As a low FODMAP diet can be quite restrictive, it is not recommended to be followed long-term. A strict low FODMAP diet can also be low in some important nutrients, which also contributes to why it isn’t ideally a diet for life. Some of these nutrients commonly lacking in a low FODMAP diet can impact health both short and long term. For this reason, it is important to be mindful of including suitable low FODMAP alternative food sources of these nutrients.
Fibre plays an important role in maintaining healthy bowel function and keeps us feeling fuller for longer (and therefore helps with weight maintenance). It also influences our gut health, particularly through the role of prebiotics, which are classed as a type of fibre. Fibre can also help lower cholesterol, maintain stable blood sugar levels, and help prevent certain types of cancer.
So basically, fibre is pretty important for our health! Unfortunately, fibre is a key nutrient which a low FODMAP diet often lacks. Good sources of fibre include wholegrain breads/cereals, fruit, veggies, legumes, nuts and seeds. Since a low FODMAP diet restricts intake of a lot of these foods, it is no surprise it often lacks fibre. Below are some good low FODMAP fibre sources:
- Low FODMAP fruits – particularly raspberries, kiwi fruit, and banana.
- Low FODMAP veggies – particularly green beans, eggplant, broccoli and pumpkin.
- Tinned lentils
- Walnuts, peanuts and macadamias (or peanut butter).
- Rolled oats
- Chia seeds, pumpkin seeds and sunflower seeds
- Slendier noodle/pasta range
- Purebread gluten-free range and Helga’s lower carb bread
The biggest role calcium plays is in bone and teeth health. When we don’t eat enough calcium in the diet, our body will compensate by using calcium from our bones instead. This can then lead to soft, brittle bones and consequently diseases like osteoporosis and osteoarthritis. The best food sources of calcium are dairy products and fish bones (found in sardines and tinned salmon). Since lactose is restricted on a low FODMAP diet, calcium intake can drop. Here are some low FODMAP calcium-rich food sources:
- Lactose-free milk and yoghurt (look for ones which are fortified with calcium).
- Tinned sardines and tinned salmon with the bones crushed up
B12 is an important nutrient which plays a key role in forming red blood cells. Our red blood cells are crucial for delivering oxygen and nutrients throughout our body, so we need plenty of them. The only reliable source of B12 is animal products. This includes beef, fish, egg yolk, oysters, cheese and sardines. Intake of B12 could potentially drop on a low FODMAP diet due to restricted intake of dairy products. This may be particularly relevant for those who don’t eat much meat and especially those who are vegetarian/vegan.
Lactose-free dairy products still contain the same nutrients as regular dairy products, they simply have a lactase-enzyme added to help with digestion. Alternatives such as soy products and almond milk will not contain B12, so if you choose these it is important to obtain B12 from other sources like meat and fish.
Prebiotics are a type of fibre that promotes the growth of good gut bacteria. Unfortunately, a low FODMAP diet often decreases intake of prebiotics. This is because certain FODMAPs act like prebiotics. Reducing intake of prebiotic foods long-term can cause a decrease in good gut bacteria, which can cause increased sensitivity to FODMAPs (i.e worsens IBS symptoms). See our article on prebiotics and FODMAPs for more detail, as well as some good low FODMAP prebiotic sources.
Why a low FODMAP diet isn’t recommended long term
The risk of nutrient deficiencies, such as those mentioned, is one reason why a low FODMAP diet should not be long-term. This highlights the importance of identifying trigger foods, to ensure you only need to restrict FODMAPs which trigger your IBS symptoms.