Metabolic Acidosis in CKD: How Bicarbonate Therapy Slows Kidney Decline

Jan 26 2026

Why Your Kidneys Can’t Keep Up With Acid

Your kidneys don’t just filter waste-they also keep your blood from turning too acidic. When they start failing, acid builds up. That’s called metabolic acidosis. It’s not rare. In fact, nearly half of people with stage 5 chronic kidney disease (CKD) have it. And if left untreated, it doesn’t just make you feel tired-it speeds up kidney damage, eats away at your muscles, and weakens your bones.

Normal blood bicarbonate levels sit between 22 and 29 mEq/L. When they drop below 22, your body is struggling to neutralize acid. In CKD, this happens because damaged kidneys can’t excrete hydrogen ions or make enough new bicarbonate. It’s not a side effect-it’s a direct consequence of declining kidney function.

The Real Cost of Low Bicarbonate

Low bicarbonate isn’t just a lab number. It’s a silent driver of complications. Studies show that for every 1 mEq/L drop in serum bicarbonate, your risk of kidney function decline jumps by 12%. Patients with levels under 20 mEq/L are twice as likely to need dialysis within three years compared to those above 22 mEq/L.

Here’s what else happens:

Muscle wasting: Acid breaks down muscle protein. You lose strength, get fatigued faster, and struggle to recover from illness.
Bone loss: Your body pulls calcium from bones to buffer acid. Over time, this leads to osteoporosis and fractures.
Heart strain: Acidosis makes your heart work harder. It’s linked to higher blood pressure and increased risk of heart failure.
Slower kidney decline: Correcting acidosis can slow the drop in eGFR by nearly 6 mL/min/year-equivalent to gaining 2-3 years of kidney function.

The evidence is clear: treating metabolic acidosis isn’t optional. It’s one of the few interventions in CKD that actually changes the disease course.

Sodium Bicarbonate: The Go-To Treatment

The most common fix? Sodium bicarbonate. It’s cheap, effective, and has been used since the 1950s. A 2018 trial with 740 CKD patients showed that taking 0.5-1.0 mEq/kg/day of sodium bicarbonate raised bicarbonate levels by 4-6 mEq/L and cut the rate of kidney decline by 5.9 mL/min/1.73m² compared to placebo.

Typical doses:

650 mg tablets (7.6 mEq of bicarbonate) - taken once or twice daily
1 teaspoon of baking soda = 50 mEq - but this is rarely used due to high sodium content

It works. But here’s the catch: each 500 mg tablet has 610 mg of sodium. For someone with high blood pressure, heart failure, or swelling, that’s dangerous. Many patients see their blood pressure jump from 130/80 to 160/95 within weeks. That’s why doctors often avoid it in advanced CKD patients with fluid overload.

A patient surrounded by floating foods—acidic meats dissolving as alkaline fruits glow, symbolizing dietary healing.

Alternatives When Sodium Is a Problem

If you can’t tolerate sodium bicarbonate, there are other options-but none are perfect.

Sodium Citrate (Shohl’s Solution)

This liquid form delivers 1 mEq/mL of citrate, which your body converts to bicarbonate. It’s gentler on the stomach than baking soda, but still contains sodium. Some patients find it easier to swallow than pills, but taste is still an issue.

Calcium Citrate

This is a popular switch for patients with heart issues. Each 500 mg tablet gives 120 mg of elemental calcium. It avoids sodium entirely. But there’s a trade-off: calcium can build up in your blood. Studies show a 27% higher risk of kidney stones in long-term users. Most doctors cap daily calcium intake at 1,000 mg to avoid hypercalcemia.

Potassium Citrate

It sounds ideal-citrate plus potassium, both good for bones and kidneys. But in CKD, potassium builds up. Around 18% of patients on potassium citrate develop dangerous hyperkalemia (potassium >5.0 mEq/L). The National Kidney Foundation advises against it in stages 3b-5 unless you’re severely low in potassium. Even then, it’s risky.

Veverimer: The Treatment That Didn’t Make It

Veverimer was supposed to be the game-changer. A non-absorbed polymer that traps acid in your gut and lets you pee it out-without sodium, potassium, or calcium. Phase 2 trials showed a 4.3 mEq/L bicarbonate boost in 12 weeks. But in phase 3, it fell short. The difference from placebo was just 2.07 mEq/L (p=0.065). No FDA approval. Development paused. The hope is still alive, with Tricida planning a new submission in 2024.

Diet: The Forgotten Therapy

Medications aren’t the only way. Food matters. A lot.

Meat, cheese, and grains produce acid. Fruits and vegetables produce base. Your daily acid load can be measured with something called PRAL (Potential Renal Acid Load). A steak has a PRAL of +9.5 mEq per 100g. An apple? -2.2 mEq. Swap one meat-heavy meal for two servings of veggies, and you cut acid by 15-20 mEq/day.

A 2010 study found that patients who ate 5-9 servings of fruits and vegetables daily raised their bicarbonate by 1-3 mEq/L-enough to slow kidney decline. In one clinic, a patient raised their bicarbonate by 3.5 mEq/L in six months just by switching to plant-based meals under dietitian supervision.

But here’s the problem: adherence is low. Only 35% of patients hit the target PRAL of less than 0 mEq/day. Most find it hard to track, cook differently, or afford fresh produce. That’s why diet alone rarely works unless paired with medication.

Who Gets Treated-and Who Doesn’t

Despite strong guidelines, only 43% of CKD patients with low bicarbonate get alkali therapy. Why?

Pill burden: Patients take an average of 4.2 tablets a day. Many stop because it’s too much.
Taste: 41% of patients hate the flavor of liquid alkali. Some mix it in orange juice-adding sugar they shouldn’t have.
Side effects: Bloating, nausea, and gas affect 29%.
Disparities: Black patients are 20% less likely to get treatment than white patients. Rural patients get it 14% less often than urban ones.

Doctors aren’t always on the same page either. Many still think low bicarbonate is “just a lab value.” But KDIGO guidelines say clearly: start alkali therapy when bicarbonate drops below 22 mEq/L. That’s a Grade 1B recommendation-strong, based on solid evidence.

Patients walking toward therapeutic doorways in a surreal clinic, each reflecting their kidney disease struggle.

What’s the Right Target?

Is 24 mEq/L better than 22? Is 26 too high?

The KDIGO 2024 draft now recommends 22-29 mEq/L instead of 23-29. Why? New data shows even 22 mEq/L still protects your kidneys. But there’s a twist: a 2020 study found a U-shaped curve. The lowest death risk was between 24-26 mEq/L. Below 22? Higher risk. Above 26? Also higher risk, especially in older adults.

So the new thinking is personalization:

Heart failure? Target 24-26 mEq/L.
Older, frail, malnourished? 22-24 mEq/L is safer.
Younger, stable CKD? Aim for 24-26.

It’s not one-size-fits-all anymore. Your doctor should consider your age, heart health, and nutrition-not just the number on the chart.

Monitoring and Next Steps

If you have CKD and haven’t had your bicarbonate checked in the last six months, ask for it. It’s a simple blood test. If it’s below 22 mEq/L, talk about treatment.

Here’s a practical plan:

Get your serum bicarbonate tested. Do it every 3-6 months if stable, monthly if starting treatment.
If it’s low, start with diet: add 5-9 servings of fruits and vegetables daily. Cut back on processed meats and cheese.
If after 3 months it’s still below 22, add sodium bicarbonate (650 mg once or twice daily).
Watch for swelling, high blood pressure, or cramps. If they appear, switch to calcium citrate.
Avoid potassium citrate unless your potassium is low-and even then, monitor closely.
See a renal dietitian. Two sessions can teach you how to read PRAL scores and make sustainable changes.

The goal isn’t perfection. It’s progress. Even a 2 mEq/L rise in bicarbonate can delay dialysis by years. That’s not just a lab result-it’s more time with your family, more energy, fewer hospital visits.

What’s Coming Next?

Research is moving fast. The COMET-CKD trial, enrolling 1,200 patients, is comparing high-dose vs. low-dose sodium bicarbonate. Results come in late 2025. Meanwhile, a new citrate-free alkali supplement (TRC001) is showing promise-better taste, fewer stomach issues, and a 4.1 mEq/L bicarbonate boost in 12 weeks.

There’s also a bigger picture. If every CKD patient with metabolic acidosis got proper treatment, the U.S. could prevent 28,000 cases of kidney failure each year. That’s $1.4 billion saved in healthcare costs.

But none of that matters if patients don’t get tested, don’t get treated, or don’t stick with it. The tools are here. The evidence is clear. What’s missing is consistent action-from doctors, patients, and the system.