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I found an ad for a nutritional supplement called Plant Enzymes. This is a "Dear Abby" letter from a food critic with digestive problems, and he is looking for advice.

Dear Abby:

I am food critic who writes for a major weekly news magazine. I love all types of food from all around the world. My problem is that almost every time I eat, I get heartburn, diarrhea, cramps, or constipation. It is getting so bad that I am starting to wonder if I should find a new job and eat only the few foods that still agree with me (Saltine crackers and turkey jerky). My girlfriend works in a health food store. She says that I should try a nutritional supplement called Plant Enzymes. She says that her customers are buying up bottles of this stuff as fast as they can keep it in stock. But I don't want to waste my money on something that won't do any good. Abby, can you please explain what enzymes are and tell me whether I should buy this product?

Sincerely, Chronic Indigestion.

Dear Chronic:

I am sure this problem is very frustrating for someone in your line of work! Let me see if I can help.

To begin with, you asked about enzymes. Enzymes are molecules that help speed up chemical reactions inside the body’s cells. For example, when you eat a meal, you are really eating a mix of carbohydrates, fats, and proteins. Once the food is inside your body, enzymes go to work, cutting up the molecules into small pieces that your body can use. The body uses some of those small pieces to fuel its mitochondria, which are microscopic ‘furnaces’ that generate a molecule called ATP. That’s called respiration. Unlike food, ATP is a form of energy that the body can directly use. In a similar way, a power plant uses energy in coal to generate electricity. Our cells also use food molecules to build new molecules. For example, when you eat a protein-rich steak, your digestive enzymes cut the protein into small pieces called amino acids. Then, your cells use those amino acids to build new proteins.

It turns out that enzymes are one of many classes of proteins. The product you are asking about contains plant enzymes; the people who manufacture Plant Enzyme pills claim that the eight plant-derived enzymes in their product will help you digest your food. The enzymes in the product are amylase, proteases, cellulase, lactase, lipase, bromelain, and papain. The fact is that your body makes most of these enzymes itself! Some of them break down two-ringed sugars (disaccharides) like lactose. The human body can easily digest these sugars to make the fuel that generates ATP. So we don’t need plant-derived lactase – we make it ourselves. Another enzyme we make ourselves is amylase, which begins the digestion of starch. We also make plenty of proteases, which break proteins down into amino acids.

There are two enzymes in the product that we don't make ourselves: bromelian and papain. Bromelian is a protease derived from pineapple, and it's why grandma never adds raw pineapple to Jell-O: the bromelain digests the gelatin so it can’t gel. Papain is also a protease, but derived from papaya. I'm not sure why they added these to the formulation, but at any rate, we make protease ourselves, so we don’t need to get it from those fruits. Cellulase breaks down cellulose, a complex carbohydrate that plants produce and that our cells cannot digest. It therefore passes through the body intact. It might sound like a good idea to take cellulase enzymes, because you would get more energy from food. But cellulose is fiber, which lowers cholesterol, prevents cancer, and keeps your intestines working smoothly. I don’t think it’s wise to take cellulase, even if it would work in the human body.

And the fact is, it probably wouldn't work, and that goes for the other plant enzymes too. You can’t just eat an enzyme (or any other protein) and expect it to work inside your cells. Instead, when you eat the enzyme, you digest it into animo acids, then you use those small parts to build new molecules specific to your own body.

So, Chronic, I don't see any reason for you to waste your money on this Plant Enzymes product. Instead, you should see a doctor. You could also check the internet for some easy ways to manage heartburn and irritable bowel syndrome; you may have one or both of these disorders, which can be very uncomfortable.

Reference:
NowFoods. 2014. Plant Enzymes - 240 Veg Capsules. Accessed at http://www.nowfoods.com/Plant-Enzymes-240-Veg-Capsules.htm on 1/1/15.

[Note: this sample assignment is too long at 772 words. We included more details than are in our textbook. Chapter key words are bold-faced and in red -- notice how easy it is to use more than the required three].

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Contemporary Issues in Biology -- BIOL 1003 Mariëlle H. Hoefnagels, Ph.D. © 2004-2015. biology1003 at OU dot edu (at = @, dot =.) Last Updated August 5, 2014 11:02 PM