All things allium on the low FODMAP diet

Josephine and I were recently out for dinner in Sydney and heard from a food expert that there are over 40 different varieties of onions….who knew!

What we do know however is that onions are typically off the table for many people with irritable bowel syndrome (IBS).

In this month’s blog we cover all things allium, including onions, garlic and leeks.

We look at why they can be a problem in terms of FODMAPS, what you should avoid and what you can have instead…including some new testing results from Monash that will please garlic lovers.

What’s the problem?

Onion and garlic both contain a type of FODMAP called fructans. We all lack the enzymes needed to break down fructans into simple sugar units, which means they pass through the small intestine into the large intestine intact. There they are rapidly fermented by good gut bacteria to produce gases. This is great for the good bacteria in your large intestine – especially the Bifidobacteria and Lactobacilli. However, it’s not so good if you have irritable bowel syndrome (IBS). People with IBS tend to have heightened visceral sensitivity. This causes an increased perception of pain and discomfort in the large intestine when it is stretched by excess gas. They experience painful cramping and bloating after eating fructans, whereas those without IBS do not.

What to avoid

If you are in the elimination phase of the low FODMAP diet and avoiding all high fodmap foods including those with fructans, you need to avoid the following in the allium family:

• ·        Brown (Vidalia) onions

• ·        White onions

• ·        Spanish (red) onions

• ·        The white bulb of spring onions (scallions)

• ·        White garlic

• ·        Black fermented garlic

• ·        Garlic powder

• ·        Leeks (white bulb) – have no more than 1 tbsp/14g per meal

Watch out for..

Watch out for sauces or even processed meats that may have garlic and onion. On ingredient lists these can be hidden as “herb and spice powder”, “vegetable powder” or “seasonings”… this can be tricky.

Green for go!

Here are some allium options that get a green light (in small serves at least).

• The green part of spring onions (scallions) - 1 and ½ cups (75g) per meal

• Garlic shoots - 33g (6 tbsp.)

• Garlic chives - 80g (1 cup)

• Chives (5g)

• The green leaves of leeks - 1 cup

Josephine has been flexing her green fingers recently. Her top tip is to cultivate your own spring onions. You can re-grow the green part of spring onions simply by planting the bulbs in a pot or placing in water.

Pickle pick me up

It’s interesting to note that processing can influence the fodmap content of foods. Large pickled onions for example are low FODMAP up to a serving size of 2 onions if drained. It appears that the water soluble fructans leach out of the onions into the surrounding pickling liquid and the fructan content in the onions is reduced by around 80%.

Recent testing by Monash has found that the same is true for garlic. One clove of pickled garlic is low FODMAP when drained.

We think pickled onions would work well in a Low FODMAP version of a Ploughman’s Lunch with 20g of cheddar cheese, 20g of Camembert, 5 walnuts, plus cucumber (up to 75g), cos lettuce and a slice of sourdough bread.

Pickled garlic would work well in a vinaigrette dressing, or in a tomato sauce, where you might add a little red wine vinegar for tartness anyway.

Other ways to add flavour

Onion and garlic are used to add powerful flavour to food across many different cultures. Here are some alternative approaches (there is more on this in our blog on flavour).

• Herbs (such as basil, coriander, oregano, parsley, rosemary and thyme)

• Spices (such as cumin, coriander, cumin, turmeric – avoid blends that may have garlic powder)

• Asafoetida powder (use a small pinch only for flavour similar to onion)

• Ginger

• Lemon and lime juice add a real zing to steamed veggies or fish

• Salt and pepper

• Stock (made without onions/garlic) or try San Elk low FODMAP vegetable stock powder

• Chilli (contains capsaicin which may trigger gut symptoms in some people)

With a special mention for…

• ·        Garlic infused olive oil

As mentioned above fructans are water soluble. This means that unfortunately, you can’t add a whole clove of garlic to a sauce and pick it out later. The fructans will be dispersed throughout the whole sauce.

However, fructans do not dissolve in oil. Whilst many of the lovely aromatic compounds in garlic do dissolve in oil. That means that you can enjoy garlic infused olive oil, without suffering the ill effects of the fructans. Check out our recipe to make garlic infused oil here, and use it in dishes where you would previously have added garlic, such as our new dip recipe.

In the longer term…

It’s important to work through all three stages of the low FODMAP process to work out which FODMAPs trigger your symptoms and at what level.

Fructans are prebiotics – food for good gut bacteria. They are fermented into beneficial short chain fatty acids as well as the troublesome gas. Try and reintroduce onions, garlic, chives and leeks back into your diet if you can, even if it is at low levels, to keep your gut bacteria happy. Many people leave testing fructans until the end of the reintroduction stage, but try not to skip it.

Some challenges including fructans may also be better tolerated if the challenge food is consumed less frequently (e.g., every second day). If it is well tolerated, it can be repeated on consecutive days to assess tolerance to more frequent exposure.

Very low quantities may also be ok. Monash also recommend testing garlic and onion in rice-based dishes, such as fried rice, rather than wheat-based dishes to lower the overall FODMAP load of the dish.

Dietitians also recommend re-testing a few months or years later to see if tolerance has changed.

Check out alternative souces of prebiotics to feed your good gut bacteria - and after all it is Global Prebiotics Week, so now is the time!

Check out our blog on the topic, or try our DAILY GUT HEALTH BOOST range with the low FODMAP prebiotic PHGG.

Written by: Dr Mary Webberley, Chief Scientific Officer at Noisy Guts. Mary has a background in biology, with two degrees from the University of Cambridge and post-doctoral research experience. She spent several years undertaking research into the diagnosis of IBS and IBD. She was the winner of the 2018 CSIRO Breakout Female Scientist Award.