Corticosteroids profoundly alter the metabolism of sodium, calcium, potassium, and glucose. Adjusting what one eats while on cortisone is not limited to “eating less salt”: each side effect calls for a targeted, measurable dietary adjustment, which can sometimes contradict another. This article compares the main nutritional areas to monitor during treatment with prednisone or its equivalent, distinguishing between what falls under medical consensus and what requires individual assessment.
Sodium, calcium, potassium: nutritional thresholds to know under corticosteroids
| Nutrient | Effect of corticosteroids | Dietary goal | Foods to prioritize |
|---|---|---|---|
| Sodium (salt) | Water and salt retention, risk of hypertension | Limit intake, avoid prepared dishes and cold cuts | Spices, herbs, salt-free bread, fresh vegetables |
| Calcium | Increased urinary loss, risk of osteoporosis | Aim for about 1000 to 1200 mg of calcium per day | Dairy products, broccoli, almonds, calcium-rich mineral waters |
| Potassium | Urinary leakage, risk of cramps and fatigue | Compensate through daily diet | Banana, legumes, spinach, avocado |
| Vitamin D | Intestinal absorption of calcium disrupted | At least 800 IU of vitamin D per day | Fatty fish, egg yolk, moderate sun exposure |
| Proteins | Muscle wasting (protein catabolism) | Maintain sufficient protein intake at each meal | Meat, fish, eggs, legumes |
| Fast sugars | Increased blood sugar, risk of diabetes | Limit isolated sugars, prefer complex carbohydrates | Whole grains, vegetables, whole fruits |
This table summarizes the main areas. However, priorities vary according to the prescribed dose, duration of treatment, and each patient’s history. A diet that is too restrictive on multiple fronts at once can cause other imbalances, a point rarely addressed in public recommendations.
To learn more about Conseils Cuisine, the site details sample menus adapted to corticosteroid therapy with concrete recipes.
Low-salt diet under cortisone: where to draw the line without risk
The most common advice when starting corticosteroid treatment is to reduce salt. The reasoning is straightforward: corticosteroids promote sodium retention, which increases blood pressure and causes edema. Banning chips, savory biscuits, hard cheeses, cold cuts, and smoked fish is the first reflex recommended by most doctors.
The difficulty arises when the restriction becomes excessive. In patients on high doses of prednisone who already eat little, too strict a sodium restriction can lead to hyponatremia (abnormally low blood sodium levels). This risk, documented in recent years, particularly affects the elderly or malnourished individuals.
In practice, a few guidelines help limit sodium without falling into the opposite excess:
- Replace table salt with spices, lemon, fresh herbs, or gomasio (a mixture of sesame and lightly salted)
- Read labels: industrial prepared meals and regular bread concentrate a major part of daily sodium
- Opt for salt-free or reduced-sodium bread, available at bakeries or in the dietary section
- Keep at least one low-salt dairy product per day to avoid sacrificing calcium intake in the name of salt reduction
The doctor or dietitian is best placed to set an appropriate threshold. Limiting salt does not mean eliminating it entirely, especially in cases of prolonged treatment or significant fatigue.
Calcium and vitamin D under corticosteroids: systematic or targeted supplementation
Bone loss related to corticosteroids is a well-known side effect. To compensate for it, health articles often recommend supplementing with calcium and vitamin D from the start of treatment. The 2024 recommendations from the European Calcified Tissue Society provide nuance: supplementation should address a documented deficiency, not be automatic.
For someone who already consumes three dairy products a day, regularly eats broccoli or almonds, and drinks calcium-rich mineral water, dietary intake may be sufficient to meet the target. Conversely, a lactose-intolerant person or one who avoids dairy products will almost certainly need a supplement.
Vitamin D follows the same logic. A blood test allows for checking the actual level before prescribing supplementation. In cases of renal insufficiency or a history of kidney stones, excess supplemented calcium can worsen the situation. This precaution, present in recent European recommendations, is rarely mentioned in dietary guides aimed at the general public.
Proteins and muscle wasting: an often underestimated area
Corticosteroids accelerate protein catabolism, meaning the breakdown of muscle proteins. Over several weeks of treatment, muscle wasting becomes visible and contributes to feelings of weakness. Maintaining protein intake at each meal (meat, fish, eggs, legumes) helps slow this process.
Patients who simultaneously reduce salt, fats, and sugars sometimes end up eating too little overall. The risk of malnutrition exists, particularly among the elderly or those whose appetite is already diminished by the treated illness. The weight gain often associated with corticosteroids does not affect all patients equally: some gain weight due to water retention and fat redistribution while losing muscle mass.
Blood sugar and sugary foods: adapt without over-restricting
Corticosteroids increase blood sugar, sometimes significantly. People who are already diabetic or have risk factors should monitor their blood sugar more frequently at the beginning of treatment. For others, the rules are similar to those of a classic balanced diet.
Preferring whole grains (brown rice, semi-whole pasta, grain bread) over fast sugars slows glucose absorption. Consuming a sweet food at the end of a meal rather than in isolation limits the blood sugar spike. Vegetables, rich in fiber, also help smooth the glycemic response.
Three servings of vegetables per day is a minimum under corticosteroid therapy, both for the fiber and for the potassium and micronutrients they provide. Whole fruits remain recommended, provided they are not replaced by industrial fruit juices, which are much more glycemic.
What matters under cortisone is not to apply a single strict diet but to adjust each nutritional area (salt, calcium, proteins, sugars) according to one’s actual situation. An assessment with a doctor or dietitian at the beginning of treatment helps prioritize areas and avoid a useful restriction in one area creating an imbalance in another.
