Your liver works as the body’s sugar bank, holding glucose and releasing it to keep blood sugar steady between meals. When liver disease such as cirrhosis or hepatitis weakens it, blood sugar can drop too low.1RCEMLearning. Role of Liver (including Liver Disease and Starvation) The risk is easy to overlook because many people with liver disease also have diabetes, where high sugar gets most of the attention. Preventing lows is largely about timing food, since the body can’t cover long gaps on its own.
Why A Damaged Liver Lets Blood Sugar Fall
The liver supplies sugar in two ways. It releases stored sugar, and it makes new sugar from building blocks. Diseases that damage liver cells, including alcohol-related liver disease, cirrhosis (scarring of the liver) and hepatitis, weaken both jobs.2RCEMLearning. Role of Liver (including Liver Disease and Starvation) With a smaller store to draw on, cirrhosis behaves like a state of speeded-up starvation, and an overnight fast hits like a much longer one.3PubMed Central. An Overview of the Molecular Mechanisms Contributing to Musculoskeletal Disorders in Chronic Liver Disease: Osteoporosis, Sarcopenia, and Osteoporotic Sarcopenia
After dinner, a scarred liver refills its store only partly. By early morning that small store is used up, so lows often show up before breakfast or after a skipped meal.
To make up the gap, the body breaks down muscle protein into building blocks for new sugar.4PubMed Central. An Overview of the Molecular Mechanisms Contributing to Musculoskeletal Disorders in Chronic Liver Disease: Osteoporosis, Sarcopenia, and Osteoporotic Sarcopenia Repeated fasting means repeated muscle breakdown and gradual muscle loss.5PubMed Central. Molecular Mechanism Contributing to Malnutrition and Sarcopenia in Patients with Liver Cirrhosis Eating less makes this worse, because the need to make new sugar rises while muscle shrinks.6PubMed Central. Molecular Mechanism Contributing to Malnutrition and Sarcopenia in Patients with Liver Cirrhosis
Insulin is often part of the picture too. People with moderate cirrhosis often have high insulin levels because the pancreas reacts more strongly to sugar.7PubMed Central. Mechanisms of hyperinsulinaemia in Child’s disease grade B liver cirrhosis investigated in free living conditions More insulin plus less liver sugar can push glucose down, especially in people taking diabetes drugs.
Cirrhosis often causes high readings for a few hours after meals, because of insulin resistance. Between meals and overnight, though, the thin reserve runs out and the same person can run low. A single reading gives only part of the picture.
Alcohol, Kidney Disease And Medicines That Raise The Risk
Breaking down alcohol uses up a chemical helper that the liver also needs to make new sugar.8PubMed Central. Impact of Alcohol on Glycemic Control and Insulin Action While alcohol is being processed, the liver’s sugar-making is switched down.9Alcohol and Alcoholism. A Review of the Effects of Alcohol on Carbohydrate Metabolism Drinking without food is especially risky when the liver already stores little sugar. If you have liver disease, avoid alcohol; it also harms the liver directly.
Kidneys release some sugar too, and moderate to severe kidney disease reduces it.10PubMed Central. Hypoglycemia in Patients with Diabetes and Renal Disease Insulin is also cleared more slowly when kidney filtering falls very low, below about 15 to 20 on an eGFR report.11PubMed Central. Hypoglycemia in Patients with Diabetes and Renal Disease So insulin and some diabetes pills linger longer and act harder. Poor nutrition in kidney failure adds to this by starving the body of sugar-making building blocks.12PubMed. Hypoglycemia associated with renal failure
Low eating, older age, liver disease and kidney disease are the main settings for medicine-caused lows, especially in combination.13PubMed. Drug-induced hypoglycemia. A review of 1418 cases So ask your doctor to review every diabetes drug and dose whenever your liver or kidney tests change.
Insulin and sulfonylureas such as glipizide cause most lows. A dose that suited you before your diagnosis may now be too strong. Never adjust it alone; bring your glucose log to visits, and ask whether a lower-risk option suits your liver. Bring a full list of every medicine, including over-the-counter products and supplements, because several things can add to the effect of diabetes drugs.
Risks stack. Vomiting, diarrhea or a poor appetite cut the sugar coming in while the usual dose stays the same, so a low becomes more likely. Ask your care team ahead of time which medicines to hold or reduce on days you can’t eat normally, rather than deciding in the moment. Check glucose more often on those days, since a reading shows trouble earlier than symptoms do.
Liver Cancer And Rare Causes
Some liver cancers make too much of a growth hormone that acts like insulin.14International Journal of Case Reports and Images. Severe hypoglycemia complicating hepatocellular carcinoma The damaged liver can’t process its unfinished form, which reaches tissues easily and drives sugar uptake.15Journal of Case Reports and Images in Oncology. Non-islet cell tumor causing hypoglycemia: A paraneoplastic complication of hepatocellular carcinoma Unexplained severe lows in someone with liver cancer need prompt tests.
These lows happen even without diabetes medicines, which is why they are easy to miss in people who have never had diabetes. They can be severe and frequent, and tend to appear during fasting, often early in the morning or after a long gap between meals. Doctors often check glucose together with insulin and related hormone levels during a low, to tell this cause from others. Treating the tumor is usually what reduces these lows, with sugar-rich feeding used to bridge the time until then.
In children, lows that keep coming back are an important clue to inherited metabolic liver disease.16PubMed Central. Metabolic Liver Diseases Presenting as Pediatric Onset Hypoglycemia: A Hepatologist’s Primer In one such condition, glycogen storage disease type 1a, transplant brought sugar back to normal and ended cornstarch feeds.17PubMed. Liver transplantation for glycogen storage disease type Ia
Parents may notice sleepiness, poor feeding, sweating or seizures during a long gap between meals. A child with repeated lows needs testing during an episode to look for an inherited cause, rather than being told it is just a skipped meal.
Signs Of Low Sugar And Why You May Not Feel Them
- Shaking, sweating and a fast heartbeat
- Hunger, anxiety or irritability
- Confusion, slurred speech or drowsiness
- Seizures or passing out with severe lows
- A meter reading under 70 mg/dL (3.9 mmol/L), which counts as low
Repeated lows dull the adrenaline alarm response.18PubMed Central. Autonomic dysfunction in chronic liver disease People then stop feeling lows coming, which leads to more lows.19PubMed Central. Autonomic dysfunction in chronic liver disease After that, a meter reading is more reliable than how you feel.
Low sugar and liver-related confusion both cause confusion and sleepiness. Liver confusion builds slowly, while low sugar can come on in minutes. Always check sugar first; it is quick, and a low is easily treated. Family members can watch for unusual morning grogginess, night sweats or nightmares, and odd behavior before meals, and check sugar with a meter when they see these.
What To Do When Your Sugar Is Low
Take 15 grams of fast sugar, such as 4 glucose tablets or half a cup of juice. Recheck after 15 minutes and repeat if you’re still under 70 mg/dL. Then eat a snack with starch and protein, since your liver can’t keep levels up afterward. Crackers with cheese or half a sandwich give slower fuel; eat the snack unless your next meal is due within about an hour.
Avoid a few common mistakes. Chocolate’s fat slows sugar absorption, so use juice or tablets. Don’t stop after one juice; recheck. And tell your doctor about every bad low.
Glucagon shots work by telling the liver to release stored sugar. In cirrhosis, sugar rises much less after glucagon.20PubMed Central. Severe hypoglycemia in patients with liver cirrhosis and type 2 diabetes So if someone can’t swallow or won’t wake, call emergency services rather than relying on a glucagon rescue shot.
When helping someone drowsy, check glucose with a meter right away if one is available, because confusion from a low looks similar to liver-related confusion. If the person is awake enough to follow instructions and swallow safely, give juice or glucose tablets. If they’re too drowsy, don’t put food or drink in their mouth, since it can enter the airway. Call emergency services, place them on their side, and stay until help arrives. Tell responders about the liver disease and any diabetes medicines.
Hospitals give sugar by drip, often 10% dextrose when glucose is under 100 mg/dL.21Reviews in Gastroenterology & Hepatology. Hypoglycemia in Liver Disease: Causes and Management They aim to keep glucose above 100 and under about 140 to 180 mg/dL.22Reviews in Gastroenterology & Hepatology. Hypoglycemia in Liver Disease: Causes and Management In sudden liver failure, severe lows are common, so patients are often given a sugar drip and checked frequently.23Royal Infirmary Edinburgh. Protocol for Assessment and Management of Patients with Acute Liver Failure
Preventing Lows Day To Day
Overnight is the longest fast, so a late evening snack helps people with cirrhosis.24PubMed. Effect of a late evening snack on the blood glucose level and energy metabolism in patients with liver cirrhosis While awake, aim for meals or snacks every 3 to 4 hours, and never skip breakfast.
A good late snack pairs starch with protein, such as toast with peanut butter or yogurt with fruit, so it releases fuel slowly through the night. Roughly 200 calories is common advice for cirrhosis. Eat it close to bedtime so it covers the longest gap, rather than at dinner time. Because cirrhosis can come with salt and fluid limits, ask a dietitian to shape the snack around those rules instead of copying a generic list.
A continuous glucose monitor, or CGM, is a skin sensor that reads sugar all day. In people with cirrhosis and diabetes, one sensor’s readings were clinically acceptable almost all the time, even with fluid buildup.25PubMed Central. Clinical Performance of Flash Glucose Monitoring System in Patients with Liver Cirrhosis and Diabetes Mellitus A sensor can help catch silent night lows, though a fingerstick should confirm a low reading.
Check glucose before breakfast and at bedtime, since those readings show whether the overnight gap is being covered. Check more often if you take insulin or a sulfonylurea, have been ill, or have had a recent low. Keep glucose tablets in your bag, car and bedside table. Write down each low with the time, what you ate, any alcohol and your doses, then bring the log to visits.
Questions To Ask Your Liver Team
- Are my diabetes medicine doses still safe for my liver and kidneys?
- Should I use a sensor?
- Should my adrenal function be tested?
- Could a dietitian plan my snacks?
If a transplant is on the table, ask what it means for sugar. A new liver restores sugar storage, and lows from liver failure usually end. Diabetes may still need treatment afterward.