Research Update: Resistant Starch

By: Dr. Alan Christianson

You’ve heard the buzz about Resistant Starch (RS), but what about the science? So many new supplements hit the market hard after one or two exciting findings and then fizzle when larger studies don’t show the same results.

I wanted to keep you up to date with the top updates from the world of RS.

The image shows how RS fits in the whole world of carbohydrates. Notice that it is the exact opposite of fructose, the worst carb.



It was the early 1990’s when the first studies about resistant starch (RS) started rolling out—an exciting, recently discovered food constituent shown to lower colorectal cancer risks. It does this by binding with and eliminating toxins, like ammonia and phenols, from the intestinal tract. [1]

By the late 1990’s, further benefits began to emerge. It appeared RS could also improve inflammatory bowel disease, such as Crohn’s disease and ulcerative colitis. [2] The researchers found RS helped because gut bacteria converts RS into short-chain fatty acids, like butyrate, which are known to heal the colon.

Later work showed RS may do more to heal the gut than probiotic supplements because of its twofold effects: It can act as a prebiotic and raise the number of good bacteria, and it can act as a symbiotic, helping the good bacteria adhere better to the intestinal surface. [3]

All these benefits were especially remarkable considering that literature reviews and safety studies showed RS was so safe, it didn’t require even the minimal level of regulation needed for supplements. [4]

Researchers soon noticed participants in some RS studies were experiencing healthy weight loss and improvements in blood sugar regulation. These observations inspired studies (starting in 2004) to see if RS could help the growing problems of obesity and diabetes.

Several studies showed RS was effective to help weight loss, reduce visceral fat, reduce insulin resistance and improve blood sugar regulation. [5]

What do we know now, and what do the latest studies tell us?

Unlike so many encouraging studies that don’t pan out, the positive effects of RS keep showing up in new research, almost on a daily basis.

The last review summarized over a decade of studies, verifying that RS has been clinically proven to: [6]

1. Help weight loss
2. Reduce body fat
3. Increase mitochondrial energy production
4. Improve gut health
5. Prevent cancer
6. Reduce abdominal fat
7. Improve insulin sensitivity

Where can RS be found in your diet?

Of common foods, beans contain the highest concentration of RS by far. Although all types of beans have RS, white beans (including navy, northern and cannellini) are the highest. [7]

Other foods with lower amounts of RS include: potatoes that have been cooked and cooled, raw oats, unripe bananas and cashews.

It’s worth noting that the vast majority of studies used RS in dosages above 10,000 or 15,000 milligrams daily. This is five to tenfold above the amounts found in normal servings of any conventional food source of RS. Although eating a variety of foods high in RS undoubtedly will produce health benefits, concentrated forms of RS may yield quicker and more predictable results.

One of the densest sources of RS commercially available is RS2 pea starch. It’s a commercially-available, flavorless powder and has been used in meal replacement products. It’s easily absorbed in water, free of plant toxins and hypoallergenic.

Another source of RS is unmodified potato starch. This is a flavorless powder, yet some with autoimmune conditions have concerns about consuming nightshade plants due to a toxic alkaloid, called solanaceae.

Corn starch has also been used as a food supplement; however, it is less than ideal because many have concerns about both GMO exposures from corn products and corn as an allergen.

RS is a great example of the healing power of nature. It is a safe food constituent clinically shown to improve numerous health conditions.

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[1] Hylla S, Gostner A, Dusel G, Anger H, Bartram HP, Christl SU, Kasper H, Scheppach W, “Effects of resistant starch on the colon in healthy volunteers: possible implications for cancer prevention,” The American Journal of Clinical Nutrition, 1998 Jan;67(1):136-42.
[2] Jacobasch G, Schmiedl D, Kruschewski M, Schmehl K, “Dietary resistant starch and chronic inflammatory bowel diseases,” International Journal of Colorectal Disease, 1999 Nov;14(4-5):201-11.
[3] Topping DL, Fukushima M, Bird AR, “Resistant starch as a prebiotic and synbiotic: state of the art,” Proceedings of the Nutrition Society, 2003 Feb;62(1):171-6.
[4] Goldring JM, “Resistant starch: safe intakes and legal status,” Journal of AOAC International, 2004 May-Jun;87(3):733-9.
[5] Tapsell LC, “Diet and metabolic syndrome: where does resistant starch fit in?” Journal of AOAC International, 2004 May-Jun;87(3):756-60.
[6] Keenan MJ, Zhou J, Hegsted M, Pelkman C, Durham HA, Coulon DB, Martin RJ, “Role of resistant starch in improving gut health, adiposity and insulin resistance,” Advances in Nutrition, 2015 Mar 13;6(2):198-205. doi: 10.3945/an.114.007419, print 2015 Mar.
[7] Åkerberg AK, Liljeberg HG, Granfeldt YE, Drews AW, Björck IM, “An in vitro method, based on chewing, to predict resistant starch content in foods allows parallel determination of potentially available starch and dietary fiber,” Journal of Nutrition, 1998;128:651–660.

Dr. Alan Christianson is an Arizona-based Naturopathic Physician who helps people overcome adrenal and thyroid disorders and achieve lasting fat loss.  He authored the New York Times' bestselling Adrenal Reset Diet, and The Complete Idiot’s Guide to Thyroid Disease.  Dr. Christianson is the founding physician behind Integrative Health.