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World Digestive Health Day 2022 - Nutrition Myth Busting

29 May 2022

For World Digestive Health Day 2022 (29th May), we teamed up with our Preferred Performance Nutrition Supplier Yakult and the English Institute of Sport’s (EIS) Performance Nutrition team to bust some myths around digestive health and its impact on high-performance athletes.

By sharing this information, we hope that athletes will feel more informed to make the right nutrition decisions, and know when to ask an expert for help.

Mhairi Keil, Senior Performance Nutritionist at the EIS, drew on her experience working with British Gymnastics and GB Snowsport to address the following myths around digestive health, in conversation with the Microbiome Matters podcast.

Myth 1 – Collagen supplements can prevent or repair leaky guts

Collagen is the major protein found in connective tissues, so I think this has come about because of its presence in many of these structures, and it is present in the gut lining. In my opinion there isn’t sufficient research to show that taking collagen will actually impact on the repair or strengthening of the gut lining, to prevent any gastro-related issues. So my understanding is that you wouldn’t take collagen for that. We do use collagen in a sporting setting, and some of our athletes will take collagen, but it’s more related to tendon and ligament repair and strengthening, particularly if they’ve had a tendon or ligament-based injury. So we do use them – we just don’t use them for the gut.
Myth 2 – If you experience gut symptoms while exercising, you have a food intolerance
There’s a number of reasons why you might experience any gastro issues during exercise, and some of this can just be down to mechanical factors of the exercise that you’re doing. So you’ll have heard a lot more of it in running and we experience it in trampolining, because of the forces and the pull, which can cause inflammation to the gut lining. Then, should someone consume a food, it can trigger an issue, but it’s not that they have an actual allergy or sensitivity to that specific food or that nutrient. It can be very misleading – there will be issues that arise in the heat or just due to the intensity of the work that’s being done. When the blood is redirected to the muscles in really high intensity workloads, and suddenly there’s a reperfusion of the gut as exercise ends, that can cause injury to the gut. So there’s a number of reasons why issues arise, and we have to look at the environment the sport is being done in, the intensity and the individual when these issues arise.
So often we will look at food training diaries, and get athletes to input when symptoms occur, and what food they’ve consumed, to see if there’s any pattern, but it’s such a complex area, and we’d often refer them out to a specialist in the field, to get clarification or start tests. If someone is constantly in this training environment, be that the heat, the intensity of the workload they’re doing or the mechanical fractures that just never go away because of the nature of the training that they’re doing, it’s really difficult to pinpoint what the issue is, so we need the support to clarify that. But certainly having a gastro symptom as a result of exercise or during exercise does not mean that there is an allergy or sensitivity to a food.
Myth 3 – Finger prick, IgD, hair and electrodermal tests are all valid as food intolerance tests
These haven’t been shown to be reliable, specifically when you look at IgD, the antibodies haven’t shown to be reliable in identifying an allergy or food intolerance or sensitivity. If we get an athlete who is showing gastro symptoms related to the food they’re consuming, we will refer them to a specialist and we will get the tests from a medical practitioner, a doctor, and we will refer to a clinical specialist or dietitian who focuses on the gut to look at what’s really happening here, and get the right tests done for the right allergies and intolerances or sensitivities.
Myth 4 – Allergies, intolerances and sensitivities are all the same thing
There is quite a significant difference and I think people get confused and say they have a food allergy, but an allergy is quite a significant immunological response to a food or a nutrient, such as a peanut allergy that can result in a significant response that can lead to death. It’s very different to an intolerance, which is more gastro symptoms such as bloating, gas, IBS-type symptoms. Those can be really uncomfortable for an athlete to have to train with and quite difficult in many situations, so they’re very significant, but very different to an allergy. Typically an allergy is quite clear and you get a lot more physiological responses – swelling of the lips, itching, scratching, swelling around the neck area.
An intolerance we need to look at, and ask if it’s a sensitivity and we just need to reduce the level that they might consume. Someone might be lactose intolerant, for example, but they can tolerate a certain level of lactose; they might find it very difficult to consume a pint of milk, but they might be able to consume a yoghurt or some cheese. So it means looking at them on a continuum as to what is tolerable to them without causing them any gastro issues which would impact on their performance and how they feel.
Myth 5 – Since high fibre diets and wholegrain options are good for gut health, they should always be chosen by athletes
It’s not true, and it would depend on the nature of the sport. You’ll see from our e-book that before certain competitions or races, or certain training sessions, someone might actually want to reduce the fibre that they consume, because this can cause more significant issues for them when they’re training. It [fibre] can be quite difficult to digest, and takes longer to digest, and therefore that creates challenges for them when they’re eating close to a training session in order to fuel for that training session. Sometimes we actually recommend taking the fibre down, to try and minimise the risk that they would have any gastro-intestinal issues that would disrupt their training or competition performance.
So while fibre is super healthy, we try to fit it in for those athletes at times when they’re not training, or rest days, or further away from their immediate training sessions. It might be that someone has a lower fibre day, if they’ve got double training sessions or high intensity training sessions. We might just remove the fibre on that specific day, or they could break after their second training session, where they could get more of a fibrous meal in, so we’re still giving them fibre and the nutrients that they obtain from that, but maybe that specific day is a low fibre day and we pick it up in the rest of the week, or on specific days throughout the week.
Find out more about World Digestive Health Day
Find out more about the EIS Performance Nutrition team
Find out more about Yakult