Bicarbonate

When you have chronic illness, it isn’t uncommon to have problems with electrolyte imbalances. Because of that, I’ve decided to do a series that talks about what they are, how the body uses them and things that we can do to manage our electrolytes. And this is the final installment of that series! I left the most complicated entry for last…

Let me preface this discussion of bicarbonate with the fact that it is an intricate part of the acid-base balance which is often considered the most difficult concept to master for Medical Surgical nurses. Bicarbonate is complex and it is difficult to talk about it’s function in the body in a simple or straight forward manner. I’m going to do my best to talk about it here without going fully into the acid-base balance of the body. That being said, there is no way to discuss bicarbonate’s function within the body without also discussing at least the metabolic side of the acid-base balance.

Bicarbonate is an essential component of the physiological pH buffering system in the human body. Up to ¾ of the carbon dioxide in the human body is converted to carbonic acid which is quickly turned to bicarbonate. Bicarbonate is an alkali so helps to keep the acid-base balance of the body stable. Bicarbonate alongside water, hydrogen, hemoglobin, phosphate and carbon dioxide makes up the buffering system which is required to act quickly if pH changes are detected. This could be caused by an electrolyte imbalance or the inability to remove carbon dioxide – a waste product – from the body. If bicarbonate levels are too high or too low, then this can suggest that the body is struggling to maintain its acid-base buffering system.

A normal level of bicarbonate is 19-24. The normal pH of the blood is a narrow range: 7.35-7.45 and becomes dangerous if it is above or below that range. Normally, the body will compensate when the pH of the blood moves outside of the range so that the pH is quickly corrected and returned to the safe range.

Metabolic Acidosis

Metabolic acidosis is a condition in which there is too much acid (or not enough base) in the body fluids. Bicarbonate is the body’s primary base. Thus, under normal conditions, when the pH becomes acidic (drops below 7.35) the body will convert carbonic acid to bicarbonate and will have the kidneys reabsorb bicarbonate. This increase in bicarbonate will return the pH to the normal range. Thus, acidosis is always a condition of too much acid as well as too little base. If you don’t have enough bicarbonate in your body, your pH will shift towards being acidic (less than 7.35). If the bicarbonate level drops below 19, it can effect the pH of the blood.

The kidneys play a major role in the regulation of acid-base balance by reabsorbing bicarbonate and excreting titratable acids and ammonia into the urine. When someone suffers kidney disease, their kidneys are not performing these functions as well which can lead to an acid-base imbalance. If the kidneys are failing to reabsorb the bicarbonate, the levels of bicarbonate in the blood can decrease leading to metabolic acidosis. Likewise, if the kidneys are not able to excrete the acid and ammonia in the urine, the amount of acid in the blood can rise and cause metabolic acidosis.

The symptoms of metabolic acidosis are:

  • A fast heart rate
  • Weakness and feeling tired
  • The need to take long and deep breaths
  • Headache and/or confusion
  • Loss of appetite, nausea and/or vomiting

Many medications can have an impact on the acid-base balance of the body and should be monitored with regular lab work to ensure that this balance is being maintained.

Medicines that may lower your bicarbonate levels include:

  • Methicillin
  • Nitrofurantoin
  • Tetracycline
  • Thiazide diuretics
  • Triamterene

Drugs have been linked to lactic acidosis such as:

  • Metformin
  • Linezolid
  • Propofol
  • intravenous epinephrine
  • inhaled beta agonists (such as albuterol)
  • nucleoside reverse transcriptase inhibitors (NRTIs) (HIV medications)

Metabolic Alkalosis

Metabolic alkalosis is an imbalance where the pH of the blood has become too alkaline or greater than 7.45. This can be caused by an increase in the base (bicarbonate greater than 24) or a decrease in the amount of acid in the body. It can occur in a variety of conditions. It may be due to digestive issues, like repeated vomiting, that disrupt the blood’s acid-base balance. It can also be due to complications of conditions affecting the heart, liver and kidneys. In mild cases, you might not experience symptoms. Severe forms of metabolic alkalosis can affect kidney functioning.

Medical conditions that cause metabolic alkalosis include:

  • Cystic fibrosis.
  • Dehydration.
  • Electrolyte imbalances, which affect levels of sodium, chloride, potassium and other electrolytes.
  • High levels of the adrenal hormone aldosterone (hyperaldosteronism).
  • Low levels of chloride in the blood (hypochloremia).
  • Recurrent vomiting, which occurs with cyclic vomiting syndrome, gastro paresis, migraines and many other disorders.

Medicines that may raise your bicarbonate levels include:

  • Fludrocortisone
  • Barbiturates
  • Bicarbonates
  • Hydrocortisone
  • Loop diuretics
  • Steroids

The symptoms of metabolic alkalosis include:

  • Irritability.
  • Muscle twitching.
  • Muscle cramps.
  • Muscle spasms.
  • Fatigue.
  • Confusion.
  • Tremor.
  • Tingling and numbness.
  • Abnormal heart rhythm (arrhythmia).
  • Seizures.
  • Coma.

Bicarbonate Supplements

If you have any degree of an acid-base imbalance or suspect that you do, you need to be seen and followed by your doctor. An acid-base imbalance can quickly become life threatening and isn’t something you should ever try to self manage. So, no supplement advice here. Go see your doctor and follow their directions. Seriously, don’t mess around with this one.

Diet and Metabolic Acidosis

When considering diet as a means to prevent metabolic acidosis, you are looking to have a kidney supportive diet. This is a diet that reduces the kidney’s work load which makes it less likely that your body will have a metabolic imbalance due to kidney disfunction. This type of kidney supportive diet is generally only needed when a person is already experiencing kidney disease.

DASH Diet

The first kind of kidney support diet is the DASH diet. DASH stands for Dietary Approaches to Stop Hypertension. The DASH diet is a healthy-eating plan designed to help treat or prevent high blood pressure (hypertension). However, research has shown that this kind of diet is also more gentle to the kidneys and can facilitate better kidney function. The National Kidney Foundation recommends this diet to reduce your risk of going into metabolic acidosis when you have chronic kidney disease.

When following DASH, it is important to choose foods that are:

  • Rich in potassium, calcium, magnesium, fiber and protein
  • Low in saturated fat
  • Low in sodium

The DASH diet provides daily and weekly nutritional goals. The number of servings you should have depends on your daily calorie needs.

Here’s a look at the recommended servings from each food group for a 2,000-calorie-a-day DASH diet:

  • Grains: 6 to 8 servings a day. One serving is one slice bread, 1 ounce dry cereal, or 1/2 cup cooked cereal, rice or pasta.
  • Vegetables: 4 to 5 servings a day. One serving is 1 cup raw leafy green vegetable, 1/2 cup cut-up raw or cooked vegetables, or 1/2 cup vegetable juice.
  • Fruits: 4 to 5 servings a day. One serving is one medium fruit, 1/2 cup fresh, frozen or canned fruit, or 1/2 cup fruit juice.
  • Fat-free or low-fat dairy products: 2 to 3 servings a day. One serving is 1 cup milk or yogurt, or 1 1/2 ounces cheese.
  • Lean meats, poultry and fish: six 1-ounce servings or fewer a day. One serving is 1 ounce cooked meat, poultry or fish, or 1 egg.
  • Nuts, seeds and legumes: 4 to 5 servings a week. One serving is 1/3 cup nuts, 2 tablespoons peanut butter, 2 tablespoons seeds, or 1/2 cup cooked legumes (dried beans or peas).
  • Fats and oils: 2 to 3 servings a day. One serving is 1 teaspoon soft margarine, 1 teaspoon vegetable oil, 1 tablespoon mayonnaise or 2 tablespoons salad dressing.
  • Sweets and added sugars: 5 servings or fewer a week. One serving is 1 tablespoon sugar, jelly or jam, 1/2 cup sorbet, or 1 cup lemonade.

When following the DASH diet, there is a major focus on reducing the amount of salt consumed. Just by following the above serving recommendations you will reduce your sodium intake. You can further reduce your sodium by not adding salt to your food when you are cooking or at the table. Buying low sodium versions of foods will also help reduce your salt intake.

Potential Renal Acid Loads (PRAL) Diet

Alternatively, you can choose a diet that focuses on the Potential Renal Acid Loads (PRAL) of a food. Every food has to be broken down by the body and in that process it either produces acidic or alkalic biproducts. A few produce neutral biproducts, but most foods will sway our acid-base balance in one direction or the other. When we introduce more acid into our system, our kidneys have to compensate by increasing the amount of bicarbonate it reabsorbs and by excreting more acid. Thus, decreasing consumption of foods that increase your body’s acid will decrease your kidney’s work load and make it less likely that you will go into metabolic acidosis.

Average potential renal acid loads (PRAL) of certain food groups (related to 100 g edible portion):

Food GroupPRAL (mEq/100 g)
Fruits and fruit juices−3.1
Vegetables−2.8
Fats and oils0
Milk and whey based products+1.0
Bread+3.5
Noodles, spaghetti+6.7
Fish+7.9
Cheese (protein <15 g/100 g)+8.0
Meat and meat products+9.5

Thus, on this kind of diet, the primary source of calories will be from fruits, vegetables and fat sources since they do not increase the acid in the body. The secondary calorie sources will be from milk products and breads since they have a low impact on the acid in the body. When following this diet, it is essential to ensure that you are still getting enough proteins. While protein is broken down into acids, it is still an essential nutrient for the body.

Going onto a PRAL diet is much more complex to keep track of and much more difficult to ensure that all dietary needs are being met. This is the biggest reason that it is not the most recommended diet for kidney support. However, it is one that science has good evidence for. If you think this might be a good diet for you consider seeing a dietician to help you starting out.

Other Kidney Support Diets

There are many other diets out there that are designed to support the kidneys. Most of them are for specific disease processes and are not required unless you have that disease. A renal dialysis diet is an example of this. If you are not receiving dialysis, you don’t need this kind of diet.

If you are at risk for metabolic acidosis because you have kidney disease or have had metabolic acidosis in the past, you may benefit from talking with a dietician about the ways you can modify your diet to better support your kidneys and prevent future episodes of metabolic acidosis.

Diet and Metabolic Alkalosis

Chloride-Responsive Alkalosis

If you have only a mild chloride-responsive alkalosis, you may only need to make an adjustment in your diet, such as increasing your intake of salt (sodium chloride). The chloride ions will make your blood more acidic and reduce the alkalosis. I have a whole post about chloride that covers supplementing chloride, so I won’t go over that again here.

But in the context of chloride-responsive alkalosis, you can have metabolic alkalosis because your chloride level is too low and increasing you chloride may be all that’s required to correct the acid-base imbalance. That means that making sure you’re getting enough chloride in your diet will be a way for you to prevent getting metabolic alkalosis in the future. That being said, chloride can help shift your acid-base balance even if it wasn’t the cause of the imbalance. Supplementing or getting more chloride in your diet can be one way to increase the acid in your body. You just have to monitor your levels to be sure that you are not taking in too much.

Potassium-Responsive Alkalosis

Just like a low chloride can lead to metabolic alkalosis, so can a low potassium. Unlike chloride, potassium is not used as a treatment unless your levels are low. I also have a post on potassium, so I won’t review the supplementation of potassium here.

Nausea Control Diet

Vomiting is the most common cause of metabolic alkalosis. The gastric juices have a high content of hydrochloric acid, a strong acid. Its loss causes an increase in the alkalinity of the blood. The vomiting can result from any number of stomach disorders. By figuring out and treating the cause of the vomiting, your doctor can cure the metabolic alkalosis. However, many of these stomach conditions are chronic and thus managing the nausea becomes a chronic need. But there are dietary management strategies that can help. Keep in mind that these are general guides and speaking to your doctor is a good idea if you suffer from chronic nausea and vomiting.

Don’t force yourself to drink or eat if you’re nauseated or vomiting. It’s a good idea to avoid eating for about 4 to 8 hours if you’re vomiting often. Along the way, try small sips of water. After your stomach settles down a bit, begin to replace some of the chemicals and fluids that you might have lost because of the vomiting. Try sipping chicken or vegetable broth, a sports drink, or small bites of gelatin. These will help keep you hydrated. Don’t rely only on clear liquids for more than 2 days in a row — they don’t have enough nutrients. If you cannot tolerate more then a clear liquid diet after two days, it is time to see your doctor.

You may find that the odor of food triggers your symptoms of nausea and vomiting. You might want to ask a friend, spouse, or partner to cook for you while you leave the house so you don’t have to smell the food cooking. Staying out of the kitchen can help since it’s so closely associated with foods and smells. Order take-out if possible. You can also try eating food from sealed containers. You also might find that your food likes and dislikes change from day to day. Try new things until you find something you can tolerate. It’s also good to try to drink 8 or more cups of liquid each day if you can. See if you can drink another half cup of fluids for each time you vomit. Yes, I know that’s a lot of fluid for an upset stomach, but that’s really the goal that you’re aiming for. Keep in mind that you don’t need to drink it all at once.

When and how to eat if you’re nauseated:

  • Eat small meals frequently. If you feel sick to your stomach between meals, try to eat 6 to 8 small meals during the day and a snack at bedtime.
  • Eat food cold or at room temperature, not hot, to reduce its smell and taste.
  • Don’t eat in a warm room. The air may seem stuffy and stale and may make your stomach feel worse.
  • Rinse your mouth with warm water before and after meals. This helps get rid of any bad tastes in your mouth.
  • Sit up or lie back with your head raised for at least an hour after eating if you need to rest. Keeping your head up helps reduce nausea.

What to eat if you’re nauseated:

  • Eat poultry or soy. Try turkey, chicken, or soy foods if you find you suddenly don’t like red meat. This can be a common trigger for nausea and vomiting.
  • Eat dry foods, such as crackers, toast, dry cereals, or bread sticks, when you wake up and every few hours during the day. They provide nutrients and help settle your stomach.
  • Eat cool foods instead of hot, spicy foods. Consider non-fat yogurt, fruit juice, sherbet, and sports drinks. Spicy foods may upset your stomach even more.
  • Don’t eat foods that are very sweet, greasy, or fried. They may upset your stomach even more. Consider baked, boiled, or mashed potatoes; rice; cream soups made with low-fat milk; fruit-flavored gelatin; pretzels; or low-fat pudding.
  • Try bland, soft, easy-to-digest foods on days when you’re having a flare. A poached egg on dry toast or a poached chicken breast with plain noodles is a good option. Baby foods can also be a good choice. Being pureed makes foods easier to digest and thus are less likely to irritate the stomach.
  • Eat foods that don’t have a strong smell. Smells may trigger nausea.

Diet is often not enough to control nausea and vomiting when you have a chronic stomach condition. It is essential that you treat the stomach condition itself. You may also need medications for the nausea and vomiting.

Your PCP

Your Primary Care Provider (PCP) really will be your best ally when managing an acid base imbalance or when trying to reduce the risk of one. They will be the person that will be ordering your monitoring lab work to make sure that your diet changes or supplementation is meeting your goals. They will also be the ones that will help you make sure that you are taking the right amount of the supplement. Not to mention it is most likely going to be your PCP who is helping you manage those underlying conditions that is causing you to have the risk for an acid-base imbalance. It is also possible that your supplements could interact with medications that you are taking. Your PCP and your pharmacist are your best allies for monitoring for these possible interactions. So it is super important to keep your doctor in the loop whenever you are adding in supplements.

Series Conclusion

And that’s it for the electrolyte series. I hope that you found some useful information in these articles. I plan on do more series of articles in the future. I haven’t decided yet on the topic for the next series, but I will most likely keep Wednesday as the day for the series. Any topics you’d like to see a series on? Let me know in the comments!

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