News on Nutrition
Passed on from shesqueals :
www.msnbc.msn.com/id/38528158/ns/health-diet_and_nutrition/
After having read the book Good Calories, Bad Calories by Gary Taubes I can't say I'm surprised by this. It is well explained in his book how the human body processes fat in food differently from carbohydrates in food, along with the associate hormone and metabolic responses, and is similarly supported by several articles I have read more recently which go into the mechanisms of LDL / HDL production.
In a nut shell:
LDL and HDL are both Lipoproteins, meaning there is a protein in the structure of the molecule that attaches and collects lipids (fats).
LDLs use APO B proteins as their structural foundation, while HDL's use APO A proteins. Both are made by cells, mainly in the liver.
When a diet higher in carbohydrates is eaten (typical of many low fat diets) the body produces Insulin so that the cells can absorb the carbohydrates into the cells to break down. Insulin also triggers the liver to collect excess carbohydrates out of the blood and converts them into triglycerides (a type of fat). It then makes APO B proteins to package them into LDL to be shipped to fat cells for storage. In short, APO B protein is associate with LDLs (made from carbohydrates) being shipped from the liver to the tissues.
When a diet higher in fat and protein is eaten (and lower in carbohydrates) the liver is stimulated to produce APO A protein whose job it is to collect triglycerides, VLDL, and cholesterol out of the blood stream to create molecules of HDL (mono-unsaturated fats seem to have the greatest stimulatory affect in this, or are easily absorbed by APO A proteins). The HDL is either transfered back to the liver to be oxidized into a useful form, or prepared for excretion from the body. The side benefit is that while APO A is absorbing the blood triglycerides, it also absorbs arterial deposits of triglyceride plaques. In short, APO A protein is associated with HDLs (made from free triglycerides) being shipped from the tissues and blood back to the liver.
On a side note, on a low carbohydrate diet blood sugar tend to be low, stimulating the pancreas to make glucagon (a hormone that is the opposite of Insulin) that increases the amount of cellular fat breakdown.
Hence why the article makes sense that higher fat/protein diets stimulate the production of more HDL than the low fat/high carbohydrate diets.
One caveat about this explanation: It is very simplified and leaves out quite a bit concerning the mechanisms involved. Also, I am not an expert, and can only say this is my understanding of the topic from what I have read as a biology teacher. I believe it is accurate, but if anyone finds any mistakes in the above explanation, please let me know.
www.msnbc.msn.com/id/38528158/ns/health-diet_and_nutrition/
After having read the book Good Calories, Bad Calories by Gary Taubes I can't say I'm surprised by this. It is well explained in his book how the human body processes fat in food differently from carbohydrates in food, along with the associate hormone and metabolic responses, and is similarly supported by several articles I have read more recently which go into the mechanisms of LDL / HDL production.
In a nut shell:
LDL and HDL are both Lipoproteins, meaning there is a protein in the structure of the molecule that attaches and collects lipids (fats).
LDLs use APO B proteins as their structural foundation, while HDL's use APO A proteins. Both are made by cells, mainly in the liver.
When a diet higher in carbohydrates is eaten (typical of many low fat diets) the body produces Insulin so that the cells can absorb the carbohydrates into the cells to break down. Insulin also triggers the liver to collect excess carbohydrates out of the blood and converts them into triglycerides (a type of fat). It then makes APO B proteins to package them into LDL to be shipped to fat cells for storage. In short, APO B protein is associate with LDLs (made from carbohydrates) being shipped from the liver to the tissues.
When a diet higher in fat and protein is eaten (and lower in carbohydrates) the liver is stimulated to produce APO A protein whose job it is to collect triglycerides, VLDL, and cholesterol out of the blood stream to create molecules of HDL (mono-unsaturated fats seem to have the greatest stimulatory affect in this, or are easily absorbed by APO A proteins). The HDL is either transfered back to the liver to be oxidized into a useful form, or prepared for excretion from the body. The side benefit is that while APO A is absorbing the blood triglycerides, it also absorbs arterial deposits of triglyceride plaques. In short, APO A protein is associated with HDLs (made from free triglycerides) being shipped from the tissues and blood back to the liver.
On a side note, on a low carbohydrate diet blood sugar tend to be low, stimulating the pancreas to make glucagon (a hormone that is the opposite of Insulin) that increases the amount of cellular fat breakdown.
Hence why the article makes sense that higher fat/protein diets stimulate the production of more HDL than the low fat/high carbohydrate diets.
One caveat about this explanation: It is very simplified and leaves out quite a bit concerning the mechanisms involved. Also, I am not an expert, and can only say this is my understanding of the topic from what I have read as a biology teacher. I believe it is accurate, but if anyone finds any mistakes in the above explanation, please let me know.