Skip to main content

Higher dietary vitamin C intake can improve your liver function and blood sugar levels

Higher dietary vitamin C intake can improve your liver function and blood sugar levelsNon-alcoholic fatty liver disease (NAFLD) is a liver disease that is spreading like a bushfire. NAFLD is associated with obesity and metabolic syndrome, which is an early stage of type 2 diabetes. What you eat plays a major role, and a large Chinese study has actually demonstrated that higher dietary intake of vitamin C can improve blood sugar levels and the liver function. It is also wise to lower your intake of carbohydrates, especially fructose that can put a huge strain on the liver and turn it into a virtual “fat factory”.

Non-alcoholic fatty liver disease is caused by an accumulation of fat in the liver. Many people suffer from NAFLD without knowing it. The disease is often related to metabolic syndrome, a condition characterized by insulin resistance, overweight (apple-shaped body and enlarged waist circumference), hypertension, and elevated blood lipid levels. Metabolic syndrome is an early stage of type 2 diabetes, a disease that is also spreading like an epidemic.
Furthermore, non-alcoholic fatty liver is linked to inflammation and an increased risk of developing fibrosis, liver cirrhosis, and primary liver cancer.
A major factor involved in most chronic diseases, non-alcoholic fatty liver included, is oxidative stress, which is a condition where harmful free radicals outnumber the protective antioxidants.,
Free radicals are highly reactive atoms that the body generates as part of its energy metabolism and other physiological processes. But free radicals must be controlled and kept on a tight leash to prevent them from causing oxidative damage to cholesterol, cell membranes, and DNA. These free radical attacks can result in cellular damage, inflammation, and chronic diseases.

Vitamin C has numerous functions and is a powerful antioxidant

The Chinese scientists back up their study by arguing that what you eat, including your vitamin C intake, plays a major role in terms of the risk non-alcoholic fatty liver disease. Vitamin C is primarily a very important antioxidant that neutralizes free radicals. The nutrient is also important for different enzyme processes and is believed to regulate levels of different lipids that are found in the liver and in the bloodstream.
A study (Musso et al.) that was published earlier has already demonstrated that people with non-alcoholic steatohepatitis (fatty liver combined with inflammation) have lower vitamin C intakes than healthy controls. Another study of Korean men (Han et al.) reported a link between low vitamin C intake and an increased risk of non-alcoholic fatty liver.
An earlier Chinese study has shown that 12 weeks of vitamin C supplementation improves liver health and glucose metabolism in the liver. Still, studies of the relation between vitamin C and non-alcoholic liver disease show conflicting results, which is why the Chinese scientists wanted to look closer at the relation by measuring various biomarkers of liver function and glucose/lipid metabolism.

The new study confirms vitamin C’s role in liver function and glucose metabolism

The Chinese scientists used data from the China Health and Nutrition Survey (CHNS), a population study with over 8,000 participants from nine provinces in four regions. The participants’ dietary vitamin D intake was calculated with help from diet questionnaires. The researchers also looked at levels of biomarkers such as plasma ferritin and hemoglobin A1c (HbA1c).
Ferrin is a protein in plasma that reflects the body’s iron stores. Inflammation, metabolic syndrome, and chronic liver ailments such as non-alcoholic fatty liver disease (NAFLD) can result in elevated ferritin levels.
Hemoglobin A1c is a measure of a person’s average blood glucose levels over the last two to three months. It is a useful way to assess a person’s blood sugar regulation.
The recommended daily vitamin C intake in China is 100 mg. According to the results, around 25 percent of the study participants got less than 100 mg of vitamin C daily and that is too little. The scientists also observed that participants with higher vitamin C intake levels had lower levels of plasma ferritin and HbA1c. They did not, however, find any relation between vitamin C and lipid metabolism.
Nonetheless, this study shows that a high vitamin C intake has the potential to improve the liver and function and glucose metabolism.
The study is published in Frontiers in Nutrition.
The Chinese recommendations for vitamin C intake are higher than in Denmark, where the daily reference intake (RI) level is set at 80 mg. It is therefore very likely that people suffering from non-alcoholic fatty liver disease and other diseases characterized by oxidative stress and inflammation need more vitamin C. If you suffer from NAFLD you should also limit your intake of carbohydrates, where fructose is one of the big culprits.

  • Fruit and berries are rich sources of vitamin C
  • Avoid consuming too much fruit – especially juice that is very high in fructose
  • Remember to include cabbage, red bell pepper, parsley, spinach, green peas, and herbs that are really high in vitamin C
  • If you take a vitamin C supplement, you are better off with a non-acidic vitamin C source that is gentle on the stomach

How can excessive carbohydrate intake cause non-alcoholic fatty liver disease?

Carbohydrates from the diet are normally broken down into monosaccharides such as glucose and fructose. Glucose, which is primarily found in starchy foods like potatoes, rice, wheat, corn, and refined sugar, is absorbed quickly in the bloodstream and provides fast energy to the brain and muscles. Fructose that is normally found in fruit, honey, refined sugar, wine, and sweeteners like corn syrup and high-fructose corn syrup (HFCS) continues from the intestine straight to the liver where most of it is stored. Fructose, which is very sweet, does not provide fast energy like glucose.
If you consume too much fructose, it may flood the liver cells. This causes excess fructose to be stored as fat. The liver literally becomes a fat factory with a disrupted lipid metabolism (lipogenesis.) Large quantities of fructose can therefore lead to non-alcoholic fatty liver disease, metabolic syndrome, and type 2 diabetes.
What we eat means a lot, and the combination of consuming too many carbohydrates and too much omega-6 and trans fatty acids is particularly damaging to your health.

Fructose sources

  • HFCS (high-fructose corn syrup)
  • Sugar (refined sugar in particular), honey
  • Fruit, berries, and juice in particular
  • Wine and beer
  • Light products, soft drinks, and candy
  • Coffee creamer and many industrially processed foods

Dietary advice for the general population and for diabetics has been misleading for decades

Over the past decades, we have been advised to stick with a low-fat diet. The argument has been that dietary cholesterol is the culprit when it comes to cardiovascular diseases. What we must not forget is that cholesterol is an essential compound and a building block of all our cell membranes. Cholesterol is also needed for the body’s synthesis of vitamin D, Q10, and steroid hormones. Cholesterol only becomes a threat to our health if it free radicals attack and oxidize it, which causes it to form plaque on the inside of the blood vessel walls.
Elevated cholesterol levels are often seen in conjunction with insulin resistance and a disrupted sugar metabolism caused by a diet with far too many carbohydrates. This can burden the pancreas and the liver.
It appears that the misguided promotion of carbohydrate-rich diets and the widespread consumption of junk-food have contributed to the obesity epidemic and the growing rate of non-alcoholic fatty liver disease and type 2 diabetes. In contrast, a Danish study from 2019 has revealed that diabetics thrive better on a diet with fewer carbohydrates This new message supports several international studies. People with sensitive blood sugar, non-alcoholic fatty liver disease, and diabetes should therefore strive to eat a diet with less carbohydrate and plenty of protein. Also, they should aim for a better balance between omega-3 and omega-6 fatty acids.
It is also important to get plenty of chromium, as this mineral improves the effect of insulin, the hormone that helps glucose into the cells.


Xiaoqin Luo et al. Dietary Vitamin C Intake is Associated with Improved Liver Function and Glucose Metabolism in Chinese Adults. Frontiers in Nutrition 31 January 2022

Brittany Dewdney. A Sweet Connection? Fructose´s Role in Hepacellular Carcinoma. Biomolecules. March 2020

Alireza Farrokhian et al. The Influences of Chromium Supplementation on Metabolic Status in Patients with Type 2 Diabetes Mellitus and Coronary Heart Disease. Biological Trace Element Research 2020

Bispebjerg Hospital. Færre kulhydrater forbedrer type-2 diabetikeres evne til at regulere blodsukkeret. Nyhedsbrev 10. august 2019

Mads J Skytte et al. A Carbohydrate-reduced high-protein diet improves HbA1c and liver fat content in weight stable participants with type 2 diabetes: a randomized trial. Diabetologica. First online 23 July 2019

Frida - Parametre (

Pernille Lund. Sådan får du styr på dit blodsukker og din vægt. Ny videnskab 2013

  • Created on .