Life Extension Magazine®

Black beans having low glycemic index and high fiber

Super Food: Black Beans

High in anthocyanins and fiber, black beans attenuate blood sugar spikes and provide anticancer effects.

Scientifically reviewed by: Holli Ryan, RD, LD/N, in August 2023. Written by: Life Extension Editorial Staff.

Like many legumes, black beans originated in South and Central America, but their taste and versatility have made them popular the world over.

The signature black coat of the bean contains key phytonutrients and anthocyanins that are often more commonly associated with dark-colored fruits and vegetables. And with 15 grams of protein per cup, black beans have become a staple food for vegetarians and vegans.

Black beans are cost-effective, versatile, and chock full of vitamins and minerals, making this superfood a perfect addition to any healthy diet.


Black beans have a low glycemic index, which means they are more slowly digested and cause a slower rise in blood sugar levels.

This is because most of the starch in black beans is resistant starch, which is not easily digested. This allows it to pass through the digestive tract without being broken down, which prevents it from being converted to simple sugars.

Black beans can also help attenuate the blood sugar spikes caused by higher glycemic foods. In one study, when adults with type II diabetes consumed black beans with rice, it helped lessen the blood sugar spikes associated with eating rice alone.1

Cancer and Heart Disease

Black beans’ shells are an excellent source of phytonutrients and anthocyanins, such as malvidin, delphinidin, and petunidin.

Anthocyanins have numerous anticancer effects—including anti-inflammation, anti-mutagenesis, inducing cell cycle arrest, stimulating apoptosis of cancer cells, preventing cancer cells from spreading, and even making cancer cells more sensitive to chemotherapy.2

Epidemiological studies suggest that consuming more anthocyanins reduces the risk of cardiovascular disease.3 This is likely due in part to their beneficial effect on endothelial function and inflammation.

Additionally, black beans are high in fiber, higher intake of which has been associated with a lower risk of colorectal cancer.4


  1. Nutr J. 2012 Apr 11;11:23.
  2. Br J Pharmacol. 2017 Jun;174(11):1226-43.
  3. Adv Nutr. 2011 Jan;2(1):1-7.
  4. BMJ. 2011 Nov 10;343:d6617.