Amber Waves of Grain
Amber Waves of Grain

Miguel Carrera posted a link to an interesting article in the comments of my recent post on whole grains. Published in BioMed Central, it is titled Agrarian diet and diseases of affluence - Do evolutionary novel dietary lectins cause leptin resistance? I found it to be a very interesting and informative study, so I decided to pull it out of the comments and post on it. I’m pulling out some key excerpts, but there is much more in the paper, along with additional context.

This paper looks at “the prevalence of diseases of affluence, such as obesity, cardiovascular disease and diabetes type 2, between agrarian and non-agrarian societies,” using staple foods of the diet as the dividing line.

The diet of an agrarian society is based on large amount of seeds from grass such as cereals (e.g. wheat, rice, maize). Cereals are per definition rare or absent in a non-agrarian diet. Non-agrarian societies can be further divided into hunter-gatherer and horticultural societies. The diet of a hunter-gatherer society is based on hunting, fishing and gathering wild plants and insects. Hunting and gathering is thought to represent the original mode of life common to all prehistoric humans during the Palaeolithic (i.e. the Old Stone Age 2.6 million-10, 000 years ago). Horticultural societies obtain the bulk of their food from gardening, which sometimes implies heavy dependence on a single starchy cultivar such as a root crop (e.g. manioc).
….
Moreover, when people living in non-agrarian societies migrate to an agrarian society or when their own society becomes agrarian they contract diseases of affluence, which illustrates the general rule that there is no genetic protection against diseases of affluence, only genetic variation in degree of susceptibility.

It’s easy to see why cereals make up little to none of the caloric intake of non-agrarian societies. The calories obtained from the small amounts of grains found in the wild do not offset the caloric energy required to process them. Remember that humans cannot just grab hold of wheat or any other grass and chow down on the grains. You can also see an overall decrease in height, as well as degradation in markers of health, in the fossil record at the time that humans settled into civilizations, fueled by grains. The lack of all essential vitamins in the grains results in diseases such as pellagra and beri-beri when the grains aren’t properly treated, such as by nixtamalization by the Aztecs.

Since nothing in biology makes sense except in the light of evolution [16], we look at the cereal component of human diet from an evolutionary perspective.

Ahhh…if only more researchers felt this way we wouldn’t be living with a dietary pyramid based on all the wrong foods.

…there is a subclass of lectins only found in grasses like cereals. Many plant lectins are thought to play a role in the plants defence against being eaten. Accordingly, plant lectins have an obvious preference for binding to sugar structures of animal, fungal or microbial origin, and are usually at highest concentrations in plant parts essential for reproductive success such as seed germs. …Thus, lectins are present in our food, they are heat-stable and resistant to breakdown in the gastrointestinal tract, they bind to the surface epithelium of the digestive tract and they can lead to anti-nutritional, mild allergic or other subclinical effects in humans and animals. …Hence, lectins have sufficient properties to affect the leptin system indirectly, through effects on metabolism central to the proper function of the leptin system, and possibly also directly through interaction with leptin or the leptin receptor.

So it seems possible that beyond the mere caloric value of the foods we’re eating, other factors in the food can influence hormonal systems, pushing us towards obesity. The authors go on to describe the possible direct interaction between lectins and the leptin receptors or some other indirect methods through which lectins could affect leptin resistance.

It all comes back to the fact that grains are not a food that the human animal is built to consume in any large quantities, at least not without some work to ferment or sprout them. Our modern extruded processed grains are extremely detrimental to health. From lectins to gluten, there are plenty of ways that grains disrupt your system. I promise anyone that if they ditch the grains from their diet and replace them with fruits and vegetables, their health will improve markedly.


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