Educational information, not medical advice — ask your doctor or midwife.
Barley is a cereal grain, grown for food and beer for thousands of years. Its botanical name is Hordeum vulgare. You meet it as pearl barley in soup, as malt in beer, and as barley water.
In Irish it is eorna. Barley water is made by simmering the grain and straining off the liquid, often with lemon. European households gave it to people who were ill, feverish or recovering.
Here is the honest verdict. The soluble fibre in barley, called beta-glucan, lowers cholesterol in human trials. Most older folk uses are untested, and tradition alone proves neither effect nor safety.
The part that does the work is beta-glucan, a soluble fibre in the grain.
In water, beta-glucan forms a thick gel. The gel traps bile acids in the gut so they leave the body. The liver then pulls cholesterol out of the blood to make new bile acids.
This chain is not just a test-tube idea. Human trials show a small but real drop in LDL ("bad") cholesterol.
The same gel slows how fast food leaves the stomach. In people, that blunts the rise in blood sugar after a meal. The fibre also adds bulk and water to stools.
Barley water is a different matter. It is mostly water, with a little starch and fibre. Any comfort it brings may come from the fluid alone.
Its old use for bladder and kidney complaints has not been tested in good human studies. Drinking more fluid does dilute urine, but that is not the same as treating an infection.
Barley is sold mainly as a food, and that is how most people use it.
- Pearl barley: polished grain for soups and stews. - Pot or hulled barley: less polished, with more fibre. - Barley flakes and barley flour: for porridge and baking.
- Barley water: grain simmered in water and strained, sometimes with lemon and sugar. - Bottled lemon barley water: a soft drink, often low in actual barley. - Malt and malt extract: sprouted, dried barley, used in brewing and in sweet tonics.
- Roasted barley tea: known as mugicha in Japan and boricha in Korea. - Barley grass powder or juice: made from the young green leaves, not the grain. - Beta-glucan capsules and powders: concentrated fibre supplements.
Labels vary a great deal in fibre content. A supplement will state grams of beta-glucan; a soft drink usually will not.
Barley is one of the oldest crops of Europe and the Near East.
Greek and Roman writers described ptisane, a thin barley gruel or barley water. It was a standard drink offered to the sick and the feverish.
In Ireland, eorna was a daily grain. Barley water was kept as a home drink for invalids and nursing mothers. Folk use also tied it to urinary complaints and "gravel" in the kidneys.
Victorian kitchens made lemon barley water for fevers and for children. Malt extract was sold as a tonic for thin or tired people.
These were household customs, written down by cooks and physicians of the day. They record what people believed, not what the drink was shown to do.
Call emergency services if you get swelling of the lips, tongue or throat, wheeze, or a spreading rash after eating barley. That is a severe allergic reaction.
See your doctor if you have lasting diarrhoea, weight loss or bloating after eating grains. That can mean coeliac disease and needs testing before you cut out gluten.
See your doctor too if you have burning urine with fever or back pain, or if your cholesterol stays high despite diet changes.
In the UK, EU and US, barley is an ordinary food with no restrictions. Food regulators in both the EU and the US allow a claim that barley beta-glucan helps lower cholesterol. Barley grass powders and beta-glucan capsules are sold as food supplements, not as medicines.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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