Archives of Internal Medicine (168: 1617-1624, 2008) supports that notion. The study documents the prevalence of six cardiometabolic risk factors (elevated blood pressure; elevated triglyceride level; decreased HDL level; elevated fasting glucose level; insulin resistance; systemic inflammation) in normal, overweight, and obese individuals. The study found that nearly 24% of all normal-weight individuals were ”metabolically abnormal” by virtue of having at least two of the six risk factors. And conversely, 54% of the overweight individuals were still metabolically healthy. The study suggests that just being overweight does not necessarily mean that an individual is at increased risk for heart disease.

A study published last December tends to support the hypothesis that being overweight is not as important a factor previously thought (Journal of the American Medical Association 298:2507-2516, December 5, 2007). In this study, 2603 adults over the age of 60 were tested for cardiovascular fitness (gentle treadmill test) and then mortality was followed for 12 years. Overweight individuals did have a higher mortality rate than did normal-weight individuals (18 vs 13 deaths per 1000 person-years). However, even more striking was the effect of fitness; mortality rate of the least-fit quintile was four times that of the most fit quintile (33 vs. 8 deaths per 1000 person-years.) Among the older generation at least, maintaining cardiorespiratory fitness may be more important than maintaining a normal body weight. Whether this is also true for younger individuals remains to be seen.

California Bans Trans Fats

The State of California has banned the use of trans fats in most food products. The ban goes into effect for all restaurant products in 2010 and for all retail baked goods in 2011. Packaged foods will not be affected, however.

Trans fats are created by bubbling hydrogen through liquid oil at high temperature. The resultant partially hydrogenated oil is a solid at room temperature. Trans fats prolong the shelf life and (some say) improve the flavor of foods. They were popular as a deep-frying oil until it became apparent that they raise the levels of low-density lipoproteins (the bad cholesterol), thereby potentially contributing to heart disease. Some restaurant chains, most notably McDonalds, have already discontinued the use of trans fats in their deep-fryers, and other chains are following suit.

The California ban raises an interesting question: Whose responsibility is it to legislate our health? The California Restaurant Association argued (unsuccessfully) that it should be the federal government, not the states – otherwise, restaurants with outlets in many states could face a wide array of different rules.

But if the government won’t act, should the states be allowed to? Until California’s law is challenged in federal courts, the answer is “Yes”. What do YOU think?

Teens and Energy Drinks

There’s growing concern among school officials and health care workers that teen use of energy drinks such as Red Bull and Spike Shooter are early warning signs of the willingness to take risks. According to researchers, high consumption of energy drinks is associated with aggressive and risky behaviors, including substance abuse, violence, and unprotected sex. No one is saying yet that these energy drinks cause such behaviors, but parents should probably be aware that teens who are willing to abuse caffeine may be more likely to engage in other risky behaviors as well. The research is published in the March issue of The Journal of American College Health and discussed in a recent news article (“Taste for Quick Boost Tied to Taste for Risk”, New York Times online May 27, 2008.)

The energy drink Spike Shooter contains 428 mg of caffeine in 12 ounces, or about 12x that of Coke or Pepsi and 2-5 times that in a cup of coffee. Teens have been sent to the emergency room with heart palpitations, jittery behavior, and sweating as a result of drinking too many energy drinks. Some teens are combining these drinks with alcohol in the mistaken belief that it makes them less drunk.

Do your students use energy drinks, and do they know what's in them?

Probiotic Dietary Supplement Not Always Beneficial

Probiotics are dietary supplements containing beneficial yeasts or bacteria. Available over-the-counter, probiotics are sometimes recommended by nutritionists and doctors as a way to re-establish the body's natural digestive flora after a course of antibiotics. They're supposed to be good for you.

However, a research group testing the hypothesis that probiotics are beneficial in preventing the infectious complications of a specific life-threatening disease (acute pancreatitis) actually found just the opposite. In a carefully designed double-blind, placebo-controlled study of 298 patients at high risk for acute pancreatitis, the patients given a probiotic preparation had a higher death rate (16%) than the controls (6%).

The finding, although startling, should not be used to conclude that probiotics are a bad idea under other circumstances. Obviously we need to know a lot more about probiotics and how they might affect the outcome of specific diseases before we can draw more general conclusions. But for now at least, probiotics should not be given to in patients at high risk for acute pancreatitis.

The original article can be found in the online version of The Lancet (DOI:10.1016/S0140-6736(08)60207-X).

A Function for the Appendix?

It has long been thought that the small blind-ended pouch near the end of the small intestine called the appendix is vestigial, i.e. it no longer serves any useful function in humans. But now scientists at Duke University hypothesize that the appendix may indeed still have a function. In a September 7 article online in the Journal of Theoretical Biology, the researchers speculate that the appendix serves as a reservoir (or safe haven) for “good” bacteria in the event that a severe bout of diarrhea flushes out most of the bacteria in the small and large intestines. After the diarrhea has passed, according to the scientists, the bacteria in the appendix could emerge to repopulate the intestines.

It’s an interesting thought, but this is speculation, not yet proved. The Journal of Theoretical Biology is a vehicle for ideas, not hard scientific data. My question would be if the appendix does serve a useful function, why don’t most animals have one? (Apparently only humans, rabbits, and two species of marsupials have an appendix.) An admittedly equally speculative explanation might be that while the appendix does harbor bacteria that help repopulate the gut after a bout of diarrhea in humans, that function is not so significant that it confers significant survival value any more. In other words, the appendix ultimately still may be considered vestigial.

The concept of survival value of a given structure or function is an important one for students to understand when discussing evolution, of course.

Obesity in Close Mutual Friends

If your closest friend becomes obese your risk of obesity goes up dramatically, according to researchers. And it was not just a matter of the friends eating the same foods, because the relationship holds even if the friends are separated geographically. Your risk also goes up if you have a sibling or a spouse who becomes obese, though the effect is not as great as between best friends.

How might social relationships affect obesity? Researchers speculate that when a person who becomes obese is already a close mutual friend, a sibling, or a spouse, one may tend to perceive obesity as more acceptable than if the person is a total stranger. Close mutual friends may also influence a person’s eating habits, even if the friends are not always together.

The data also offer a clue for why many of the most successful weight-loss programs are those that offer peer support. By modifying a person’s social network to include people who are also trying to lose weight, one’s view of normal and acceptable begins to change. The bottom line is that obesity is not just a medical problem with genetic roots, but also a public health problem with social causes. Understanding obesity will require a full understanding of both.

Would You Eat Your Placenta?

It’s called placentophagy (or placentophagia). There are no statistics on the percentage of new moms who do it, but there are a surprising number of references to it on the Web. There are even recipes for preparing placenta – placenta pills; placenta blended with V8 juice; placenta sauteed with olive oil and garlic; placentaburger; placenta lasagna; even placenta smoothies! Maybe I'm just not adventurous, but I think I'll pass on this one.

Proponents argue that most mammals eat their placenta (true, but what’s the relevance?) and that eating the placenta confers nutritional or health benefits to the new mom, including reduction of post-partum pain, depression and bleeding (largely untested). There are lots of anecdotal testimonials from new moms who say they feel just great after eating portions of their placenta. But hey, if you’re willing to chow down on your placenta in the first place based solely on your belief system, is it any surprise that you would report feeling better afterwards? There are even fathers trying it. Call me a skeptic, but what would it do for the father?

Eating raw human blood products could increase the risk of contracting hepatitis B, C, and HIV. And anyone thinking about frying up some placenta for its alleged health benefits should know that there are plenty of other ways (pharmaceutical drugs, hormones, and vitamin pills) to reduce post-partum pain, bleeding, and depression, or to maintain good post-partum nutrition.

Instructors could use this topic to explain the difference between belief and scientific evidence; between anecdote and statistically significant data. They could also have students research the topic, bring in statements about the health benefits of eating the placenta, and then discuss (or vote) on whether the statements are closer to “belief/anecdote” or to “science/data” so they can begin to see the differences. Who knows, they might even find that there is some good scientific evidence out there that I am not aware of.