The Science Behind Pickling and FODMAPs
To understand how pickling affects FODMAPs, you must first know what FODMAPs are. FODMAP is an acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are short-chain carbohydrates and sugar alcohols that are poorly absorbed in the small intestine of sensitive individuals. When they reach the large intestine, gut bacteria ferment them, producing gas and other symptoms commonly associated with Irritable Bowel Syndrome (IBS), such as bloating, pain, and gas.
FODMAPs are water-soluble, which is a key factor in how certain processing methods, including pickling, can reduce their levels. By soaking foods in a liquid, some of the fermentable carbohydrates can leach out of the food and into the surrounding fluid. This process can be intentionally used to lower FODMAP content, as seen with canned legumes where rinsing is recommended to remove the FODMAP-laden liquid.
The Two Main Types of Pickling
There are two primary methods of pickling, and each affects FODMAPs differently:
- Quick Pickling (Vinegar-Based): This method involves submerging vegetables in a hot mixture of vinegar, water, and spices. The primary effect on FODMAPs comes from the leaching of water-soluble FODMAPs into the vinegar-based brine. Because this method does not involve a long fermentation, it does not rely on beneficial bacteria to break down the carbohydrates.
- Fermented Pickling (Salt Brine): This traditional method relies on a saltwater brine and allows for natural fermentation over time. The bacteria that thrive in this environment consume the sugars, including some FODMAPs, as part of the fermentation process. These can include beneficial probiotics. However, the results are not always predictable, as some fermented foods, like sauerkraut, can end up high in FODMAPs.
Water-Soluble FODMAPs: Leaching and Reduction
Since many FODMAPs, such as Fructans and Galacto-oligosaccharides (GOS), are water-soluble, submerging food in liquid is a straightforward way to reduce its FODMAP concentration. This is the principle behind rinsing canned beans to make them low FODMAP. The same logic applies to pickling, especially for foods rich in fructans, like onions. Studies have shown that when onions are pickled, their fructan content is reduced as it leaches into the brine. This is why Monash University has found certain pickled onions to be low FODMAP in specific serving sizes, particularly larger ones. To achieve a similar effect at home, thorough rinsing after cooking or soaking is crucial.
Fermentation's Unpredictable Role
While fermentation in salt brine can introduce probiotics and potentially reduce FODMAPs, it is not a guaranteed solution. The bacteria in the fermentation process break down carbohydrates, but the outcome varies widely depending on the food. For instance, the long fermentation used in making traditional sourdough bread is known to break down fructans, making it a low FODMAP option. In contrast, Monash University testing has shown that while gherkins (pickled cucumbers) remain low FODMAP after fermentation, other fermented vegetables, like red cabbage used for sauerkraut, can become high FODMAP. This highlights why relying on tested products and serving sizes, rather than assumptions, is vital for those with IBS.
The Critical Role of Ingredients in the Brine
For those following a low FODMAP diet, the ingredients in the pickling brine itself are just as important as the vegetable being pickled. Store-bought pickles often contain high-FODMAP ingredients for flavor, most notably garlic and onion. These fructan-rich components can infuse the entire brining liquid with FODMAPs, contaminating the otherwise low-FODMAP vegetables. This makes homemade pickling a safer and more reliable option. When making your own pickles, you can use low FODMAP alternatives like garlic-infused oil or asafoetida powder to achieve a savory flavor without the high-FODMAP content.
Comparison of Pickled Foods and FODMAP Content
| Pickled Food | Pickling Method | FODMAP Outcome | Important Considerations |
|---|---|---|---|
| Beetroot | Vinegar-based (tested) | Low FODMAP at 75g serving | Portion control is essential. Avoid high FODMAP ingredients in the brine. |
| Large Onions | Vinegar-based (tested) | Low FODMAP | The leaching process works more effectively on larger onions. Small pickled onions may still be high FODMAP. |
| Gherkins | Fermented/Vinegar-based | Low FODMAP | The fruit is naturally low FODMAP. Check ingredients in commercial products for garlic/onion. |
| Sauerkraut | Fermented | High FODMAP | Fermentation can increase FODMAPs in cabbage, especially the polyol mannitol. Small servings may be tolerated, but exercise caution. |
| Kimchi | Fermented | Varies | Typically contains high FODMAPs like garlic and onion. Some specific products or recipes may be low FODMAP. Check app for tested versions. |
Tips for Enjoying Pickled Foods on a Low FODMAP Diet
- Read Labels Carefully: Always scrutinize the ingredient list of store-bought pickles. If garlic, onion, or high-fructose corn syrup are listed, avoid them.
- Opt for Homemade: Making your own pickles gives you complete control over the ingredients, allowing you to use low-FODMAP spices and ingredients. This is the safest way to enjoy pickled foods on the diet.
- Adhere to Portion Sizes: Even for pickled foods that are tested and deemed low FODMAP, portion size is critical. Always check the Monash University app for safe serving recommendations.
- Rinse and Drain: For canned or jarred legumes and some vegetables, rinsing the food thoroughly after draining can help remove residual FODMAPs that have leached into the liquid.
- Use Infused Oils: When creating your own brine, use garlic-infused olive oil instead of fresh garlic to get the flavor without the fructan content.
- Consider Both Methods: Understand whether a pickle is vinegar-based or fermented. While fermented options may offer probiotic benefits, their FODMAP content is less predictable.
Conclusion
In conclusion, the claim that pickling automatically removes FODMAPs is a simplification. The truth is more complex. While the process can reduce FODMAP content in certain foods, like beetroot and large onions, it is not a universally effective method. The leaching of water-soluble carbohydrates into the pickling liquid is the primary mechanism of FODMAP reduction, but it is heavily dependent on the food and the specific preparation. Ingredients in the brine, especially in commercial products, can introduce new sources of FODMAPs, while the unpredictable nature of fermentation can sometimes increase them. For a reliable approach, it is essential to check verified sources like the Monash University FODMAP app and, for best results, make your own pickles using low FODMAP-friendly ingredients. Following careful portion control is always recommended. This careful approach can allow you to enjoy the tangy flavor of pickled vegetables without triggering your IBS symptoms. For more information, the Monash FODMAP blog provides excellent resources on how food processing affects FODMAP content [https://www.monashfodmap.com/blog/food-processing-and-fodmaps-what-you/].
What is the difference between quick pickles and fermented pickles in terms of FODMAP content?
Quick vs. Fermented: Quick pickles (made with vinegar) rely on the leaching of water-soluble FODMAPs, while fermented pickles rely on bacteria to consume FODMAPs. Fermentation can be unpredictable and may not always result in a lower FODMAP product.
Why are store-bought pickles often not low FODMAP?
High FODMAP Brine: Many commercial pickle brines contain high-FODMAP ingredients like garlic and onion, which infuse the pickles with fructans and other fermentable carbohydrates.
Is pickled beetroot low FODMAP?
Yes, in specific serving sizes: Monash University has tested pickled beetroot and found it to be low FODMAP in a serving size of up to 75 grams (about 1/2 cup).
Are pickled onions low FODMAP?
Depends on the size: Monash University testing showed that large pickled onions were low FODMAP, but small pickled onions contained high levels of fructose. The size difference likely impacts the leaching process.
Can I eat sauerkraut on a low FODMAP diet?
Proceed with caution: Sauerkraut is fermented cabbage, and Monash testing has shown that it can become high in the polyol mannitol during fermentation. Always check the app for safe portion sizes.
How can I make my own low FODMAP pickles?
Control Ingredients: To make low FODMAP pickles, use low-FODMAP vegetables (like cucumbers or carrots) and a brine made from vinegar, water, salt, and low-FODMAP spices. You can use garlic-infused oil for flavor.
Do all fermented foods become low FODMAP?
No: Fermentation's effect on FODMAPs is not consistent. While it can reduce FODMAPs in some foods (e.g., sourdough), it can increase them in others (e.g., sauerkraut).
How does pickling differ from canning for reducing FODMAPs?
Similar Process: Both pickling (under acidic conditions) and canning can reduce FODMAPs via leaching, where water-soluble FODMAPs dissolve into the liquid. It's crucial to discard the liquid in both cases.
