Starch

Studies in people

• Benefit

  Gut bacteria³

  Some starch resists digestion and is fermented by gut bacteria, and research suggests it may have health-related benefits.

• Open question

  Gut bacteria response⁴

  In people, resistant starch changes gut bacteria differently, and scientists cannot yet predict how each person's gut germs respond.

• Benefit

  Gut adaptation after bowel surgery⁵

  In people with short bowel syndrome, starch is absorbed or fermented almost completely and may help the gut adapt.

• Open question

  Diabetes risk from food⁶

  Starch is a main source of food energy, and how fast the body digests it is linked to diabetes.

• Benefit

  Blood sugar response⁷

  Cooling cooked white rice then reheating it raised resistant starch and lowered blood sugar response in healthy adults.

• Benefit

  Weight loss and blood sugar⁸

  In people with excess weight, taking resistant starch for 8 weeks led to weight loss and better blood sugar control.

• Benefit

  Colon and bowel health⁹

  In people, resistant starch feeds gut bacteria and may help protect against bowel cancer.

• Benefit

  Blood sugar and fullness¹²

  Resistant starch in a meal left ten men with lower blood sugar and insulin, and feeling less full.

Animal and lab studies only

• Benefit

  Colon cancer risk¹⁸

  In animal studies, resistant starch suppressed colon tumors caused by high-fructose corn syrup by reshaping gut bacteria.

• Open question

  Gut bacteria and solids¹⁹

  In lab studies, starch fed the gut bacteria of infants, especially once they started eating solids.

Study type not stated

• Benefit

  Gut health and blood sugar¹³

  Resistant starch, a kind of starch your body can't digest, feeds gut germs and may help with diabetes and obesity.

• Benefit

  Blood sugar and kidney health¹⁴

  Replacing simple carbs with resistant starch may help blood sugar and kidney health, but more human studies are needed.

• Open question

  Gut health¹⁵

  Some starch passes undigested to the large bowel, where gut bacteria feed on it and make acids that may affect colon health.

• Benefit

  Gut bacteria and blood sugar¹⁷

  Resistant starch feeds gut bacteria that may help prevent type 2 diabetes and obesity, though how is not fully known.

Single cases of misuse or overdose

One person or one incident, such as an accidental overdose or a mistake in a kitchen or factory. They are real, but a single case does not show what happens at normal amounts, so the signal does not count them.

• Blood acid buildup¹¹

  A woman who ate large amounts of corn starch every day built up propylene glycol, which turned into acid in her blood.

How it’s made and used

• Gut enzyme digestion²

  Young babies digest starch very differently from one another, relying on a specific gut enzyme to break it down.

• Blood sugar after bread¹⁰

  How wheat bread is made and what goes into it changes how fast the body turns its starch into blood sugar.

• Food ingredient delivery¹⁶

  Starch can be made into porous particles that carry food ingredients, the review says.

• How fast starchy foods digest²⁰

  Starch in biscuits broke down more slowly than in breads, which digested fastest in this test.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.