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What about grains?

As I said in my last post our Paleolithic ancestors did not use grains as food and many researchers and health professionals think that we should not be eating them today. Lets look at the use of grains for the last 10,000 years and how that use has changed in the recent past. I will be using wheat, and specifically bread, as a primary example, since we eat so much of it, but much of what is true for wheat also applies to rye, oats, corn, rice and other grains. Grains are energy dense, containing about 10-20 times more energy (calories) than most succulent fruits and vegetables. Compositionally, grains consist of 12-14% water, 65-75% carbohydrates, 2-6% lipids and 7-12% protein. Cereals are quite similar to each other in composition, being low in protein and high in carbohydrates (1).

It is thought that humans began cultivating grains around 10,000 years ago. In the raw state grains are indigestible due to the tough, cellulose-containing cell walls that surround the nutrients and make them unavailable to human digestive enzymes. Our ancestors must have figured out early on that extensive processing was necessary in order to obtain sustenance from grains. Grinding the grain using stones was an early method of breaking the kernels apart and the resulting flour or meal could then be soaked and cooked in various ways. It is thought that bread making started about 4300 years ago in Egypt when someone left a mixture of flour and water out for a few days and it started to bubble. This starter was mixed with more flour and water and the first sourdough bread was born.. Cultures around the world developed methods of soaking, sprouting and fermenting grains to both preserve them and make them release their nutrients (1). In all of these instances they used the grain whole.

Though it is much more complex than described here, the wheat seed consists of 3 basic parts.
1. Bran: Forming the outer layer of the seed, the bran is a rich source of niacin, thiamin, riboflavin, magnesium, phosphorus, iron and zinc. The bran also contains most of the seed’s fiber.
2. Germ: The part from which a new plant sprouts, the germ is a concentrated source of niacin, thiamin, riboflavin, vitamin E, magnesium, phosphorus, iron and zinc. The germ also contains protein and some fat.
3. Endosperm: Also called the kernel, the endosperm makes up the bulk of the seed. It contains most of the grain’s protein and carbohydrate and has small amounts of vitamins and minerals.
Whole grain products contain all three parts of the wheat seed, while refined grain products contain only the starchy endosperm. While we throw away most of the nutrients of the grain when we make white flour, we also discard the majority of the so-called anti-nutrients, most of which occur in the bran and germ. We are being urged to eat whole grains, but unless they are properly prepared we are not absorbing and utilizing the nutrients that occur in the grains.

The two major anti-nutrients in wheat are phytates and enzyme inhibitors. Phytates are salts of phytic acid and occur in many plants, but are especially abundant in cereal grains. They are capable of forming insoluble complexes with calcium, zinc, iron, magnesium and other nutrients and interfering with their absorption by the body. Phytates reduce the bioavailability of minerals, and the solubility, functionality and digestibility of proteins and carbohydrates. Enzyme inhibitors are molecules that bind to enzymes and decrease their activity. Protease (enzyme that breaks down protein) and amylase (enzyme that breaks down starch) inhibitors occur widely in cereal grains. They are believed to impair health and growth by interfering with digestion and causing pancreatic abnormalities and metabolic disturbances. Since both phytates and enzyme inhibitors are most abundant in the bran and germ of the wheat, whole grain products that are not properly pre-treated in order to inactivate them will not release their nutrients during digestion.

Cooking of grains is necessary in order to disrupt cell walls and make digestion possible, but it does not affect the anti-nutrients present. Grains contain phytases (enzymes that break down phytate) and if these have not been inactivated by extrusion (breakfast cereals) or heat treatment there is appreciable degradation of phytates in the human stomach and intestines. But humans eat grains that have been heated or extruded; therefore the phytases are inactivated and cannot break down the phytates. (2). Soaking, sprouting and/or fermenting of grains all must be done prior to cooking in order to reduce the content of phytates and enzyme inhibitors. Phytates broken down during germination of grains make minerals available for the growing plant. Soaking and germination increase phytase activity and decrease phytate content, but fermentation is even more effective. Fermentation creates a slightly acid medium, which increases the ability of phytases already present in the grain to reduce phytate content by catalyzing the conversion of phytate to inorganic phosphate, thus releasing bound minerals (3, 4). Although enzyme inhibitors tend to be heat stable, there are numerous reports that their levels are also reduced during fermentation of grains (1).

Applying this knowledge to bread-making, we begin to see where problems arise. Today we do not think of bread as a fermented product, but this kind of natural leavening remained the norm until the 20th century, when bread made from commercially prepared yeast was introduced. Prior to the 1950s most bakeries ran 2 shifts of workers because the dough was fermented throughout the night with a long and slow natural fermentation process. But this required 2 shifts of workers so corporate bakers introduced the fast loaf (3 hours from start to finish). This increased profits by eliminating the second shift of workers. Today some bakeries produce bread in just 40 minutes from start to finish. These fast processes effectively eliminate the fermentation step by greatly increasing the amount of yeast used. Naturally fermented bread, e.g., sourdough, is left to proof for at least 8 hours and often longer. This proofing affords time for bacteria in the sourdough culture to produce lactic and other organic acids that lower the pH to ~5.5 and effectively activate phytases to degrade phytates. Sourdough fermentation reduces the phytate content to a much greater extent than yeast. The rapid processing of whole grain flour into bread leaves the phytates and enzyme inhibitors mostly intact and greatly reduces the nutrients available from the bread. With the new interest in whole grains from the nutrition and medical communities it is important to emphasize that the grains must be properly prepared.

There are two other problems with rapidly made bread: gluten, which comprises about 80% of the protein in wheat, and starch digestion. Gluten is found in the endosperm complexed with starch, and is what gives yeast bread its elasticity, or ability to rise. In fact, extra gluten is often added to yeast bread for this purpose. A far greater amount of gluten is now present in regular yeast breads, both white and whole grain, since it is found in the endosperm, possibly leading to the steep rise in gluten intolerance that has occurred recently. Only when wheat gluten is properly broken down into amino acids by fermentation is it healthy for human consumption. If not, it is potentially one of the most highly allergenic foods we eat, since it can pass whole into the blood. During sourdough bread-making gluten is hydrolyzed by proteases during the acidification that occurs from the microorganisms that are present in sourdough culture. Gluten is not so important for structure in fermented breads as it is in ‘regular’ bread. The increased contents of water-soluble polysaccharides (chains of sugar molecules) in sourdough fermented bread dough compared to straight dough contribute to the water absorption and gas retention (rising) capacities of the dough, as observed in rye baking. (5, 6). The other aspect of regular yeast breads compared with sourdough is the body’s reaction to the starch. Being finely ground, the starch in both white and whole wheat bread is quickly broken down into glucose in the digestive tract and absorbed into the blood stream, causing a rapid rise in blood glucose and resultant insulin. It has been shown that the acids formed during sourdough fermentation retard the outpouring of glucose into the bloodstream and lower the insulin response. (7).

Should we be eating grains? For most of us they are probably fine in moderation and properly prepared. We are used to light and fluffy loaves of bread, even whole grain varieties, and most of us are unaware of the effects of commercial processing, such as high yeast levels, accelerants, proofing agents and bromide, that regular bread undergoes. There are whole grain breads made with sprouted grains, usually found in the freezer section of health food stores. Unfortunately, while the sprouting is beneficial, the makers of these breads often add extra gluten and yeast rather than using a sourdough process. If you live in an area where good traditional sourdough bread is available try it. Otherwise maybe you would enjoy making your own.

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