Oatmeal is not only a simple and tasty comforting way to start your day, but this popular breakfast choice also provides powerful heart-health benefits. Oats, scientifically known as Avena sativa, are a whole grain food. Some processing of the grain is involved to yield the edible flakes you make into oatmeal, blend into smoothies, or grind into flour. Oats offer a range of nutritional benefits. Most notably, studies show that eating oats can lower total cholesterol and low-density lipoprotein cholesterol (LDL) cholesterol blood levels, known risk factors for heart disease. 
Let’s dive into the research behind oats and cholesterol.
How do oats lower cholesterol?
Oatmeal is rich in viscous soluble fiber, specifically one called beta-glucan. One serving of oatmeal (½ cup or 40 grams of dry oats) contains approximately two grams of beta-glucan.  Fibers are not broken down during digestion, and viscous soluble fibers, like beta-glucan, move through the digestive tract slowly and absorb water along the way to form a gel-like substance.
To appreciate how soluble fibers like beta-glucan lower cholesterol levels, it's important to understand how they interact with bile. The liver uses cholesterol to make bile, a substance that is then stored in the gallbladder and released into the gastrointestinal tract to help break down any fats present during digestion.  The sticky, soluble fiber gel in the intestines binds to the cholesterol-containing bile, blocking its reabsorption and forcing it to be excreted along with it through stool instead. As a result, the liver has to produce more bile, so it pulls cholesterol from the blood to do so, thereby leading to lower blood cholesterol levels.
While all soluble fibers work in this manner to lower cholesterol, beta-glucans are especially efficacious. And the scientific evidence supporting beta-glucans is so strong that the United States Food and Drug Administration (FDA) allows food manufacturers to advertise that their oat products are heart-healthy. 
How much can you expect your cholesterol to lower from eating oats?
The cholesterol-lowering effect of oats, in particular, is well-documented, but the exact effect size varies between studies. That is likely due in part to the variability in study designs including the serving of oats eaten, the form in which they were consumed, and the study length. Nonetheless, most research supports that daily intake of oats can reduce total cholesterol and LDL cholesterol levels by approximately 4-10 percent. [5-9] While this is a lesser effect than the cholesterol-lowering abilities of medications like statins, this cholesterol reduction is still beneficial since it can be achieved with an affordable and side-effect-free bowl of oatmeal.
How quickly does oatmeal lower cholesterol?
Current evidence suggests daily oatmeal intake can lower cholesterol in five to six weeks.  However, some studies report significant declines in total and LDL cholesterol in as short as four weeks.  However, consistency over time is key to lowering cholesterol, and some people may see changes more quickly than others. Getting a cholesterol test every three to six months allows you to see how those dietary changes impact your blood cholesterol levels.
How much oatmeal should you eat a day to lower cholesterol?
According to the FDA, three grams of beta-glucan daily can help reduce LDL cholesterol levels and the associated cardiovascular disease risk.  To get that quantity of beta-glucan, you would need to eat 1.5 servings of oatmeal (¾ cup or 60 grams of dry oats) daily. This statement is in line with current research, which reveals cholesterol-lowering effects between 40 and 100 grams of dry oats per day. [5-8] It is unclear whether less frequent consumption of oatmeal would have the same effect.
What type of oatmeal is best for lowering cholesterol?
Oats come in different varieties and are processed to varying degrees for palatability and cooking ease. 
- Steel-cut oats: Steel-cut oats are the least processed type of oat. The oat groat is simply cut into two to three pieces with a steel blade. They are chewy in texture and require soaking and extended cooking.
- Old fashioned or rolled oats: Rather than cutting the oat groats into pieces, the oats are steamed, pressed with a roller, and then dried. This significantly reduces cooking time with no soaking required and provides a creamy texture.
- Instant oats: Similarly to rolled oats, instant oats are also steamed and rolled, but for a longer period, and they are rolled into even thinner pieces. As a result, they absorb water easily and cook very quickly.
All three oat varieties are considered whole grains and contain nearly identical amounts of beta-glucan fiber. Since steel-cut oats are the least processed, they typically contain slightly higher amounts of fiber.  But despite their similar beta-glucan contents, some scientists note that the processing of oats and the form in which they are prepared likely changes the properties of beta-glucan and how it works in the body. [10,14] Many studies have not reported the physiochemical or structural characteristics of the oat products used or the exact quantity of beta-glucan in the product. There is also variability in the form and manner that the oat-containing foods were prepared (for example, were they prepared with water, milk, or a milk alternative, and what other foods if any were consumed at the same time).
As such, it is unclear at this time if and how the type of oat impacts its ability to lower cholesterol. What is evident, however, is that oat consumption is linked to lower cholesterol, so any type of oat will do if you're looking for cholesterol-lowering benefits.
What’s the best way to prepare oatmeal to help lower cholesterol?
How you prepare a daily bowl of oatmeal can either boost the nutritional value of that meal or leave your taste buds bland and your stomach unsatisfied. Here are a few ways to help spruce up your bowl of oatmeal.
Add even more fiber: Yes, oats already contain fiber, but there are several foods you can mix into oatmeal to up that fiber count even more.
- Fresh or frozen fruits (berries, bananas, apples)
- Chia seeds
- Ground flax meal
- Pumpkin puree
Add protein and healthy fats: Protein and fats are key nutrients that help prevent blood sugar spikes, boost satiety after the meal, and fight inflammation. These effects also influence heart health. [15,16]
- Nuts (almonds, walnuts, pecans, etc.)
- Seeds (pumpkin, hemp, sunflower, etc.)
- Nut/seed butters (peanut butter, almond butter, sun butter)
- Milk or milk alternative (soy and cow’s milk offer the most protein per serving)
- Protein powder (mix in a scoop of your protein powder)
Add flavoring agents: Consider adding some spices or extracts to further enhance the flavor of your oats.
- Pumpkin pie spice
- Vanilla extract
- Almond extract
While pre-portioned oatmeal packages are a convenient option, they often include high amounts of added sugar and salt. Instead, opt for plain oats (which can also come in instant single-serve packets) and add your own flavorings instead.
If oatmeal is not your breakfast of choice, there are many other ways you can incorporate oats into your diet and still reap their heart-healthy benefits. You can also:
- Blend oats into your smoothies
- Mix oats into baked goods or pancakes
- Make snack bars, energy balls, or homemade granola with oats
There is strong evidence to support the cholesterol-lowering effects of oats, which is attributed to their high concentration of the soluble fiber beta-glucan. Eating approximately ¾ cup of oats per day (about 1.5 servings of 60 grams of dry oats) can be an easy, side-effect-free, and tasty way to help lower cholesterol levels and promote heart health.