How Kidney Bean Extract Does and Does Not Help With Carb Blocking

Do white kidney beans block carbs?

A recent e-mail asked me this:

I just read your Vinz Cafe. I was wondering what your views/thought on white kidney bean extract to block carbs and starch?

White kidney beans as a supplement are something I’ve never looked at closely before, so I was curious to see what I would find out.

My initial response after looking around was. But after a closer look I became more accepting of the stated physiological function of kidney bean extract, but remain boorish on their ability to mediate the effects of insulin resistance and blood glucose levels

The Condensed Truth

In my opinion the abbreviated story about white kidney bean extract goes something like this:

They’re probably effective at blocking alpha amylase, an enzyme that cleaves long carbohydrates into shorter ones.

They work on starch, but not sugar or high fructose corn syrup. So they might help slowing the carb load from a pasta dinner but not your bottle of coke or sweets.

They’re safe and have no observable side effects

They work better with people who have high carb diets than low-carb diets

Not all White Kidney Bean Extracts are Created the Same only one clinically studied for safety and efficacy, White Kidney Bean Phase 2 is the first white kidney bean extract clinically shown to reduce the digestion of starch and promote weight loss

Let’s take a closer look at how this supplement works, where its usefulness begins and ends, and other options you have to get similar effects in your body.

White Kidney Bean Extract Inhibits Phase 2

All of white kidney bean’s physiological activity boils down to its ability to block an enzyme called alpha-amylase from breaking down certain carbohydrates within your body. Starches are long chains of sugars that your body breaks down into smaller ones so it can use its individual units of sugar for energy. To accomlish this task it uses the enzymes amylase and alpha-glucosidase to accomplish this task. Amylase is present in your saliva, but most of its work is done in the intestine after its been secreted by your pancreas after a meal.

The theory goes that since white kidney bean blocks amylase, carbs that would otherwise be digested rapidly are digested slowly or not-at-all. It sort of creates the effect of eating fiber since it turns digestable carbs into non-digestable carbs.

After reading through various papers I’ve decided that this process happens as advertised. White kidney bean extract really does stop alpha-amylase from the pancreas and seems to do so in a manner that’s pretty robust to various physiological conditions.

What’s less clear is how this one mechanism relates to the broader goals of blood sugar control, weight loss, and low-carb dieting more generally…..especially in the long run.

However, your thinking about the benefits of white kidney bean extract need to come with the following caveats:

It does not work on sucrase, the enzyme that breaks down sugar. Sugar is probably the larger problem when it comes to carbohydrate induced obesity

It stops alpha-amylase secreted from the pancreas, but not beta-amylase, which is secreted by some forms of bacteria that live in your gut

Other enzymes can do the same work as amylase, just not as effectively. For example, maltase can also break down starch in your intestine, which is why kidney bean extract doesn’t work as well with people who already have a low carb lifestyle.

The evidence becomes much more spotty when you look at how using kidney bean extract helps to combat broader health issues like weight loss and insulin resistance.

Overall

By the end of my research I’ve decided that I would tentatively recommend taking a kidney bean extract supplement for the following people:

Someone looking to lower their carbohydrate intake but does not know where to start or is unclear how they’d fit a low-carb diet into their lifestyle
For use on “cheat days”, when you know you’ll be eating a lot of starchy food
Before traveling or social occasions, situations that throw a lot of simple carbs your way
Given its harmless nature and low price, I don’t see too much downside to experimenting with its use as long as you understand what it is and isn’t capable of doing.