Studies show that eating oats every day can help lower cholesterol, especially low-density lipoprotein (LDL) cholesterol, which contributes to heart disease. This is largely due to a dietary fiber called beta-glucan, which helps remove LDL from the blood so the liver can break it down, reducing LDL levels by up to 10%.
How do oats help lower cholesterol?
Oats are rich in dietary fiber. The type of fiber thought to lower cholesterol is a soluble fiber called beta-glucan. Soluble fiber absorbs water to form a gel-like substance that increases intestinal viscosity (stickiness) and slows intestinal motility (movement through the digestive tract).
In addition to aiding digestion, the beta-glucan (OBG) in oats may help lower LDL cholesterol by interacting with acids in bile (digestive fluids).
Bile acids are synthesized from cholesterol in the liver and secreted into the small intestine to help break down fats when you consume food. OBG binds to these acids and prevents them from being reabsorbed in the intestine and returned to the liver for reuse. Removing bile acids in the stool forces the liver to take cholesterol from the blood to produce more bile acids, reducing the amount of cholesterol circulating.
Reducing LDL can significantly reduce your risk of atherosclerosis and coronary artery disease (CAD). LDL contributes to both of these diseases by promoting the formation of fatty plaques on the walls of the arteries, causing them to harden, narrow, and gradually restrict blood flow.
How much do you need?
Health experts suggest that the beta-glucan in oats may help lower blood cholesterol, reducing the risk of heart disease, and this health claim can be made on product labels. Eating 3 grams (g) of OBG per day, equivalent to 70 g (1 cup) of cooked oats, is thought to be enough to lower cholesterol levels. Eating more does not appear to provide more or less benefit.
Current studies also show that OBG has little or no effect on “good” high-density lipoprotein (HDL) cholesterol levels and has no significant effect on triglycerides (fats in the blood), which also contribute to heart disease.
Is one type better than another?
There is no evidence that one type of oats is inherently better than another for providing OBG. Other sources of OBG include uncooked oats, oat bran, and foods containing oats, which may be just as effective.
1. Cooked oats
Oats cooked in liquid will extract more OBG and increase their viscosity, unlike raw oats in granola or muesli. 10 Research suggests that viscosity plays a larger role in LDL reduction than the actual amount of OBG in raw oats.
2. Baked goods
Baking at high temperatures reduces the viscosity of OBG by drawing water out of the oat fibers. For some foods, such as oat-based breakfast cereals and pastries, this may limit their LDL-lowering ability.
3. Oat bread
Fermentation may enhance the effects of OBG in fermented foods such as yeast oat bread. The fermentation of OBG produces short-chain fatty acids, which may also help lower cholesterol.
4. Oat bran
Oat bran, the outer layer of the oat groat, is rich in both soluble and insoluble fiber. This may be a good alternative because the OBG in oat bran is more easily absorbed in the gut. However, you may need to eat more of it, as oat bran contains about 33% less OBG per serving than cooked oats.
Other Health Benefits of Oats
In addition to their effects on high cholesterol and heart disease, oats may be useful in treating other health conditions such as:
- High blood pressure: Oats contain a chemical called gamma-aminobutyric acid (GABA) that slows the heart rate and helps lower blood pressure.
- Type 2 diabetes: OBG may help control blood sugar by increasing intestinal viscosity, slowing the emptying of the intestines and the breakdown of glucose.
- Obesity: Oats slow intestinal motility and prevent blood sugar spikes, so people often feel fuller for longer after eating. This may help prevent overeating, which can lead to obesity.
Although oats have many benefits, they should not be considered a substitute for medical treatment for any condition. If you decide to include oats in your daily routine, do so as part of a healthy, balanced diet rich in fruits, vegetables, whole grains, lean proteins, low-fat dairy and healthy fats.
