It’s been confusing to me why eating soluble fiber reduces cholesterol levels. It’s usually presented as reducing cholesterol absorption from food but that didn’t make sense since food sources of cholesterol have little impact on our cholesterol levels.
I looked into this and here’s the explanation (I have no biochemistry background so please verify this for yourself).
Soluble fiber binds with bile acids – which are made of cholesterol. This removes bile acids from your system – and the liver then pulls cholesterol from the blood to make new bile acid, reducing the cholesterol level in the blood.
The soluble fiber that binds with bile acid is then excreted through the feces.
Soluble fiber in your gut – say from breakfast – impacts the bile acid absorption for up to 18 hours. It takes about 1.5 cups of cooked oat meal or 1-2 tsp of Metamucil (psyllium fiber) to do this.
Adding oat bran to oatmeal is beneficial, but once you’ve added 2 Tbps, you’ve probably maximized the benefit. Once you’ve got 3-5 grams of soluble fiber in the gut, you’ve maxed out the absorption of cholesterol.
Soluble fiber interacts with bile acid – and not much with the food you eat.
Our body’s maximum production of cholesterol is at night, peaking between midnight and 4 am, up to 3x greater production at night than during the day.
Some people take statin medications to lower cholesterol levels. Some take them in the morning but some have to be taken at dinner. Why? Statins with a shorter half life need to be taken at dinner so that they reduce the overnight production of cholesterol, while other. Some statins, like rosuvastatin, have a longer half life and are typically taken with breakfast (they work all day).
Related
Why doe eating pistachios and certain other nut lower cholesterol?
Here’s an answer from AI assistance.
Eating pistachio nuts lowers cholesterol through a combination of replacing unhealthy fats, blocking cholesterol absorption, and modulating specific metabolic enzymes. Research indicates that pistachios can reduce LDL (“bad”) cholesterol by approximately 9–12% when consumed as part of a healthy diet, a reduction comparable to the effect of statin medications
Here is how they work:
1. Superior Fatty Acid Profile
Pistachios are rich in monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). When you eat pistachios, these healthy fats replace saturated fats (found in red meat and butter) in your diet. This shift directly lowers the liver’s production of LDL cholesterol and improves the overall lipid profile https://www.sciencedirect.com/science/article/pii/S0002916523241581 https://www.sciencedaily.com/releases/2008/09/080926105025.htm.
2. High Phytosterol Content
Pistachios contain the highest concentration of phytosterols (plant sterols) of any nut. Phytosterols have a chemical structure similar to cholesterol, which allows them to compete with cholesterol for absorption in the digestive tract. By blocking the body from absorbing dietary cholesterol, phytosterols force the liver to pull more cholesterol from the blood to process, effectively lowering blood levels https://www.sciencedirect.com/science/article/pii/S0002916523241581 https://www.sciencedaily.com/releases/2008/09/080926105025.htm.
3. Fiber and Antioxidants
The fiber in pistachios binds to cholesterol in the digestive system, preventing it from entering the bloodstream. Additionally, pistachios are rich in antioxidants like lutein, gamma-tocopherol (a form of Vitamin E), and flavonoids. These compounds help prevent LDL cholesterol from becoming oxidized, a key step in the formation of arterial plaque https://www.sciencedirect.com/science/article/pii/S0002916523241581 https://www.psu.edu/news/campus-life/story/pistachios-lower-cholesterol-provide-antioxidants.
4. Regulation of Metabolic Enzymes (SCD Activity)
A distinct mechanism identified in clinical studies is the effect on stearoyl-CoA desaturase (SCD), an enzyme that converts saturated fats into monounsaturated fats. Pistachio consumption has been shown to reduce SCD activity. Since high SCD activity is linked to higher cholesterol and triglyceride levels, lowering this enzyme’s activity helps reduce overall lipid levels in the blood https://www.sciencedirect.com/science/article/pii/S0002916523241581 https://www.sciencedaily.com/releases/2008/09/080926105025.htm.
Dose-Dependent Results
Studies show a “dose-response” relationship:
- 1 serving per day (approx. 1.5 oz or 30g) can lower LDL cholesterol by about 9%.
- 2 servings per day (approx. 3 oz or 60g) can lower LDL cholesterol by about 11.6% and significantly improve ratios like total cholesterol to HDL https://www.sciencedirect.com/science/article/pii/S0002916523241581 https://www.psu.edu/news/campus-life/story/pistachios-lower-cholesterol-provide-antioxidants.
By incorporating pistachios into a Mediterranean-style diet, patients can achieve significant heart health benefits, potentially reducing the risk of early death without the side effects often associated with medication https://www.sciencedirect.com/science/article/pii/S0002916523241581.
