Oats: Heart Health from an Ancient Grain
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Culinary Medicine
by Lori A Smolin, PhD and
Oats have been part of our diet for thousands of years, cultivated as early as the Bronze Age in Europe. [1] They are still popular today because they are relatively economical to produce and provide a variety of nutrients and phytochemicals. In the United States oats are most commonly eaten as oatmeal, but we also eat them in ready-to-eat cereals and granola bars, as well as in baked goods. [2] Eating oats can reduce your risk of heart disease and diabetes, help manage body weight, and promote gut health. [3,4]
Nutrients and Phytochemicals in Oats
Nutritionally, oats have several characteristics that set them apart from other grains. They are lower in carbohydrates and higher in fat, protein, and fiber than most cereal grains. A serving of oatmeal (1/2 cup uncooked) contains about 150 calories, 27 g carbohydrate, 2.5 g fat, 5 g protein, and 4 g fiber and provides thiamin and other B vitamins along with minerals like phosphorus, magnesium, iron, and zinc. Oats are high in soluble fiber, most of it from beta-glucans.[5] This soluble fiber forms a viscous solution when mixed with water and contributes to many of the health benefits attributed to oats[3,6] Oats also contain a variety of phytochemicals including phenols, flavonoids, and phytosterols. Avenanthramides, phenols unique to oats, are powerful antioxidants that also have antiproliferative and anti-inflammatory properties.[5] In addition, unlike many grains, oats are naturally gluten free. However, those with gluten sensitivity should look for oats specifically labeled “gluten-free” because most commercial oats in the U.S. are cross-contaminated with gluten.[7]
Oats and Health
Oats are best known for their effects on heart health. The beta-glucans in oats have been shown to lower blood levels of unhealthy LDL cholesterol.[7,8] The aforementioned viscous layer formed by beta-glucans in the small intestine inhibits the absorption of cholesterol and reabsorption of bile acids, which are made from cholesterol. The body then uses available cholesterol to synthesize more bile acids, lowering circulating levels of LDL cholesterol.[4] Short chain fatty acids produced by the microbial breakdown of beta-glucans in the gut may also reduce cholesterol synthesis. [3,9] The avenanthramide phytochemicals in oats further benefit heart health by helping prevent free radical damage that promotes atherosclerosis.[5]
Consuming oats also helps manage diabetes and keep body weight in a healthy range. The viscous nature of beta-glucans slows overall transit through the gastrointestinal tract. This slows the digestion of starch and the absorption of glucose in the small intestine, which delays and reduces the rise in blood glucose levels and insulin release after a meal. [Paudel]. By slowing stomach emptying and the absorption of nutrients beta-glucans increase satiety and reduce food intake, helping to manage body weight.[3,10].
The fiber in oats supports gut health, both by affecting fecal bulk and by promoting a healthy microbiota. [4] Beta-glucans, along with other fibers, increase the fecal volume and weight, which enhances the ease and frequency of bowel movements. The short chain fatty acids produced by fermentation of beta-glucans create an acidic environment that promotes the growth of beneficial microorganisms and inhibits the growth of pathogens.
Oat Processing: From Groats to Flour
How oats are processed affects their texture, cooking time, and health benefits. The least processed form of cooked oats are groats, which are whole oat kernels from which the loose, inedible hulls have been removed. They have a chewy texture and nutty flavor but take an hour to cook. Steel-cut, or Irish oats, are groats that have been cut into smaller pieces. They have a creamier texture and take about half the time to cook. Rolled, or old-fashioned oats, are further processed by steaming, rolling them into flakes, and then drying. Oatmeal made from rolled oats has a sweeter flavor and cooks in 5 to 10 minutes. Quick oats are a variation of rolled oats that are cut into smaller pieces and rolled thinner, allowing them to cook even faster. Instant oats are rolled even thinner and precooked, allowing them to rehydrate quickly in hot water or the microwave. While quick to cook, they are often high in added sugars. [11] Many ready-to-eat cereals are made from oats. Rolled oats are also used to make cold cereals such as granola and muesli as well as granola bars. Oat flour, which is made by finely grinding whole oat groats, is used to make popular breakfast cereals like Cheerios and Toasted Oats. Despite different levels of processing, all of these forms contain the bran, germ, and endosperm and are thus considered whole grains.
While all varieties of oats are healthy, the less processed forms are best because they take longer to digest, leading to a lower glycemic response, which is the change in blood glucose after eating. [12] Groats take the longest to digest. Steel-cut oats are still slow to digest, which makes them another good choice for blood sugar regulation. Old-fashioned oats are easier to digest and have a slightly higher glycemic response than groats and steel-cut oats but are still a healthy choice.[13]. Quick oats and instant oats are more processed and therefore more readily digested.
Ready-to-eat oat cereals made from oat flour are similar to quick or instant oats in terms of their effect on transit through the gastrointestinal tract and, if low in added sugars, glycemic response.[14] The potentials benefits of these on transit time and blood glucose may be reduced by the sugars that are commonly added to these cereals. Oat bran cereal, which consists of just the high-fiber bran portion of the grain, is high in beta-glucans and other fibers and is also lower in calories and carbohydrates than other oat products, making it a good choice for weight loss.
Eat Your Oats
Oats are a great choice for breakfast but can be eaten for any meal. They are an affordable and filling source of plant-based protein, provide plenty of fiber, and offer numerous health benefits. They easily fit into a vegetarian or vegan diet and can be enjoyed with a variety of toppings like fruit and nuts. On a lazy rainy weekend, you can spend an hour cooking some oat groats or make a batch of baked oats to last you through the week. Or, if you only have a minute, add water to some instant oats or pour some Cheerios into a bowl. When you are baking muffins or cookies, try replacing a quarter of your all-purpose flour with oat flour to increase the fiber in your cookies. In the evening, you can spend a few minutes preparing some overnight oats to have a healthy breakfast ready to go in the morning.
Recipes with oats:
References
[1] Stewart D, McDougall G. Oat agriculture, cultivation and breeding targets: implications for human nutrition and health. British Journal of Nutrition. 2014;112(S2):S50-S57. doi:10.1017/S0007114514002736
[2] Research and Markets Ltd. Research and Markets. researchmarkets2025. Accessed September 27, 2026. https://www.researchandmarkets.com/report/united-states-oatmeal-market
[3] Joyce SA, Kamil A, Fleige L, Gahan CGM. The Cholesterol-Lowering Effect of Oats and Oat Beta Glucan: Modes of Action and Potential Role of Bile Acids and the Microbiome. Frontiers in Nutrition2019;6(171). doi:10.3389/fnut.2019.00171
[4] Paudel D, Dhungana B, Caffe M, Krishnan P. A Review of Health-Beneficial Properties of Oats. Foods2021;10(11):2591. doi:10.3390/foods10112591
[5] Alemayehu GF, Forsido SF, Tola YB, Amare E. Nutritional and Phytochemical Composition and Associated Health Benefits of Oat (Avena sativa) Grains and Oat-Based Fermented Food Products. , ed.Capurso C The Scientific World Journal2023;2023:1-16. doi:10.1155/2023/2730175
[6] Londre R. Start your day with healthy oatmeal. Mayo Clinic Health System October 6, 2021. Accessed September 27, 2026. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/start-your-day-with-healthy-oatmeal
[7] Science Insights Team. Are Oats a Grain? Cereal Type, Nutrition, and Gluten – Science Insights. Science Insights March 12, 2026. Accessed September 27, 2026. https://scienceinsights.org/are-oats-a-grain-cereal-type-nutrition-and-gluten/
[8] Ho HV, Sievenpiper JL, Zurbau A, et al. The effect of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apo B for CVD risk reduction: a systematic review and meta-analysis of randomised-controlled trials. Br J Nutr. 2016;116(8):1369-1382. doi:10.1017/S000711451600341X
[9] Whitehead A, Beck EJ, Tosh S, Wolever TM. Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2014;100(6):1413-1421. doi:10.3945/ajcn.114.086108
[10] Rebello CJ, O’Neil CE, Greenway FL. Dietary fiber and satiety: the effects of oats on satiety. Nutrition Reviews2016;74(2):131-147. doi:10.1093/nutrit/nuv063
[11] Quakeroats.com2022. Accessed September 27, 2026. https://www.quakeroats.com/oats-do-more/why-oats/the-difference-between-our-oats
[12] Musa-Veloso K, Noori D, Venditti C, et al. A Systematic Review and Meta-Analysis of Randomized Controlled Trials on the Effects of Oats and Oat Processing on Postprandial Blood Glucose and Insulin Responses. The Journal of Nutrition Published online December 9, 2020. doi:10.1093/jn/nxaa349
[13] Kubala, J. 6 Healthiest Types of Oats for Fiber and Heart Health. Health. Jan 7, 2026.
[14] Wolever TMS, Johnson J, Jenkins AL, Campbell JC, Ezatagha A, Chu Y. Impact of oat processing on glycaemic and insulinaemic responses in healthy humans: a randomised clinical trial. British Journal of Nutrition2019;121(11):1264-1270. doi:10.1017/s0007114519000370