Oats (Avena sativa L.) are grown worldwide and provide a necessary food staple for people in many countries. Avena sativa is commonly eaten or taken as a medicinal supplement for its highly-acclaimed health benefits.
The plant is comprised of a seed (oat), leaves and stems (oat straw), and bran (the outer layer of the whole oats). Various parts of the Avena sativa plant are used to make medicinal herbal supplements, providing a wide range of health benefits.
Parts of the Plant
The various parts of the plant include:
- The fresh milky seed: These are oats that are harvested early, during the “milky” stage. Early-harvested oats have the highest level of minerals, such as potassium and magnesium, and are available as a supplement.
- The mature seed: These are eaten as food (oatmeal). Oatmeal is rich in nutrients such as silicon, manganese, zinc, calcium, phosphorus, and vitamins A, B1, B2, and E. This is the endosperm, which is the usual product of milling.
- Whole oat groats: Groats are whole grains. The hulled kernels include the cereal germ, fibre rich bran, and endosperm. Whole oat groats contain high levels of nutrients such as soluble fibre, proteins, unsaturated fatty acids, vitamins, minerals, and other phytochemicals.
- Oat straw: These are the leaves and stems of the plant, which contain very high iron levels, as well as manganese and zinc.
- Oat (oat bran): This soluble fibre has been linked to improving heart health and lowering cholesterol. Oat bran can be found as a whole-grain food product as well as a medicinal supplement.
The outer husk of the oat must be removed, as it is not digestible by humans.
Health Benefits
Oats are a rich source of protein, minerals, fats, beta-glucan, polysaccharides (complex carbohydrates), and dietary fibre. They also contain many other nutrients, such as antioxidants, and lipid (fat) lowering chemicals, which include flavonoids, saponins, and sterols.
Avena sativa has been examined in clinical research studies as a remedy for many medical conditions. However, more clinical research evidence is needed to prove its safety and effectiveness.
Oats have been linked to benefits in conditions such as:
- Anxiety
- Bladder weakness
- Constipation
- Diverticulosis
- Gout
- Inflammatory bowel disease
- Irritable bowel syndrome (IBS)
- Joint and tendon disorders
- Kidney conditions
- Nerve disorders
- Opium and nicotine withdrawal
- Gallstones
- Skin disorders
- Stress
Oats have been examined in clinical research studies and found to offer many health-promoting effects. Oat bran may block substances that contribute to diabetes and high cholesterol. It may also provide a feeling of fullness, helping to promote weight loss.
Cholesterol-Lowering Effects
Studies have found that oat beta-glucan may lower fats (lipids and lipoproteins) in the blood. Eating oatmeal and oat bran lowers total blood cholesterol and "bad" cholesterol.
In a 2016 study, oat bran as a fibre source significantly lowered lipoproteins, both total cholesterol, and LDL. Lipoproteins are a combination of proteins and fats that move through the blood. By reducing these lipoproteins, oat bran lowered the risk of heart disease in those with mildly high cholesterol levels.
Avena sativa is thought to lower cholesterol by providing high amounts of fibre in the diet. At least 750mg of soluble fibre per serving supports health claims of lowering the risk of heart disease.
Heart Health
In 1997 the Food and Drug Administration (FDA) approved the heart health benefit of fibre from oats. It started allowing products to list this benefit on their packaging. Oat bran was also found in some studies to lower blood pressure.
Nervous System Effects
Studies found that Avena sativa supported cognitive performance in stressful situations and boosted overall healthy mental functioning.
In one study, a 1,600mg dose of oat herb extract was found to improve attention, concentration, and the ability to maintain focus during tasks performed by adults at various levels of cognitive functioning.
Immune Response
Studies have found that beta glucan helped white blood cells reach the site of infection quickly and improved the white blood cell’s bacteria-killing properties.9
