Metabolic Acidosis in CKD: How Bicarbonate Therapy Slows Kidney Decline

By Lindsey Smith On 8 Jan, 2026 Comments (15)

When your kidneys start to fail, they don’t just stop filtering waste-they also lose their ability to keep your blood’s acid levels in check. This leads to metabolic acidosis, a hidden but dangerous problem that accelerates kidney damage, wastes muscle, and weakens bones. It’s not rare. In fact, nearly half of people with advanced chronic kidney disease (CKD) have it. And most don’t even know.

What Is Metabolic Acidosis in CKD?

Metabolic acidosis happens when your blood becomes too acidic because your kidneys can’t get rid of acid or make enough bicarbonate to balance it. Normal blood bicarbonate is 22-29 mEq/L. When it drops below 22, you’re in acidosis. In stage 3 CKD, about 15% of people have it. By stage 5, that number jumps to 42%. It’s not just a lab value-it’s a signal your kidneys are struggling to do their most basic job: maintaining chemical balance.

Why does this matter? Acid buildup doesn’t just sit there. It triggers a chain reaction. Your body pulls calcium from your bones to neutralize the acid, leading to osteoporosis. It breaks down muscle tissue for energy, causing weakness and fatigue. It strains your heart and raises blood pressure. And worst of all, it speeds up the decline of your kidney function. Studies show that keeping bicarbonate above 22 mEq/L cuts the risk of kidney failure by 23%.

Why Bicarbonate Therapy Is the Standard

The most common treatment is sodium bicarbonate. It’s cheap, available over the counter as baking soda, and sold in tablet form (650 mg = 7.6 mEq of bicarbonate). A major 3-year trial with 740 CKD patients found that those taking sodium bicarbonate (0.5-1.0 mEq/kg/day) slowed their kidney decline by nearly 6 mL/min/1.73m² compared to those who didn’t. That’s the difference between reaching dialysis in 5 years versus 10.

But it’s not simple. Each 500 mg tablet of sodium bicarbonate contains 610 mg of sodium. For someone with high blood pressure or heart failure, that’s risky. One study found patients on sodium bicarbonate had a 32% higher chance of being hospitalized for heart failure than those on calcium citrate. So while it works, it’s not safe for everyone.

Alternatives to Sodium Bicarbonate

If you can’t take sodium bicarbonate, there are other options-but each has trade-offs.

Sodium citrate (Shohl’s solution): Similar to bicarbonate but less likely to cause gas or bloating. One teaspoon provides about 50 mEq of alkali. Taste is bitter, so many mix it with orange juice-which adds sugar you may need to avoid.
Potassium citrate: Good for people with low potassium, but dangerous if your potassium is already high. Nearly 1 in 5 CKD patients on potassium supplements develop dangerous hyperkalemia (potassium >5.0 mEq/L). Guidelines now warn against using it in stages 3b-5 unless potassium is confirmed low.
Calcium citrate: Helps with acid and gives you calcium. But too much can raise blood calcium levels, increasing kidney stone risk by 27%. Most doctors cap it at 1,000 mg of elemental calcium per day.
Veverimer: A non-absorbed pill that traps acid in your gut. It was promising-raised bicarbonate by 4.3 mEq/L in early trials. But its final phase 3 trial in 2021 missed its goal. No FDA approval yet, though the manufacturer is re-analyzing data for a 2024 resubmission.

Medical monitor showing kidney function curves, with patient eating healthy foods and taking pills side by side.

Dietary Changes: The Forgotten Treatment

Many people don’t realize that what you eat can be as powerful as any pill. Acid-producing foods-meat, cheese, processed grains-add 40-60 mEq of acid to your daily load. Base-producing foods-fruits and vegetables-remove acid. One study showed patients who switched to 5-9 daily servings of fruits and vegetables increased their bicarbonate by 3.5 mEq/L in six months, without any pills.

But it’s hard. A renal dietitian will help you map out your meals. For example:

100g of chicken = +9.5 mEq acid load
100g of cheddar cheese = +8.0 mEq acid load
100g of spinach = -2.8 mEq acid load
100g of apples = -2.2 mEq acid load

Getting your daily acid load below zero (PRAL score < 0) is ideal. But only 35% of patients on dietary counseling reach that goal. It takes time, coaching, and real effort.

Who Should Be Treated-and When?

KDIGO guidelines say: Start alkali therapy when bicarbonate drops below 22 mEq/L. That’s a Grade 1B recommendation-strong, based on solid evidence. But what’s the target? That’s where things get messy.

Some experts say aim for 24-26 mEq/L. Others warn that going above 26 may raise death risk in older patients. A 2020 study found the lowest mortality happened when bicarbonate stayed between 24 and 26. For someone with heart failure, 22-24 might be safer. For someone with muscle wasting, 25-27 might help more.

Here’s what most nephrologists do:

Check bicarbonate every 3-6 months in stable CKD.
If it’s under 22, start with diet: add 5 servings of fruits/vegetables daily.
If no improvement after 3 months, add oral alkali.
Start low: 650 mg sodium bicarbonate once or twice daily.
Monitor blood pressure, weight, and potassium every 4 weeks.
Adjust dose to hit 23-29 mEq/L, avoiding side effects.

Heroic bicarbonate figure fighting acid monster inside a body, with fruits raining down as healing symbols.

Why So Many Patients Go Untreated

Despite clear guidelines, only 43% of CKD patients with low bicarbonate get treatment. Why?

Pill burden: Patients average 4.2 pills a day. That’s hard to stick to.
Taste: Liquid forms taste awful. One patient said she had to mix baking soda with orange juice-adding sugar she shouldn’t have.
Side effects: 29% report bloating, nausea, or cramps.
Access: Rural patients are 30% less likely to get treatment than urban ones. Black patients are 9% less likely than White patients.
Awareness: Many doctors still don’t check bicarbonate regularly. It’s not part of routine labs like creatinine or eGFR.

The result? Thousands of preventable kidney failures each year. The National Institute of Diabetes and Digestive and Kidney Diseases estimates correcting metabolic acidosis could prevent 28,000 cases of ESRD annually in the U.S.-and save $1.4 billion.

What’s Next?

Research is moving fast. The COMET-CKD trial, enrolling 1,200 patients, is testing high-dose versus low-dose bicarbonate. Results come in late 2025. A new citrate-free alkali supplement (TRC001) showed a 4.1 mEq/L bicarbonate boost with half the stomach upset of older forms.

KDIGO’s 2024 draft guidelines are already shifting. They’re expanding the target range to 22-29 mEq/L, acknowledging that even 22 can protect your kidneys. The future is personalization: a 75-year-old with heart failure gets a lower target than a 50-year-old with muscle loss.

But right now, the best tools we have are simple: check your bicarbonate. Eat more plants. Take your pills. Monitor your blood pressure. Don’t let a treatable condition quietly steal your kidney function.

What is the normal bicarbonate level for someone with CKD?

For people with chronic kidney disease, the target serum bicarbonate level is 23-29 mEq/L, according to KDIGO guidelines. Some experts now say 22-29 mEq/L is acceptable, especially if you have heart failure or are elderly. Levels below 22 mEq/L indicate metabolic acidosis and should be treated.

Can I just use baking soda instead of prescription bicarbonate?

Yes, one teaspoon of baking soda contains about 50 mEq of bicarbonate, which is equivalent to several prescription tablets. But it’s not recommended without medical supervision. Baking soda is pure sodium bicarbonate, so it can spike your sodium and worsen high blood pressure or heart failure. Always talk to your nephrologist before using it.

Does potassium citrate help with acidosis in CKD?

Potassium citrate can help neutralize acid, but it’s risky in CKD. About 18% of patients develop dangerous high potassium levels (hyperkalemia) on this treatment. It’s only recommended if you have low potassium (below 3.5 mEq/L) and your doctor closely monitors your levels. Most guidelines now advise against it in stages 3b-5.

How long does it take for bicarbonate therapy to slow kidney decline?

In clinical trials, patients on bicarbonate therapy showed slower kidney decline within 6-12 months. The landmark 2018 study showed a clear benefit after 3 years, with eGFR decline slowed by nearly 6 mL/min/1.73m². The key is consistency-treatment must be maintained long-term to protect kidney function.

Can diet alone fix metabolic acidosis in CKD?

Diet can help, but it’s rarely enough on its own. Eating 5-9 servings of fruits and vegetables daily can raise bicarbonate by 1-3 mEq/L. For patients with severe acidosis (bicarbonate <18 mEq/L), that’s not enough. Diet works best as a first step or combined with low-dose alkali therapy. Many patients need both.

Is there a new drug coming for metabolic acidosis in CKD?

Veverimer was the most promising new drug, but its phase 3 trial failed in 2021. The company plans to resubmit to the FDA in 2024 with new data. A new citrate-free alkali supplement (TRC001) is in early trials and shows better tolerance than current options. But as of 2026, no new FDA-approved drug is available. Sodium bicarbonate and dietary changes remain the standard.