Class 8A – Nutrition and Health – Questions from Students for Exam 1

Joseph Dixon ♦ February 18, 2019 ♦ Leave a comment

Here are great questions from 2 students in class:

Student 1:

Hello Professor,   I have some questions on material regarding the first exam, which I am honestly a bit nervous about. I haven’t taken a science class since my sophomore year of high school and was never really good at it. I’d also like to come to one of your office hours after the exam to go over it if that’s possible, but here are the questions I have:

– Is DSHEA a good or bad thing? From the lecture and research I’ve done, I’ve seen more thing saying it is a negative addition to the field of nutrition, but I thought it was good because it had such benefits like making FDA responsible, established a term for dietary supplements, etc.

Answer: DSHEA is a terrible law! It totally tied the hands of the FDA to regulate dietary supplements.   It has caused the supplement industry to become huge! And the 40 billions of dollars Americans spend on supplements is probably 98% wasted money. I believe it is one of the earlier examples of the assault on science and the truth.

– Do we need to know the specifics on experiments? For example, the Vitamin C experiment?

Answer: You do not have to know the specifics. The nutrient balance study is performed by giving an animal or human a specific nutrient free diet and depleting them of a specific vitamin or mineral. Then it is added back to their diet. Many of these studies were done in the early 1900s. We learned an amazing amount from these students. The vitamin C one was just an example. I call these studies the first Foundation of Nutrition – without them we would not know much about vitamins. The “Media Nutrition Experts,” who push supplements, would have think we don’t know much about vitamins, but we do. So I want you to know about these.

– Chapter 3 is where I had the most questions and where most of my confusion began. Am I right to say that we discussed the mechanism of fire because their use of energy is similar? Also I did not understand the question “Does the cell use little fires for energy?”

Answer: Fire and metabolism are similar in ways and not similar in ways. I have made a list:

Fuel   –   both use reduced compounds for fuel – long hydrocarbons are the best!

Oxygen – both use oxygen in the exact proportions to the carbons burned

Carbon dioxide – both produce carbon dioxide

Steps involved – fire – only needs a few direct steps; metabolism is in a human – may require 20 to 40 enzyme reactions – a long process

Where it takes place – fire – in an open space; metabolism in a human – inside the cells of the body, which are very small.

– Also I did not understand the question “Does the cell use little fires for energy?”

Answer:   Well, do they??? No, it is impossible, so the cell must get energy using a different process – it is called metabolism. This question is a thought question.

– It’s not on the review sheet, but will we need to know the process of photosynthesis and how to create/draw the bonds involved in that process?

Answer: Photosynthesis is one of the most complicated processes ever conceived – you don’t need to know it or draw bonds! I wish I knew it!

– Is glucose transported into the intestinal enterocyte through hepatic portal circulation?

Answer: Glucose is transported into the intestinal enterocyte from the lumen of the intestine into the enterocyte cell using the sodium/glucose co-transporter (discovered by Dr. Crane). Only after it is transported out of the enterocyte does glucose enter the blood of the portal vein and go to the liver.

– Is the storage polysaccharide in animal cells starch or glycogen? In my notes I have references to both being the answer. Answer: Starch is in plants; Glycogen is in human cells

– Would the total kcal of glycogen stored in humans be located in your chapter 4 part 1 powerpoint on page 34? Answer: It is located in several places – especially the big diagram where I went over glucose uptake and distribution. Total amount is about 2600 Kcal total. Liver holds what_______? Muscle holds ______?

– Do we need to know how to draw the mono/di/polysaccharides or be able to say it’s for example glucose-glucose, glucose connected with alpha bonds, etc.?

Answer: You do not need to drawn anything right now. It is good to know that they are linked with alpha bonds because human digestive enzymes can break them down.

– Will we have to describe the historical story of carbohydrates? Answer: Everything that is on the story of carbohydrates Super diagram is in the other slides. You just need to know the BIG Stuff, like historically, all grain were hand ground. Also, we make high fructose corn syrup from mostly cornstarch.

– I was unable to find the major tissue that will not take glucose up if a person is Type 2 diabetic.

Answer: It is muscle: I mentioned this several times in class- after hundreds of millions of dollars of research we still don’t know why muscle stops taking up glucose in Type 2 diabetes. Therefore, the glucose goes very high in blood – called hyperglycemia!

Student 2:

I am emailing in regards to a question I had about the exam. I am wondering if we need to memorize the nutrition timeline or the years, or should we just know why it is important? Hope to hear from you soon.

Answer: It is a hard question to answer.  I think the ages of Nutrition as opposed to individual years are important to know and DSHEA is important to know.  But I think it is good to have an idea how nutrition has advanced over the past 120 years or more.

Thanks for the Great Questions!  Joe Dixon