# Nutrition in alpha-1 antitrypsin deficiency
Nutritional choices play a role in the health of people with alpha-1 antitrypsin deficiency (AATD), especially since the disease can affect both the lungs and the liver. However, research on specific diets in AATD is still limited; much knowledge comes from studies on lung diseases and liver conditions in general, and must be applied carefully to this rare disease.
Protein-rich nutrition
ResearchediPositive results in clinical studies, not yet standard treatment
A protein-rich diet means eating more protein via animal sources (meat, fish, eggs, dairy) or plant-based sources (legumes, nuts, tofu).
In AATD, protein intake becomes relevant because the body continuously tries to compensate for the deficiency of alpha-1 antitrypsin (AAT), and because damaged liver or lung tissue requires repair. Studies on AATD-related liver damage have established that protein metabolism plays a role in how severe the disease becomes (sources 2025, 2026). However: how much protein is ideal, and whether more protein slows the disease itself, has not been clearly established for AATD patients.
It is known from general studies that people with chronic liver disease should be careful with very large amounts of protein, because this can strain the liver. This may also apply to AATD patients with liver involvement.
Antioxidant-rich dietary pattern (vegetables, fruit, nuts)
ResearchediPositive results in clinical studies, not yet standard treatment
An antioxidant-rich dietary pattern contains many vegetables, fruits, nuts, seeds and whole grains. These foods contain substances that can reduce oxidative stress — damage that occurs when the body is not well protected against harmful molecules.
AATD is characterized in part by oxidative stress in the lungs and liver. Recent studies have examined whether natural substances (isothiocyanates from cruciferous vegetables) can reduce this stress and provide alpha-1 antitrypsin-like protection (source 2025). This research is still experimental and has been done mainly in laboratory settings.
From broader research on chronic lung and liver diseases, we know that an antioxidant-rich diet is generally beneficial for health.
Mediterranean dietary pattern
ResearchediPositive results in clinical studies, not yet standard treatment
The Mediterranean pattern consists of many vegetables, olive oil, fish, legumes, nuts and moderate red meat and dairy. This pattern has repeatedly been found to be beneficial for both lung function and liver diseases, among other things because it has an anti-inflammatory effect.
For AATD specifically, there are no randomized studies, but given the underlying role of inflammation in both organ systems affected by AATD (lungs and liver), this pattern would theoretically be appropriate. However, this has never been directly investigated in AATD cohorts.
Diet with less salt and fewer processed foods
ResearchediPositive results in clinical studies, not yet standard treatment
Salt restriction and avoidance of highly processed foods (with much sugar, trans and saturated fats) are recommended for people with chronic liver disease, because this can prevent water and salt retention and supports liver function.
In AATD, this becomes relevant as liver function declines. Studies on AATD-related liver damage have established that the amount and progression of liver fibrosis can differ per person (sources 2025, 2026), and that nutritional factors can partly contribute. However, specific guidelines for AATD patients are lacking.
Ketogenic diet
UnproveniNo scientific evidence that it works
A ketogenic diet severely restricts carbohydrates and shifts nutrition towards fats and protein, with the aim of setting metabolism to fat burning.
There is no research that has specifically examined ketogenic eating in AATD. Ketogenic diets can put more strain on the liver and are not recommended for people with existing liver disease — and AATD can come with that. Without evidence of benefit, this diet is not recommended for AATD.
Fasting and intermittent fasting
ExperimentaliOngoing in study setting, outcome still unknown
Periodic fasting (for example 16 hours of not eating, 8 hours of eating) or intermittent fasting have been studied for liver diseases because this may promote autophagy (cellular cleansing).
For AATD, this has not been specifically studied. Given that some recent studies suggest that cellular cleansing (lipophagy, in 2024) may help break down misfolded alpha-1-antitrypsin, this is interesting, but not yet verified in human patients or nutritional interventions. Fasting can be risky for people with active liver disease and is not recommended without guidance.
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**Nutritional choices are individualized.** With AATD, it is important that you discuss with your treating physician or a dietitian experienced with liver and/or lung disease what suits your situation. This especially applies if you already show signs of liver disease or lung damage.
_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._