Starch

Overview

Starch is one of the three naturally occurring toxic things in our food supply, alongside polyunsaturated fats and excess iron. The government and the American Dietetics Association have spent almost fifty years promoting the idea that complex carbohydrates have some advantage over sugars, but the underlying science says the opposite: starch turns into pure glucose within minutes, has a glycemic index near the top of the food list (very close to pure glucose), stimulates insulin more powerfully than fruit sugar, and feeds the bacteria of the lower intestine when it is not fully digested. On top of that, Gerhard Volkheimer demonstrated that raw or undigested starch granules pass through the intestinal wall intact and lodge in arterioles, killing the cells downstream and accelerating aging. Ray Peat's position was that starch should be either avoided or, at least, prepared in ways that minimize these harms (thorough cooking and combining starches with saturated fat).

Key Points

• Starch is digested into pure glucose almost instantly and stimulates insulin like glucose itself. In a physiology lab, a ten-gram dose of corn starch fed to rats was completely absorbed within ten minutes, with no trace of starch paste left in the digestive tract. The glycemic index of typical cooked starch is near the top of the food list, very similar to pure glucose, which means starch produces a quick, powerful stimulation of insulin and a corresponding burst of fat synthesis when the load exceeds what the liver can take up.

• Gerhard Volkheimer demonstrated that intact starch granules cross the intestinal wall into the bloodstream. Feeding medical students a cup of corn starch slurry, he found unprocessed starch grains in their veins within thirty minutes, in their urine and bile within forty-five minutes to an hour, and in their cerebrospinal fluid about an hour and a half later. Potato starch granules can reach 100 microns in diameter, ten times the size of a red blood cell, so they plug arterioles long before they reach capillaries. This process is called persorption: the cells of the intestinal wall are pressed on one side and the particle pops out the other.

• Chronic starch feeding caused premature aging in mice through micro-infarcts (localized areas of dead tissue) in every organ. When Volkheimer sliced up mice that had been fed a high-starch diet for several months, every organ contained small nests of dead, deteriorating cells downstream from a lodged starch grain blocking an arteriole or capillary. It was like having a shotgun working internally, killing little pockets of cells in the heart, brain, kidneys, and other tissues. This is one of the mechanisms by which a high-starch diet accelerates the aging process.

• Starch is the main bacteria-promoting food in the intestine and a major source of endotoxin. Undigested starch and complex fibrous materials passing into the lower small intestine and colon feed bacteria that produce lipopolysaccharide, the molecule called endotoxin. Endotoxin stimulates nitric oxide and serotonin production, turns off metabolism, slows oxidation, and is the main reason that having too many bacteria in the intestine creates obesity, lethargy, and shortened life. Animal experiments with rats fed indigestible starch-like fibers also produce anxious and aggressive behavior.

• SIBO makes even simple starch problematic. In people with low stomach acid, hypothyroidism, or PPI use, bacteria colonize the small intestine. Once that happens, even easily digested starches feed bacteria before absorption can occur. This is now a recognized condition called small intestinal bacterial overgrowth.

• Starches are more powerfully diabetogenic than sugar, contrary to dietetic advice. Starches increase insulin resistance very quickly, as if you were eating fat, because they do not support the body's own production of saturated fat the way fruit sugars do. The combination of starch and polyunsaturated fats causes the greatest disturbance of blood sugar, much more than eating white sugar candy. In animal feeding studies that ran five or more weeks, the starch-fed animals gained twice as much weight as the sucrose-fed animals on the same caloric intake.

• Grains are also a source of excess phosphate, which drives parathyroid hormone and degenerative disease. Grains, beans, nuts, and seeds are very high in phosphorus relative to calcium, and phosphate stimulates the bacterial breakdown of fibers in the intestine while calcium suppresses that breakdown. A high phosphate intake activates parathyroid hormone, which dissolves bone and calcifies arteries and kidneys. Most Americans now have five to seven times as much phosphate in their diet as calcium, when the ratio should be roughly equal, ideally with calcium slightly higher.

• Phytic acid in unrefined grains triggers inflammation. Whole grain breads, raw or semi-raw oats, and brown rice contain phytic acid. A derivative, phytanic acid, is used as a vaccine adjuvant precisely because it provokes an inflammatory response. The "rustic" breads with visible grains and nuts marketed as healthy are among the worst offenders.

• Nixtamalized corn and very thoroughly cooked potatoes are the least harmful starch preparations. A corn tortilla processed in alkali (lime water) has the starch granules opened up so that they are easy to digest, in contrast to bean polysaccharides that human enzymes cannot work on at all. Potatoes boiled for forty to sixty minutes and eaten with plenty of butter or coconut oil are reasonably safe, because the fat slows absorption, allows digestive enzymes more time to break down the starch, and suppresses bacterial growth on whatever passes into the lower intestine.

• Potato is unique among plant foods for the quality of its protein and its keto acid content. Norman Curie rated potato protein at about 105% of egg yolk on his scale, compared to about 6% for rice. The clear liquid between the starch granules contains keto acids that the brain and heart can use as substitute fuel for sugar or fatty acids, making juiced potato (with the starch settled out and discarded) an effective anti-stress food. The New Guinea highland populations who ate potatoes for fifty weeks of the year were studied and found to be well-muscled and generally healthy.

Notable Quotes

"The typical well-cooked starch, when it is digested, releases pure glucose. And in my first physiology lab, a professor had us feed, it was a 10-gram dose of corn starch to the lab rats. And she said, 'Wait 10 minutes and then operate on the rat and see how far this huge glob of starch paste had migrated.' And it turned out that there was no trace of any starch paste left in the rat after 10 minutes."

[Ray Peat — KMUD: Sugar, Part 1]

"Starches have a very quick ability to turn into glucose, where fructose is a very slow, controlled converter into glucose."

[Ray Peat — East West Healing: Glycemia, Starch and Sugar in Context]

"Starch is the main bacteria promoting food. The bacteria living on these foods that we don't digest produce endotoxin, and the endotoxin stimulates the production of nitric oxide."

[Ray Peat — KMUD: Digestion and Emotion]

"He found that it caused mice to age prematurely and when he sliced them up, he found that in every place that one of these starch grains lodged in an arteriole or capillary, the surrounding cells would be starved of nutrients and would die. It was like having a shotgun working internally, killing little pockets of cells."

[Ray Peat — KMUD: California SB 277 and Degradation of the Food Supply]

"Starches are much more powerful stimulants to insulin and the stress reactions."

[Ray Peat — KMUD: Food Additives]

When you give bacteria resistant starch, it's actually one of the worst things you can do for your health because it increases the turnover rate of the colony there and then this increases the amount of endotoxin.

[Georgi Dinkov — Digestion and Mood [Generative Energy #10]]

Important Things To Consider

The fattening effect of "sugar" is mostly the starch that surrounds it. White flour cakes, cookies, pies, breads, and pastas raise blood sugar and insulin much more than the sugar itself in those products. A Los Angeles group testing soft drinks found that they contained four to five times more starch-like polysaccharide calories than the fructose and glucose on the label, which is the real reason high fructose corn syrup beverages are so fattening. Plain ice cream, by contrast, has almost no starch and is much less fattening per calorie.

"Resistant starches" and prebiotic fibers marketed as health foods are the most problematic. Poorly digested starches that pass into the lower intestine produce the greatest bacterial overgrowth and the most endotoxin. Animal experiments using soluble indigestible fibers showed that rats fed these became anxious and aggressive. The food industry has promoted them as beneficial because the short chain fatty acids they yield (butyric, propionic, lactic) appear protective locally, but the systemic effects include carcinogenesis and inflammation.

Cook starches thoroughly and eat them with saturated fat. Boiling potatoes for forty to sixty minutes breaks down the starch granules so they are less likely to cross the intestinal barrier intact. Combining starch with butter, coconut oil, or milk slows absorption and gives digestive enzymes more time to work, and the saturated fat also suppresses bacterial growth on whatever reaches the lower intestine. Mashed potatoes with plenty of milk and butter are the typical example.

Sourdough fermentation and nixtamalization make grain starches somewhat less harmful. The longer sourdough digests, the more the starch turns toward sprout, which is mostly sugar, protein, and water rather than starch and indigestible protein. Nixtamalization (boiling corn with lye or lime) opens up the starch granules and liberates some of the bound minerals. Soaking beans for three days as they approach sprouting also converts storage protein into growth protein and is less toxic.

Sugar eaten alongside or after starch reduces some of the damage. Quickly absorbed sugars (fruit, honey, white sugar, lactose in milk) have a defensive effect against the bacterial products of starch digestion, decreasing the inflammatory reaction to endotoxin. Having a glass of orange juice or a small dessert after a starchy meal is a practical way to reduce the downstream harm.