In depth
Systemic sclerosis and diet
The real dietary problem in this disease is not which foods to put on the plate or leave off it. It is that eating becomes physically hard, and the weight on the scale is the last thing to show it. So this page is about finding that early rather than about choosing between foods.
What the research found.
One study put four different assessment tools against 56 people with systemic sclerosis and reported every answer. Malnutrition came out at 16.1 percent by one, 17.9 percent by another, 23.2 percent by a third, and 62.5 percent by the fourth. A body mass index below 18.5 was found in only 5.4 percent of them.
One French study assessed 120 people against national criteria, and 71 of them were malnourished. That is 59.2 percent of the group, and 30 of those 71 met at least one criterion for severe malnutrition. Severe malnutrition correlated strongly with a mouth opening below 35 mm in that group.
One study measured muscle loss two ways in 62 people. It came out at 42 percent by a skeletal mass index and at 55 percent by hand grip strength. By either measure, the affected group had longer disease, more malnutrition, higher skin scores, and worse transfer of carbon monoxide.
One study asked what malnutrition costs, in 129 people with this disease. The 10.9 percent who were malnourished scored worse on every quality of life measure except bodily pain and self-reported health. The disease-specific function score was 1.6 against 0.91, at P equals 0.001, where a higher score means worse function.
Preis and colleagues, European Journal of Clinical Nutrition, 2018
One survey asked 156 people with systemic sclerosis about eating, and 79 percent had gut conditions. Of the whole group, 26 percent were dealing with those conditions every day, and 23 percent reported recent weight loss. Only 29 percent had ever seen a dietitian, while 69 percent wanted to.
Samm and colleagues, Journal of Scleroderma and Related Disorders, 2024
One survey scored Mediterranean diet adherence in 387 Italian patients. It came out optimal in 14.7 percent, moderate in 71.3 percent, and low in 14.0 percent of them. Poorer adherence was associated with more depressed mood, more time missed at work, and worse reported Raynaud's and finger ulcers in that group.
Start with what isn't here
No diet has ever been tested in a trial in systemic sclerosis, and that is the first thing worth saying about this page. Twelve sources are behind what follows, and not one of them changed what anybody ate and then watched what happened next. They describe people at a single moment rather than following them through a change.
That decides what everything below it can mean, so it belongs at the top rather than buried in a caveat. Every figure here describes a group of people as they were on the day somebody measured them. Nothing in that evidence shows that changing what you eat changes the course of your disease, and this page won't imply that it does.
What the research does cover is something different, and it turns out to be more useful than a list of foods to eat or avoid. It covers what happens to eating itself in this disease. It also covers how often that goes unnoticed by everybody in the room, including the people treating you.
Malnutrition is common here
One French study assessed 120 people against the national criteria their country uses for this, and 71 of them came out malnourished. That is 59.2 percent, a startling proportion for something so rarely discussed at an appointment. Thirty of those 71 met at least one criterion for severe malnutrition rather than the milder form of it.
Other studies report figures a good deal lower than that, and the spread between the highest and the lowest is wide enough to be genuinely confusing. One of 140 people found 9.2 percent, from 4.4 to 14.0 percent. One of 129 people found 10.9 percent, and one of 98 put 23.5 percent of them at high risk.
So the published rates run all the way from 9.2 percent to 62.5 percent across the literature. Read cold, that looks like a field of studies contradicting each other. It isn't that at all, and the next section explains what is really going on underneath the spread.
Why the published rates differ so much
One study answered this question directly, and it did so in the simplest way available. It put four different assessment tools against a single group of 56 patients and then reported all four of the answers. That rarely happens, because reporting four answers to one question looks like a failure to decide.
Malnutrition came out at 16.1 percent by one tool and 17.9 percent by the next. The third tool put it at 23.2 percent, which is already more than a third above the figure the first one gave. Then the fourth tool put those 56 people at 62.5 percent, which is nearly four times the first answer.
Nothing about those patients changed between the first number and the fourth, because it was one group throughout. The tool changed, and the tool is what moved the answer. So the first question to ask about any malnutrition figure in this disease is which instrument produced it.
That has a practical consequence for you rather than for the researchers alone. Say somebody tells you your nutrition screen came back normal and there is nothing to worry about. The useful follow-up is asking which screen they used, because four of them gave four different answers about one group.
The scale is the measure that misses it
This is the most useful single fact on the page, and it is the reason the section exists at all. Go back to that study of 56 people. A body mass index below 18.5, which is the conventional marker of being underweight, was found in only 5.4 percent of them.
Meanwhile 62.5 percent of that group were malnourished by one of the four sets of criteria. So more than half of them had a nutrition problem while nineteen in twenty had a perfectly normal weight. Those two facts describe one group of people on a single afternoon.
The authors of that study say plainly what they think ought to be screened on in place of weight. They recommend unintentional weight loss, gut symptoms, and a measure of body composition. Weight on its own does not appear anywhere on that list, which is the point of naming it.
So a normal number on the scale is not reassurance in this disease, whatever it feels like at the time. Weight is the last measure to move when nutrition is going wrong. It is also the first one most people reach for, including a good many clinicians in a busy clinic.
Why it happens, and it isn't appetite
The mechanics of eating are the problem here rather than any loss of appetite. Return to the French study of 120 people, where severe malnutrition correlated strongly with a mouth opening below 35 mm. Skin tightening around the mouth stops being a cosmetic detail the moment it decides how much food can physically get in there.
One study of 98 people found this from another angle, using a different screening tool again. Mouth opening was lower in the high-risk group, at P equals 0.003, and bowel involvement was commoner there too, at P equals 0.021. The skin score was higher in that group as well, at P equals 0.014.
One survey of 156 patients puts the gut side of this about as plainly as it can be put. Of them, 79 percent had gut conditions and 26 percent were dealing with them every single day. Recent weight loss was reported by 23 percent.
Read those three studies together and what is happening stops being mysterious at all. Getting food into the mouth is harder than it was, and what does get in is absorbed worse further down. Neither of those problems is solved by wanting to eat more, which is why willpower is the wrong frame here.
Muscle loss comes with it
One study measured muscle loss two ways in 62 people, and it reported both of the answers. It came out at 42 percent by a skeletal mass index and at 55 percent by hand grip strength. The measurement problem from earlier turns up again.
What did not move between the two measurements was the description of the people affected. By either measure, they had longer disease duration and more malnutrition than the people without the loss. They also had higher skin scores, worse capillaroscopy scores, more esophageal involvement, and lower transfer of carbon monoxide across the lung.
One larger study of 140 people found muscle loss in 29 of them, which is 20.7 percent, from 14.0 to 27.4 percent. Eleven of those 29 were malnourished as well. So the two problems overlap a good deal without being one problem, and a person can have either on its own.
What it costs
One study of 129 people asked whether any of this is felt by the person living with it. The answer was yes, and it held across almost every measure the study took. A nutrition figure on a chart can look abstract until somebody asks what it does to an ordinary day of your life.
The malnourished group scored worse on almost every quality of life scale the study used. The two exceptions were bodily pain and self-reported health, which came out level between the groups. The disease-specific function score was 1.6, with a standard deviation of 0.73, against 0.91 with a standard deviation of 0.61 in the well-nourished group. That difference came in at P equals 0.001, and a higher score on that scale means worse function.
Age and disease duration did not differ between the two groups, which is what makes this worth reporting. So it is not a picture of people who have simply been ill longer. It is a difference that belongs to nutrition itself, in two groups matched on the obvious alternative explanation for it.
The one diet study, and how to read it
One survey scored Mediterranean diet adherence in 387 Italian patients, sorting them into three bands. Adherence was optimal in 14.7 percent, moderate in 71.3 percent, and low in 14.0 percent of them. That is the whole of the diet evidence in this disease, and it is a questionnaire rather than a trial of anything.
Poorer adherence was associated with more depressed mood and with more working time missed. It also correlated with worse reported Raynaud's and with more finger ulcers, and the adherence score correlated inversely with reflux. Taken at face value, that reads like a diet doing something to a disease.
Now read it more carefully, because the study design decides what the finding can support. This is a snapshot, and the diet and the symptoms were recorded at one moment in time. People who feel worse very plausibly eat worse, and that would produce this result with the arrow pointing the other way.
Its own authors describe the work as preliminary and call for future study of the diet's role. That is their wording rather than a hedge added here. It is the honest position on a cross-sectional finding, and this page is not going to improve on it.
People want help here and are rarely offered it
One survey of 156 patients found that only 29 percent of them had ever seen a dietitian at all. Sixty-nine percent wanted to, and the topics they most wanted covered were managing symptoms and losing weight. The distance between those two figures is the whole of this section.
A separate survey asked 74 rheumatologists what their own patients ask them for. Dietary advice to control symptoms came up for 58.1 percent of those doctors, and requests about reflux came up for 74.3 percent. So the subject is being raised in the room by the people on both sides of it.
The referral still often does not happen, and the reason is not mysterious. Dietetic time is scarce, and a nutrition problem that the scale hides does not look urgent on a busy list. That is a reason to ask for the referral rather than to wait for it, and asking costs you nothing.
What to mention
Unintentional weight loss belongs at the top of the list of things to mention to your team. The scale moves last here, so a small drop is easy to dismiss. Say it anyway, even when the amount sounds far too small to be worth taking up an appointment with.
Say if your mouth is getting harder to open than it used to be. That one measurement is the thing most strongly tied to severe malnutrition in this disease, and it came from the largest study on the page. You will notice it before anybody measures it, because you eat every day and they see you twice a year.
Say if gut symptoms are a daily event or an occasional one. Treat severe diarrhea as a reason to call, not a reason to wait for the next appointment. It was the only symptom significantly linked to a gut that stops moving, at an odds ratio of 3.39 from 1.56 to 7.38.
That isn't a diet, and this page has not handed you one. It is what the evidence in this disease supports, and that is a good deal narrower than what most readers come here wanting. The work here is finding the problem early rather than choosing between one food and another.
Common misconceptions.
Myth. There's a scleroderma diet.
Reality. No diet has been tested in a trial in this disease, and that is not a technicality. One survey scored Mediterranean diet adherence in 387 Italian patients and found poorer adherence associated with lower mood and worse reported symptoms. Its own authors call that preliminary and ask for further work, and it is a snapshot, so it cannot say which came first. Anything sold as a scleroderma diet has cleared no bar, because there's no bar to clear yet.
Myth. My weight is fine, so my nutrition is fine.
Reality. Weight is the measure that misses this, which is the single most useful thing on that page. In one study of 56 people, 62.5 percent were malnourished by one set of criteria, while a body mass index below 18.5 was found in only 5.4 percent. So more than half were malnourished while nineteen in twenty had a normal weight. Those authors recommend screening on unintentional weight loss, gut symptoms, and body composition instead of on the scale.
Myth. The studies disagree about how common malnutrition is.
Reality. They mostly agree once you know which tool each one used, which is the part a headline leaves out. Published rates range from 9.2 percent to 62.5 percent, which looks like chaos. One study settled it by putting four tools against 56 patients and getting 16.1, 17.9, 23.2, and 62.5 percent. So the spread is a measurement difference rather than a disagreement about patients.
Myth. This is about appetite.
Reality. It is mostly about mechanics, and the difference is not a quibble. In one French study of 120 people, severe malnutrition correlated strongly with a mouth opening below 35 mm. In another of 98 people, mouth opening was lower in the high-risk group at P equals 0.003, and bowel involvement was commoner there at P equals 0.021. So the problems are getting food in and absorbing it, and neither one is solved by wanting to eat more.
Myth. There's no help for this.
Reality. Most people have simply not been offered help, which is a different problem. One survey of 156 patients found that 29 percent had ever seen a dietitian, while 69 percent of them wanted to. A separate survey of 74 rheumatologists found 58.1 percent of their patients asking for dietary advice. So the demand appears on both sides of the appointment, and it is worth asking for a referral yourself, because waiting to be sent one can take a long time.
Cautions specific to this condition.
- Mention unintentional weight loss, because the question may not come up unless you raise it. One survey found 23 percent of patients had lost weight recently, and weight is the last measure to show a problem.
- Ask for a dietitian referral if eating is hard. Only 29 percent of patients in one survey had ever seen one and 69 percent wanted to.
- Say if your mouth is getting harder to open. Severe malnutrition correlated strongly with a mouth opening below 35 mm in one study of 120 people.
- Treat severe diarrhea as a reason to call. It was the only symptom significantly linked to a gut that stops moving, at an odds ratio of 3.39 from 1.56 to 7.38.
- This page gives no diet, no supplement, and no target for any blood level. Nothing here has been tested by changing what anybody ate.
- Ask what tool was used before taking a malnutrition result either way. Four tools gave four answers in the same 56 people.
Discuss any change with the rheumatologist who manages your care. Nothing here replaces that conversation.
Questions patients ask.
Is there a diet for systemic sclerosis?
No diet has been tested in a trial in this disease. One survey scored Mediterranean diet adherence in 387 Italian patients, and poorer adherence was associated with lower mood and worse reported symptoms. That is a snapshot, so it cannot say which came first, and its own authors describe the work as preliminary. What the research does cover is malnutrition, which is common here and missed remarkably often.
How common is malnutrition in this disease?
Published rates range from 9.2 percent to 62.5 percent, and the tool used explains most of that spread. One French study of 120 people found 59.2 percent malnourished by national criteria, and 30 of them met at least one criterion for severe malnutrition. One study of 140 people found 9.2 percent, from 4.4 to 14.0 percent, by a different set of criteria.
Why don't the studies agree?
They mostly do agree, once you know what each one measured. One study put four assessment tools against 56 patients and got 16.1, 17.9, 23.2, and 62.5 percent back. Nothing about the patients changed between those four numbers, because they were one group assessed four ways. So the first question to ask about any figure on this page is which tool produced it, and that applies to all of them.
Can I rely on the scale?
No, and this is the most useful thing on the page. In that study of 56 people, a body mass index below 18.5 was found in only 5.4 percent, while 62.5 percent of them were malnourished by one set of criteria. The authors recommend screening on unintentional weight loss, gut symptoms, and body composition rather than on weight.
Why does this happen in scleroderma?
Because eating becomes hard in a physical way rather than a motivational one. In one French study, severe malnutrition was associated with a mouth opening below 35 mm, and in one study of 98 people mouth opening was lower among those at high risk. Bowel trouble was commoner in that high-risk group too, and one survey found 79 percent of patients had gut problems. So it is getting food in and taking it up, in that order.
What about muscle loss?
It is common, and it is measured two different ways. One study of 62 people found 42 percent by a skeletal mass index and 55 percent by hand grip strength. One study of 140 people found 20.7 percent, from 14.0 to 27.4 percent, and 11 of those 29 people were malnourished as well. By either measure, the affected group had longer disease, higher skin scores, and worse carbon monoxide transfer.
Does being malnourished change how I feel?
One study of 129 people asked that directly and got a clear answer. The malnourished group scored worse on almost every quality of life measure, the exceptions being bodily pain and self-reported health. The disease-specific function score was 1.6 against 0.91, at P equals 0.001, where a higher score means worse function. Age and disease duration did not differ between the two groups, so this is not simply a picture of people who have been ill for longer.
Should I take vitamin D?
This page gives no supplement and no target for any blood level, and that is deliberate. One study did find vitamin D lower in patients than in controls, at a standardized mean difference of minus 6.19 from minus 9.9 to minus 2.3. That held even though the patients took supplements more often than the controls did. Ask your team to measure before you take anything.
References.
- Wojteczek A; Dardzińska JA; Małgorzewicz S et al. Prevalence of malnutrition in systemic sclerosis patients assessed by different diagnostic tools. Clin Rheumatol. 2020;39:227-232. 10.1007/s10067-019-04810-zCross-sectional study of 56 patients with systemic sclerosis
- Rivet V; Riviere S; Goulabchand R et al. High prevalence of malnutrition in systemic sclerosis: Results from a French monocentric cross-sectional study. Nutrition. 2023;116:112171. 10.1016/j.nut.2023.112171Cross-sectional study of 120 patients meeting ACR/EULAR criteria for systemic sclerosis followed at one French tertiary referral centre between 1 January 1985 and 1 January 2019
- Türk İ; Cüzdan N; Çiftçi V et al. Malnutrition, associated clinical factors, and depression in systemic sclerosis: a cross-sectional study. Clin Rheumatol. 2020;39:57-67. 10.1007/s10067-019-04598-yCross-sectional study of 98 patients with systemic sclerosis
- Caimmi C; Caramaschi P; Venturini A et al. Malnutrition and sarcopenia in a large cohort of patients with systemic sclerosis. Clin Rheumatol. 2018;37:987-997. 10.1007/s10067-017-3932-yCross-sectional study of 141 consecutive systemic sclerosis outpatients
- Corallo C; Fioravanti A; Tenti S et al. Sarcopenia in systemic sclerosis: the impact of nutritional, clinical, and laboratory features. Rheumatol Int. 2019;39:1767-1775. 10.1007/s00296-019-04401-wCross-sectional study of 62 patients meeting the ACR/EULAR 2013 criteria for systemic sclerosis
- Preis E; Franz K; Siegert E et al. The impact of malnutrition on quality of life in patients with systemic sclerosis. Eur J Clin Nutr. 2018;72:504-510. 10.1038/s41430-018-0116-zCross-sectional study of 129 patients with systemic sclerosis
- Paolino S; Pacini G; Schenone C et al. Nutritional Status and Bone Microarchitecture in a Cohort of Systemic Sclerosis Patients. Nutrients. 2020;12. 10.3390/nu12061632Study of 36 postmenopausal women meeting the ACR 2013 criteria for systemic sclerosis
- Samm DA; Macoustra A; Crane R et al. Views of nutrition needs in patients with systemic sclerosis. J Scleroderma Relat Disord. 2024;9:216-222. 10.1177/2397198324126486824-item online survey
- Efthymiou E; Pardali EC; Gkouvi A et al. Knowledge and perceptions of medical practitioners on the role of nutrition in systemic sclerosis. J Scleroderma Relat Disord. 2026;11:e000005. 10.1136/jsrd-2026-000005Cross-sectional survey of 74 rheumatologists in Greece using the Views on Education and Nutrition in Scleroderma questionnaire
- Natalello G; Bosello SL; Campochiaro C et al. Adherence to the Mediterranean Diet in Italian Patients With Systemic Sclerosis: An Epidemiologic Survey. ACR Open Rheumatol. 2024;6:14-20. 10.1002/acr2.11627Cross-sectional epidemiologic survey of 387 patients from four Italian systemic sclerosis referral centres
- Hax V; Gasparin AA; Schneider L et al. Vitamin D and Cytokine Profiles in Patients With Systemic Sclerosis. J Clin Rheumatol. 2020;26:289-294. 10.1097/RHU.0000000000001112Case-control study of 50 patients with systemic sclerosis and 35 non-matched healthy controls
- Ross L; Lin L; Hansen D et al. Prevalence, clinical characteristics, and hospital course of systemic sclerosis-associated pseudo-obstruction. Clin Rheumatol. 2025;44:4541-4551. 10.1007/s10067-025-07676-6Analysis of 1
This page gathers the published research on this subject into one place. The studies behind it were published between 1989 and 2026, and every figure links to the paper it came from. Those studies were peer reviewed. This summary of them was not. Dr. Sarah Luebker is reviewing these pages one at a time and has not reached this one yet, so it carries no medical review date and nothing here is her opinion or her advice to you. Each page gets updated as she reaches it. It is here in the meantime because the science is worth having in one organized place that is easy to find and easy to read. Talk to your own clinician before acting on any of it.