Oats are not usually used as a stand-alone treatment and tend to form part of an overall management program.
Several clinical trials have shown a marked reduction in total and LDL-cholesterol using oat-based cereals and also oat milk (6% reduction).
Oat bran has been shown to reduce LDL-cholesterol by 16% in 140 hypercholesterolaemic subjects consuming 56 g oat bran/day for 12 weeks. In overweight men consuming an oat-based cereal (14 g dietary fibre) for 12 weeks, LDL-cholesterol was most significantly affected, with a reduction in concentrations of small, dense LDL-cholesterol and LDL particle number. No adverse changes occurred in blood triacylglycerol or HDL-cholesterol concentration. In another clinical trial, a group consuming wholegrain oat-based cereals experienced a 24.2 mg/dL reduction in total cholesterol levels and a 16.2 mg/dL decrease in LDL-cholesterol levels. Oats do not generally affect total and LDL-cholesterol levels in people with normal serum cholesterol levels. (See Clinical note: Major lipids affecting cardiovascular disease risk, in on Vitamin B3.)
The lipid-lowering effects of a hypocaloric diet containing oats has been shown in a clinical trial to result in significantly greater decreases in total and LDL-cholesterol than a hypocaloric diet alone. In addition, a RCT of moderately hypercholesterolaemic men consuming oat milk, deprived of insoluble fibre but still containing 0.5 g/100 g beta-glucan (750 mL/day) for 5 weeks, also showed a 6% reduction in total and LDL-cholesterol.
Results of RCT suggest that consumption of oat-based cereals may reduce SBP and reduce or eliminate requirements for antihypertensive medications in some people.
The inclusion of wholegrain oat-based cereals was found in a RCT to decrease blood pressure in hypertensive patients and reduce requirements for antihypertensive medications. ‘Seventy-three percent of participants in the oats group versus 42% in the control group were able to stop or reduce their medication by half. Treatment group participants whose medication was not reduced had substantial decreases in blood pressure’. In another RCT, overweight subjects consuming a hypocaloric diet containing oats (45 g/4.2 MJ dietary energy/day) for 6 weeks experienced a reduction in SBP that was more significant than a hypocaloric diet alone (oats -6 ± 7 mmHg, control -1 ± 10 mmHg, P = 0.026). Lipid-lowering effects were also noted.
A clinical trial assessing the itch experienced by burns patients found that the group using a product with 5% colloidal oatmeal reported significantly less itch and requested significantly less antihistamine treatment than the control group.
Commission E approves topical use in baths for inflammatory and seborrhoeic skin disease, especially with itch.
BLOOD SUGAR REGULATION
The ability of oats to delay glucose absorption, and therefore reduce the postprandial glycaemic response, provides a theoretical basis for their use as part of an overall treatment protocol in diabetes and hypoglycaemic conditions. A RCT of 12 patients with type 2 diabetes demonstrated that 30 g oat bran flour, high in beta-glucan, had a low glycaemic response and decreased the postprandial glycaemic response of an oral glucose load in a series of 2-hour meal glucose tolerance tests.
A RCT has shown that in a 50 g portion of carbohydrate, each gram of beta-glucan reduces the Gl by 4 units, making it a useful adjunct to reduce the postprandial glycaemic response without affecting palatability. Another trial showed a 1 5.03 mg/dL drop in plasma glucose levels versus controls when consuming wholegrain oat-based cereals.
Oats: Other Uses
Traditionally, oats are considered a nervous system nutritive and therefore used during times of convalescence. More specifically, the straw is prescribed for nervous debility and exhaustion, whereas the seed is considered more stimulating and said to gently improve energy and support an overly stressed nervous system.
Preliminary trials have suggested an improvement in sexual interest and performance in people taking oats in combination with nettles. The effects were more consistent in males than females. Further trials are required to confirm the benefits of oats in isolation.
Interestingly, oats are also used as supportive therapy during nicotine and morphine withdrawal; however, reliable clinical evidence is currently limited and does not fully support these recommendations.
Due to its high soluble fibre content, oats are also used as an aid to weight loss. Taken before meals, they increase satiety and therefore enable smaller food portions to satisfy hunger.
Oats: Dosage Range
• 1-4 g three times daily of oatmeal or straw.
• Australian manufacturers recommend 20-40 mL/week 1:2 tincture.
• Topically for itch: 5% colloidal oatmeal in a suitable carrier or 100 g cut herb in a bath.
• The inclusion of wholegrain oat-based cereals or oat bran may be a useful adjunct to the treatment of hyperlipidaemia and hypertension and to delay glucose absorption. 75 g dried oatmeal (equivalent to — 3 g soluble fibre daily).