Find out about the evidence behind nutrition and MS.
A ‘healthy diet’ is unarguably important for everyone, whatever their age or circumstance. Whilst there are differing ideas around this, it is generally agreed, a diet with plenty of varied vegetable and fruit, a range of whole foods providing core macronutrients such as protein and fibre, and reducing or eliminating processed foods and those with added salt or sugar is beneficial (British Nutrition Foundation; NHS Eatwell guide).
Diets high in processed foods have been implicated in the rise in autoimmune conditions across the globe (Lerner 2015) whilst a healthy diet has been proven to improve brain health, reduce likelihood of cardiovascular disease, diabetes and metabolic syndrome – all common comorbidities in MS (Magyari 2020) – and improve outcomes in those living with these conditions.
Specific diets including plant-based (Kahleova 2017) and Mediterranean (Franquesa 2019) have been advocated as a prevention and treatment option for these health problems. People with MS who have cardiovascular risk factors may experience increased lesion burden, and a greater rate of brain atrophy (Kappus 2016; Mowry 2018). The ketogenic diet has also been found beneficial for some populations and research into its impact on neurological conditions, whilst limited in human studies, has suggested improvements in cognitive symptoms, mitochondrial function and oxidative stress (Pavlón 2021; Paoli 2014).
There is also evidence suggesting when we eat may be as important as what we eat with regard to metabolic health, sleep, mitochondrial function and oxidative stress with research around time-restricted feeding, fasting and eating in line with the body’s circadian rhythm all highlighting health benefits (Queiroz 2021; Adafer 2020; Panda 2018)
Finally, a healthy diet plays an important role in gut health (Leeming 2019). There is a clear relationship between the gut-brain axis and the presence of neurological disease, although whether this is causal or consequential is not yet clear (Parodi & Rosbo 2021), and there is considerable evidence from both human and animal studies demonstrating a relationship between the gut microbiome and inflammatory autoimmune disorders (Vijay 2021), although there are still many unknowns in this area.
There is very little argument now that the quality of someone’s diet has a direct impact on their health (Herman 2021; Campbell 2006) and health-related quality of life (Vajdi 2020). In MS specifically, there is amassing evidence around the importance of high quality, non-inflammatory diet in reducing levels of disability and symptom burden (Fitzgerald 2018), and slowing progression (Alhaj 2023), with one recent editorial in Neurology announcing that ‘there is sufficient evidence to recommend a healthy diet as an adjunct intervention in MS’ (Spain 2023). Not only found to increase severity of MS, an inflammatory diet has been found to significantly increase risk of developing MS (Alhaj 2023).
A 2022 review of nutrition in MS reported that diet may influence MS onset, course, and quality of life in patients (Stoiloudis 2022), and whilst there is no gold-standard ‘diet’ to follow for those with MS, the Overcoming MS diet, along with other MS-specific diets such as the Wahls protocol and Swank diet share many similar core principles. These all encourage a high quality, whole-foods based diet including a wide range of colourful vegetables and fruit, an emphasis on leafy greens, and a balanced macro-nutritional profile, whilst avoiding processed foods, and eliminating dairy. The inclusion or exclusion of meat sources varies between diets.
Whilst all of these diets have been studied within the context of a wider healthy lifestyle programme, they have also been associated with improved outcomes for people with MS; reduced fatigue, increased quality of life, (Wahls 2021) and lower levels of disability (Simpson-Yap 2021). The high-quality, whole-food approach and reduction of processed foods, sugar and salt all create crossover with well-researched diets such as the Mediterranean diet which finds positive outcomes across various populations (Papadaki 2020), and the MIND diet which is associated with improvements in cognition and preserved brain health (Arjmand 2022).
The Overcoming MS diet has specific messaging around dairy and fat consumption and encourages elimination of all dairy and saturated fats.The following sections provide a brief and balanced summary of the current evidence-base regarding this; for those seeking more detail Jakimovski et al’s thorough review of experimental and clinical findings around lifestyle modifications in MS is an ideal starting point (Jakimovski 2019).
The Overcoming MS diet is one which advocates for a healthy and high quality diet for the whole family, not just the person living with MS, and this is as relevant regarding choices about dairy as about fats. Regardless of choice around dairy consumption across the whole family, increased awareness of the relationship between dairy produce, particularly cow’s milk, and health (Wilmet & Ludwig 2020), and the effect of processing and interference from external influences on dairy’s nutritional profile are important (van Lieshout 2019).
The Overcoming MS diet, as with some other MS diets, including the Wahls protocol and the McDougall diet, eliminates dairy. There is currently no conclusive evidence in favour of blanket elimination of all dairy for all people with MS. However, there is much that we do know.
Milk consumption has been associated with higher rates of neurodegenerative and neurological conditions including MS, schizophrenia and Parkinson’s (Malosse 1992; Niebuhr 2011) and increased risk of type 1 diabetes (Chia 2017; Gerstein 1994). A recent meta-analysis which remained in favour of dairy amongst the general populace still noted dairy-associated risks in certain populations including those with Parkinson’s or potential allergies and intolerances (Zhang 2021).
There is evidence to suggest that some people with autoimmune conditions, which includes MS, may experience worsening of their underlying condition when consuming dairy or gluten through a process known as molecular mimicry. Casein A1 and gliadin can cause the body to further attack the body or contribute to worsening inflammation through autoimmune ‘mistaken identity’ (Rojas 2018; Kristjánsson 2007).
In MS, casein may trigger inflammation which specifically damages the myelin sheath around the neuron, through various processes caused by molecular mimicry, although current evidence for this is confined to mouse studies at present. One study found casein affected remyelination through mimicry of myelin oligodendrocyte glycoprotein (MOG) (Vojdani 2015) whilst another found it to cause demyelination in the central nervous system through mimicry of the MAG antibody produced in response to casein itself (Chunder 2022).
Additionally, immune system cross-reactivity has also been found to be triggered by butyrophilin, another protein found in cow’s milk. This can be mistaken for myelin proteins (Eichinger 2021) meaning multiple mimicries may occur simultaneously, increasing the potential damage this may cause in some.However, there needs to be more research in the area of MS to draw firm conclusions.
There is inconsistency in the conclusions drawn across dairy and health and whilst many have found unfavourable outcomes over the years, a recent umbrella review of evidence across a broad populace suggests that dairy is, on balance, usually more beneficial than harmful to most when considered across a sequence of health-related outcomes, including cardiovascular health and diabetes (Zhang 2021).
Quality and type of dairy factors into these outcomes; a review in the New England Journal examining the health effects of cow’s milk consumption highlights misinformation around healthful benefits in lower quality products, and notes that replacement of dairy with other high calcium foods such as leafy green vegetables may be equally beneficial to high quality dairy (Willett 2020).
We must conclude that, as in most areas of medicine, a level of individualism is at play and that some people may experience molecular mimicry whilst others may not. The Overcoming MS diet advocates for the most healthful and least inflammatory food choices, and for those with MS who experience gluten or dairy intolerances or notice an exacerbation in symptoms when consuming dairy, elimination may be advisable. Experimenting with the full Overcoming MS diet and monitoring changes may also be useful. Ultimately, a person-centred approach and mindfulness of the potential impact of dairy are needed here.
The relationship between fats and health is a complex one, but it is clearly understood that some fats are beneficial whilst others are harmful. However, whilst simplified messaging around elimination of one category of fat may be helpful in supporting healthy choices, the biological interplay between fats and health are not simple, and the source of the fat and the quality of the food it is found it also impacts the level of benefit or harm, as explained fully in an excellent review paper by Liu et al (2017).
Saturated fats have been consistently associated with morphological and functional changes in neurons, triggering a process causing dysregulation of neuronal metabolism that leads to insulin resistance, decreased glycolysis, altered mitochondrial function and endoplasmic reticulum stress all of which appear to contribute to cognitive decline (Sánchez-Alegría 2022). However, saturated fats come in different length chains, and the length of the fatty acid chain and the source of the fat, both affect the impact on the body (Anarson 2019). This has led to recent reviews calling for better messaging around saturated fat and its role in health (Teicholz 2022).
A recent longitudinal study in a predominantly Eastern population found that saturated fat intake, when compared with carbohydrate intake, was associated with a lower mortality, a reduction in body fat and inflammation, and an increase in muscle mass (Dehghan 2017). The study has been criticised as ‘misleading’ but its findings do support growing opinion that the type and quality of saturated fat, and the diet it is consumed as part of, must be considered when looking at its impact on the body – and therefore an individualised approach must be taken regarding its intake.
This picture of saturated fats is complex, nuanced and in places, conflicting, and the Overcoming MS diet continues to advocate for eliminating them. Furthermore, specific studies have associated saturated fats with worsened outcomes for people with MS in particular. Increased lipids and lipoproteins have been associated with MS disease activity (Gafson 2018) whilst over a 34 year period, people with MS who observed a low saturated fat diet showed significantly less deterioration and much lower death rates than did those who consumed more fat than prescribed (Swank 1990).
Dietary lipids such as polyunsaturated fatty acids (PUFA) are important for the structural and functional roles in neurons (Chianese 2018) and regulate several processes within the brain, such as neurotransmission, cell survival and neuroinflammation (Bazinet 2014). However, optimising the balance of these lipids such as the ratio of omega-3 to omega-6 consumption is crucial; the benefits are lost if there is an overabundance of omega-6, which in turn is associated with neuroinflammation (Layé 2010).
A good balance of omega 3: 6 is thought to be between 1:2 and 1:4 depending on a person’s level of health (Simopoulos 2016); the current Western diet is heavily weighted towards a high level of omega-6 (Simopoulos 2002) and may be closer to a ratio of 1:30 (Erasmus 1993).
The balance of these two PUFAs for healthful benefits is essential in everyone, yet for people with MS, there are disease-related implications for getting this balance right. Certain lipid mediator pathways play a role in the pathogenesis of MS and although research in this area is very young, it bears consideration. A recent study examining the implications of bioactive lipid mediators caused by omega 3 and 6’s intake found an association with disability, biochemical parameters including serum neurofilament light (sNfL) and MRI measures (Broos 2023).
In people with MS, protecting brain health is of vital importance, and the growing evidence suggests that limited saturated fats, and keeping polyunsaturated fats to predominantly omega-3 types is in line with preserving brain function, maintaining neuronal health, and reducing likelihood of chronic inflammation.
In terms of symptom management, reducing saturated fats is also evidenced to optimise cognition (Cederholm 2013), and reduce the impact of diabetes, insulin resistance or metabolic syndrome on cognition (all common comorbidities experienced by people with MS (Ciampi 2020; Magyari 2020). Meanwhile, watching the balance of omega-3 to omega-6 may also support symptom management in terms of reducing inflammation and risk of neuropsychiatric disorders (Bazinet 2014).
