More research needed on 'super foods'

  • Green bananas are a good source of resistant starch, which is believed to reduce blood sugar.

    Green bananas are a good source of resistant starch, which is believed to reduce blood sugar.

Updated 4/14/2021 10:19 PM

There have been claims that resistant starch is a "super food," offering many health benefits. Some claims have reasonable medical research to support them, while other claims are not supported by the medical studies.

Resistant starch is any starch that is resistant to the pancreatic enzyme alpha-amylase. This enzyme breaks down starch into two basic sugars, glucose and maltose. Amylase is found in a number of tissues; it is most concentrated in the saliva and pancreatic juice secreted into the first part of the intestines, the duodenum. Resistant starch is, to a great extent, unaffected by amylase. It is able to make it into the large intestine where bacteria use it as a food source producing numerous compounds, many believed to be anti-inflammatory as well as a preventive to cancer.


There are numerous medical studies suggesting a positive effect on inflammation but deeper analysis of the research suggests otherwise.

There are four basis categories of resistant starch:

• Type 1: Grains, seeds and some beans.

• Type 2: Commonly in raw potatoes and green bananas.

• Type 3: Formed when starchy foods are cooked and cooled.

• Type 4: Man-made chemical process.

There is reasonable research on the effect of all the categories of resistant starch on improving glycemic control (reducing blood sugar) and cholesterol levels, possibly reducing the risk of diabetes and heart disease. The data suggesting that resistant starch reduces overall inflammation is less convincing.

Inflammation is the foundation stone for many chronic illnesses including Type 2 diabetes and heart disease. In the presence of inflammation, the body makes compounds like tumor necrosis factor-alpha, interleukin-6 and C-reactive protein. These compounds potentiate the negative effects of oxidative stress leading to insulin resistance and high cholesterol. Select dietary changes have been shown to have a powerful effect on reducing oxidative stress as well as the risk of many chronic illnesses.

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There are many studies exploring the effect of resistant starch on overall inflammation. However, the data are conflicting. Some studies show a positive result while others do not. One recent study published in Complementary Therapies in Medicine (2021) combined the results of a number of studies into one study called a meta-analysis. The results of this meta-analysis did not show any benefit from resistant starch on reducing common blood markers of inflammation tumor necrosis factor-alpha, interleukin-6 and C-reactive protein. Most of the studies used a corn-based form (type 4) of resistant starch. In another meta-analysis (2019) resistant starch reduced triglyceride levels in healthy individuals and participants with Type 2 diabetes reported significant weight loss. However, this study also did not show benefit for reducing markers of inflammation.

What does this mean? There is enough positive data to stimulate further study. Dietary changes are a powerful for promoting health and longevity. Just at this time, the excitement about resistant starch does not live up to the research. There is no downside except, perhaps, a change in bowel function if too much resistant starch is consumed. Moderation in all things is a good guide.

• Dr. Patrick Massey is president of ALT-MED Medical and Physical Therapy, 1544 Nerge Road, Elk Grove Village.

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