Barley is one of the most nutritious grains you can eat. Its standout feature is beta-glucan, a type of soluble fiber that lowers cholesterol, slows blood sugar spikes, and feeds beneficial gut bacteria. The FDA authorizes heart health claims for barley based on just 3 grams of beta-glucan per day, putting it in the same category as oats for cardiovascular protection.
How Barley Lowers Cholesterol
The beta-glucan in barley reduces blood cholesterol by changing how your body processes bile acids. Your liver uses cholesterol to make bile acids, which help digest fat. Beta-glucan binds to those bile acids in your gut and pulls them out of circulation, forcing your liver to draw more cholesterol from your blood to make replacements. A study published in the British Journal of Nutrition found that 3 grams of high-molecular-weight beta-glucan per day significantly reduced total cholesterol levels through this mechanism.
Interestingly, the cholesterol-lowering effect varies from person to person based on genetics. People carrying a specific variation in a gene involved in bile acid production showed greater LDL (“bad” cholesterol) reductions from the same amount of barley fiber. This helps explain why some people respond dramatically to adding barley to their diet while others see more modest changes.
The FDA recognizes this benefit formally: foods providing 3 or more grams of beta-glucan soluble fiber per day from whole oats, barley, or a combination of both can carry a label claim about reducing the risk of coronary heart disease. A half-cup of cooked hulled barley gets you roughly a third of the way there.
Blood Sugar and Insulin Effects
Barley has a remarkably low glycemic index compared to most grains. Whole-grain (hulled) barley scores as low as 21 to 36 depending on the cultivar, while pearled barley comes in around 35. For context, white rice typically lands between 70 and 80. That difference matters for anyone managing blood sugar or trying to avoid the energy crashes that follow high-glycemic meals.
A meta-analysis of 31 controlled trials found that barley supplementation significantly reduced blood sugar levels at 30, 60, and 120 minutes after a meal. Insulin levels also dropped at 30 and 60 minutes, meaning the body needed less insulin to handle the same amount of carbohydrate. The reductions were meaningful: blood sugar dropped by about 10 to 12 mg/dL in the first hour after eating compared to control meals.
One important caveat: these benefits are short-term, meal-to-meal effects. The same meta-analysis found no significant changes in fasting blood sugar or HbA1c (a marker of long-term blood sugar control) from barley intake alone. Barley smooths out the spikes, but it’s not a standalone solution for managing diabetes over months or years.
Barley also triggers the release of GLP-1, a gut hormone that slows stomach emptying and signals fullness to the brain. Research in both humans and animals has consistently shown higher GLP-1 levels after barley consumption. One study found that eating boiled barley kernels at dinner led to lower blood sugar the following morning at breakfast, compared to eating white wheat bread. That “second meal effect” makes barley particularly useful as an evening grain.
Gut Health and Butyrate Production
Beyond beta-glucan, barley contains fructan and resistant starch, two types of fiber that your gut bacteria ferment into short-chain fatty acids. The most important of these is butyrate, the primary fuel source for the cells lining your colon. Butyrate helps maintain the gut barrier, reduces inflammation, and may protect against colorectal disease.
A study tracking people who ate fiber-rich barley found that fecal butyrate concentrations jumped from 0.99 mg/g to 1.43 mg/g during the intake period, a roughly 44% increase. Levels of other beneficial fatty acids rose too: propionic acid increased by about 57%, and acetic acid nearly doubled. The population of butyrate-producing bacteria in the gut grew from 5.9% to 8.2% of the microbial community.
There’s a catch, though. When participants stopped eating barley, every one of those markers returned to baseline within a month. Butyrate-producing bacteria dropped back to 5.4%, and short-chain fatty acid levels fell to pre-study levels. The takeaway: barley’s gut benefits require consistent intake. A one-time bowl of barley soup won’t reshape your microbiome.
Researchers noted that fructan and resistant starch, rather than beta-glucan, appeared to be the main drivers of these gut changes. This is worth knowing because it means barley offers a different set of gut benefits than oats, which are high in beta-glucan but lower in resistant starch.
Hulled vs. Pearled Barley
Hulled barley is the whole-grain form. Only the tough, inedible outer hull has been removed, leaving the bran and germ intact. It’s chewier, takes longer to cook (usually 40 to 50 minutes), and delivers the full spectrum of fiber, vitamins, and minerals.
Pearled barley has been polished to remove some or all of the outer bran layer along with the hull. It cooks faster, has a softer texture, and works well in soups and risottos. But you lose a portion of the fiber and nutrients in the process. Pearled barley still has a low glycemic index (around 35), so it’s far from a poor choice. It’s just not technically a whole grain.
If you’re eating barley specifically for its beta-glucan content, pearled barley still delivers. Beta-glucan is distributed throughout the barley kernel, not concentrated in the bran. But for maximum resistant starch, fructan, and mineral content, hulled barley is the better option.
Soaking and Preparation
Like most whole grains, barley contains phytic acid, a compound that binds to minerals like iron, zinc, and calcium and reduces how much your body absorbs. Soaking barley before cooking breaks down some of this phytic acid and improves mineral availability. Depending on the grain and how you plan to cook it, soaking times typically range from 15 minutes to overnight, with longer soaks being more effective. An overnight soak in room-temperature water also cuts cooking time for hulled barley by 10 to 15 minutes.
Who Should Avoid Barley
Barley contains gluten. Specifically, it contains hordein, a storage protein in the same family as wheat gluten. For people with celiac disease, barley triggers the same autoimmune response as wheat and rye, damaging the lining of the small intestine and impairing nutrient absorption. Research has found that barley’s toxic effect on celiac patients is produced even more readily than that of oats, and medical guidelines recommend its complete exclusion from a gluten-free diet.
People with non-celiac gluten sensitivity may also react to barley, though the severity varies. If you follow a gluten-free diet for any reason, barley is off the table, and that includes malt, barley flour, and barley-based beverages.