Oats are a type of cereal grain that refers specifically to the edible seeds of oat grass. The Food and Drug Administration allows products with oats to claim on food labels a reduced risk of coronary heart disease with the consumption of beta-glucan, a soluble fiber from whole grain oats. Oatmeal is great for those trying to lose weight and control hunger levels due to its high water and soluble fiber content.
Oats are available in a variety of forms, based on how they are processed. The following are the types of oats in order of least to most processed. Although the nutritional content between steel-cut and instant oats is relatively similar, their effects on blood sugar are not. The least processed oats, like groats or steel-cut, generally take longer to digest so they have a lower glycemic index than rolled or instant oats.
- Oat Groats: The whole oat kernels that have been cleaned, with only the loose, inedible hulls removed. Groats contain the intact germ, endosperm, and bran. Oat bran, which contains the most fiber in a groat, can be removed and eaten as a cereal or added to recipes to boost fiber content.
- Steel-Cut or Irish: Oat groats that have been cut into two or three smaller pieces either using a steel blade. The larger the size of the pieces, the longer they will take to cook.
- Scottish Oats: Oat groats that have been stone-ground into a meal, creating a porridge-like texture when cooked.
- Rolled or Old-Fashioned: Oat groats that have been steamed, rolled and flattened into flakes, and then dried to remove moisture so they are shelf-stable.
- Quick or Instant: Oat groats that are steamed for a longer period and rolled into thinner pieces so that they can absorb water easily and cook very quickly. Be aware that many brands of instant oats come sweetened or flavored, so be sure to check the ingredients for no added sugar or toxic chemical flavorings.
The nutrient composition of oats is well-balanced. They are a good source of carbs and fiber. Oats also contain more protein and fat than most grains.
Oats are loaded with vitamins, minerals and antioxidant plant compounds. Half a cup of dry oats contains:
- Manganese: 191% of the RDI
- Phosphorus: 41% of the RDI
- Magnesium: 34% of the RDI
- Copper: 24% of the RDI
- Iron: 20% of the RDI
- Zinc: 20% of the RDI
- Folate: 11% of the RDI
- Vitamin B1 (thiamin): 39% of the RDI
- Vitamin B5 (pantothenic acid): 10% of the RDI
- Smaller amounts of calcium, potassium, vitamin B6 (pyridoxine) and vitamin B3 (niacin)
A half a cup of oats also has 51 grams of carbs, 13 grams of protein, 5 grams of fat and 8 grams of fiber, but only 303 calories. This means that oats are among the most nutrient-dense foods you can eat.
Oats contain large amounts of beta-glucan, a type of soluble fiber. Beta-glucan partially dissolves in water and forms a thick, gel-like solution in the gut. The health benefits of beta-glucan fiber include:
- Reduced LDL and total cholesterol levels
- Reduced blood sugar and insulin response
- Increased feeling of fullness
- Increased growth of good bacteria in the digestive tract
Beta-glucan fiber attracts water and increases the viscosity of digested food, which increases the volume of food in the gut. This slows down digestion and the rate that nutrients are absorbed, which in turn increases satiety. Short-chain fatty acids produced from bacteria that ferment beta-glucan fibers may also increase satiety through a chain reaction of events that regulate appetite hormones.
Cereal fibers, as found in wheat bran and oat bran, are considered more effective than fiber from fruits and vegetables. The breakdown and fermentation of beta-glucan oat fiber has also been reported to increase the diversity of gut microbiota. This may in turn improve certain digestive issues such as diarrhea, constipation, and irritable bowel syndrome.
Many studies have shown that the beta-glucan fiber in oats is effective at reducing both total and LDL cholesterol levels. Beta-glucan may increase the excretion of cholesterol-rich bile, thereby reducing circulating levels of cholesterol in the blood. Oxidation of LDL cholesterol, which occurs when LDL reacts with free radicals, is another crucial step in the progression of heart disease. It produces inflammation in arteries, damages tissues and can raise the risk of heart attacks and strokes. One study reports that antioxidants in oats work together with vitamin C to prevent LDL oxidation.
Whole oats are high in antioxidants and beneficial plant compounds called polyphenols. Most notable is a unique group of antioxidants called avenanthramides, which are almost solely found in oats. Avenanthramides may help lower blood pressure levels by increasing the production of nitric oxide. This gas molecule helps dilate blood vessels and leads to better blood flow.
In addition, avenanthramides have anti-inflammatory and anti-itching effects. Ferulic acid, also found in large amounts in oats, is another antioxidant. The FDA approved colloidal oatmeal as a skin-protective substance back in 2003. But in fact, oats have a long history of use for the treatment of itching and irritation in various skin conditions. Oat-based skin products may improve uncomfortable symptoms of eczema.
Note that skin care benefits pertain only to oats applied to the skin, not those that are eaten.
How to Buy
You can buy oats in bulk in your local co-op or packaged. If you buy packaged, be sure they are not flavored or sweetened.
Although oats are naturally gluten-free, they are sometimes contaminated with gluten. That’s because they may be harvested and processed using the same equipment as other grains that contain gluten.
If you have celiac disease or gluten sensitivity, choose oat products that are certified as gluten-free.
How to Store
Like all grains, oatmeal should be kept in an airtight container to discourage moisture and bugs. Store in a cool, dark cupboard up to three months or refrigerate up to 6 months.
Due to its high oil content, oat bran should be refrigerated.
Oats contain a natural antioxidant which discourages rancidity, thus oat flour has a bit longer shelf life than whole wheat flour. Refrigerate and use within 3 months.
How to Cook
- Oatmeal: A breakfast favorite, cooked oats pair well with fruits, nuts, and seeds. Follow package directions for exact cooking times. Generally, less-processed oats such as steel-cut take 25-30 minutes to cook, whereas instant oats take 1-2 minutes.
- Overnight Oats: A quick, easy no-cook solution for a nutrient-dense breakfast or snack. In a medium glass jar, add ½ cup old-fashioned or rolled oats (not instant), ½-1 cup liquid such as nut milk, and ½ cup of any chopped fruit (banana, melon, apple, grapes, berries). Additional optional ingredients include a few tablespoons of non-dairy yogurt, 1-2 tablespoons of chia/flaxseeds, nuts, or any spices. Complimentary spices for oatmeal include cinnamon, nutmeg, mace, and ginger. Tightly screw on the lid and shake the jar vigorously until all ingredients are incorporated well. Refrigerate overnight or for at least four hours. The oats will soften and the mixture will thicken into a pudding-like texture.
- Oat Flour: These are oats that have been ground to a flour-like consistency. Although it may be tempting to substitute oat flour for regular flour in baked recipes, keep in mind that oat flour lacks gluten, a crucial component that adds structure, moisture, and volume to a baked product; without it, cookies would crumble and breads would become dense and lack volume. However, oat flour can add chewiness to cookies and a boost of nutrients to breads. Substitute 25-30% of flour in a recipe with oat flour for best results.
- Oat Risotto: Oats can be used in savory dishes. An example is replacing rice in risotto with whole oat groats or steel-cut oats. Typically, the oats are first toasted for a few minutes in hot oil with aromatics like shallots or diced onion. Then vegetable stock and/or water are added, 1 cup at a time, stirring well after each addition, until the oats are cooked (about 25 minutes).
- Add ½ cup dry old-fashioned oats to batter, such as for breads and cookies.
- Add 2-3 tablespoons of oat bran to any hot or cold cereal
- Instant oatmeal may not be used interchangeably with rolled oats (old-fashioned oatmeal) or quick-cooking oatmeal. Since it has already been cooked and dried, it can turn your baked goods into a gummy mess.
- Oatmeal is commonly used in breads, muffins, cookies, granola, muesli, stuffings, and pilaf, but it is most widely consumed as a hot cooked cereal (porridge).
- Oat flour may also be used as a thickener in soups and stews.
- Since its gluten content is very low, oat flour needs to be combined with all-purpose gluten free baking flour when used in leavened breads or the bread will not rise properly.
- To make homemade oat flour, simply place rolled oats in your food processor and process to a flour consistency. Sift out any large particles.
Equivalents and Measurements:
- Oat flour may be substituted for up to 1/3 of the required whole wheat flour in baked goods.
- 1 pound old-fashioned rolled oats = 5 to 5-3/4 cups
- 1 cup rolled oats = 1-3/4 cups cooked
- 1 cup raw rolled oats = 3 ounces