probiotics and prebiotics paper

All right, at the very great risk of looking excessively lazy, here’s what I did while offline. Pretty much all I did in the way of homework. Pretty painful. Wrote it over a single very long night and into the next day, missing half of the next day’s classes but attending, stupidly enough, PE because that’s where attendance counts most and nearly falling a whole bunch of times trying and failing to learn a new roundhouse kick… Oh, let’s just get it over with. Here you go.

Paper #2 for class on Food Science, Review of Probiotics/Prebiotics articles

Amy Brown defines probiotics in her textbook Understanding Food: Principles and Preparation as “live microbial food ingredients (i.e., bacteria) that have a beneficial effect on human health” (Brown 2011, G-6) In middle-class America, the idea of voluntarily consuming bacteria is counter-intuitive. We spend a great deal of time and money trying to find new ways to kill bacteria in our food supplies before they reach us. We take antibiotics for serious diseases. We pasteurize cheese and beer; killing most of the microorganisms that make these products to reduce our chances of ingesting toxic bacteria. We are even trained to fuss at children for eating off our “germy” home floors. We refuse to eat any but the freshest restaurant produce. Yet we are also quite prone to fads.

Researchers and salesmen have proposed many reasons for us to indulge in the recurring fad of probiotics. The most common claim is that products alleviate undesirable gastrointestinal symptoms such as bloating, irregularity, gas, stomach discomfort, and diarrhea (Schardt 2006, 7-9). Yogurt in particular has been used in diarrhea patients for centuries (Brown 2011, 222). Preliminary research seems to show that some probiotics can shorten the duration of colds and help balance a digestive system upset by hospital- or antibiotic-induced infections (Schardt 2006, 8-9 under Stonyfield Farm Yogurt and Florastor).  Also, probiotics are classified as food and thus seem to have fewer risks and gentler regulations than medicines like antibiotics.

Consuming live bacteria is certainly not without risk, though. Some challenges to the probiotic industry include reducing risk of gastrointestinal upset possibly caused by the bacteria themselves (Schardt 2006, 8 under DanActive Drink) and preventing contamination by wild bacteria and early spoilage. Various strains of bacteria may cause allergic reactions. Testing is difficult and expensive and relies on volunteers, which introduces a high probability of bias. As the term “probiotic” is not tightly regulated, confusion can easily result as to what exactly a product contains. Some manufacturers make claims bordering on panacea for poorly tested products (Schardt 2006, 9 under Culturelle). All of this can be dangerous to the unwary consumer.

Another consideration to remember is that researchers are just beginning to look into what causes a change in human gut microflora. A strong contender for the post is diet (Wu et al. 2011, 1-5); others might include genetics and cultural or geographical environment. One study connected all three in a study of how the gut may influence obesity and vice versa (Flier and Mekalanos 2009, 1-3). Probiotics introduce new bacteria into the gut (though not in large amounts) and thus could theoretically have a direct influence on the composition of the gut microbiome. Yet long-term studies should be performed, especially on the effect of multiplying “good” bacteria to crowd out and place a barrier between the body’s immune system and “bad” bacteria. There is so much bacteria in the human gut that it will take researchers some time to find out whether some bacteria are more important than others in disease prevention and control (Wu et al. 2011, 3).

Probiotics have a mixed reliability rate; sometimes there is research to support health claims blazoned on packaging, but sometimes the evidence is elusive. Before deciding to incorporate any product containing probiotics into their diet, consumers ought to check any scientific studies performed on the specific strain of bacteria for success rate as proof of packaging claims. For example, in an article summarizing this information for several products on the market in 2006, some probiotics were in a far more advanced stage of testing than others: the bacteria in Kashi Vive Cereal had never even been tested for health benefits, while the yeast in Florastor reduced incidence of diarrhea after a course of antibiotics in several large, well-done studies (Schardt 2006, 8-9). For further contrast, the DanActive Drink was only studied in a small population of elderly men and women in Italy, and a fourth of the study’s participants suffered from such intense gastrointestinal problems while using the drink that their daily dose was halved (Schardt 2006, 8). Thus, unless a consumer takes the time to research any probiotic health claims himself, he could end up paying top dollar for a product that is untested and may even be harmful.

According to its website, the National Yogurt Association’s “Live Active Culture Seal” is an official seal voluntarily placed on yogurt products that contain a certain quota of live bacteria. Because this seal is voluntary and counts both starter bacteria used to ferment the yogurt and added probiotics, naturally high levels of starter bacteria can make the designation somewhat misleading (Douglas 2008, 514).

According to the Brown textbook, prebiotics are “Nondigestible food ingredients…that support the growth of probiotics” (Brown 2011, G-7). Mostly, prebiotics are fibers that pass through the stomach undigested and become food for gut bacteria, which can react to provide mutual benefit or to attack their host. Prebiotics thus may also influence the bacterial population of the human gut.

Considering that research into the benefits of probiotics is inconclusive and I am generally healthy and broke, I would not change my own diet to incorporate this new food trend. Nor (in the logical tradition of “if it ain’t broke don’t fix it”) would I recommend specialized probiotics to other healthy friends. According to a microbiologist who wrote a book on the subject, the only reasons for a healthy person to take probiotics are if he is about to take antibiotics, go to the hospital, or travel outside of the country (Schardt 2006, 7). A case might be made for their use in an ill person who is suffering from a specific condition that a specific strain of bacteria is scientifically proven to alleviate. However, specialized probiotics are too new, expensive and unproven to recommend to the average person. Yogurt would be a safer choice for anyone wishing to follow the newest diet trends.

Reference List

Brown, Amy. 2011. Understanding Food: Principles and Preparation. 4th ed. Belmont: Wadsworth, Cengage Learning.

Douglas, Linda C., PhD, RD. and Mary E. Sanders, PhD. 2008. Perspectives in Practice: Probiotics and Prebiotics in Dietetics Practice. Journal of the American Dietetic Association 108, no. 3 (March): 510-521.

Flier, Jeffrey S. and John J. Mekalanos. 2009. Gut Check: Testing a Role for the Intestinal Microbiome in Human Obesity. Science Translational Medicine 1 no. 6 6ps7 (November 11): 1-3.

National Yogurt Association. (accessed October 14, 2011).

Schardt, David. 2006. Helpful Bacteria: Should you take probiotics? Nutrition Action Healthletter (December): 7-9.

Wu, Gary D., Jun Chen, Christian Hoffmann, Kyle Bittinger, Ying-Yu Chen, Sue A. Keilbaugh, Meenakshi Bewtra, Dan Knights, William A. Walters, Rob Knight, Rohini Sinha, Erin Gilroy, Kernika Gupta, Robert Baldassano, Lisa Nessel, Hongzhe Li, Frederic D. Bushman, and James D. Lewis. 2011. Sciencexpress Report: Linking Long-Term Dietary Patterns with Gut Microbial Enterotypes. Science 334 no. 6052 (September 1, 2011): 1-4. 10.1126/science.1208344 (downloaded September 25, 2011).



I’ve never thought of the gut as a “microbiome.” But according to one of the newest nutrition trends, a change in what we eat influences what kinds of bacteria grow in our digestive system. Since we have a symbiotic relationship with those bacteria (the reasoning goes), changing the types of colonies we encourage and discourage might change just about everything about how we feel and which diseases we get. In a study published last month (full reference in previous post, short: Linking Long-Term Dietary Patterns with Gut Microbial Enterotypes, Wu et al) researchers found an association between diets focused on vegetables or meats and different taxa of bacteria. Though these associations aren’t strong enough to control or even explain every part of our gut bacterial composition, they may play a role in why we high-animal protein/fat Westerners get different diseases than people who eat more carbs and less meat. Pretty neat, huh? The human body is such an intricate mystery.

the family meal

Because food is such a tradition in my own religion, I feel I must digress here and add in a bit from my ‘other’ education: “Because the Gospels describe the Last Supper as a Passover meal, we tend to forget that it was also a meal. Eating and the etiquette of the table were deeply significant in ordinary Jewish life, and textured with religious meaning. Among Jews in Jesus’ day, who you ate with was as important as what you ate and how you ate. Since eating was an act of fellowship and acceptance, to eat with sinners was to accept them as friends and companions (Mk 2:15-16).” (~Leonard J. Vander Zee, Christ, Baptism, and the Lord’s Supper) Theologically, Jesus is the bread of life. In the special meal we at my church call The Lord’s Supper, we invite all who have professed belief in Christ and been baptized to eat with us, no matter what sin we’re each struggling with. That’s because in eating this bread and wine, we become a part of a family that spans the world and the centuries. Its purpose is not to discipline, but to unite. Maybe that’s what attracted me to the study of nutrition.

citation styles

I’m experimenting with NoodleBib tonight. It’s working, but oddly. Some things just don’t seem to do as well as others.

Douglas, L. C., PhD, RD., & Sanders, M. E., PhD. (2008, March). Probiotics and
Prebiotics in Dietetics Practice. Journal of the AMERICAN DIETETIC 
ASSOCIATION, 108(3), 510-521.

Flier, J. S., & Mekalanos, J. J. (2009). Gut Check: Testing a Role for the
Intestinal Microbiome in Human Obesity. Science Translational Medicine, 
1(6), 6ps7.

Wu, G. & Lewis, J. Science 334 no. 6052 (2011); Published online September 1, 2011 (10.1126/science.1208344).

Schardt, D. (2006, December). Helpful Bacteria: Should you take probiotics?
Nutrition Action Healthletter, 7-9.

incomplete proteins

The unfortunate truth is that anyone wishing to be a vegetarian has a lot of dietary work cut out for him or her. It’s easier to understand one component to why this is so if you know a little basic biochemistry, thus:

Almost every single process in a human cell involves proteins. These proteins are mostly manufactured inside the cell itself from building blocks called polypeptides, which are in turn made up of long chains of amino acids. These chains are made to order according to blueprints in every single cell’s DNA. Which proteins are made in cells helps determine your hair colour, your eye colour, your tendency to add fat around your middle before your hips, just about every unique physical characteristic about you.

Most organisms concentrate amino acids around their young, storing them up so that their progeny have enough protein to survive the difficult growing process. That’s why eggs, milk, nuts, seeds, beans, and grains are so high in protein. (Meat is a good protein source because animals also store protein in their muscle.) Leaving out animal products for a moment, what’s wrong with eating a diet composed entirely of nuts? Ok, ignoring scurvy, you’d also be limiting the amount of amino acids you can absorb from those nuts. Why? Because we make certain essential amino acids out of other essential amino acids, and nuts are deficient in two of those key protein components (lysine and isoleucine, but you probably don’t have to know that on your next test). Fortunately for vegans everywhere, legumes (beans) are not limiting in either of the amino acids that make nuts a problem food-but are deficient in two others (tryptophan and methionine), which can be provided by nuts or grains (which are limited in lysine, isoleucine, and threonine). Thus, if you eat beans and rice, you’ve got a complete protein source.

What effect could this have on vegetarians? Meat provides a complete protein source without any supplementation. It also provides a good amount of extra calories from fat and sometimes higher risks of foodborne illness (bacteria love meat precisely because it’s so protein-rich). But if a vegetarian wants a high-quality food source, they must combine their protein sources and eat them at generally the same time to get the same benefits Calvin the Carnivore gets from his slab of hamburger. (I think it was within the same day, but will have to find evidence and document for you.)

To all you brave vegetarians and especially vegans out there, I salute you. It takes a lot of effort and planning to eat like you do and stay healthy.

microwave cooking

In one of my most recent labs, we tried using the microwave for a few of the major food groups (my midsection still winces at the memory of those microwaved muffins). Microwaves work by exciting the molecules in food directly with radio waves. This type of ‘radiation cooking’ is considered pretty harmless, but it’s probably not a good idea to stick your face up close to the door. The excited molecules transfer their energy to surrounding food particles and thus heat the food. The more you stir and let them sit, the more evenly most foods will heat. Here’s a summary of what worked in our lab and what didn’t:

Bechamel (basic white sauce): perfection. But honestly, how can something that has so much butter taste bad? This was quite simple and a viable alternative to the stovetop method but not really a timesaver. You have to stir and test the sauce so often that it feels like the microwave door is never closed. We made it with margarine and reconstituted nonfat dry milk (NFDM), which sounds gross but didn’t taste too bad.

Stale bread: not so great. Since we let the test subject cool off before tasting, it ended up even staler than before due to moisture loss.

Ground beef: shaped into a patty ~1/2 inch thick and set on a plate sprayed with PAM. Did you know the colour of a patty doesn’t necessarily indicate its doneness? This is why it’s so important to actually use a thermometer to check cooked meat (internal temperature should be 160 F). We ended up with a decently brown colour and a good internal temperature, but the meat tasted rubbery and gross (secondhand report, I wasn’t brave enough to try it). Why? Great question.

Carrots: cut into long, thin slices and placed in bowls with water. We covered one bowl and left the other open for 2 minutes at full power to observe the steaming effects. Rather to no one’s surprise, the covered carrot won the doneness taste test. It was sweeter, flatter, lighter, and softer than the uncovered carrot. Steaming added convection heating (hot air/liquid constantly rising to top of an enclosed space) to radiation heating (microwaves), allowing the covered carrot to cook more thoroughly and evenly.

Muffins: we made a basic muffin mix (NFDM, flour, baking powder, sugar, salt, egg and oil) and poured it into 6 Pyrex cups sprayed with PAM. 3 went into the microwave, 3 into the oven. Microwaved subjects were (or would have been, if not for experimental error) larger than oven subjects and had this horrible gluey, tough texture where oven subjects were slightly crisp on the outside and firm on the inside. Why? I’d guess the swift heating did something to the starches-or didn’t do something which the slow heating accomplished, but again, great question. I’ll have to ask at the next test-tomorrow.

So if  you’re out of time and want to eat hot and healthy, microwave steam some veggies. Don’t go for the muffins, unless you’re sure of the recipe. This one looks tasty. I’ll try it sometime and let you know how it goes.

night before the test

Well, the title says it all. I’m studied-or more accurately-hulu’d out. Here’s a bit of today’s material for your enjoyment:

Foodborne illness is a broad term that applies to any illness transmitted to humans by food. Food infection is more specific to illnesses brought on in humans by eating food full of bacteria or other living microorganisms, while food intoxication is specific to ingesting food full of toxins. A foodborne outbreak is defined as two people getting the same disease from the same contaminated and ingested source. Cheery work, ain’t it?

The most recent high profile foodborne outbreak covers nearly half the states and involves contaminated Colorado cantaloupes. Why would the contaminated cantaloupes be in so many different places? Maybe the farm is just huge, or maybe the pathogen affected crops that were harvested at different times. There are currently 100 reported cases but could be many more, because foodborne illness is often underreported due to embarrassment or belief that it’s not really a big deal. Listeria (the cantaloupe contaminant) isn’t even usually found in produce-just in meat and soft, unpasteurized cheese. It’s a coward that only affects the weak (pregnant women, young children, compromised immune system patients, or the elderly). The reason it’s so scary is that it can grow quite well at refrigerator temperatures, something normal bacteria can’t do. All affected cantaloupe should be off store shelves as of now, but it can take quite a while to show symptoms of listeriosis so cases are still being reported.

Well, hope you enjoyed that. I’m off to study yet more, and hulu yet less.

food evaluation: sensory criteria

All non-personal information and quotes in this post come from Understanding Food: Principles and Preparation (fourth edition) by Amy Brown (chapter 1, pages 1-5). I have substantially modified wording and pulled out important concepts. If you, blog audience of currently 0, notice a problem with my citation form, please let me know.

People evaluate food based on many, many criteria. Some of the most basic come from sensory data: how does this look, smell, taste, sound, and feel? Other things that can influence your decisions about specific foods are your memories, religion, culture, health, emotional state, wallet, and especially who you’re with (or not with).

Sensory data happens to be the easiest thing for marketers, food scientists, and chefs to manipulate, so this is where the study of food science starts: with a description of what each sense can measure. In deference to logic, I shall follow in part my textbook’s order of presentation: sight is usually the first introduction we have to a specific food. Grocery stores and the best restaurants have figured this out: I don’t even really like the taste of Lucky Charms, but I simply cannot walk by a box without craving it. And don’t even get me started on the Golden Arches. Sound may be presented at the same time as sight or anywhere throughout the continuum of introduction to swallowing, and is also a regrettably delectable byproduct of frying. The quintessential example of this category is the ‘snap crackle pop’ of Rice Crispies. Oh, how I crave thee now, sweet marshmallowy delicacy. Add to the list of things not to do when hungry: write about food.

Right up there with sound and sight in information we receive early about a food is its smell. (Trivia: Normal people can distinguish “2,000 to 4,000” different scents, while “some highly trained individuals can distinguish as many as 10,000.” Which, btw, would get major bragging rights in my book. Opera singer status.) They get you here with the fries. Have you ever walked by a pizza parlor or a teriyaki stand? You know it’s a bad idea. You know something that smells that good cannot possibly taste that good. It doesn’t matter. You are now inexorably, exhaustively hungry and the thought of your healthy carrot stick snack waiting at work simply does not cut it.

The next thing I notice is touch, how a food feels in the hands or the mouth or on the utensil. Depending on how hot that soup is, I may never even get to taste. Some interesting components of this category are astringency (the pucker reaction) and chemethesis (the reason we think of habaneros as hot and cucumbers as cool), which both seem more like flavour components than touch to me. But also in this category are the normal touch sensations of consistency, tenderness and texture. As all the good descriptor words were taken by the textbook, come to your own understanding about the difference between these two qualifications.

Last but greatest, taste. Foodie scientists have pulled out this category by subtracting smell from flavour in a 75:25 proportion and calling the remaining sense taste. Thus this sensation relies solely on your tastebuds and their chemical performance. We humans distinguish five specific tastes, dear imaginary blog reader: sour, salt, sweet, bitter, and umami (savoury). I had major umami for dinner tonight (which is a glaring misuse of the word, but it’s a little late for the rational editor to take over.)

Hope you enjoyed the first installment! Do not expect them all to be this long and detailed.

promises, promises

All right, I’ll have to stop commenting on how long it’s been since updates. That only reinforces the problem. Sorry about last month; school has obviously begun and homework (not to mention catching up on Hulu’s collection of One Piece) could not wait. That does not mean, however, that I can’t start writing again. (No one’s complaining yet!)

So here goes.

I’m a full-time nutrition student who also aims to work at least 10 hours every week, become a top-notch archer, protest abortion, pray more often, read more improving books, and organize a couple of major events this semester. I may be insane. That’s ok. But I have decided that since I have no time, YOU, dear blog audience of 0, will also receive whatever benefit I am able to wring from my first-class college education. For this month of October, I will be posting an article every weekday summarizing a class topic in hope that it helps me on the next few tests 😉 Most of this information will be easily verifiable from common knowledge internet sources (wikipedia, googling, etc.) but for kicks I will cite. Enjoy, and pray with me that this will get off the ground!