Nutrition and IgAN (IgA Nephropathy): A Practical, Evidence-Based Guide
By Katie Lenhoff, APD, ANBSc
IgA Nephropathy (IgAN), also called Berger’s disease, is a form of chronic kidney disease (CKD) caused by immune complexes (Immunoglobulin A) depositing in the glomeruli (the kidney’s filtering units). Over time, this can trigger inflammation, scarring, and gradual loss of kidney function. While medications and blood pressure control are core elements of treatment, dietary choices play a crucial supporting role in managing IgAN and slowing disease progression.
The Role of Diet in Kidney Health
The kidneys regulate fluid balance, electrolytes (like sodium, potassium and phosphate), and metabolic waste. In IgAN, compromised kidney function can make these roles harder. By following a dietary pattern that is low in ultra-processed foods, low in salt, high in fibre and moderate in animal protein, you can reduce the workload on the kidneys.
It is important to note that there is no standard “kidney” or “IgAN” diet. This is because dietary requirements vary depending on your lab results, stage of kidney disease, nutrition status, etc.
There is a lot of information on the Internet about the “kidney diet” that is either outdated or more relevant to someone with end-stage kidney disease.
Sodium (Salt): One of the Most Important Dietary Factors
Why sodium matters:
Excessive sodium increases fluid retention and blood pressure. High blood pressure accelerates kidney damage and can worsen proteinuria (protein in the urine), a hallmark of IgAN.
Recommended sodium intake:
Aim for daily sodium below 2,300 mg (this equates to 1 teaspoon of salt).
Practical tips for low-sodium eating:
Read labels on all packaged foods for “sodium” content:
<150mg/100g is low salt
150-400mg/100g is moderate
>400mg/100g is high salt
Limit processed meats, canned soups, takeaway meals, instant noodles, salted nuts, crisps and pretzels, large amounts of cheese, olives, condiments and gravies, etc.
Cook at home and use herbs, spices, vinegar, and pepper to flavour meals instead of salt.
Protein: Support but Don’t Overload
Protein is found in meat, chicken, fish, eggs, dairy, legumes, tofu and small amounts in nuts, seeds, and wholegrains. Protein is essential for tissue repair, maintaining muscle mass, and overall health — but protein metabolism produces waste that the kidneys must filter. In people with IgAN, excessive protein intake can increase the kidneys’ workload, possibly contributing to further injury.
Most people with IgAN should follow a diet that is moderate in protein. The exact grams of protein per day will vary person to person. A Kidney Specialist Dietitian can calculate your needs based on factors such as weight, age, protein lost via the kidneys and activity level. For most people with IgAN, it is recommended that you do not exceed more than approx 150g of meat/chicken/fish per serve. It is generally recommended that you avoid protein bars, protein shakes and other products that have been fortified with protein. Research indicates that plant-based proteins are often easier on the kidneys, so replacing meat/chicken/fish with legumes, beans, tofu, tempeh can be beneficial.
Dietary Fibre and Plant-Rich Eating
Dietary fibre, found in wholegrains, legumes, vegetables, fruits, nuts and seeds, supports digestive health, stabilises blood glucose, reduces cholesterol, and may help reduce systemic inflammation. High-fibre patterns often replace highly processed, sodium-rich foods that are detrimental in CKD.
Choose wholegrain varieties (e.g., multigrain bread, rolled oats, quinoa, barley), include legumes regularly (add to curries, pastas, salads), top cereals and salads with seeds, have nuts and fruit as a snack, bulk up meals with vegetables.
Fluid Intake and Other Nutrients
Maintaining appropriate fluid balance helps the kidneys flush waste. While there is no universal fluid prescription, staying adequately hydrated supports kidney function. Discuss individual fluid goals with your healthcare team, especially if you have oedema or hypertension.
Potassium
It is a commonly held belief that if you have kidney disease and you consume high-potassium plant foods such as bananas, spinach, and avocado, this will put pressure on your kidneys and cause further damage. This is false — the research tells us that there is no benefit in limiting potassium in your diet if your blood potassium levels are within range. Often plant foods containing potassium are rich in vitamins, fibre, antioxidants and can have blood pressure-lowering effects — avoiding them unnecessarily could be doing more harm than good.
It is, however, important to note that if you have kidney disease, such as IgAN, you should avoid salt substitutes such as Diet Rite Lite Salt or Heart Salt. These products have replaced sodium chloride with potassium chloride.
Phosphate
Phosphate levels may need monitoring if kidney function declines, but restrictions are individualised based on bloodwork. If you do need to limit phosphate, it is important to note that inorganic phosphate found in phosphate additives are more readily absorbed by the body compared to naturally found phosphate. Phosphate additives are found in processed meats, takeaway meals, cola beverages, processed cheese, etc.
Working With Healthcare Professionals
Successfully applying dietary changes in IgAN means working with a Kidney Specialist Dietitian. Together, they can tailor recommendations based on lab results, kidney function stage, blood pressure, lifestyle, and personal preferences.
Summary
For people with IgA Nephropathy:
Limit sodium to generally <2,300 mg/day (often targeting 1,500–2,000 mg) to protect blood pressure and kidney health.
Moderate protein intake to reduce kidney workload while preventing malnutrition.
Choose high-fibre, plant-rich foods to improve overall kidney and cardiovascular health.
Work with healthcare providers to adjust diet based on individual needs, lab results, and disease stage.
These strategies don’t replace medical treatment but form a cornerstone of comprehensive IgAN care focused on slowing progression, managing blood pressure, reducing proteinuria, and supporting overall health.
About the Author
Katie is an Accredited Practising Dietitian and Nutritionist with over 16 years of experience, specialising in renal nutrition. She previously served as Senior Renal Dietitian at Fiona Stanley Hospital in Perth, Australia, where she managed complex kidney conditions.
A graduate of Curtin University in Western Australia (WA), Katie has completed advanced renal training and has held leadership roles within the profession, including Chair of the WA Kidney Dietitian Interest Group.
In 2022, Katie founded Katie Lenhoff Nutrition, a private practice dedicated to delivering personalised, evidence-based nutrition care that improves long-term kidney outcomes and enhances quality of life for people living with kidney disease.