Whether you have chronic kidney disease (CKD) or not, everyone needs to be mindful of the amount of chocolate they eat. For some people living with CKD, chocolate can pose an additional problem due to its naturally high potassium and phosphate content. Chocolate can be bad for your kidneys, but that doesn’t mean it always is. Here, we’ll explore the way chocolate and the nutrients it contains impact your kidney health, both negatively and positively.
The Nutritional Profile of Chocolate
Chocolate is derived from cocoa beans, which contain cocoa flavanols. The main ingredients in chocolate bars are chocolate liquor, sugar and some varieties may contain milk and cocoa butter. In order for a product to be called “dark chocolate” it must contain at least 15% chocolate liquor, but most dark chocolates contain 50% or more. Milk chocolate contains chocolate liquor, sugar and milk, and should contain at least 10% chocolate liquor and 12% dairy. White chocolate is made of cocoa butter, sugar, milk and vanilla.
Chocolate even has some other healthy attributes - it’s a source of magnesium, potassium, phosphorus and fiber.
The Health Benefits of Chocolate
There are some advantages to adding a little chocolate to your diet if your doctor says it's okay. As with all things, moderation is key. Obtaining those health benefits relies on the type and quality of chocolate you consume. Low-quality chocolate containing high levels of milk, sodium, sugar, and preservatives is far from a healthy option. On the other hand, high-quality dark chocolate containing a high percentage of cocoa (above 85%) offers health benefits if you have kidney disease. Consuming chocolate can mitigate some kidney disease complications.
Several studies¹ shows that chocolate consumption has neuroprotective, anti-inflammatory, and cardioprotective effects.
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Antioxidant Properties
One class of antioxidants is flavonoids,² a polyphenoliccompound. You can find flavonoids in fruits, vegetables, chocolate, and more. Cocoa products have a greater antioxidant capacity and higher amounts of flavonoids per serving than all teas and red wines. These compounds protect against heart disease and atherosclerosis, two major conditions often associated with kidney disease.
Cardiovascular Improvements
Dark chocolate provides two major benefits to your cardiovascular system: It lowers blood pressure and cholesterol. For those at risk of heart disease, a 2012 study³ found that daily chocolate consumption was a cost-effective way to reduce the chances of a cardiac event. It reduces total cholesterol and LDL cholesterol while lowering blood pressure. These all are important factors in controlling kidney disease.
Another randomized controlled trial⁴ investigated the impact of cocoa flavanols (CF) on the cardiovascular system of end-stage kidney disease patients on dialysis. It reported a significant improvement of vascular function by 53% over the short term. When participants took CF-rich supplements for 30 days, the researchers noted an increase in baseline function by 18%. The study reported that the impressive reversal in artery narrowing is comparable with the effects of statins in patients with end-stage kidney disease.
Mitigating Inflammation in CKD
Having CKD itself can lead to inflammation in the body. Chemicals in chocolate can help to reduce inflammation and oxidative stress. Researchers found that giving patients on dialysis 40 g of 70% dark chocolate three times a week resulted in a reduction in the inflammatory marker TNF-α without having any impact on potassium or phosphorus levels.
Good Source of Vitamins and Minerals
Besides having amazing antioxidant power, dark chocolate also is a good source of other vitamins and minerals, particularly copper, magnesium and iron!
Read also: Low-Carb Chocolate Pie Guide
The Potential Downsides of Chocolate for Kidney Health
Although chocolate has many health benefits, there are some downsides to chocolate consumption. This especially applies to milk chocolate candy bars, so it’s important to stick to high-quality dark chocolate in small amounts.
Potassium
Potassium reduces the effects of sodium without much downside for most people. However, that relies on your body's ability to process the potassium properly to use its sodium-reducing properties. Those with kidney disease often can't eliminate high amounts of potassium efficiently, which could cause hyperkalemia (high potassium levels in the blood). Dark chocolate, which has the most chocolate liquor, is highest in potassium at 159 mg per ounce. However, your average chocolate bar is not just one ounce, they are typically 1.55 oz or larger. Not everyone with chronic kidney disease needs to limit potassium.
Phosphorus
Like potassium, high phosphorus levels are harder to eliminate if you have kidney disease. Like the vast majority of foods, chocolate does contain some phosphorus. Phosphorus is found naturally in the cocoa bean itself as well as any milk that has been added. But remember, we do need phosphorus in our diet. When it comes to phosphorus control for CKD, the source of phosphorus is the most important factor to consider. We do not absorb all of the phosphorus from natural food sources. Phosphorus additives, however, are 90-100% absorbed. Is it possible to get too much phosphorus from chocolate? Yes… but it all comes back to portion size. If you are eating multiple servings of chocolate bars, you’ll be getting multiple servings of phosphorus which may be an issue if you deal with high phosphorus levels.
Sodium
Chocolate products can be high in sodium. If the sodium-to-potassium ratio is unfavorable, you lose all the benefits of getting the potassium in the first place. Sodium is hard for the body to get rid of, so your blood pressure will go up if you have too much.
Saturated Fat
The fat build-up in the cardiovascular system isn't good for you. Although good fat benefits your body, saturated fats are primarily empty calories that can cause heart and cardiovascular problems. However, most of the saturated fat in dark chocolate is in the form of stearic acid, which research⁵ suggests is non-atherogenic. This means it doesn’t cause plaque build-up in your arteries. A meta-analysis⁶ of 60 controlled feeding trials concluded that stearic acid doesn’t impact cholesterol, meaning it is cholesterol-neutral.
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Some chocolate products, particularly milk chocolate, are high in other harmful saturated fat. Be sure to balance your nutritional intake when eating chocolate, and keep your daily saturated fat consumption at reasonable levels.
Sugar
Many non-dark chocolate products are high in sugar, which largely provides empty calories without much nutritional benefit. For those with diabetes or pre-diabetes, too much sugar can raise your blood sugar levels. This will worsen your diabetes symptoms and your kidney disease. Everyone should limit the amount of added sugars they eat in a day. If you have diabetes, you should look at the nutritional labels of your favorite chocolate products before eating them.
Oxalate
Chocolate contains a compound called oxalate which is found in many plant foods. Some people with kidney issues may need to watch their intake of oxalates, but not everyone. The oxalate in chocolate comes from the chocolate liquor derived from the cocoa bean - so luckily milk and white chocolate, which has less of the actual chocolate liquor, are low in oxalate.
Incorporating Chocolate into a Renal Diet: Practical Tips
If you have been advised to limit these minerals, our Kidney Kitchen kidney dietitians suggest choosing a chocolate-coated or chocolate-covered option like a Kit Kat, Breakaway or Blue Riband bar, rather than a solid chocolate bar. Kidney Kitchen also offers a chocolate recipes collection, as well as advice on kidney-friendly baking.
When it comes to food and nutrition, there is no one-size-fits-all advice for people living with kidney disease. Your kidney dietitian will be able to tell you what you should be watching out for (for example, low potassium, low phosphate, high or low protein). Kidney Kitchen makes these recommendations easy to follow, with recipes that have analysed by kidney dietitians and approved by the BDA Renal Nutrition Group.
Portion Control
When eating chocolate, aim to keep the amount you eat at approximately 100 calories which is a good portion size for a snack. Eating 100 calories worth can look different in different shapes and sizes: for example, four (4) teaspoons of semisweet chocolate chips or 1.5 squares of a dark chocolate bar each contain approximately 100 calories.
Choosing the Right Type of Chocolate
If you’re deciding between white chocolate, milk chocolate and dark chocolate, choose the dark sweet for your sweetie. When choosing a chocolate treat, if possible, first look at the list of ingredients and nutrition label. Some chocolates may have added sources of saturated fat such as palm oil. Also, if the first ingredient listed is sugar, then it may not be the healthiest choice compared with other chocolates. Those who are watching oxalates should be aware that dark chocolate is considered high in oxalate - but a kidney dietitian can show you how to get your dark chocolate fix in.
Monitoring Nutrient Intake
If you have kidney disease, it’s important to watch your intake of sodium, potassium, and phosphorus. It’s best only to consume 20-30g of dark chocolate with a minimum percentage of 70% pure cocoa.
Alternatives to Chocolate
You don’t have to give up on all treats just because you’re concerned about your kidney health.
- Hard candy: Hard candy, including fruity and sour varieties, is lower in potassium and saturated fats.
- Chewy candy: Chewy, sticky candy, such as taffy and marshmallow-based products, are also lower in potassium, phosphorous, and saturated fat, making them more kidney-friendly options.
- Shortbread cookies: Many baked goods contain chocolate, but plenty of chocolate-free varieties also exist.
Other Foods to Limit or Avoid on a Renal Diet
Following a kidney-friendly diet and avoiding or limiting certain foods can help decrease the accumulation of waste products in your blood, improve your kidney function, and prevent further damage (3).
Here are some foods you should try to limit or avoid on a kidney diet:
- Dark-colored sodas: Dark-colored sodas should be avoided on a renal diet, as they contain phosphorus in its additive form, which is highly absorbable by the human body.
- Avocados: Consider avoiding avocados on a renal diet if a doctor or dietitian has advised you to lower your potassium intake.
- Canned foods: Canned foods are often high in sodium. Avoiding, limiting, or buying low sodium varieties is likely the best to reduce your overall sodium consumption.
- Whole wheat bread: White bread is typically recommended over whole wheat bread on a renal diet due to its lower phosphorus and potassium levels. All bread contains sodium, so it’s best to compare food labels and choose a lower-sodium variety.
- Brown rice: Brown rice has a high content of phosphorus and potassium and will likely need to be portion-controlled or limited on a renal diet. White rice, bulgur, buckwheat, and couscous are all good alternatives.
- Bananas: Bananas are a rich source of potassium and may need to be limited on a renal diet. Pineapple is a kidney-friendly fruit, as it contains much less potassium than certain other tropical fruits.
- Dairy products: Dairy products contain high amounts of phosphorus, potassium, and protein and should be limited to a renal diet. Despite milk’s high calcium content, its phosphorus content may weaken bones in those with kidney disease.
- Oranges and orange juice: Oranges and orange juice are high in potassium and should be limited to a renal diet. Try grapes, apples, cranberries, or their juices instead.
- Processed meats: Processed meats are high in salt and protein and should be consumed in moderation on a renal diet.
- Pickles, processed olives, and relish: Pickles, processed olives, and relish are high in sodium and should be limited on a renal diet.
- Apricots: Apricots are a high potassium food that should be avoided on a renal diet. They offer over 400 mg per 1 cup (165 g) raw and over 1,500 mg per 1 cup (130 g) dried.
- Potatoes and sweet potatoes: Potatoes and sweet potatoes are high-potassium vegetables. Boiling or double-cooking potatoes can significantly reduce their potassium content.
- Tomatoes: Tomatoes are another high-potassium fruit that should likely be limited on a renal diet.
- Processed foods: Packaged, instant, and premade meals are highly processed items that can contain very large amounts of sodium and lack nutrients. It’s best to limit these foods on a renal diet.
- Leafy green vegetables: Leafy green vegetables like Swiss chard, spinach, and beet greens are full of potassium, especially when served cooked. Although their serving sizes become smaller when cooked, their potassium contents remain the same.
- Dried fruits: Nutrients are concentrated when fruits are dried. Therefore, the potassium.