Ask the expert: Diet

Every week there seems to be media coverage of a new piece of research, suggesting that what you eat or drink could make a difference to how your MS progresses. But diet is a hugely controversial topic in the MS world, partly because it's so hard to do research. As two new large scale studies of diet begin in the US, we put some of your questions to Dr Conor Kerley, a registered dietitian who was diagnosed with MS when he was 16.

I'd recommend that people speak to a healthcare professional, like a local dietitian. The best place to start is to simply increase your fruits and vegetables because the evidence we have shows that fruits and vegetables are beneficial for your heart, your brain, your muscles, your bones and so on. I don't think it's very difficult to say, “let's eat more fruits and vegetables”. I think a good rule of thumb is to try and include fruits and vegetables in every single meal. So you know, some berries with your breakfast, some salad on your lunch, some chopped vegetables with your dinner, something like that. It can be a simple thing to do. If someone's already eating fruit and vegetables at each meal, try to increase it; so if someone is eating one portion at each meal, maybe aiming for 2–3 portions at each meal might be a good goal.

A recent study published found that children and teenagers who developed MS had consumed less iron in their diets - but this doesn't mean there's a straightforward link.  Anybody who went on to develop MS and had a low iron intake might have had lots of other differences from those who did not develop MS. Iron is really important, particularly for our blood cells which help carry the oxygen which give us energy. If someone has a low iron intake, the first major issue is going to be a low energy problem. However, simply improving iron does not always help that energy issue. We need enough iron, but too much iron is not a good thing.

If you are concerned about your iron levels, it's best to speak to a healthcare professional, preferably a dietitian, because there are small little things we can do to increase our iron absorption. For example, not having tea or coffee with meals.

This is a tricky question because in science we look at evidence and there's lots of different types of scientific studies which provide different levels of scientific evidence. The gold standard is what we call a double-blind trial. This means that we have two different people in two different arms of the study – so the participant and the researcher – and neither of them know which treatment they're getting. But obviously if I randomised someone to a gluten free diet versus a low fat diet, they're going to know which diet they're on. This has led a lot of doctors and scientists to say that research on particular diets isn't reliable because it wasn't done in this manner.

So proof is really hard to come by, particularly when we talk about a complicated illness such as MS. We do not have definitive proof but we certainly have studies which show how a certain diet can work which would make sense. Then we have small studies, which are not perfect, but all suggest that a diet low in saturated fats (found in butter, cheese and red meats), high in polyunsaturated fats (found in seeds, nuts and fatty fish like salmon, sardines and mackerel) and heavily based on fruits and vegetables – maybe with the addition of whole grains (oats and wholemeal bread) and legumes (chickpeas and lentils) – is going to be quite well balanced and perhaps beneficial for MS. Also, it does seem that sunlight and vitamin D are quite important as well as aspects like exercise, stress reduction, mindfulness and sleep.

What a lot of these studies will do is ask say 1,000 people with MS, how much coffee do you drink? And then the people who drink the most coffee end up being the healthiest or having the most energy. However, there is a lot more going on that's different between those who drink more coffee and those who drink less coffee, so it's a really complicated question to answer.

I'm not aware of any evidence that coffee is really bad for anybody, including those with MS. In fact, there are some studies showing that coffee may be beneficial in some neurological disorders and may have other beneficial effects. I wouldn't recommend anybody drinks excessive amounts of coffee but 1-2 cups per day should be fine for most people. If somebody enjoys coffee, keep drinking it, guilt free, but perhaps skip the creamy, sugary cappuccinos and the sugary piece of cake!

Red wine is a very interesting story with MS and heart health. It does seem that there are some beneficial components in red wine, however they are also present in red grape juice so it's not something specific to the red wine. The particular study that was reported showed that people who drank red wine had fewer relapses and did a little bit better. But it also showed that they had more lesions on their brains. The evidence is that the lesion load on someone's brain predicts their future disability. So, I don't think red wine is going to be the worst thing for people with MS, but I don't think it's going to be the best thing either.

I'm a registered dietitian so I'm a big fan of diet over supplements in most scenarios, except vitamin D which comes from the sun. Unfortunately for about six months of the year, from about September to March, in a country which lies so far from the equator, it doesn't matter how good the weather is, it doesn't matter how much sun we have, we're not going to make any vitamin D.

I recommend taking a vitamin D supplement in the winter time, from September to March. I think a good place to start is 2,000 International Units (IU) per day. However I do advise most people to get a blood test to make sure they're taking the correct dose. I also recommend that people get vitamin D3 which is cholecalciferol, as opposed to vitamin D2, and is available in pharmacies.

Finally, I recommend people take it with a meal because fatty acids help the absorption of vitamin D. If you take it first thing in the morning or last thing at night without any food in your tummy it's not going to be absorbed as well. So build it into your daily routine; have it with lunch, have it with dinner, whatever it is, have it on a daily basis.

Conor Kerley is a registered dietitian with a particular interest in autoimmune conditions, vitamin D, plant-based nutrition and heart and lung disease. He has a bachelor's degree in Human Nutrition and Dietetics, and a PhD in Nutrition. He's currently working as a content specialist with the Centre for Nutrition Studies in New York, USA. 

You can follow Conor on Facebook @conorkerleyhealth and Twitter @ConorKerley.

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