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Health Benefits of Eating Black Turtle Beans

Black turtle beans, commonly known as black beans, are a variety of the common bean (Phaseolus vulgaris). Like all common beans, black beans are loaded with protein, fiber, molybdenum, zinc, and copper. But the health benefits of black turtle beans go way beyond the call of duty as these little black gems offer extraordinary antioxidant benefits resulting from their high concentration of anthocyanins. Anthocyanins are flavonoid pigments that give many black and blue fruits, berries and legumes their extraordinary health benefits.

Note: Like all common beans, raw black turtle beans contain toxic lectins and therefore you should always cook them properly before eating them.

Black Beans Top the List of Antioxidant-Rich Beans

A study published in the Journal of Agricultural and Food Chemistry in 2003 investigated the antioxidant activity of 12 common varieties of dry beans. Black beans came out on top, having more antioxidant activity, gram for gram, than the other beans. The researchers also found that the darker the seed coat of the bean, the higher the flavonoid content (in general). Among the tested varieties, white beans had the lowest levels of flavonoids and yielded the weakest antioxidant activity.

Health benefits of eating black beans
The black bean has more antioxidant activity than any other bean.

The strong antioxidant properties of black turtle beans are largely attributable to their high concentration of anthocyanins such as delphinidin, petunidin, and malvidin. The overall anthocyanin content of black beans is estimated to be around 214 milligrams per 100 grams1. Anthocyanins are healthful flavonoid pigments that give foods like blueberries, blackcurrants, raspberries, red grapes — and black beans — their intense color and superior antioxidant properties. In terms of antioxidant capacity, anthocyanins have even been shown to beat Trolox, which is a vitamin E analog and which often serves as a control antioxidant in research studies2.

But what exactly are the health benefits of eating antioxidant-rich foods like black turtle beans? Antioxidants protect cells from free radicals which are harmful atoms that can cause damage to the cells in your body. The cellular damage caused by free radicals can lead to a number of degenerative and chronic diseases such as Alzheimer's disease, many cancers, heart disease, immune system problems, atherosclerosis, dementia, diabetes, thrombosis, and even certain eye disorders.

Black Beans Offer Beauty Benefits

Apart from providing protection against diseases, the free radical fighting properties of anthocyanins and other flavonoids present in black turtle beans can deliver beauty benefits by preventing signs of premature aging of the skin induced by an overdose of sunlight. When your skin is exposed to ultraviolet light, it produces enzymes called metalloproteinases which help repair sun-damaged collagen fibers. That said, not all metalloproteinases are beneficial; some of them break down collagen and elastin, which can eventually cause wrinkles. Free radicals are known to stimulate the production of these harmful metalloproteinases.

In addition to providing antioxidants that can help keep wrinkles at bay, black beans provide lots of protein as well as zinc and copper which are among the best nutrients for fighting wrinkles.

Molybdenum in Black Beans Has Detoxifying Poperties

If the health benefits of black turtle beans discussed above are not enough to convince you to add these lovely legumes to your diet, consider this: black beans provide a substantial amount of molybdenum. Molybdenum — which was discovered in 1778 by Karl Scheele, a Swedish chemist — is a trace mineral that plays an essential role in human health. Molybdenum is needed to form and activate several important detoxifying enzymes in the human body, including aldehyde oxidase and sulfite oxidase.

Aldehyde oxidase neutralizes acetaldehyde, a toxic substance that is released when yeast, alcohol and fungi are metabolized. The damaging effects of acetaldehyde range from cancer-causing properties to an ability to deactivate an enzyme that is responsible for the conversion of linoleic acid into gamma linolenic acid. Gamma linolenic acid is an anti-inflammatory substance with strong health promoting properties.

Sulfite oxidase converts sulfites (potentially harmful) into sulfates (harmless). The potentially harmful sulfites enter the body through diet as they are commonly used as a preservative in foods and alcoholic drinks. In sensitive individuals, sulfites have been shown to trigger asthma symptoms ranging from mild wheezing to potentially life-threatening asthmatic reactions.

Black Beans Rank Low on the Glycemic Index

With a glycemic index value of 30, black beans are considered a low glycemic food. The glycemic index, or GI, ranks foods and beverages based on their blood glucose raising potential. Foods that are high on the glycemic index (such as white rice, boiled parsnips, and white bread) break down with ease and cause blood sugar and insulin levels to surge after meals, which is followed by rapidly dropping blood sugar levels. The sharp 'rise and fall' effect on blood sugar levels can put extra strain on the body and ultimately lead to several health problems such as adult-onset diabetes, increased cravings for sweets, altered mood, tiredness, and cardiovascular disease.

Black beans and other low GI foods, on the other hand, are absorbed slowly into the bloodstream, which helps keep your blood sugar levels stable. This in turn helps prevent cravings for sweet foods and control mood swings. Additionally, low GI foods like black beans can fight insulin resistance associated with diabetes and lower your risk of developing heart disease and stroke.

But the health benefits of eating low GI foods such as black turtle beans do not end there. Substituting low GI foods for high GI foods also offers great weight loss benefits. When the carbohydrates in our food cause our blood sugar levels to rise, a hormone called insulin is produced by the body. The purpose of insulin is to decrease the concentration of glucose in the blood by stimulating the uptake of glucose by the body's muscle and liver cells. These cells are responsible for storing glucose, in the form of glycogen, for later use as energy. However, the body's total storage capacity for glycogen is limited. If you're an average person, you can store about 300-400 grams of carbohydrate in your muscles and about 60-100 grams in your liver. To get rid of any excess carbohydrates that cannot be stored in the muscles or liver, the body will convert them into fat and store the fat in your butt, belly and thighs.


1. Takeoka GR, Dao LT, Full GH, et al. (1997). Characterization of Black Bean (Phaseolus vulgaris L.) Anthocyanins. Journal of Agricultural and Food Chemistry, 5(9), 3395-3400
2. Wang H, Cao G, and Prior R (1997). Oxygen Radical Absorbing Capacity of Anthocyanins. Journal of Agricultural and Food Chemistry, 45(2), 304-309