Question

In lectures we have put together the pieces of the big picture, so now you know that carbohydrate metabolism and respiration of glucose is linked with fat metabolism and protein metabolism. You can see how they are all interconnected, and how one can turn into another, if not used for energy. On the metabolic map you can see how excess glucose can be turned into fat, excess amino acids can be turned into glucose or fat, and why fat cannot be turned into glucose. So, using the metabolic map, I want you to explain the following situation: Ms. JP is a 45 year old patient, who has been trying to lose weight with a very low fat diet. Her food intakes consist mostly of carbohydrate-rich foods, such as breads, potatoes, rice, fruit, with very little fat- she tries to avoid salad dressings, fatty foods, fried foods, any fats and oils, etc. Recently, Ms.JP came for her checkup to a family doctor and had to do a routine blood work, which revealed that her blood triglycerides were high and her blood sugar indicated border-line diabetes! Her physician diagnosed her with Metabolic Syndrome. Ms. JP was shocked! She thought, she was eating so healthy! What is wrong with this picture? How can it be that Ms.JP's serum triglycerides are high, even though she is on a low-fat diet? Explain, using the steps on the metabolic map how exactly excess carbs turned into fat in this patient. Explain step by step: what compound turns into what compound on the map. (Hint: use the Metabolic Map Video for help - find it in the Supplemental Videos in your lecture resources)

Answer 1

Even though Ms. JP has followed a very low-fat diet, her triglycerides level raised. This is because of her high intake of carbohydrate diet that converts into fat. When the body consumes a high amount of carbohydrate it turns into starch after metabolism and stored as glucose in the body. The insulin secreted by the pancreas transmits this glucose into the body cells which utilizes as energy. Intake of too much of carbohydrate increases the blood glucose level and insulin are resistance to excess glucose. This excess glucose is converted into triglycerides and stored in the liver. If it is not utilized further it builds up the triglyceride level and simultaneously blood sugar level. Thus the Ms. JP carbohydrate diet increases her blood triglyceride level.

Glucose

I

Fatty acids --- Triacyl Glycerol ----Glyceraldehyde ------ Glucose 6 phosphate

I

Fructose 6 phosphate

I

Fructose 1,6 BIS phosphate

I

Phosphoenolpyruvate

I

Pyruvate ----------- ketone bodies ------- fatty acids

I |

Acetyl CoA

I

Fatty acids