Whether you nibble on them fresh, bake them in scones or blend them in smoothies, blueberries add a nutritional boost to whatever you eat. Patients with low kidney function can consume them, because these patients often have to avoid many otherwise healthy foods, such as brocolli, orange juice and lentils.
Nutrients
With only 7.2 mg of vitamin C, a scant amount of most B vitamins and 40 IU of vitamin A in a 1/2 cup serving, blueberries might not seem like such nutritious snack. Those nutrients are packed into a mere 42 calories. A study published in a 2004 "Journal of the Science of Food and Agriculture" showed that blueberries are rich in quercetin, anthocyanin and other flavonoid compounds that have anti-oxidant activity. These compounds may protect against some cancers.
Potassium
Patients with low kidney function often have elevated levels of potassium. If the patient's potassium begin to creep up, most nephrologists recommend that the patient limit their potassium intake to less than 2,000 to 3,000 mg per day. A 1/2 cup serving of blueberries has only 57 mg of potassium, which fits easily into a low-potassium diet. Portion control is important. A 1 cup serving has 114 mg of potassium, which is nearly 6 percent of the 2,000 mg allotment.
Phosphorus
Patients with low kidney function also tend to have high phosphorus levels. This is dangerous because high phosphorus levels start to pull calcium from the bones, which raises serum calcium levels. In addition to weakening the skeleton, the increased serum calcium creates calcium deposits in blood vessels and muscles. The National Kidney Foundation recommends that dietary phosphorus should be limited to 800 to 1,000 mg/day if phosphorus levels increase. Given that a 1/2 cup of blueberries has only 9 mg of phosphorus, this is not an issue.
Recommendations
Given that fresh blueberries are low in potassium and phosphorus, you can include them in your renal diet. Just be careful not to mix them with other foods that you should avoid. For example, putting them in yogurt-based smoothies is not a good idea because the yogurt has too much phosphorus and potassium. If you make blueberry pancakes and other baked treats such as scones, use white flour instead of whole wheat flour to keep the total potassium and phosphorus down.
References
- "Journal of the Science of Food and Agriculture;" Flavonoid Glycosides and Antioxidant cCapacity of Various Blackberry, Blueberry and Red Grape Genotypes Determined by High-performance Liquid Chromatography/mass Spectrometry Mi Jin Cho et al.; 2004
- U.S. National Nutrient Database: Blueberries, Raw
- National Kidney Foundation: KDOQI -- Guideline 4. Restriction of Dietary Phosphorus in Patients with CKD
- National Kidney Foundation: KDOQI Clinical Practice Guideline for Nutrition in Children with CKD: 2008 Update
