# Nutrition in diabetes with severe complications
Introduction: why nutrition becomes different
In diabetes with severe complications, nutrition plays a different role than in the early stages of the disease. It is no longer only about blood sugar management, but also about supporting kidney, heart and digestive function, preventing further breakdown of muscle tissue, and dealing with side effects of intensive treatments. At the same time, nutritional requirements become more complex: what is good for the kidneys may be different from what is good for the heart, and nutrition for dialysis patients follows very different rules than for patients without kidney failure.
The information below describes what is known about nutrition in this phase. It is not a diet and not a nutrition plan — you always create that together with your healthcare provider or dietitian, taking into account your specific complications and medications.
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Blood sugar and eating pattern
How you eat (timing, composition, portion sizes) remains important for your blood sugar levels, especially if you use insulin or other blood sugar-lowering medications.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Regular meals and food with plenty of fibre help keep blood sugar fluctuations narrower.
However, with severe complications, your stomach may work more slowly (gastro-intestinal stasis) due to nerve damage, or you may be able to eat much less due to nausea or loss of appetite. In those cases, nutritional adaptation goes hand in hand with medication adjustment — something your doctor and dietitian work on together. Interactions with GLP-1 agonists (medications that are increasingly used) can also affect your eating pattern and body weight, especially in the first weeks of use.
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Nutrition and kidney function
When the kidneys are severely damaged, nutritional requirements change significantly. This depends on the stage of kidney failure and whether you are already on dialysis.
**With reduced kidney function without dialysis:**
Proteins (meat, fish, cheese, eggs) are partially excreted by the kidneys. When the kidneys are not working as well, certain breakdown products of proteins can accumulate.
ProveniIncluded in official guidelines, or approved by EMA or FDA
An adjusted amount of protein can help reduce the burden on the kidneys; however, this is not complete protein restriction, but a conscious choice in amount and type.
Potassium (in bananas, potatoes, tomatoes, dried fruit) can also accumulate. Too much sodium (salt) can worsen blood pressure and fluid retention. Phosphate (in dairy products, nuts, wholegrain products) can affect bone mineralisation.
This requires a personalised plan — differences between patients are large.
**With dialysis:**
Dialysis patients must pay much closer attention to protein, potassium, phosphate and fluid.
ProveniIncluded in official guidelines, or approved by EMA or FDA
The nutritional requirements for dialysis patients are strictly defined and regularly checked through blood tests. This is not a preference, but a medical necessity. Your nephrologist and dietitian will create a personalised plan together.
Recent research (August 2026) shows that malnutrition and loss of muscle strength are associated with worse outcomes in patients with kidney failure; at the same time, nutrition must meet strict limits. This requires a good balance, which your treatment team can help determine.
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Muscle tissue and nutrition
With severe complications, muscle strength often decreases — both because the disease itself has a catabolic effect (through high blood sugars, inflammatory processes), and because you can move less or because your medications affect this. This is sometimes called "sarcopenia".
ProveniIncluded in official guidelines, or approved by EMA or FDA
Adequate protein (in the right amount and distribution throughout the day) is needed to maintain muscle mass. In dialysis patients, protein needs increase because dialysis also removes proteins.
ResearchediPositive results in clinical studies, not yet standard treatment
Regular muscle training (if medically feasible) works together with adequately protein-rich nutrition. Research shows that preventing muscle breakdown is important for your overall mortality and quality of life — not only for mobility, but also for heart function and immune defense.
Vitamin D also plays a role in muscle and bone health; some patients have deficiencies, especially with kidney failure. This is checked with your doctor.
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Heart and vascular health
Diabetes with complications is almost always accompanied by heart and vascular disease. Nutrition can reduce this risk.
ProveniIncluded in official guidelines, or approved by EMA or FDA
A pattern with plenty of vegetables, fruit, whole grains, fish and limited saturated fat helps keep blood pressure and cholesterol in better ranges. This helps protect the heart.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Limiting salt helps lower blood pressure. This is especially important if you also have kidney problems.
When your kidneys are seriously damaged, however, different rules apply for certain nutrients (such as potassium, see above), so the pattern usually needs to be adjusted.
Nutrition cannot prevent you from getting serious heart disease, but can help limit further damage.
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Nutrition and medication effectiveness
Many medications for serious diabetes complications work better or differently depending on what you eat.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Certain nutrients can make medications absorb better or worse. For example: a meal with high fat can change the absorption of certain substances. This varies by medication.
Nutrition can also affect side effects of medications — for example, nausea, diarrhea or constipation occur differently depending on your eating pattern and nutritional composition.
These are reasons why you always discuss your medications and nutrition together with your care provider. Making major dietary changes on your own can undermine the effectiveness of your treatment.
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Malnutrition and quality of nutrition
Serious complications are often accompanied by reduced appetite, nausea, fatigue, or simply less enjoyment of eating. This risk of malnutrition is real and serious.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Malnutrition increases the risk of infections, poor wound healing, hospitalizations and higher mortality. We see this in all research.
Your nutrition doesn't need to be "perfect" — rather: you need to get as much energy and nutrients inside you in a way that is feasible for you. This can mean: more frequent small meals, choosing food you really like, sometimes nutritional supplements (not because they are "better", but because they are feasible), and sometimes accepting that your regular food doesn't meet all requirements.
This is something your dietitian evaluates continuously — not just once, but repeatedly, because your needs change.
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Special attention: anemia and bone health
Research from 2026 shows that many patients with diabetes and kidney failure also have anemia. This affects your nutrition:
ProveniIncluded in official guidelines, or approved by EMA or FDA
Iron, B12 and folic acid are important for blood cell formation. Much iron is found in red meat, fish, legumes and grains, but iron absorption also depends on your stomach acid and medications.
Bone health is threatened by high blood sugar, reduced movement, and with kidney failure by disturbances in calcium balance and hormones.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Calcium and vitamin D are important here, but dosage and forms must be chosen carefully in consultation with your doctor, especially with kidney failure.
These are not things to handle yourself with supplements, but topics to discuss with your care team.
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Nutrition as part of care
With serious complications, nutrition is not a "lifestyle topic", but part of medical care. It requires collaboration between your doctor, nephrologist, dietitian, nurse specialist and yourself.
Regular evaluation of your nutritional status (via weight, blood values, how you feel, what you eat) is part of good care. If you notice that you are eating less, are more nauseous, lose a lot of weight or don't know what you can still eat — tell your care provider immediately. This is medical information, not a personal failure.
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_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._