What are Amylase Trypsin Inhibitors (ATIs)?
Amylase/trypsin inhibitors (ATIs) are a family of proteins found in the seeds of many plants, particularly cereals. In nature, these proteins serve as a natural defense mechanism for the plant, protecting it from pests and pathogens by inhibiting the digestive enzymes (amylase and trypsin) of insects and other animals. For the vast majority of the human population, consuming these foods poses no issue. However, a small percentage of people can experience adverse reactions to ATIs, which are increasingly understood to trigger innate immune system responses.
Foods with the Highest ATI Content
ATIs are most notably present in cereal grains, especially those containing gluten. These include:
- Wheat: All wheat species, both modern and ancient varieties like spelt and emmer, contain significant amounts of ATIs. Since wheat is used to produce staples like bread, pasta, and biscuits, it is a primary source of ATIs in many diets.
- Rye: This grain contains dimeric inhibitors that are highly homologous to wheat's dimeric inhibitors.
- Barley: Barley grains also contain ATIs, with forms similar to those found in wheat.
- Other Cereals: In addition to the gluten-containing grains, ATIs are also present in other cultivated cereals, including maize, millet, and rice, though at varying levels.
ATIs in Legumes
Besides cereals, some legumes also contain enzyme inhibitors, including trypsin inhibitors. However, the exact composition and potential for innate immune activation differ from the ATIs found in gluten-containing cereals.
- Soybeans: These are well-known to contain trypsin inhibitors. The processing of soybeans, such as heat treatment during the production of soybean meal, can effectively reduce the activity of these inhibitors. Some research indicates that soy consumption may interfere with thyroid medication absorption, but it does not generally affect thyroid function in iodine-replete individuals.
- Other Legumes: Many other beans and legumes, such as white kidney beans, also contain compounds that can inhibit amylase, potentially impacting blood glucose levels.
ATI and Health Implications
While not a problem for most people, ATIs can be a concern for those with pre-existing conditions related to inflammation or immune sensitivity.
Activation of the Innate Immune System
ATIs are resistant to breakdown by digestive enzymes and can pass through the intestinal lining. There, they can activate a receptor called Toll-like receptor 4 (TLR4) on immune cells, triggering the release of inflammatory cytokines. This innate immune response is not an allergic reaction, but a general inflammatory one.
Non-Celiac Wheat Sensitivity (NCWS)
For individuals with NCWS, who experience symptoms related to wheat ingestion but do not have celiac disease or a wheat allergy, ATIs may play a prominent role. While other factors in wheat, such as FODMAPs, are also considered, the inflammatory response triggered by ATIs has been suggested as a potential mechanism for NCWS symptoms.
Inflammatory Bowel Disease (IBD) and Other Conditions
Research in animal models has shown that ATIs can worsen conditions like inflammatory bowel disease. Studies in mice have also suggested that dietary ATIs might aggravate pathological markers of Alzheimer's disease, though human studies are lacking.
Celiac Disease
In celiac disease, ATIs are not the primary trigger but may exacerbate the immune response caused by gluten. Some studies suggest that ATIs could enhance the inflammatory reaction in celiac patients, potentially intensifying the autoimmune process.
High ATI vs. Low ATI Food Alternatives
When considering dietary changes, particularly for those with sensitivities, understanding ATI levels in different foods is important. Here is a comparison of some common high-ATI foods and lower-ATI or ATI-free alternatives.
| High-ATI Food (Cereals) | Lower-ATI or ATI-Free Alternative (Grains/Starches) |
|---|---|
| Wheat (Bread, Pasta) | Rice (including brown rice), Oats (less inflammatory ATI types), Quinoa |
| Barley (Soup, Cereals) | Buckwheat, Millet, Corn |
| Rye (Bread, Crackers) | Sweet Potatoes, White Potatoes, Cassava |
| Spelt | Pseudocereals (like amaranth), Legumes (properly cooked) |
Impact of Food Processing on ATIs
Food processing methods, particularly those involving heat and fermentation, can impact the level and activity of ATIs. Sourdough fermentation, for example, has been shown to have a proteolytic effect, leading to the digestion of some ATI forms and potentially lowering inflammatory activity. However, the effects of standard cooking methods like boiling or baking are less clear, with some studies showing reduced ATI activity and others showing retention. Due to these inconsistencies, the effects of processing on ATIs consumed via processed food remain an active area of research.
Conclusion: Navigating a Diet with ATI-Containing Foods
ATIs are a natural component of many staple foods, particularly cereals and legumes. While most people tolerate them well, they can contribute to inflammatory responses in susceptible individuals, such as those with NCWS or IBD. A balanced approach involves being mindful of potential triggers, ensuring a diet rich in a variety of nutrients, and consulting a healthcare professional if you suspect a sensitivity. For some, reducing intake of high-ATI cereals might be beneficial, especially if coupled with a focus on naturally lower-ATI alternatives. Food processing like proper cooking and sourdough fermentation may offer ways to mitigate the impact of ATIs, though more research on their effects in human physiology is needed.
For more detailed scientific reviews on ATI research, you can refer to authoritative sources like the National Institutes of Health (NIH).
