Nutrition
Friend or Foe? Understanding Grains and Your Health
Are grains friend or foe? The science reveals it depends on the type, quantity, and your individual health status. A deeper look at gluten, ATIs, and wheat germ agglutinin.
Nutrition
Are grains friend or foe? The science reveals it depends on the type, quantity, and your individual health status. A deeper look at gluten, ATIs, and wheat germ agglutinin.
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When it comes to grain consumption, opinions are clearly divided. For some, the wheat kernel is the plant-based embodiment of the devil, while others swear by their daily whole-grain bread and fresh-grain porridge.
Somewhere in between are people who, due to statements from the media and self-proclaimed health experts, now only have one giant question mark on their foreheads and no longer know what to believe. We want to make this question mark (at least partially) disappear today ;) Because, as you'll read shortly, much remains unknown to science even today.
Gluten is a major keyword in this debate, and there are many uncertainties here too. Is only wheat gluten harmful? What about spelt or rye? More on that later.
What many people miss: Besides gluten, there are other proteins in grains that can potentially be problematic. It's possible that people in whom celiac disease has been definitively ruled out still experience problems when consuming grains.
Let's take a small excursion into the world of grain proteins!
Or briefly: ATIs. These proteins serve the plant as protection against pests. They inhibit the digestive enzymes amylase and trypsin and are meant to prevent the plant from being eaten. The highest amounts of ATIs are found in gluten-containing grains. In spelt, in fact, even more than in wheat (1).
Unfortunately, ATIs are also largely resistant to degradation in the human digestive tract and can stimulate immune system receptors there, the so-called TLR4 receptors, triggering an immune response (2).
This is also demonstrated by a recent study from the laboratory of ATI researcher Dr. Dr. Schuppan using a mouse model of multiple sclerosis (3). Mice receiving ATI-containing pellets became ill earlier and developed more severe symptoms than mice whose feed contained no ATIs.
Good news for bread lovers: Schuppan and colleagues also showed that the ATI content and the resulting immune system activation can be significantly reduced through sourdough fermentation (4).
This protein, called WGA (wheat germ agglutinin) for short, also serves the plant as protection and is extremely resistant to digestive enzymes. WGA belongs to the group of lectins – proteins that specifically bind to carbohydrate structures found, for example, on the surface of red blood cells or the intestinal epithelium.
Some studies suggest that WGA can bind to and damage the intestinal mucosa, potentially resulting in leaky gut (5,6). This allows lectins to enter the bloodstream, where they can either directly or through lectin antibodies produced by the body promote the development of autoimmune diseases.
One study showed that lectin-specific antibodies also react with the body's own proteins, such as the thyroid enzyme TPO (thyroid peroxidase), because both proteins have structural similarities (7). A link to Hashimoto's thyroiditis (autoimmune thyroid disease) could certainly be plausible here.
Admittedly, that was quite a few conditional statements. In fact, while there are high-quality cell and animal studies on these mechanisms, human studies are lacking. Just because something seems plausible doesn't mean it's necessarily reality. Nevertheless, WGA is high on the list of suspects. We look forward to further studies!
That gluten, more precisely gliadin, could transiently open the intestinal barrier in everyone – and thus the gateway to a host of diseases like MS, colitis, or insulin resistance – we have addressed many times before.
Today, let's take a step back: What exactly is gluten anyway?
Gluten is a collective term for the storage proteins of grain varieties that trigger an immunological reaction in celiac patients. This refers not only to wheat, but also to spelt, rye, barley, and (to a lesser extent) oats.
The storage proteins are further subdivided into prolamines and glutenins. Each grain does have its "own" storage proteins among the prolamines and glutenins, but in the case of gluten-containing varieties, these appear to be so closely related to each other that the immunological reaction to them – with the exception of oats – is very similar.
In wheat, the main storage protein – a prolamine – is called gliadin. In rye, we find secalin analogously, in barley hordein, and in oats avenin.
The grains marked in red are considered gluten-containing, while those marked in green are gluten-free. Note: Although corn, rice, and millet also contain prolamines and glutenins, they are considered gluten-free precisely because they do not trigger an immunological reaction in celiac patients.
The terms gliadin and gluten are often confused and incorrectly used synonymously, which certainly contributes significantly to the prevailing confusion about grains. Gliadin occurs ONLY in wheat or its close relatives such as spelt, einkorn, or emmer.
Let's turn to the special case of oats. Evolutionarily, oats separated from other grasses earlier. Therefore, the storage protein avenin shows a significantly weaker immune reaction, which is also why it is often tolerated in celiac disease (as long as there is no contamination with other gluten-containing grains!)
Whether grains are friend or foe cannot be answered across the board. In addition to quantity, variety, and preparation method, it also always depends on the individual. Genetic predisposition, health status, and lifestyle play an important role here.
We don't want to deny grain consumption to anyone completely; rather, we want to encourage reflection. A reduction in grain consumption would probably be beneficial for most people, and not just because of the potentially problematic proteins.
Especially if you already suffer from autoimmune diseases or metabolic disorders, you should think twice about whether that morning jam bread couldn't be replaced with a serving of scrambled eggs – or at least with an oat porridge ;-)
