Purple veggies and tubers may have anti-diabetic properties

Purple veggies and tubers may have anti-diabetic properties

Anthocyanins are organic substances that give many fruits, vegetables, and tubers their reddish-orange and blue-violet hues. Anthocyanins have been found to have favourable impacts on inflammation, the energy metabolism, and the gut flora.

A comprehensive review of the research reveals how the effects of purple vegetables and tubers on energy metabolism. Also, inflammation and gut microbiota may help prevent and control type 2 diabetes.

Studies in terms of anti-diabetic characteristics, acylated anthocyanins, present in vegetables like red-cabbage and purple sweet potatoes were conducted. They may be superior to nonacylated anthocyanins, which are present in blackberries and blackcurrants.

The CDC estimates that around 37 million Americans—or about 1 in 10 people—have diabetes, and that 90–95% of them have type 2 diabetes.

In a typical state, the hormone insulin transports glucose (sugar) from the blood into the cells, where it is used as an energy source. Nevertheless, type 2 diabetes causes the body to improperly use or create insulin. This causes glucose to build up in the blood rather than be utilised by cells.

Diabetes, if improperly controlled, has a long list of negative effects on health. This ncludes heart disease, high blood pressure, nerve damage, eye damage and vision loss, renal illness, and foot issues.

Research has shown that a diet high in fruits and vegetables can delay or prevent the onset of diabetes. Also, it improve the well-being of people with diabetes-related health problems. Even though there are many factors that can increase the risk of developing type 2 diabetes, including a family history of the disease.

Fruits and vegetables have a high concentration of polyphenols, which is what is responsible for their health advantages. Plants get their red-orange to blue-violet colours from a specific family of polyphenols called anthocyanins.

Consumption of foods high in anthocyanins, particularly berries, has been linked to a lower risk of type 2 diabetes. This is according to research from the United States and Finland.

Acylated vs. nonacylated anthocyanins

Based on their molecular makeup, anthocyanins can be classified as either acylated or nonacylated.

Nonacylated anthocyanins do not have a “acyl group,” which is a chemical compound made up of two carbon atoms and one oxygen atom double-bonded to one another with a single connection to another carbon atom.

Atherosclerotic pigments that have been acylated are more enduring and resistant to digestion than those that have not been acylated. Because of this, they pass through the stomach and upper intestine without being digested and absorbed, instead moving on to the colon where they are extensively broken down by gut microbes.

Nonacylated anthocyanins are mostly found in elderberry, blackberry, and blackcurrant. However, acylated anthocyanins are present in red radish, purple maize, black carrot, red cabbage, and purple sweet potato.

It is challenging to make definitive judgements regarding the changes in biological activity between studies on the two types of anthocyanins. This is due to differences in study design and analysis techniques.

Yet according to Dr. Baoru Yang, a professor of food sciences at the University of Turku, and the other authors of the review, acylated anthocyanins may have better anti-diabetic characteristics than nonacylated anthocyanins.

Consider other variations in the sources of acylated and nonacylated anthocyanins. According to Dr. Taylor C. Wallace, founder and CEO at the Think Healthy Group and adjunct professor in the Department of Nutrition and Food Studies at George Mason University, as reported by Medical News Today.

Anthocyanins promote gut health

Using animal models, researchers have examined how different anthocyanins affect the bacteria that make up the gut microbiome.

Nonacylated anthocyanins from black rice were found to boost the number of specific gut bacteria. Notably Akkermansia muciniphila, in a rat research. It has been demonstrated that A. muciniphila improves glucose metabolism in type 2 diabetic mice by enhancing insulin secretion.

Acylated anthocyanins may be found in foods like purple sweet potatoes and Concord grapes. They have also been proven to have an impact on the gut microbiota by enhancing the growth of good bacteria. They reduces the proliferation of bad bacteria, and boosts the production of short-chain fatty acids. This is good for gut health and glycemic control.

The bulk of studies conducted to date, according to Dr. Wallace, are not sophisticated or validated enough “to actually know what happens to anthocyanins in the GI system,” he told MNT.

To truly understand if there is a difference, purified radio labelled non-acylated and acylated anthocyanins should be administered in humans, he added. To his knowledge, this has not been done because it is quite expensive.

Anthocyanins lower blood glucose levels

The suppression of enzymes involved in carbohydrate digestion is one of the pharmacological actions of anthocyanins, and it lowers blood glucose levels. Moreover, studies have demonstrated that anthocyanins activate the liver’s and muscles’ lipid and glucose metabolism pathways. This also aid in decreasing blood sugar levels.

One study found that diabetic mice given unrestricted access to food for two weeks who were supplemented with mulberry fruit extract containing nonacylated anthocyanins had blood glucose levels that were roughly 30% lower than mice who weren’t fed.

In a related study, diabetic mice were given acylated anthocyanin extracts from purple sweet potatoes for four weeks at a daily dose of 500 mg/kg body weight. Also, the treatment groups showed a significant drop in blood glucose and an improvement in insulin sensitivity.

Anthocyanin activation of the AMPK (AMP-activating protein kinase) and PI3K/AKT (phosphoinositide 3 kinase/protein kinase B) pathways, which are essential for glucose and lipid metabolism, has been linked to anthocyanins’ ability to reduce blood glucose levels.

Dr. Wallace made the observation that as the majority of the research listed in the study employed anthocyanin-rich extracts as opposed to purified anthocyanins, additional polyphenols and flavonoids could have had synergistic effects.

The majority of flavonoids have the ability to interfere with sugar absorption by adhering to sugars and blocking the enzymes that break down carbohydrates.

Anthocyanins lower inflammation 

An immediate inflammatory immunological response is brought on by eating carbohydrates or fat. Inflammation often subsides rapidly, but if it persists, it may develop into a chronic condition. Obesity, insulin resistance, and type 2 diabetes can result from chronic inflammation that damages the insulin-secreting cells in the pancreas.

Nonacylated and acylated anthocyanins were added to the diets of diabetic mice in experiments to reduce inflammation. The improvement in glucose metabolism in diabetes is caused by the reduction in inflammation, which also lowers insulin resistance.

The NF-B inflammation pathway is inhibited by anthocyanins, which has been demonstrated in numerous studies to have an anti-inflammatory impact. Additional studies have demonstrated that nonacylated anthocyanins stimulate the Nrf2 pathway, which aids in the production of antioxidant proteins to guard against inflammation- or injury-induced oxidative damage.


  • https://www.medicalnewstoday.com/articles/purple-vegetables-and-tubers-may-have-superior-anti-diabetic-properties
  • https://www.medigoo.com/news/purple-vegetables-and-tubers-may-have-significant-anti-diabetic-properties/
  • https://dunyanews.tv/en/Health/703893-Purple-vegetables-and-tubers-may-have-superior-anti-diabetic-properties

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